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Sample records for lanthanide oxide nanorods

  1. Zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Chik, Hope Wuming

    Non-lithographic, bottom-up techniques have been developed to advance the state of the art and contribute to the development of new material structures, fabrication methods, devices, and applications using the Zinc Oxide material system as a demonstration vehicle. The novel low temperature catalytic vapour-liquid-solid growth process developed is technologically simple, inexpensive, and a robust fabrication technique offering complete control over the physical dimensions of the nanorod such as its diameter and length, and over the positioning of the nanorods for site-selective growth. By controlling the distribution of the Au catalysts with the use of a self-organized anodized aluminum oxide nanopore membrane as a template, we have been able to synthesize highly ordered, hexagonally packed, array of ZnO nanorods spanning a large area. These nanorods are single crystal, hexagonally shaped, indicative of the wurtzite structure, and are vertically aligned to the substrate. By pre-patterning the template, arbitrary nanorod patterns can be formed. We have also demonstrated the assembly of the nanorods into functional devices using controlled methods that are less resource intensive, easily scalable, and adaptable to other material systems, without resorting to the manipulation of each individual nanostructures. Examples of these devices include the random network device that exploits the common attributes of the nanorods, and those formed using an external field to control the nanorod orientation. Two and three terminal device measurements show that the as-grown nanorods are n-type doped, and that by controlling the external optical excitation and its test environment, the photoconductivity can be altered dramatically. Self assemble techniques such as the spontaneous formation of nanodendrites into complex networks of interconnects were studied. Controlled formation of interconnects achieved by controlling the placement of the catalyst is demonstrated by growing the

  2. Oxidation dynamics of aluminum nanorods

    SciTech Connect

    Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

    2015-02-23

    Aluminum nanorods (Al-NRs) are promising fuels for pyrotechnics due to the high contact areas with oxidizers, but their oxidation mechanisms are largely unknown. Here, reactive molecular dynamics simulations are performed to study thermally initiated burning of oxide-coated Al-NRs with different diameters (D = 26, 36, and 46 nm) in oxygen environment. We found that thinner Al-NRs burn faster due to the larger surface-to-volume ratio. The reaction initiates with the dissolution of the alumina shell into the molten Al core to generate heat. This is followed by the incorporation of environmental oxygen atoms into the resulting Al-rich shell, thereby accelerating the heat release. These results reveal an unexpectedly active role of the alumina shell as a “nanoreactor” for oxidation.

  3. Oxidation dynamics of aluminum nanorods

    NASA Astrophysics Data System (ADS)

    Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya

    2015-02-01

    Aluminum nanorods (Al-NRs) are promising fuels for pyrotechnics due to the high contact areas with oxidizers, but their oxidation mechanisms are largely unknown. Here, reactive molecular dynamics simulations are performed to study thermally initiated burning of oxide-coated Al-NRs with different diameters (D = 26, 36, and 46 nm) in oxygen environment. We found that thinner Al-NRs burn faster due to the larger surface-to-volume ratio. The reaction initiates with the dissolution of the alumina shell into the molten Al core to generate heat. This is followed by the incorporation of environmental oxygen atoms into the resulting Al-rich shell, thereby accelerating the heat release. These results reveal an unexpectedly active role of the alumina shell as a "nanoreactor" for oxidation.

  4. Photocatalytic paper using zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Baruah, Sunandan; Jaisai, Mayuree; Imani, Reza; Nazhad, Mousa M.; Dutta, Joydeep

    2010-10-01

    Zinc oxide (ZnO) nanorods were grown on a paper support prepared from soft wood pulp. The photocatalytic activity of a sheet of paper with ZnO nanorods embedded in its porous matrix has been studied. ZnO nanorods were firmly attached to cellulose fibers and the photocatalytic paper samples were reused several times with nominal decrease in efficiency. Photodegradation of up to 93% was observed for methylene blue in the presence of paper filled with ZnO nanorods upon irradiation with visible light at 963 Wm-2 for 120 min. Under similar conditions, photodegradation of approximately 35% was observed for methyl orange. Antibacterial tests revealed that the photocatalytic paper inhibits the growth of Escherichia coli under room lighting conditions.

  5. Antifouling properties of zinc oxide nanorod coatings.

    PubMed

    Al-Fori, Marwan; Dobretsov, Sergey; Myint, Myo Tay Zar; Dutta, Joydeep

    2014-01-01

    In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacterium Acinetobacter sp. AZ4C, larvae of the bryozoan Bugula neritina and the microalga Tetraselmis sp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10 mM) of zinc precursors. These coatings were tested for 5 h under artificial sunlight (1060 W m(-2) or 530 W m(-2)) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density of Acinetobacter sp. AZ4C and Tetraselmis sp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement of B. neritina larvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae of B. neritina were not affected by Zn(2+) ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions.

  6. Antifouling properties of zinc oxide nanorod coatings.

    PubMed

    Al-Fori, Marwan; Dobretsov, Sergey; Myint, Myo Tay Zar; Dutta, Joydeep

    2014-01-01

    In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacterium Acinetobacter sp. AZ4C, larvae of the bryozoan Bugula neritina and the microalga Tetraselmis sp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10 mM) of zinc precursors. These coatings were tested for 5 h under artificial sunlight (1060 W m(-2) or 530 W m(-2)) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density of Acinetobacter sp. AZ4C and Tetraselmis sp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement of B. neritina larvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae of B. neritina were not affected by Zn(2+) ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions. PMID:25115521

  7. Method for providing oxygen ion vacancies in lanthanide oxides

    DOEpatents

    Kay, D. Alan R.; Wilson, William G.

    1989-12-05

    A method for desulfurization of fuel gases resulting from the incomplete combustion of sulfur containing hydrocarbons whereby the gases are treated with lanthanide oxides containing large numbers of oxygen-ion vacancies providing ionic porosity which enhances the ability of the lanthanide oxides to react more rapidly and completely with the sulfur in the fuel gases whereby the sulfur in such gases is reduced to low levels suitable for fuels for firing into boilers of power plants generating electricity with steam turbine driven generators, gas turbines, fuel cells and precursors for liquid fuels such as methanol and the like.

  8. Mixed lanthanide oxide nanoparticles as dual imaging agent in biomedicine

    NASA Astrophysics Data System (ADS)

    Xu, Wenlong; Bony, Badrul Alam; Kim, Cho Rong; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

    2013-11-01

    There is no doubt that the molecular imaging is an extremely important technique in diagnosing diseases. Dual imaging is emerging as a step forward in molecular imaging technique because it can provide us with more information useful for diagnosing diseases than single imaging. Therefore, diverse dual imaging modalities should be developed. Molecular imaging generally relies on imaging agents. Mixed lanthanide oxide nanoparticles could be valuable materials for dual magnetic resonance imaging (MRI)-fluorescent imaging (FI) because they have both excellent and diverse magnetic and fluorescent properties useful for dual MRI-FI, depending on lanthanide ions used. Since they are mixed nanoparticles, they are compact, robust, and stable, which is extremely useful for biomedical applications. They can be also easily synthesized with facile composition control. In this study, we explored three systems of ultrasmall mixed lanthanide (Dy/Eu, Ho/Eu, and Ho/Tb) oxide nanoparticles to demonstrate their usefulness as dual T2 MRI-FI agents.

  9. A Simple Empirical Analysis of the Enthalpies of Formation of Lanthanide Halides and Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1986-01-01

    Proposes a simple and general method whereby the lattice energies of lanthanide(II) and (IV) compounds are derived directly from those found experimentally for the corresponding lanthanide(III) compounds. The method is applicable to all lanthanide halides and oxides and involves calculations which can be easily and quickly performed by students.…

  10. Interfacial Structure in Silicon Nitride Sintered with Lanthanide Oxide

    SciTech Connect

    Dwyer, C.; Ziegler, A.; Shibata, Naoya; Winkelman, G. B.; Satet, R. L.; Hoffmann, M. J.; Cinibulk, M. K.; Becher, Paul F; Painter, Gayle S; Browning, N. D.; Cockayne, D.J.H.; Ritchie, R O; Pennycook, Stephen J

    2006-01-01

    Three independent research groups present a comparison of their structural analyses of prismatic interfaces in silicon nitride densified with the aid of lanthanide oxide Ln{sub 2}O{sub 3}. All three groups obtained scanning transmission electron microscope images which clearly reveal the presence of well-defined Ln segregation sites at the interfaces, and, moreover, reveal that these segregation sites are element-specific. While some results differ across the three research groups, the vast majority exhibits good reproducibility.

  11. Praseodymium hydroxide and oxide nanorods and Au/Pr6O11 nanorod catalysts for CO oxidation.

    PubMed

    Huang, P X; Wu, F; Zhu, B L; Li, G R; Wang, Y L; Gao, X P; Zhu, H Y; Yan, T Y; Huang, W P; Zhang, S M; Song, D Y

    2006-02-01

    Praseodymium hydroxide nanorods were synthesized by a two-step approach: First, metallic praseodymium was used to form praseodymium chloride, which reacted subsequently with KOH solution to produce praseodymium hydroxide. In the second step the hydroxide was treated with a concentrated alkaline solution at 180 degrees C for 45 h, yielding nanorods as shown by the scanning and transmission electron microscopy images. The results of X-ray diffraction and energy-dispersive X-ray spectroscopy experiments indicate that these nanorods are pure praseodymium hydroxide with a hexagonal structure, which can be converted into praseodymium oxide (Pr6O11) nanorods of a face-centered cubic structure after calcination at 600 degrees C for 2 h in air. Gold was loaded on the praseodymium oxide nanorods using HAuCl4 as the gold source, and NaBH4 was used to reduce the gold species to metallic nanoparticles with sizes of 8-12 nm on the nanorod surface. These Au/Pr6O11 nanorods exhibit superior catalytic activity for CO oxidation.

  12. Electrochemical deposition of zinc oxide nanorods for hybrid solar cells

    NASA Astrophysics Data System (ADS)

    Torres Damasco Ty, Jennifer; Yanagi, Hisao

    2015-04-01

    Zinc oxide (ZnO) nanorod arrays for inorganic/organic hybrid solar cells were electrochemically deposited on indium tin oxide (ITO) substrates with a rotating disk electrode setup. The addition of a ZnO seed layer on the ITO prior to electrochemical deposition improved the morphology of the nanorods, resulting in nanorods with smaller and homogenous diameters as well as a higher degree of vertical orientation on to the substrate. The ZnO films deposited on the seeded ITO substrates had higher optical transmittance and lower concentration of defects. Chronoamperometric transient curves show that nucleation and coalescence occurred later for bare ITO substrates, indicating lower densities of initial nuclei, resulting in the growth of nanorods with larger diameters. The solar cell characteristics of the devices fabricated from the seeded ITO substrates were better. The seed layer also acts as a hole-blocking layer, preventing the direct contact between the hole-transporting polymer material and the ITO.

  13. Magnetic ordering in lanthanide-molybdenum oxide nanostructure arrays

    NASA Astrophysics Data System (ADS)

    Hagmann, Joseph; Le, Son; Schneemeyer, Lynn; Olsen, Patti; Besara, Tiglet; Siegrist, Theo; Seiler, David; Richter, Curt

    Reduced ternary molybdenum oxides, or bronzes, offer an attractive materials platform to study a wide variety of remarkable physical phenomena in a system with highly varied structural chemistry. Interesting electronic behaviors, such as superconductivity, charge density waves, and magnetism, in these materials arise from the strong hybridization of the 4d states of high-valent Mo with O p orbitals. We investigate a series of molybdenum bronze materials with Lanthanide-Mo16O44 composition that can be described as a three-dimensional array of metallic Mo8O32 nanostructures computationally predicted to contain a single charge with spin 1/2 separated by insulating MoO4 tetrahedra. This study reveals novel magnetic ordering in Lanthanide-Mo16O44 systems arising, not from the inclusion of magnetic elements, but rather from an exchange interaction between cubic Mo8O32 units. Here, we report the magnetometry and transport behaviors of a series of Lanthanide-Mo16O44 materials, emphasizing an observed low-temperature phase transition signifying the onset of antiferromagnetic ordering between the arrayed nanostructures, and relate these behaviors to their experimentally-characterized structures to reveal the intriguing physics of these correlated electronic systems.

  14. Nanorods of manganese oxides: Synthesis, characterization and catalytic application

    SciTech Connect

    Yang Zeheng; Zhang Yuancheng; Zhang Weixin . E-mail: wxzhang@hfut.edu.cn; Wang Xue; Qian Yitai; Wen Xiaogang; Yang Shihe . E-mail: chsyang@ust.hk

    2006-03-15

    Single-crystalline nanorods of {beta}-MnO{sub 2}, {alpha}-Mn{sub 2}O{sub 3} and Mn{sub 3}O{sub 4} were successfully synthesized via the heat-treatment of {gamma}-MnOOH nanorods, which were prepared through a hydrothermal method in advance. The calcination process of {gamma}-MnOOH nanorods was studied with the help of Thermogravimetric analysis and X-ray powder diffraction. When the calcinations were conducted in air from 250 to 1050 deg. C, the precursor {gamma}-MnOOH was first changed to {beta}-MnO{sub 2}, then to {alpha}-Mn{sub 2}O{sub 3} and finally to Mn{sub 3}O{sub 4}. When calcined in N{sub 2} atmosphere, {gamma}-MnOOH was directly converted into Mn{sub 3}O{sub 4} at as low as 500 deg. C. Transmission electron microscopy (TEM) and high-resolution TEM were also used to characterize the products. The obtained manganese oxides maintain the one-dimensional morphology similar to the precursor {gamma}-MnOOH nanorods. Further experiments show that the as-prepared manganese oxide nanorods have catalytic effect on the oxidation and decomposition of the methylene blue (MB) dye with H{sub 2}0009O.

  15. Growth of tungsten oxide nanorods with carbon caps.

    PubMed

    Kichambare, Padmakar; Hii, King-Fu; Vallance, R Ryan; Sadanadan, B; Rao, Apparao M; Javed, Kazi; Menguc, M Pinar

    2006-02-01

    Hybrid nanostructures consisting of tungsten oxide nanorods with mushroom-shaped carbon caps were grown on electrochemically etched tungsten tips by thermal chemical vapor deposition with methane and argon. These nanorods grow along the radial direction and are very straight and smooth. Electron microscopy revealed a dominant diameter and length of approximately 50 nm and approximately 0.6 microm, respectively. High-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS) revealed the presence of crystalline monoclinic W18O49 in the nanorods, and the cap was entirely amorphous carbon. A plausible growth mechanism involves the reduction of tungsten oxide WO3, present on the tungsten surface, by methane at 900 degrees C. PMID:16573057

  16. Stabilization of actinides and lanthanides in unusually high oxidation states

    SciTech Connect

    Eller, P.G.; Penneman, R.A.

    1986-01-01

    Chemical environments can be chosen which stabilize actinides and lanthanides in unusually high or low oxidation states and in unusual coordination. In many cases, one can rationalize the observed species as resulting from strong charge/size influences provided by specific sites in host lattices (e.g., Tb(IV) in BaTbO/sub 3/ or Am(IV) in polytungstate anions). In other cases, the unusual species can be considered from an acid-base viewpoint (e.g., U(III) in AsF/sub 5//HF solution or Pu(VII) in Li/sub 5/PuO/sub 6/). In still other cases, an interplay of steric and redox effects can lead to interesting comparisons (e.g., instability of double fluoride salts of Pu(V) and Pu(VI) relative to U, Np, and Am analogues). Generalized ways to rationalize compounds containing actinides and lanthanides in unusual valences (particularly high valences), including the above and numerous other examples, will form the focus of this paper. Recently developed methods for synthesizing high valent f-element fluorides using superoxidizers and superacids at low temperatures will also be described. 65 refs., 8 figs., 9 tabs.

  17. Broadband resonances in indium-tin-oxide nanorod arrays

    SciTech Connect

    Li, Shi-Qiang E-mail: r-chang@northwestern.edu; Sakoda, Kazuaki; Ketterson, John B.; Chang, Robert P. H. E-mail: r-chang@northwestern.edu

    2015-07-20

    There is currently much discussion within the nanophotonics community regarding the origin of wavelength selective absorption/scattering of light by the resonances in nanorod arrays. Here, we report a study of resonances in ordered indium-tin-oxide nanorod arrays resulting from waveguide-like modes. We find that with only a 2.4% geometrical coverage, micron-length nanorod arrays interact strongly with light across a surprisingly wide band from the visible to the mid-infrared, resulting in less than 10% transmission. Simulations show excellent agreement with our experimental observations. The field profile in the vicinity of the rods obtained from simulations shows that the electric field is mainly localized on the surfaces of the nanorods for all resonances. Based on our analysis, the resonances in the visible are different in character from those in the infrared. When light is incident on the array, part of it propagates in the space between the rods and part of it is guided within the rods. The phase difference (interference) at the ends of the rods forms the basis for the resonances in the visible region. The resonances in the infrared are Fabry-Perot-like resonances involving standing surface waves between the opposing ends of the rods. Simple analytical formulae predict the spectral positions of these resonances. It is suggested that these phenomena can be utilized for wavelength-selective photodetectors, modulators, and nanorod-based solar cells.

  18. Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides.

    PubMed

    Zhang, Qingnan; Hu, Shu-Xian; Qu, Hui; Su, Jing; Wang, Guanjun; Lu, Jun-Bo; Chen, Mohua; Zhou, Mingfei; Li, Jun

    2016-06-01

    The chemistry of lanthanides (Ln=La-Lu) is dominated by the low-valent +3 or +2 oxidation state because of the chemical inertness of the valence 4f electrons. The highest known oxidation state of the whole lanthanide series is +4 for Ce, Pr, Nd, Tb, and Dy. We report the formation of the lanthanide oxide species PrO4 and PrO2 (+) complexes in the gas phase and in a solid noble-gas matrix. Combined infrared spectroscopic and advanced quantum chemistry studies show that these species have the unprecedented Pr(V) oxidation state, thus demonstrating that the pentavalent state is viable for lanthanide elements in a suitable coordination environment.

  19. Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides.

    PubMed

    Zhang, Qingnan; Hu, Shu-Xian; Qu, Hui; Su, Jing; Wang, Guanjun; Lu, Jun-Bo; Chen, Mohua; Zhou, Mingfei; Li, Jun

    2016-06-01

    The chemistry of lanthanides (Ln=La-Lu) is dominated by the low-valent +3 or +2 oxidation state because of the chemical inertness of the valence 4f electrons. The highest known oxidation state of the whole lanthanide series is +4 for Ce, Pr, Nd, Tb, and Dy. We report the formation of the lanthanide oxide species PrO4 and PrO2 (+) complexes in the gas phase and in a solid noble-gas matrix. Combined infrared spectroscopic and advanced quantum chemistry studies show that these species have the unprecedented Pr(V) oxidation state, thus demonstrating that the pentavalent state is viable for lanthanide elements in a suitable coordination environment. PMID:27100273

  20. Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

    SciTech Connect

    Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

    2015-01-15

    A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln{sub 2}(phen){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O){sub 2}]{sub n} (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]{sub n} (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO{sub 4}{sup 2−} anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic–inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature. - Graphical abstract: Lanthanide sulfates and lanthanide sulfonate-carboxylates have been hydrothermally synthesized. Interestingly, sulfate anions, 2-sulfobenzoate and benzoate ligands came from the in situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. - Highlights: • In situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. • The organic–inorganic hybrid lanthanide sulfates with one-dimensional column-like structure. • The dinuclear lanthanide sulfonate-carboxylates. • The emission spectra exhibit the characteristic transition of {sup 5}D{sub 0}→{sup 7}F{sub J} (J=0–4) of the Eu(III)

  1. Selected-control synthesis of dysprosium hydroxide and oxide nanorods by adjusting hydrothermal temperature

    SciTech Connect

    Song Xuchun Zheng Yifan; Wang Yun

    2008-05-06

    Dysprosium hydroxide and oxide nanorods were prepared directly from commercial bulk Dy{sub 2}O{sub 3} crystals by facile hydrothermal process at 130 and 210 deg. C, respectively. The as-synthesized dysprosium hydroxide and oxide nanorods were investigated by various techniques of XRD, TEM, SEM, and EDS. In the process, the temperature was found to play important roles in determining produce dysprosium hydroxide and oxide nanorods.

  2. An Electrochemical Glucose Sensor Based on Zinc Oxide Nanorods.

    PubMed

    Marie, Mohammed; Mandal, Sanghamitra; Manasreh, Omar

    2015-01-01

    A glucose electrochemical sensor based on zinc oxide (ZnO) nanorods was investigated. The hydrothermal sol-gel growth method was utilized to grow ZnO nanorods on indium tin oxide-coated glass substrates. The total active area of the working electrode was 0.3 × 0.3 cm2 where titanium metal was deposited to enhance the contact. Well aligned hexagonal structured ZnO nanorods with a diameter from 68 to 116 nm were obtained. The excitonic peak obtained from the absorbance spectroscopy was observed at ~370 nm. The dominant peak of Raman spectroscopy measurement was at 440 cm(-1), matching with the lattice vibration of ZnO. The uniform distribution of the GOx and Nafion membrane that has been done using spin coating technique at 4000 rotations per minute helps in enhancing the ion exchange and increasing the sensitivity of the fabricated electrochemical sensor. The amperometric response of the fabricated electrochemical sensor was 3 s. The obtained sensitivity of the fabricated ZnO electrochemical sensor was 10.911 mA/mM·cm2 and the lower limit of detection was 0.22 µM. PMID:26263988

  3. An Electrochemical Glucose Sensor Based on Zinc Oxide Nanorods.

    PubMed

    Marie, Mohammed; Mandal, Sanghamitra; Manasreh, Omar

    2015-01-01

    A glucose electrochemical sensor based on zinc oxide (ZnO) nanorods was investigated. The hydrothermal sol-gel growth method was utilized to grow ZnO nanorods on indium tin oxide-coated glass substrates. The total active area of the working electrode was 0.3 × 0.3 cm2 where titanium metal was deposited to enhance the contact. Well aligned hexagonal structured ZnO nanorods with a diameter from 68 to 116 nm were obtained. The excitonic peak obtained from the absorbance spectroscopy was observed at ~370 nm. The dominant peak of Raman spectroscopy measurement was at 440 cm(-1), matching with the lattice vibration of ZnO. The uniform distribution of the GOx and Nafion membrane that has been done using spin coating technique at 4000 rotations per minute helps in enhancing the ion exchange and increasing the sensitivity of the fabricated electrochemical sensor. The amperometric response of the fabricated electrochemical sensor was 3 s. The obtained sensitivity of the fabricated ZnO electrochemical sensor was 10.911 mA/mM·cm2 and the lower limit of detection was 0.22 µM.

  4. Growth of zinc oxide nanorods, tetrapods, and nanobelts without catalyst.

    PubMed

    Fouad, O A

    2006-07-01

    Zinc oxide (ZnO) nanostructures with various morphologies have been synthesized without catalyst in a one-step simple redox process. The results show that ZnO nanorods, nanobelts, and tetrapods with hexagonal needled arms could be synthesized via thermal treatment of a mixture of zinc oxide and charcoal powder in a muffle furnace at 1000-1200 degrees C for 240 min. XRD analyses showed that polycrystalline ZnO phase with wurtzite crystal structure was formed. At a relatively low temperature, 1000 degrees C, the ZnO structure was found to be a bundle of denser nanorods. By increasing the reaction temperature to 1100 degrees C, tetrapod-like structures of needle-like arms with pyramidal tips were formed. With the increase of temperature up to 1200 degrees C, the morphology of ZnO nanostructures changed from nanorods and tetrapods to coalescence grains. Reaction temperature was found to be the most important experimental parameter that played an important role in controlling the mode, mechanism of growth, and formation of different ZnO morphologies. PMID:17025131

  5. The interactions between the sterically demanding trimesitylphosphine oxide and trimesityphosphine with scandium and selected lanthanide ions

    NASA Astrophysics Data System (ADS)

    Platt, Andrew W. G.; Singh, Kuldip

    2016-05-01

    The reactions between lanthanide nitrates, Ln(NO3)3 and scandium and lanthanide trifluoromethane sulfonates, Ln(Tf)3 with trimesitylphosphine oxide, Mes3PO show that coordination to the metal ions does not lead to crystalline complexes. Investigation of the reactions by 31-P NMR spectroscopy shows that weak complexes are formed in solution. The crystal structures of Mes3PO·0.5CH3CN (1) and [Mes3PO]3H3O·2CH3CN·Tf (2), formed in the reaction between ScTf3 and Mes3PO, are reported. Trimesitylphosphine, Mes3P, is protonated by scandium and lanthanide trifluoromethane sulfonates and lanthanide nitrates in CD3CN and the structure of [Mes3PH]Cl·HCl·2H2O (3) is reported.

  6. Patterns in the stability of the lower oxidation states of the actinides and lanthanides

    SciTech Connect

    Mikheev, N.B.; Auerman, L.N.; Ionova, G.V.; Korshunov, B.G.; Spitsyn, V.I.

    1986-09-01

    The authors compare the first half of the lanthanides and the second half of the actinides by considering the specifics of the electronic structure of the valence atoms of the f-, d-, and s-orbitals, consisting of he following: The lanthanides from praseodymium to europium and from dysprosium to ytterbium, as well as the actinides from californium to nobelium, have the same electronic configuration f /SUP n/ s/sub 2/ in the state of free neutral atoms, which corresponds to their divalent state. On the basis of a consideration of the energy characteristics of the valence orbitals of the elements of the lanthanide and actinide famililies and as a result of an experimental determination of the standard oxidation potential of these elements, the authors consider the profound similarity between the elements of the first half of the lanthanide family and the second half of the actinide family to be established.

  7. Fungus mediated biosynthesis and characterization of zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Venkatesh, K. S.; Palani, N. S.; Krishnamoorthi, S. R.; Thirumal, V.; Ilangovan, R.

    2013-06-01

    Recently nanomaterials have been synthesized through biological approach due to its biocompatibility, inexpensive, eco friendly and it offers easiest experimental protocol and so on. ZnO can be potentially used in various applications. This present study reports the fungus mediated extra-cellular bio synthesis of ZnO nanorods using Fusarium Solani. The dried powder was calcined at 350°C for 1 hour in air. The thermal property of the as synthesized ZnO nanopowder was analyzed through Thermo gravimetric /Differential Thermo gravimetric (TGA / DTG) analysis. The structural and morphological properties of the calcined ZnO nanopowder were studied by XRD and SEM analysis respectively. X ray diffraction result revealed that a peak located at 2θ = 36.2° with (101) plane confirms the presence of Zinc oxide with Hexagonal crystal system. The morphology of the calcined ZnO powder was analyzed by Scanning Electron Microscopy and it clearly indicates the presence of ZnO nanorods. The diameter of the nanorods is in the range of 60 to 95 nm.

  8. Synthesis and electrochemical capacitance of long tungsten oxide nanorod arrays grown vertically on substrate

    SciTech Connect

    Park, Sun Hwa; Kim, Young Heon; Lee, Tae Geol; Shon, Hyun Kyong; Park, Hyun Min; Song, Jae Yong

    2012-11-15

    Highlights: ► Growth of long amorphous tungsten oxide nanorods on a substrate. ► Formation of single-crystalline tungsten oxide nanorods by a heat-treatment. ► High electrochemical pseudocapacitance of 2.8 mF cm{sup −2}. ► Excellent cyclability of psuedocapacitance up to 1000 cycles. -- Abstract: Long tungsten oxide nanorods are vertically grown on Al/W/Ti coated silicon substrates using a two-step anodization process. The first anodization of the Al film forms a mesh-like mask of anodic aluminum oxide, and the second anodization of the W film results in the formation of a buffer layer, a bottom nanorod, and a top nanorod of amorphous tungsten oxide. A pore-widening process prior to the second anodization leads to the enhancement of nanorod length above approximately 500 nm. After a heat-treatment, the tungsten oxide nanorods are crystallized to form a single crystalline structure while the buffer layer forms a polycrystalline structure. The crystalline tungsten oxide nanorods show a cyclic voltammogram retaining the quasi-rectangular shape of an electrochemically reversible faradaic redox reaction, i.e., a typical pseudocapacitive behavior. The maximum electrochemical capacitance per apparent surface area reaches approximately 2.8 mF cm{sup −2} at the voltage scan rate of 20 mV s{sup −1}, and the excellent cyclability of charge–discharge process is maintained up to 1000 cycles.

  9. Ethylene Glycol Assisted Synthesis of Fluorine Doped Tin Oxide Nanorods Using Improved Spray Pyrolysis Deposition Method

    NASA Astrophysics Data System (ADS)

    Liyanage, Devinda; Mudiyanselage Navaratne Bandara, Herath; Jayaweera, Viraj; Murakami, Kenji

    2013-08-01

    Fluorine-doped tin oxide nanorod transparent thin films were fabricated with SnCl4·5H2O, NH4F, and ethylene glycol (EG) using an improved spray pyrolysis deposition technique. The fabricated nanorods showed a low resistance of 15.3 Ω/sq and a good transparency of 70.8%. The nanorods have a higher surface area than the conventionally used thin films.

  10. Nanorods of Various Oxides and Hierarchically Structured Mesoporous Silica by Sol-Gel Electrophoresis

    SciTech Connect

    Limmer, Steven J.; Hubler, Timothy L.; Cao, Guozhong

    2003-01-02

    In this paper, we report the template-based growth of nanorods of oxides and hierarchically structured mesoporous silica, formed by means of a combination of sol-gel processing and elecrophoretic deposition. Both single metal oxides (TiO2) and complex oxides (Pb(Zr0.52Ti0.48)O3) have been grown by this method. This method has also been applied to the growth of nanorods of mesoporous silica having an ordered pore structure, where the pores are aligned parallel to the long axis of the nanorod. Uniformly sized nanorods of about 125-200 nm in diameter and 10 um in length were grown over large areas with near unidirectional alignment. Appropriate sol preparation yielded the desired stoichiometric chemical composition and crystal structure of the oxide nanorods, with a heat treatment (500-700 C for 15-30 min) for crystallization, densification and any necessary pyrolysis.

  11. Multi-modal imaging and cancer therapy using lanthanide oxide nanoparticles: current status and perspectives.

    PubMed

    Park, J Y; Chang, Y; Lee, G H

    2015-01-01

    Biomedical imaging is an essential tool for diagnosis and therapy of diseases such as cancers. It is likely true that medicine has developed with biomedical imaging methods. Sensitivity and resolution of biomedical imaging methods can be improved with imaging agents. Furthermore, it will be ideal if imaging agents could be also used as therapeutic agents. Therefore, one dose can be used for both diagnosis and therapy of diseases (i.e., theragnosis). This will simplify medical treatment of diseases, and will be also a benefit to patients. Mixed (Ln(1x)Ln(2y)O3, x + y = 2) or unmixed (Ln2O3) lanthanide (Ln) oxide nanoparticles (Ln = Eu, Gd, Dy, Tb, Ho, Er) are potential multi-modal imaging and cancer therapeutic agents. The lanthanides have a variety of magnetic and optical properties, useful for magnetic resonance imaging (MRI) and fluorescent imaging (FI), respectively. They also highly attenuate X-ray beam, useful for X-ray computed tomography (CT). In addition gadolinium-157 ((157)Gd) has the highest thermal neutron capture cross section among stable radionuclides, useful for gadolinium neutron capture therapy (GdNCT). Therefore, mixed or unmixed lanthanide oxide nanoparticles can be used for multi-modal imaging methods (i.e., MRI-FI, MRI-CT, CT-FI, and MRICT- FI) and cancer therapy (i.e., GdNCT). Since mixed or unmixed lanthanide oxide nanoparticles are single-phase and solid-state, they can be easily synthesized, and are compact and robust, which will be beneficial to biomedical applications. In this review physical properties of the lanthanides, synthesis, characterizations, multi-modal imagings, and cancer therapy of mixed and unmixed lanthanide oxide nanoparticles are discussed.

  12. Determination of lanthanides in rock samples by inductively coupled plasma mass spectrometry using thorium as oxide and hydroxide correction standard

    NASA Astrophysics Data System (ADS)

    Raut, Narendra M.; Huang, Li-Shing; Aggarwal, Suresh K.; Lin, King-Chuen

    2003-05-01

    Determination of lanthanides by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) using modified mathematical correction method has been studied. Normally, the ICP-MS analysis of middle and heavier lanthanides becomes difficult by severe spectroscopic overlap of M +, MO + or MOH + ions from lighter lanthanides and Ba. A correction method based on a single element oxide yield measurement, is a simple approach to correct for the above spectroscopic overlaps. But the uncertainty in the oxide and hydroxide yields measurement of lanthanides and barium over a long period of time can lead to inaccurate results even under fixed plasma conditions. To correct this, thorium was adopted as an oxide and hydroxide correction standard. Using a ratio of lanthanide oxide yield to thorium oxide yield, the lanthanide correction factors (LCF) were established and incorporated in the mathematical correction scheme. The same factors were also established for hydroxide correction. The proposed modified correction scheme was applied to the determination of lanthanides by ICP-MS from the USGS Standard Rock samples AGV-1 and G-2. The results are in good agreement with the reported values. The method also proved to be useful in isotopic ratio measurement of lanthanides having severe isobaric overlaps.

  13. Fast Responsive Gas Sensor of Vertically Aligned Fluorine-Doped Tin Oxide Nanorod Thin Film

    NASA Astrophysics Data System (ADS)

    Cho, Chan-Woo; Lee, Jong-Heun; Riu, Doh-Hyung; Kim, Chang-Yeoul

    2012-04-01

    We prepared fluorine-doped tin oxide (FTO) nanorod films and a conventional FTO thin film for the application of a semiconducting gas sensor by spray pyrolysis method. The lengths of FTO nanorods (FTON, 100 and 500 nm) were controlled by changing deposition times, and FTO thin film (FTOT) was also prepared as a reference. The gas sensitivity test shows FTON with long nanorods had higher sensitivity for both hydrogen and ethanol gases but slow response and recovery times, despite an advantage of the higher gas sensitivity. FTO nanorod film with short length about 100 nm showed relatively lower sensitivity, but fast gas response and recovery characteristics. The fast response and recovery for the analyte gases are attributed to the conductance of FTO nanorods, which is closely related to the diameter and length of nanorods.

  14. Infrared plasmonics with indium-tin-oxide nanorod arrays.

    PubMed

    Li, Shi Qiang; Guo, Peijun; Zhang, Lingxiao; Zhou, Wei; Odom, Teri W; Seideman, Tamar; Ketterson, John B; Chang, Robert P H

    2011-11-22

    This article reports the study of infrared plasmonics with both random and periodic arrays of indium-tin-oxide (ITO) nanorods (NR). A description is given on the synthesis, patterning, and characterization of physical properties of the ITO NR arrays. A classical scattering model, along with a 3-D finite-element-method and a 3-D finite-difference-time-domain numerical simulation method has been used to interpret the unique light scattering phenomena. It is also shown that the intrinsic plasma frequency can be varied through careful postsynthesis processing of the ITO NRs. Examples are given on how coupled plasmon resonances can be tuned through patterning of the ITO NR arrays. In addition, environment dielectric sensing has been demonstrated through the shift of the resonances as a result of index change surrounding the NRs. These initial results suggest potential for further improvement and opportunities to develop a good understanding of infrared plasmonics using ITO and other transparent conducting oxide semiconducting materials.

  15. Thermal NF3 fluorination/oxidation of cobalt, yttrium, zirconium, and selected lanthanide oxides

    SciTech Connect

    Scheele, Randall D.; McNamara, Bruce K.; Casella, Andrew M.; Kozelisky, Anne E.; Neiner, Doinita

    2013-02-01

    This paper presents results of our continuing investigation on the use of nitrogen trifluoride as a fluorination or fluorination/oxidation agent for separating valuable constituents from used nuclear fuels by exploiting the different volatilities of the constituent fission product and actinide fluorides. This article focuses on fission products that do not have volatile fluorides or oxyfluorides at expected operations temperatures. Our thermodynamic calculations show that nitrogen trifluoride has the potential to completely fluorinate fission product oxides to their fluorides. Simultaneous thermogravimetric and differential thermal analyses show that the oxides of cobalt, zirconium, and the lanthanides are fluorinated but do not form volatile fluorides when treated with nitrogen trifluoride at temperatures up to 550°C. Our studies of gadolinium-doped commercial nuclear fuel indicate that nitrogen trifluoride can extract uranium from the non-volatile gadolinium.

  16. Hot-pressed silicon nitride with various lanthanide oxides as sintering additives

    NASA Technical Reports Server (NTRS)

    Ueno, K.; Toibana, Y.

    1984-01-01

    The effects of addition of various lanthanide oxides and their mixture with Y2O3 on the sintering of Si3N4 were investigated. The addition of simple and mixed lanthanide oxides promoted the densification of Si3N4 in hot-pressing at 1800 C under 300-400kg/ centimeters squared for 60 min. The crystallization of yttrium and lanthanide-silicon oxynitrides which was observed inn the sintered body containing yttrium-lanthanide mixed oxides as additives led to the formation of a highly refractory Si3N4 ceramic having a bending strength of 82 and 84 kg/millimeters squared at room temperature and 1300 C respectively. In a Y2O3+La2O3 system, a higher molar ratio of La2O3 to Y2O3 gave a higher hardness and strength at high temperatures. It was found that 90 min was an optimum sintering time for the highest strength.

  17. Gold Nanoparticles Supported on Magnesium Oxide Nanorods for Oxidation of Alcohols.

    PubMed

    Emayavaramban, P; Babu, S Ganesh; Karvembu, R; Kadirvelu, K; Dharmaraj, N

    2016-03-01

    Gold nanoparticles supported on magnesium oxide nanorods (Au-MgO) have been synthesised by a solution based chemical reduction method. Au-MgO nanorods were found to be an efficient heterogeneous catalyst for oxidation of alcohols with hydrogen peroxide in aqueous medium at room temperature. To find out the best reaction conditions for oxidation, optimization of catalyst quantity, solvent, mole equivalence of hydrogen peroxide were carried out. The scope of the reaction was extended to several aromatic and aliphatic alcohols, product yields were quantified by gas chromatography (GC) and GC/mass spectroscopy. Heterogeneity and reusability tests were performed. The use of water as a solvent and hydrogen peroxide as co-catalyst at room temperature makes the reaction interesting from sustainable development point of view. PMID:27455664

  18. Gold Nanoparticles Supported on Magnesium Oxide Nanorods for Oxidation of Alcohols.

    PubMed

    Emayavaramban, P; Babu, S Ganesh; Karvembu, R; Kadirvelu, K; Dharmaraj, N

    2016-03-01

    Gold nanoparticles supported on magnesium oxide nanorods (Au-MgO) have been synthesised by a solution based chemical reduction method. Au-MgO nanorods were found to be an efficient heterogeneous catalyst for oxidation of alcohols with hydrogen peroxide in aqueous medium at room temperature. To find out the best reaction conditions for oxidation, optimization of catalyst quantity, solvent, mole equivalence of hydrogen peroxide were carried out. The scope of the reaction was extended to several aromatic and aliphatic alcohols, product yields were quantified by gas chromatography (GC) and GC/mass spectroscopy. Heterogeneity and reusability tests were performed. The use of water as a solvent and hydrogen peroxide as co-catalyst at room temperature makes the reaction interesting from sustainable development point of view.

  19. Synthesis and characterization of a nanocomposite of goethite nanorods and reduced graphene oxide for electrochemical capacitors

    SciTech Connect

    Shou Qingliang; Cheng Jipeng; Zhang Li; Nelson, Bradley J.; Zhang Xiaobin

    2012-01-15

    We report a one-step synthesis of a nanocomposite of goethite ({alpha}-FeOOH) nanorods and reduced graphene oxide (RGO) using a solution method in which ferrous cations serve as a reducing agent of graphite oxide (GO) to graphene and a precursor to grow goethite nanorods. As-prepared goethite nanorods have an average length of 200 nm and a diameter of 30 nm and are densely attached on both sides of the RGO sheets. The electrochemical properties of the nanocomposite were characterized by cyclic voltammetry (CV) and chronopotentiometry (CP) charge-discharge tests. The results showed that goethite/RGO composites have a high electrochemical capacitance of 165.5 F g{sup -1} with an excellent recycling capability making the material promising for electrochemical capacitors. - Graphical abstract: The reduced graphene oxide sheets are decorated with goethite nanorods. The as-prepared composite exhibits a high electrochemical capacitance with good recycling capability, which is promising for supercapacitor applications. Higlights: Black-Right-Pointing-Pointer Ferrous ions act as reductant of graphite oxide and precursor of goethite nanorods. Black-Right-Pointing-Pointer Goethite nanorods are attached on both sides of the reduced graphene oxide sheets. Black-Right-Pointing-Pointer Composite exhibits a high specific capacitance and a good recycling capability. Black-Right-Pointing-Pointer Composite is promising for supercapacitor applications.

  20. Synthesis and lanthanide coordination chemistry of trifluoromethyl derivatives of phosphinoylmethyl pyridine N-oxides

    SciTech Connect

    Pailloux, Sylvie; Shirima, Cornel Edicome; Duesler, Eileen N.; Smith, Karen Ann; Paine, Robert T.; Klaehn, John D.; McIlwain, Michael E; Hay, Benjamin

    2009-01-01

    A synthetic route for the formation of 2-[bis-(2-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine N-oxide (1c) and 2-[bis-(3,5-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine N-oxide (1d) was developed and the new ligands characterized by spectroscopic methods and single crystal X-ray diffraction analyses. The coordination chemistry of the ligands was examined with early and late lanthanide ions. The molecular structure of one complex, [Yb(1c)(NO3)3(DMF)](DMF)(H2O)0.5, was determined by single crystal X-ray diffraction methods and the ligand found to coordinate in a bidentate fashion. This coordination chemistry is compared against lanthanide coordination chemistry observed for the related ligand, [Ph2P(O)CH2] C5H4NO.

  1. Structural, morphological and optical investigations on Sm{sup 3+} doped gadolinium oxide nanorods

    SciTech Connect

    Boopathi, G.; Mohan, R.; Raj, S. Gokul; Kumar, G. Ramesh

    2014-04-24

    One dimensional uniform Sm{sup 3+} doped gadolinium hydroxide nanorods have been prepared via simple co– precipitation technique at 60 °C temperature for 1 hour. The samples were calcinated at 750 °C to obtain Sm{sup 3+} doped gadolinium oxide nanorods. The 1D nanorods were then subjected to different characterization techniques to ascertain its structural stability and its morphology were investigated using high–resolution transmission electron microscopy. Photoluminescence (PL) spectrophotometry was investigated and the obtained results were discussed in detail.

  2. Spectroscopic characterization of zinc oxide nanorods synthesized by solid-state reaction

    NASA Astrophysics Data System (ADS)

    Prasad, Virendra; D'Souza, Charlene; Yadav, Deepti; Shaikh, A. J.; Vigneshwaran, Nadanathangam

    2006-09-01

    Well-crystallized zinc oxide nanorods have been fabricated by single step solid-state reaction using zinc acetate and sodium hydroxide, at room temperature. The sodium lauryl sulfate (SLS) stabilized zinc oxide nanorods were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and photoluminescence spectroscopy. The X-ray diffraction revealed the wurtzite structure of zinc oxide. The size estimation by XRD and TEM confirmed that the ZnO nanorods are made of single crystals. The growth of zinc oxide crystals into rod shape was found to be closely related to its hexagonal nature. The mass ratio of SLS:ZnO in the nanorods was found to be 1:10 based on the thermogravimetric analysis. Blue shift of photoluminescence emission was noticed in the ZnO nanorods when compared to that of ZnO bulk. FT-IR analysis confirmed the binding of SLS with ZnO nanorods. Apart from ease of preparation, this method has the advantage of eco-friendliness since the solvent and other harmful chemicals were eliminated in the synthesis protocol.

  3. 'Click' preparation of CuPt nanorod-anchored graphene oxide as a catalyst in water.

    PubMed

    Yang, Hyunseung; Kwon, Yongwoo; Kwon, Taegyun; Lee, Hyunjoo; Kim, Bumjoon J

    2012-10-22

    In this paper, a simple and powerful method of producing nanoparticle-anchored graphene oxide (GO) composites using a 'click' reaction is demonstrated. This method affords a facile means of anchoring of nanoparticles with various shapes and sizes on the GO. CuPt nanorods with controlled size, aspect ratio (from 1 to 11), and uniformity are synthesized. Transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy measurements are made to monitor the formation and characterize the properties of the CuPt nanorod-grafted GO composites. Their catalytic properties in the water phase are investigated using an o-phenylenediamine oxidation reaction. The results of this study clearly demonstrate that nonpolar CuPt nanorods immobilized on GO can function as a catalyst in an aqueous solution and that GO can be used as a catalytic nanorod support. PMID:22821640

  4. Microarray immunoassay for phenoxybenzoic acid using polymer-functionalized lanthanide oxide nanoparticles as fluorescent labels

    NASA Astrophysics Data System (ADS)

    Nichkova, Mikaela; Dosev, Dosi; Gee, Shirley J.; Hammock, Bruce D.; Kennedy, Ian M.

    2005-11-01

    Fluorescent properties and low production cost makes lanthanide oxide nanoparticles attractive labels in biochemistry. Nanoparticles with different fluorescent spectra were produced by doping of oxides such as Y IIO 3 and Gd IIO 3 with different lanthanide ions (Eu, Tb, Sm) giving the possibility for multicolor labeling. Protein microarrays have the potential to play a fundamental role in the miniaturization of biosensors, clinical immunological assays, and protein-protein interaction studies. Here we present the application of fluorescent lanthanide oxide nanoparticles as labels in microarray-based immunoassay for phenoxybenzoic acid (PBA), a generic biomarker of human exposure to the highly potent insecticides pyrethroids. A novel polymer-based protocol was developed for biochemical functionalization of the nanoparticles. Microarrays of antibodies were fabricated by microcontact printing in line patterns onto glass substrates and immunoassays were successfully performed using the corresponding functionalized nanoparticles. The applicability of the fluorophore nanoparticles as reporters for detection of antibody-antigen interactions has been demonstrated for phenoxybenzoic acid (PBA)/anti-PBA IgG. The sensitivity of the competitive fluorescent immunoassay for PBA was similar to that of the corresponding ELISA.

  5. CeO2 nanorods-supported transition metal catalysts for CO oxidation.

    PubMed

    Mock, Samantha A; Sharp, Shannon E; Stoner, Thomas R; Radetic, Michael J; Zell, Elizabeth T; Wang, Ruigang

    2016-03-15

    A catalytically active oxide support in combination with metal catalysts is required in order to achieve better low temperature activity and selectivity. Here, we report that CeO2 nanorods with a superior surface oxygen release/storage capability were used as an active support of transition metal (TM) catalysts (Mn, Fe, Co, Ni, Cu) for CO oxidation reaction. The as-prepared CeO2 nanorods supported 10 wt% TM catalysts were highly active for CO oxidation at low temperature, except for the Fe sample. It is found that the 10%Cu-CeO2 catalyst performed best, and it provided a lower light-off temperature with T50 (50% conversion) at 75 °C and T100 (100% conversion) of CO to CO2 at 194 °C. The atomic level surface structure of CeO2 nanorods was investigated in order to understand the improved low temperature catalytic activity. The richness of surface roughness and various defects (voids, lattice distortion, bending, steps, twinning) on CeO2 nanorods could facilitate oxygen release and storage. According to XRD and Raman analysis, copper species migrate into the bulk CeO2 nanorods to a greater degree. Since CO adsorbed over the surface of the catalyst/support is detrimental to its catalytic activity, the surface defects on the CeO2 nanorods and CeO2-TM interactions were critical to the enhanced activity.

  6. CeO2 nanorods-supported transition metal catalysts for CO oxidation.

    PubMed

    Mock, Samantha A; Sharp, Shannon E; Stoner, Thomas R; Radetic, Michael J; Zell, Elizabeth T; Wang, Ruigang

    2016-03-15

    A catalytically active oxide support in combination with metal catalysts is required in order to achieve better low temperature activity and selectivity. Here, we report that CeO2 nanorods with a superior surface oxygen release/storage capability were used as an active support of transition metal (TM) catalysts (Mn, Fe, Co, Ni, Cu) for CO oxidation reaction. The as-prepared CeO2 nanorods supported 10 wt% TM catalysts were highly active for CO oxidation at low temperature, except for the Fe sample. It is found that the 10%Cu-CeO2 catalyst performed best, and it provided a lower light-off temperature with T50 (50% conversion) at 75 °C and T100 (100% conversion) of CO to CO2 at 194 °C. The atomic level surface structure of CeO2 nanorods was investigated in order to understand the improved low temperature catalytic activity. The richness of surface roughness and various defects (voids, lattice distortion, bending, steps, twinning) on CeO2 nanorods could facilitate oxygen release and storage. According to XRD and Raman analysis, copper species migrate into the bulk CeO2 nanorods to a greater degree. Since CO adsorbed over the surface of the catalyst/support is detrimental to its catalytic activity, the surface defects on the CeO2 nanorods and CeO2-TM interactions were critical to the enhanced activity. PMID:26745742

  7. Morphological and electrochemical properties of crystalline praseodymium oxide nanorods.

    PubMed

    Shamshi Hassan, M; Shaheer Akhtar, M; Shim, Kyung-Bo; Yang, O-Bong

    2010-02-05

    Highly crystalline Pr6O11 nanorods were prepared by a simple precipitation method of triethylamine complex at 500°C. Synthesized Pr6O11 nanorods were uniformly grown with the diameter of 12-15 nm and the length of 100-150 nm without any impurities of unstable PrO2 phase. The Pr6O11 nanorod electrodes attained a high electrical conductivity of 0.954 Scm-1 with low activation energy of 0.594 eV at 850°C. The electrochemical impedance study showed that the resistance of electrode was significantly decreased at high temperature, which resulted from its high conductivity and low activation energy. The reduced impedance and high electrical conductivity of Pr6O11 nanorod electrodes are attributed to the reduction of grain boundaries and high space charge width.

  8. Localized and itinerant states in lanthanide oxides united by GW @ LDA+U.

    PubMed

    Jiang, Hong; Gomez-Abal, Ricardo I; Rinke, Patrick; Scheffler, Matthias

    2009-03-27

    Many-body perturbation theory in the GW approach is applied to lanthanide oxides, using the local-density approximation plus a Hubbard U correction (LDA+U) as the starting point. Good agreement between the G0W0 density of states and experimental spectra is observed for CeO2 and Ce2O3. Unlike the LDA+U method G0W0 exhibits only a weak dependence on U in a physically meaningful range of U values. For the whole lanthanide sesquioxide (Ln2O3) series G0W0 @ LDA+U reproduces the main features found for the optical experimental band gaps. The relative positions of the occupied and unoccupied f states predicted by G0W0 confirm the experimental conjecture derived from phenomenological arguments.

  9. Zinc oxide nanowires and nanorods fabricated by vapour-phase transport at low temperature

    NASA Astrophysics Data System (ADS)

    Xu, C. X.; Sun, X. W.; Dong, Z. L.; Yu, M. B.; My, T. D.; Zhang, X. H.; Chua, S. J.; White, T. J.

    2004-07-01

    Using zinc chloride as source material, zinc oxide nanowires and nanorods were fabricated by a vapour-phase transport method at low temperature. The nanowires grown on gold-coated silicon showed a uniform diameter of about 40 nm, and the nanorods on copper-coated silicon grew upwards to form flower-like arrays. The x-ray diffraction and transmission electron microscopy analyses demonstrated that the nanostructural zinc oxide grew along the [0001] direction. The growth process was attributed to a vapour-liquid-solid mechanism. Distinct photoluminescent behaviours were observed for zinc oxide nanostructures grown on gold-coated and copper-coated silicon wafers.

  10. Influence of volatile chlorides on the molten salt synthesis of ternary oxide nanorods and nanoparticles.

    PubMed

    Rørvik, Per Martin; Lyngdal, Tone; Saeterli, Ragnhild; van Helvoort, Antonius T J; Holmestad, Randi; Grande, Tor; Einarsrud, Mari-Ann

    2008-04-21

    A molten salt synthesis route, previously reported to yield BaTiO3, PbTiO3, and Na2Ti6O13 nanorods, has been re-examined to elucidate the role of volatile chlorides. A precursor mixture containing barium (or lead) and titanium was annealed in the presence of NaCl at 760 or 820 degrees C. The main products were respectively isometric nanocrystalline BaTiO3 and PbTiO3. Nanorods were also detected, but electron diffraction revealed that the composition of the nanorods was respectively BaTi2O5/BaTi5O11 and Na2Ti6O13 for the two different systems, in contradiction to the previous studies. It was shown that NaCl reacted with BaO (PbO) resulting in loss of volatile BaCl2 (PbCl2) and formation and preferential growth of titanium oxide-rich nanorods instead of the target phase BaTiO3 (or PbTiO3). The molten salt synthesis route may therefore not necessarily yield nanorods of the target ternary oxide as reported previously. In addition, the importance of NaCl(g) for the growth of nanorods below the melting point of NaCl was demonstrated in a special experimental setup, where NaCl and the precursors were physically separated.

  11. Graphene oxide-promoted reshaping and coarsening of gold nanorods and nanoparticles.

    PubMed

    Pan, Hanqing; Low, Serena; Weerasuriya, Nisala; Shon, Young-Seok

    2015-02-11

    This paper describes thermally induced reshaping and coarsening behaviors of gold nanorods and nanoparticles immobilized on the surface of graphene oxide. Cetyltrimethylammonium bromide-stabilized gold nanorods with an aspect ratio of ∼3.5 (54:15 nm) and glutathione-capped gold nanoparticles with an average core size of ∼3 nm were synthesized and self-assembled onto the surface of graphene oxide. The hybrid materials were then heated at different temperatures ranging from 50 to 300 °C. The effects of heat treatments were monitored using UV-vis spectroscopy and transmission electron microscopy (TEM). These results were directly compared with those of heat-treated free-standing gold nanorods and nanoparticles without graphene oxide to understand the heat-induced morphological changes of the nanohybrids. The obtained results showed that the gold nanorods would undergo a complete reshaping to spherical particles at the temperature of 50 °C when they are assembled on graphene oxide. In comparison, the complete reshaping of free-standing gold nanorods to spherical particles would ultimately require a heating of the samples at 200 °C. In addition, the spherical gold nanoparticles immobilized on graphene oxide would undergo a rapid coarsening at the temperature of 100-150 °C, which was lower than the temperature (150-200 °C) required for visible coarsening of free-standing gold nanoparticles. The results indicated that graphene oxide facilitates the reshaping and coarsening of gold nanorods and nanoparticles, respectively, during the heat treatments. The stripping and spillover of stabilizing ligands promoted by graphene oxide are proposed to be the main mechanism for the enhancements in the heat-induced transformations of nanohybrids.

  12. Zinc oxide nanorods modified indium tin oxide surface for amperometric urea biosensor.

    PubMed

    Palomera, Netzahualcóyotl; Balaguera, Marcia; Arya, Sunil K; Hernández, Samuel; Tomar, Maharaj S; Ramírez-Vick, Jaime E; Singh, Surinder P

    2011-08-01

    ZnO nanorods (ZnONR) grown onto indium-tin-oxide (ITO) coated glass surface using zinc nitrate hexahydrate/hexamethylenetetramine (HMT) in aqueous phase has been utilized for urea biosensor. Urease (Urs) was immobilized onto ZnONR/ITO at physiological pH via electrostatic interactions between Urs and ZnO to fabricate Urs/ZnONR/ITO bioelectrode. ZnONR/ITO electrode has been characterized using XRD, FE-SEM techniques and Urs/ZnONR/ITO bioelectrode using electrochemistry. The XRD and FE-SEM measurements confirm the formation of ZnO nanorods in wurtzite structure. Cyclic voltammetric and amperometric measurements on the Urs/ZnONR/ITO biolectrode for urea concentrations in the range of 1-20 mM reveal 0.4 microA mM(-1) sensitivity, with a response time of 3 seconds, and a detection limit of 0.13 mM. The Michaelis-Menten constant (Km) was calculated to be 9.09 mM. Results indicate that ZnO nanorods provide suitable microenvironment for urease immobilization and can be utilized in biosensor design and other biological applications. PMID:22103068

  13. Effect of thermal implying during ageing process of nanorods growth on the properties of zinc oxide nanorod arrays

    NASA Astrophysics Data System (ADS)

    Ismail, A. S.; Mamat, M. H.; Malek, M. F.; Abdullah, M. A. R.; Sin, M. D.; Rusop, M.

    2016-07-01

    Undoped and Sn-doped Zinc oxide (ZnO) nanostructures have been fabricated using a simple sol-gel immersion method at 95°C of growth temperature. Thermal sourced by hot plate stirrer was supplied to the solution during ageing process of nanorods growth. The results showed significant decrement in the quality of layer produced after the immersion process where the conductivity and porosity of the samples reduced significantly due to the thermal appliance. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM) electrical properties has been characterized using current voltage (I-V) measurement.

  14. Determination of effective growth time for zinc oxide nanorods using chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Ho; Umakoshi, Tomoyuki; Abe, Yoshio; Kawamura, Midori; Kiba, Takayuki

    2015-12-01

    Zinc oxide (ZnO) nanorods were grown on a ZnO seed layer using chemical solution deposition, and their growth behavior over various timescales was investigated. The structural properties of the nanorods were investigated using x-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), and the pH of the solution was measured both before and after the reaction process. It was observed that the nanorods grew in two stages, with the first stage from 0 to 6 h time and the second stage at 12-24 h of time. When they were given 24 h of reaction time, the length and aspect ratio of the nanorods reached ∼2.6 μm and ∼54, respectively. The pH value of the solution changed during the whole process, and on reaching a pH value ∼8.1 after 36 h, the nanorods exhibited very stable size dimensions. The most effective growth time to yield nanorods with high aspect ratios was determined to be 24 h.

  15. Seed-layer-free hydrothermal growth of zinc oxide nanorods on porous silicon

    NASA Astrophysics Data System (ADS)

    Kim, Soaram; Kim, Min Su; Park, Hyunggil; Nam, Giwoong; Yoon, Hyunsik; Leem, Jae-Young

    2014-05-01

    Zinc oxide (ZnO) nanorods were grown on porous silicon (PS) using hydrothermal synthesis without a metal catalyst or a seed layer. Scanning electron microscopy, x-ray diffraction, and temperature-dependent photoluminescence (PL) were carried out to investigate the structural and optical properties of the ZnO-PS sample. Most of the nanorods had an average diameter about of 120 nm and an average length of 5 µm, and were assembled into flower-like clusters where several nanorods were joined at a central point. In some cases, ZnO nanorods were merged in parallel bundles. The ZnO nanorods exhibited an overall compressive residual stress. The Zn-O bond length was 1.953 Å. ZnO-PS exhibited one PL peak in the ultraviolet (UV) range, and two peaks in the visible range. The UV and green emission peak were generated from the ZnO nanorods, while the red emission peak was attributed to the PS. The fitting parameters for Varshni's empirical equation were α = 8 × 10-4 eV/K, β = 186 K, and E g (0) = 3.375 eV, and the thermal activation energy was about 32 meV.

  16. Lanthanide-Dependent Regulation of Methanol Oxidation Systems in Methylobacterium extorquens AM1 and Their Contribution to Methanol Growth

    PubMed Central

    Vu, Huong N.; Subuyuj, Gabriel A.; Vijayakumar, Srividhya; Good, Nathan M.; Martinez-Gomez, N. Cecilia

    2016-01-01

    ABSTRACT Methylobacterium extorquens AM1 has two distinct types of methanol dehydrogenase (MeDH) enzymes that catalyze the oxidation of methanol to formaldehyde. MxaFI-MeDH requires pyrroloquinoline quinone (PQQ) and Ca in its active site, while XoxF-MeDH requires PQQ and lanthanides, such as Ce and La. Using MeDH mutant strains to conduct growth analysis and MeDH activity assays, we demonstrate that M. extorquens AM1 has at least one additional lanthanide-dependent methanol oxidation system contributing to methanol growth. Additionally, the abilities of different lanthanides to support growth were tested and strongly suggest that both XoxF and the unknown methanol oxidation system are able to use La, Ce, Pr, Nd, and, to some extent, Sm. Further, growth analysis using increasing La concentrations showed that maximum growth rate and yield were achieved at and above 1 μM La, while concentrations as low as 2.5 nM allowed growth at a reduced rate. Contrary to published data, we show that addition of exogenous lanthanides results in differential expression from the xox1 and mxa promoters, upregulating genes in the xox1 operon and repressing genes in the mxa operon. Using transcriptional reporter fusions, intermediate expression from both the mxa and xox1 promoters was detected when 50 to 100 nM La was added to the growth medium, suggesting that a condition may exist under which M. extorquens AM1 is able to utilize both enzymes simultaneously. Together, these results suggest that M. extorquens AM1 actively senses and responds to lanthanide availability, preferentially utilizing the lanthanide-dependent MeDHs when possible. IMPORTANCE The biological role of lanthanides is a nascent field of study with tremendous potential to impact many areas in biology. Our studies demonstrate that there is at least one additional lanthanide-dependent methanol oxidation system, distinct from the MxaFI and XoxF MeDHs, that may aid in classifying additional environmental organisms as

  17. Tin Oxide Nanorod Array-Based Electrochemical Hydrogen Peroxide Biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Jinping; Li, Yuanyuan; Huang, Xintang; Zhu, Zhihong

    2010-07-01

    SnO2 nanorod array grown directly on alloy substrate has been employed as the working electrode of H2O2 biosensor. Single-crystalline SnO2 nanorods provide not only low isoelectric point and enough void spaces for facile horseradish peroxidase (HRP) immobilization but also numerous conductive channels for electron transport to and from current collector; thus, leading to direct electrochemistry of HRP. The nanorod array-based biosensor demonstrates high H2O2 sensing performance in terms of excellent sensitivity (379 μA mM-1 cm-2), low detection limit (0.2 μM) and high selectivity with the apparent Michaelis-Menten constant estimated to be as small as 33.9 μM. Our work further demonstrates the advantages of ordered array architecture in electrochemical device application and sheds light on the construction of other high-performance enzymatic biosensors.

  18. Synthesis of reduced graphene oxide/ZnO nanorods composites on graphene coated PET flexible substrates

    SciTech Connect

    Huang, Lei Guo, Guilue; Liu, Yang; Chang, Quanhong; Shi, Wangzhou

    2013-10-15

    Graphical abstract: - Highlights: • ZnO nanorods synthesized on CVD-graphene and rGO surfaces, respectively. • ZnO/CVD-graphene and ZnO/rGO form a distinctive porous 3D structure. • rGO/ZnO nanostructures possibility in energy storage devices. - Abstract: In this work, reduced graphene oxide (rGO)/ZnO nanorods composites were synthesized on graphene coated PET flexible substrates. Both chemical vapor deposition (CVD) graphene and reduced graphene oxide (rGO) films were prepared following by hydrothermal growth of vertical aligned ZnO nanorods. Reduced graphene sheets were then spun coated on the ZnO materials to form a three dimensional (3D) porous nanostructure. The morphologies of the ZnO/CVD graphene and ZnO/rGO were investigated by SEM, which shows that the ZnO nanorods grown on rGO are larger in diameters and have lower density compared with those grown on CVD graphene substrate. As a result of fact, the rough surface of nano-scale ZnO on rGO film allows rGO droplets to seep into the large voids of ZnO nanorods, then to form the rGO/ZnO hierarchical structure. By comparison of the different results, we conclude that rGO/ZnO 3D nanostructure is more desirable for the application of energy storage devices.

  19. Computer-Aided Molecular Design of Bis-phosphine Oxide Lanthanide Extractants

    DOE PAGESBeta

    McCann, Billy W.; Silva, Nuwan De; Windus, Theresa L.; Gordon, Mark S.; Moyer, Bruce A.; Bryantsev, Vyacheslav S.; Hay, Benjamin P.

    2016-02-17

    Computer-aided molecular design and high-throughput screening of viable host architectures can significantly reduce the efforts in the design of novel ligands for efficient extraction of rare earth elements. This paper presents a computational approach to the deliberate design of bis-phosphine oxide host architectures that are structurally organized for complexation of trivalent lanthanides. Molecule building software, HostDesigner, was interfaced with molecular mechanics software, PCModel, providing a tool for generating and screening millions of potential R2(O)P-link-P(O)R2 ligand geometries. The molecular mechanics ranking of ligand structures is consistent with both the solution-phase free energies of complexation obtained with density functional theory and themore » performance of known bis-phosphine oxide extractants. For the case where link is -CH2-, evaluation of the ligand geometry provides the first characterization of a steric origin for the ‘anomalous aryl strengthening’ effect. The design approach has identified a number of novel bis-phosphine oxide ligands that are better organized for lanthanide complexation than previously studied examples.« less

  20. Computer-Aided Molecular Design of Bis-phosphine Oxide Lanthanide Extractants.

    PubMed

    McCann, Billy W; Silva, Nuwan De; Windus, Theresa L; Gordon, Mark S; Moyer, Bruce A; Bryantsev, Vyacheslav S; Hay, Benjamin P

    2016-06-20

    Computer-aided molecular design and high-throughput screening of viable host architectures can significantly reduce the efforts in the design of novel ligands for efficient extraction of rare earth elements. This paper presents a computational approach to the deliberate design of bis-phosphine oxide host architectures that are structurally organized for complexation of trivalent lanthanides. Molecule building software, HostDesigner, was interfaced with molecular mechanics software, PCModel, providing a tool for generating and screening millions of potential R2(O)P-link-P(O)R2 ligand geometries. The molecular mechanics ranking of ligand structures is consistent with both the solution-phase free energies of complexation obtained with density functional theory and the performance of known bis-phosphine oxide extractants. For the case where the link is -CH2-, evaluation of the ligand geometry provides the first characterization of a steric origin for the "anomalous aryl strengthening" effect. The design approach has identified a number of novel bis-phosphine oxide ligands that are better organized for lanthanide complexation than previously studied examples.

  1. Electrochemical Water Oxidation of Ultrathin Cobalt Oxide-Based Catalyst Supported onto Aligned ZnO Nanorods.

    PubMed

    Koteeswara Reddy, Nandanapalli; Winkler, Stefanie; Koch, Norbert; Pinna, Nicola

    2016-02-10

    A stable and durable electrochemical water oxidation catalyst based on CoO functionalized ZnO nanorods (NRs) is introduced. ZnO NRs were grown on fluorine-doped tin oxide (FTO) by using a low-temperature chemical solution method and were functionalized with cobalt oxide by electrochemical deposition. The electrochemical water oxidation performance of cobalt oxide functionalized ZnO NRs was studied under alkaline (pH = 10) conditions. From these studies, it is noticed that cobalt oxide functionalized ZnO NRs show electrocatalytic activity toward water oxidation with current density on the order of several mA cm(-2). Further, 30 s CoO deposited ZnO nanorods exhibited excellent galvanostatic stability at a current density of 1 mA cm(-2) and potentiostatic stability at 1.25 V vs Ag/AgCl over an electrolysis period of 1 h. PMID:26784675

  2. Synthesis and Lanthanide Coordination Chemistry of Phosphine Oxide Decorated Dibenzothiophene and Dibenzothiophene Sulfone Platforms

    SciTech Connect

    Rosario-Amorin, Daniel; Ouizem, Sabrina; Dickie, D. A.; Paine, Robert T.; Cramer, Roger E.; Hay, Benjamin; Podair, Julien; Delmau, Laetitia Helene

    2014-01-01

    Syntheses for new ligands based upon dibenzothiophene and dibenzothiophene sulfone platforms, decorated with phosphine oxide and methylphosphine oxide donor groups, are described. Coordination chem. of 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene (8) , 4, 6- bis(diphenylphosphinoylmethyl) dibenzothiophene- 5, 5- dioxide (9) and 4, 6- bis(diphenylphosphinoyl) dibenzothiophene- 5, 5- dioxide (10) with lanthanide nitrates, Ln(NO3) 3 (H2O) n is outlined, and crystal structure detns. reveal a range of chelation interactions on Ln(III) ions. The HNO3 dependence of the solvent extn. performance of 9 and 10 in 1, 2- dichloroethane for Eu(III) and Am(III) is described and compared against the extn. behavior of related dibenzofuran ligands (2, 3; R = Ph) and n- octyl(phenyl) - N, N- diisobutylcarbamoylmethyl phosphine oxide (4) measured under identical conditions.

  3. Microwave Synthesis of Zinc Hydroxy Sulfate Nanoplates and Zinc Oxide Nanorods in the Classroom

    ERIC Educational Resources Information Center

    Dziedzic, Rafal M.; Gillian-Daniel, Anne Lynn; Peterson, Greta M.; Martínez-Herna´ndez, Kermin J.

    2014-01-01

    In this hands-on, inquiry-based lab, high school and undergraduate students learn about nanotechnology by synthesizing their own nanoparticles in a single class period. This simple synthesis of zinc oxide nanorods and zinc hydroxy sulfate nanoplates can be done in 15 min using a household microwave oven. Reagent concentration, reaction…

  4. Structural and optical properties of Nd{sup 3+} doped gadolinium oxide 1D nanorods

    SciTech Connect

    Boopathi, G. Mohan, R.; Raj, S. Gokul; Kumar, G. Ramesh

    2014-04-24

    Neodymium doped gadolinium hydroxide [Nd:Gd(OH)3] nanorods were successfully synthesized at 60 °C through co-precipitation method. The dopant percentage was maintained at 5% and calcination was done at 750 °C temperature for 1 hour to form the respective neodymium doped gadolinium oxide [Nd:Gd{sub 2}O{sub 3}] nanorods. The as-formed and annealed products were investigated in detail by using powder X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM) with an energy dispersive X-ray spectrum (EDX), high-resolution transmission electron microscopy (HRTEM) and photoluminescence (PL) spectrophotometry.

  5. Field emission behavior of cuboid zinc oxide nanorods on zinc-filled porous silicon

    NASA Astrophysics Data System (ADS)

    Yu, Ke; Zhang, Yongsheng; Xu, Rongli; Jiang, Desheng; Luo, Laiqiang; Li, Qiong; Zhu, Ziqiang; Lu, Wei

    2005-01-01

    Single-crystalline zinc oxide (ZnO) nanorods with cuboid morphology have been prepared on the zinc-filled porous silicon substrate using a vapor phase transport method. Field-emission measurements showed that the turn-on field and threshold field of the cuboid ZnO nanorods film were about 3.2 and 8.2 V/μm respectively. From the emitter surface, a homogeneous emission image was observed with emission site density (ESD) of ˜10 4 cm -2. The better emission uniformity and the high ESD may be attributed to a large number of ZnO nanocrystallites as emitter on the surface of the nanorod end contributing to emission.

  6. Growth and optical properties of quadrangular zinc oxide nanorods on copper-filled porous silicon

    NASA Astrophysics Data System (ADS)

    Yu, K.; Zhang, Y.; Luo, L.; Wang, W.; Zhu, Z.; Wang, J.; Cui, Y.; Ma, H.; Lu, W.

    Zinc oxide (ZnO) nanorods with quadrangular morphology have been successfully prepared on a copper-filled porous silicon substrate using a vapor phase transport method. Scanning electron microscopy showed that the diameters of the nanorods were scattered in a range of 100-400 nm and the lengths up to 2 μm. High-resolution transmission electron microscopy and a selected-area electron-diffraction pattern confirmed that the quadrangular ZnO nanorods had a single-crystal wurtzite structure and grew along the (0001) direction. The photoluminescence spectrum under excitation at 325 nm showed an ultraviolet emission at 386 nm and a strong broad green emission at 518 nm at room temperature.

  7. Engineering surface atomic structure of single-crystal cobalt (II) oxide nanorods for superior electrocatalysis

    PubMed Central

    Ling, Tao; Yan, Dong-Yang; Jiao, Yan; Wang, Hui; Zheng, Yao; Zheng, Xueli; Mao, Jing; Du, Xi-Wen; Hu, Zhenpeng; Jaroniec, Mietek; Qiao, Shi-Zhang

    2016-01-01

    Engineering the surface structure at the atomic level can be used to precisely and effectively manipulate the reactivity and durability of catalysts. Here we report tuning of the atomic structure of one-dimensional single-crystal cobalt (II) oxide (CoO) nanorods by creating oxygen vacancies on pyramidal nanofacets. These CoO nanorods exhibit superior catalytic activity and durability towards oxygen reduction/evolution reactions. The combined experimental studies, microscopic and spectroscopic characterization, and density functional theory calculations reveal that the origins of the electrochemical activity of single-crystal CoO nanorods are in the oxygen vacancies that can be readily created on the oxygen-terminated {111} nanofacets, which favourably affect the electronic structure of CoO, assuring a rapid charge transfer and optimal adsorption energies for intermediates of oxygen reduction/evolution reactions. These results show that the surface atomic structure engineering is important for the fabrication of efficient and durable electrocatalysts. PMID:27650485

  8. Engineering surface atomic structure of single-crystal cobalt (II) oxide nanorods for superior electrocatalysis.

    PubMed

    Ling, Tao; Yan, Dong-Yang; Jiao, Yan; Wang, Hui; Zheng, Yao; Zheng, Xueli; Mao, Jing; Du, Xi-Wen; Hu, Zhenpeng; Jaroniec, Mietek; Qiao, Shi-Zhang

    2016-09-21

    Engineering the surface structure at the atomic level can be used to precisely and effectively manipulate the reactivity and durability of catalysts. Here we report tuning of the atomic structure of one-dimensional single-crystal cobalt (II) oxide (CoO) nanorods by creating oxygen vacancies on pyramidal nanofacets. These CoO nanorods exhibit superior catalytic activity and durability towards oxygen reduction/evolution reactions. The combined experimental studies, microscopic and spectroscopic characterization, and density functional theory calculations reveal that the origins of the electrochemical activity of single-crystal CoO nanorods are in the oxygen vacancies that can be readily created on the oxygen-terminated {111} nanofacets, which favourably affect the electronic structure of CoO, assuring a rapid charge transfer and optimal adsorption energies for intermediates of oxygen reduction/evolution reactions. These results show that the surface atomic structure engineering is important for the fabrication of efficient and durable electrocatalysts.

  9. Engineering surface atomic structure of single-crystal cobalt (II) oxide nanorods for superior electrocatalysis.

    PubMed

    Ling, Tao; Yan, Dong-Yang; Jiao, Yan; Wang, Hui; Zheng, Yao; Zheng, Xueli; Mao, Jing; Du, Xi-Wen; Hu, Zhenpeng; Jaroniec, Mietek; Qiao, Shi-Zhang

    2016-01-01

    Engineering the surface structure at the atomic level can be used to precisely and effectively manipulate the reactivity and durability of catalysts. Here we report tuning of the atomic structure of one-dimensional single-crystal cobalt (II) oxide (CoO) nanorods by creating oxygen vacancies on pyramidal nanofacets. These CoO nanorods exhibit superior catalytic activity and durability towards oxygen reduction/evolution reactions. The combined experimental studies, microscopic and spectroscopic characterization, and density functional theory calculations reveal that the origins of the electrochemical activity of single-crystal CoO nanorods are in the oxygen vacancies that can be readily created on the oxygen-terminated {111} nanofacets, which favourably affect the electronic structure of CoO, assuring a rapid charge transfer and optimal adsorption energies for intermediates of oxygen reduction/evolution reactions. These results show that the surface atomic structure engineering is important for the fabrication of efficient and durable electrocatalysts. PMID:27650485

  10. Enhanced Photocatalytic Performance Using One Dimensional Ordered TiO2 Nanorods Modified by Graphene Oxide.

    PubMed

    Huang, Jinzhao; Fu, Ke; Yao, Nannan; Deng, Xiaolong; Ding, Meng; Shao, Minghui; Xu, Xijin; Wei, Mingzhi

    2016-02-01

    A new architecture of one dimensional ordered TiO2 nanorods modified by graphene oxide (GO) was assembled. The GO as the higher carrier mobility can reduce the recombination of carriers, which is more favourable for the methy orange (MO) degradation. Incorporating GO with the unblocked passageway for carrier transportation of the TiO2 nanorods can separate the transport pathway of electron and hole effectively. Furthermore, the large surface areas of TiO2 nanorods grown on the GO are beneficial to the enhancement of photocatalytic properties, and the reasonable band energy level can be obtained for the architecture, which is favorable for enhancing carrier separation and transportation. Finally, the higher transparency of the structure can enhance the light absorption. The photocatalyst grown on FTO substrates makes it easier to collect and recycle. PMID:27433607

  11. Zinc-oxide nanorod/copper-oxide thin-film heterojunction for a nitrogen-monoxide gas sensor

    NASA Astrophysics Data System (ADS)

    Yoo, Hwansu; Kim, Hyojin; Kim, Dojin

    2014-11-01

    A novel p- n oxide heterojunction structure was fabricated by employing n-type zinc-oxide (ZnO) nanorods grown on an indium-tin-oxide-coated glass substrate by using the hydrothermal method and a p-type copper-oxide (CuO) thin film deposited onto the ZnO nanorod array by using the sputtering method. The crystallinities and microstructures of the heterojunction materials were examined by using X-ray diffraction and scanning electron microscopy. The observed current-voltage characteristics of the p - n oxide heterojunction showed a nonlinear diode-like rectifying behavior. The effects of an oxidizing or electron acceptor gas, such as nitrogen monoxide (NO), on the ZnO nanorod/CuO thin-film heterojunction were investigated to determine the potential applications of the fabricated material for use in gas sensors. The forward current of the p - n heterojunction was remarkably reduced when NO gas was introduced into dry air at temperatures from 100 to 250 °C. The NO gas response of the oxide heterojunction reached a maximum value at an operating temperature of 180 °C and linearly increased as the NO gas concentration was increased from 5 to 30 ppm. The sensitivity value was observed to be as high as 170% at 180 °C when biased at 2 V in the presence of 20-ppm NO. The ZnO nanorod/CuO thin-film heterojunction also exhibited a stable and repeatable response to NO gas. The experimental results suggest that the ZnO nanorod/CuO thin-film heterojunction structure may be a novel candidate for gas sensors.

  12. Sintering behavior of lanthanide-containing glass-ceramic sealants for solid oxide fuel cells

    SciTech Connect

    Goel, Ashutosh; Reddy, Allu Amarnath; Pascual, Maria J.; Gremillard, Laurent; Malchere, Annie; Ferreira, Jose M.

    2012-05-01

    This article reports on the influence of different lanthanides (La, Nd, Gd and Yb) on sintering behavior of alkaline-earth aluminosilicate glass-ceramics sealants for their application in solid oxide fuel cells (SOFC). All the glasses have been prepared by melt-quench technique. The in situ follow up of sintering behavior of glass powders has been done by high temperature - environmental scanning electron microscope (HT-ESEM) and hot-stage microscope (HSM) while the crystalline phase evolution and assemblage has been analyzed by x-ray diffraction (XRD) and scanning electron microscopy (SEM). All the glass compositions exhibit a glass-in-glass phase separation followed by two stage sintering resulting in well sintered glass powder compacts after heat treatment at 850 C for 1 h. Diopside (CaMgSi{sub 2}O{sub 6}) based phases constituted the major crystalline part in glass-ceramics followed by some minor phases. The increase in lanthanide content in glasses suppressed their tendency towards devitrification, thus, resulting in glass-ceramics with high amount of residual glassy phase (50-96 wt.%) which is expected to facilitate their self-healing behavior during SOFC operation. The electrical conductivity of the investigated glass-ceramics varied between (1.19 and 7.33) x 10{sup -7} S cm{sup -1} (750-800 C), and depended on the ionic field strength of lanthanide cations. Further experimentation with respect to the long term thermal and chemical stability of residual glassy phase under SOFC operation conditions along with high temperature viscosity measurements will be required in order to elucidate the potential of these glass-ceramics as self-healing sealants.

  13. Direct growth of cerium oxide nanorods on diverse substrates for superhydrophobicity and corrosion resistance

    NASA Astrophysics Data System (ADS)

    Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo; Kim, Dong Rip

    2015-06-01

    Superhydrophobic surfaces with anti-corrosion properties have attracted great interest in many industrial fields, particularly to enhance the thermal performance of offshore applications such as heat exchangers, pipelines, power plants, and platform structures. Nanostructures with hydrophobic materials have been widely utilized to realize superhydrophobicity of surfaces, and cerium oxide has been highlighted due to its good corrosion resistive and intrinsically hydrophobic properties. However, few studies of direct growth of cerium oxide nanostructures on diverse substrates have been reported. Herein we report a facile hydrothermal method to directly grow cerium oxide nanorods on diverse substrates, such as aluminum alloy, stainless steel, titanium, and silicon. Diverse substrates with cerium oxide nanorods exhibited superhydrophobicity with no hydrophobic modifiers on their surfaces, and showed good corrosion resistive properties in corrosive medium. We believe our method could pave the way for realization of scalable and sustainable corrosion resistive superhydrophobic surfaces in many industrial fields.

  14. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    PubMed

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications.

  15. The Thermodynamic Properties of the f-Elements and their Compounds. Part 2. The Lanthanide and Actinide Oxides

    SciTech Connect

    Konings, Rudy J. M. Beneš, Ondrej; Kovács, Attila; Manara, Dario; Sedmidubský, David; Gorokhov, Lev; Iorish, Vladimir S.; Yungman, Vladimir; Shenyavskaya, E.; Osina, E.

    2014-03-15

    A comprehensive review of the thermodynamic properties of the oxide compounds of the lanthanide and actinide elements is presented. The available literature data for the solid, liquid, and gaseous state have been analysed and recommended values are presented. In case experimental data are missing, estimates have been made based on the trends in the two series, which are extensively discussed.

  16. Iron oxide nanorods as high-performance magnetic resonance imaging contrast agents

    NASA Astrophysics Data System (ADS)

    Mohapatra, Jeotikanta; Mitra, Arijit; Tyagi, Himanshu; Bahadur, D.; Aslam, M.

    2015-05-01

    An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM-1 s-1. The enhanced MRI contrast of nanorods is attributed to their higher surface area and anisotropic morphology. The higher surface area induces a stronger magnetic field perturbation over a larger volume more effectively for the outer sphere protons. The shape anisotropy contribution is understood by calculating the local magnetic field of nanorods and spherical nanoparticles under an applied magnetic field (3 Tesla). As compared to spherical geometry, the induced magnetic field of a rod is stronger and hence the stronger magnetic field over a large volume leads to a higher R2 relaxivity of nanorods.An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM-1 s-1. The enhanced MRI contrast of nanorods is attributed to their higher surface area and anisotropic morphology. The higher surface area induces a stronger magnetic field perturbation over a larger volume more effectively for the outer sphere protons. The shape anisotropy contribution is understood by calculating the local magnetic field of nanorods and spherical nanoparticles under an applied magnetic field (3 Tesla). As compared to spherical geometry, the induced magnetic field of a rod is stronger and hence the stronger magnetic field over a large volume leads to a higher R2 relaxivity of nanorods. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00055f

  17. Shape and size transformation of gold nanorods (GNRs) via oxidation process: A reverse growth mechanism

    NASA Astrophysics Data System (ADS)

    Chandrasekar, Govindasamy; Mougin, Karine; Haidara, Hamidou; Vidal, Loïc; Gnecco, Enrico

    2011-02-01

    The anisotropic shape transformation of gold nanorods (GNRs) with H2O2 was observed in the presence of "cethyl trimethylammonium bromide" (CTAB). The adequate oxidative dissolution of GNR is provided by the following autocatalytic scheme with H2O2: Au0 → Au+, Au0 + Aun+ → 2Au3+, n = 1 and 3. The shape transformation of the GNRs was investigated by UV-vis spectroscopy and transmission electron microscopy (TEM). As-synthesised GNRs exhibit transverse plasmon band (TPB) at 523 nm and longitudinal plasmon band (LPB) at 731 nm. Upon H2O2 oxidation, the LPB showed a systematic hypsochromic (blue) shift, while TPB stays at ca. 523 nm. In addition, a new emerging peak observed at ca. 390 nm due to Au(III)-CTAB complex formation during the oxidation. TEM analysis of as-synthesised GNRs with H2O2 confirmed the shape transformation to spherical particles with 10 nm size in 2 h, whereas centrifuged nanorod solution showed no changes in the aspect ratio under the same condition. Au3+ ions produced from oxidation, complex with excess free CTAB and approach the nanorods preferentially at the end, leading to spatially directed oxidation. This work provides some information to the crystal stability and the growth mechanism of GNRs, as both growth and shortening reactions occur preferentially at the edge of single-crystalline GNRs, all directed by Br- ions.

  18. Iron oxide nanorods as high-performance magnetic resonance imaging contrast agents.

    PubMed

    Mohapatra, Jeotikanta; Mitra, Arijit; Tyagi, Himanshu; Bahadur, D; Aslam, M

    2015-01-01

    An efficient magnetic resonance imaging (MRI) contrast agent with a high R2 relaxivity value is achieved by controlling the shape of iron oxide to rod like morphology with a length of 30-70 nm and diameter of 4-12 nm. Fe3O4 nanorods of 70 nm length, encapsulated with polyethyleneimine show a very high R2 relaxivity value of 608 mM(-1) s(-1). The enhanced MRI contrast of nanorods is attributed to their higher surface area and anisotropic morphology. The higher surface area induces a stronger magnetic field perturbation over a larger volume more effectively for the outer sphere protons. The shape anisotropy contribution is understood by calculating the local magnetic field of nanorods and spherical nanoparticles under an applied magnetic field (3 Tesla). As compared to spherical geometry, the induced magnetic field of a rod is stronger and hence the stronger magnetic field over a large volume leads to a higher R2 relaxivity of nanorods.

  19. Field emission from zinc oxide nanorod bundles grown on silicon nanoporous pillar array

    NASA Astrophysics Data System (ADS)

    Wang, Ling Li; Gong, Shang Dong; Wu, Li Hong; Li, Xin Jian

    2013-04-01

    A large-area zinc oxide (ZnO) nanorod bundle array was grown on a silicon nanoporous pillar array (Si-NPA) substrate by a chemical vapor deposition method, and its field-emission properties was studied. The structural characterization disclosed that the bundles were composed of hexagonal ZnO nanorods growing along c-axis and taking roots into the silicon pillars of Si-NPA. The average diameter and length of the ZnO nanorods were ∼145 nm and ∼10 μm, respectively. The field-emission measurements showed that the turn-on field of ZnO/Si-NPA was 4.6 V/μm with an emission current density (ECD) of 1 μA/cm2, and an ECD of 420 μA/cm2 was achieved at an applied field of 8.89 V/μm. The field enhancement factor was calculated to be ∼1700 based on the Fowler-Nordheim theory. According to the obtained charge coupled device (CCD) image, the density and brightness of the emission dots increased with the applied field, and the high emission dot density was attributed to the formation of a large number of ZnO nanorod emitting tips. Our results indicated that ZnO/Si-NPA might be a promising electron emission source.

  20. Oxidic nanotubes and nanorods--anisotropic modules for a future nanotechnology.

    PubMed

    Patzke, Greta R; Krumeich, Frank; Nesper, Reinhard

    2002-07-15

    The discovery of carbon nanotubes in 1991 is a milestone in nanomaterials research. Since then, more and more anisotropic nanoparticles have been detected and characterized. The development of nanodevices might benefit from the distinct morphology and high aspect ratio of nanorods and nanotubes as these can be functionalized in unique ways such as incorporation of nanorods in nanotubes. Downscaling a broad range of materials to 1D nanoscopic structures is currently the focus of a rapidly growing scientific community. Developing general pathways to this goal would transfer a wide variety of properties to the nanoscale-a spectrum of phenomena so diverse that it would cover not only inorganic systems but all of materials science. Synthesis of real functional materials, however, always involves considerable synthetic ingenuity, interdisciplinary collaboration, as well as technological and economical realism. The major topic of this review is to provide a survey of recent progress in the synthesis of oxidic nanotubes and nanorods-with their non-oxidic counterparts briefly highlighted-and to outline the major synthetic routes leading to them. With the challenges of synthesizing bulk oxidic materials in mind, the establishment of trustworthy and uncomplicated ways of providing them as anisotropic nano-modules on an industrial scale appears to be more or less serendipity. Of the methods utilized in nanotube and nanorod synthesis solvothermal processes have emerged as powerful tools for generalizing and systematizing controlled syntheses of nano-morphologies. The flexibility and reliability of this synthetic approach is demonstrated here for the transformation of transition-metal oxides into high-quality anisotropic nanomaterials.

  1. Temperature threshold for nanorod structuring of metal and oxide films grown by glancing angle deposition

    SciTech Connect

    Deniz, Derya; Lad, Robert J.

    2011-01-15

    Thin films of tin (Sn), aluminum (Al), gold (Au), ruthenium (Ru), tungsten (W), ruthenium dioxide (RuO{sub 2}), tin dioxide (SnO{sub 2}), and tungsten trioxide (WO{sub 3}) were grown by glancing angle deposition (GLAD) to determine the nanostructuring temperature threshold, {Theta}{sub T}, above which adatom surface diffusion becomes large enough such that nanorod morphology is no longer formed during growth. The threshold was found to be lower in metals compared to oxides. Films were grown using both dc and pulsed dc magnetron sputtering with continuous substrate rotation over the temperature range from 291 to 866 K. Film morphologies, structures, and compositions were characterized by high resolution scanning electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Films were also grown in a conventional configuration for comparison. For elemental metals, nanorod structuring occurs for films with melting points higher than that of Al (933 K) when grown at room temperature with a rotation rate of {approx}5 rpm, corresponding to a value of {Theta}{sub T}{approx_equal}0.33{+-}0.01. For the oxide films, a value of {Theta}{sub T}{approx_equal}0.5 was found, above which GLAD nanorod structuring does not occur. The existence of a nanostructuring temperature threshold in both metal and oxide GLAD films can be attributed to greater adatom mobilities as temperature is increased resulting in nonkinetically limited film nucleation and growth processes.

  2. Reduced graphene oxide enwrapped vanadium pentoxide nanorods as cathode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Chen, Dezhi; Quan, Hongying; Luo, Shenglian; Luo, Xubiao; Deng, Fang; Jiang, Hualin

    2014-02-01

    Novel reduced graphene oxide/vanadium pentoxide (rGO/V2O5) nanocomposites were fabricated by coassembly between negatively charged graphene oxide and positively charged oxide nanorods. A series of characterization including X-ray diffraction, Raman spectrum, scanning electron microscopy and transmission electron microscopy indicated that the V2O5 nanorods with the width of about 50 nm and the length from a few hundred nanometers to several micrometers were enwrapped by rGO layers to form core-shell nanostructures. Compared with the pristine V2O5 nanorods, the as-prepared rGO/V2O5 nanocomposites with 13 wt% rGO showed a significantly enhanced electrochemical performance with high reversible capacities, good cycling stabilities and excellent rate capabilities as a cathode material for lithium batteries. The rGO/V2O5 nanocomposites electrodes delivered a stable discharge capacity around 140 mA h g-1 at a current density of 150 mA g-1 for 100 cycles in the voltage range of 2.5-4.0 V. Furthermore, the nanocomposites electrodes delivered discharge capacities of 287 mA h g-1 and 207 mA h g-1 during the first and 50th cycles in the voltage range of 2.0-4.0 V at a current density of 100 mA g-1, respectively. The as-synthesized nanocomposites are promising candidates for electrical energy storage applications.

  3. Cobalt-phosphate-assisted photoelectrochemical water oxidation by arrays of molybdenum-doped zinc oxide nanorods.

    PubMed

    Lin, Yan-Gu; Hsu, Yu-Kuei; Chen, Ying-Chu; Lee, Bing-Wei; Hwang, Jih-Shang; Chen, Li-Chyong; Chen, Kuei-Hsien

    2014-09-01

    We report the first demonstration of cobalt phosphate (Co-Pi)-assisted molybdenum-doped zinc oxide nanorods (Zn(1-x)Mo(x)O NRs) as visible-light-sensitive photofunctional electrodes to fundamentally improve the performance of ZnO NRs for photoelectrochemical (PEC) water splitting. A maximum photoconversion efficiency as high as 1.05% was achieved, at a photocurrent density of 1.4 mA cm(-2). More importantly, in addition to achieve the maximum incident photon to current conversion efficiency (IPCE) value of 86%, it could be noted that the IPCE of Zn(1-x)Mo(x)O photoanodes under monochromatic illumination (450 nm) is up to 12%. Our PEC performances are comparable to those of many oxide-based photoanodes in recent reports. The improvement in photoactivity of PEC water splitting may be attributed to the enhanced visible-light absorption, increased charge-carrier densities, and improved interfacial charge-transfer kinetics due to the combined effect of molybdenum incorporation and Co-Pi modification, contributing to photocatalysis. The new design of constructing highly photoactive Co-Pi-assisted Zn(1-x)Mo(x)O photoanodes enriches knowledge on doping and advances the development of high-efficiency photoelectrodes in the solar-hydrogen field.

  4. Studies on supercritical hydrothermal syntheses of uranium and lanthanide oxide particles and their reaction mechanisms

    NASA Astrophysics Data System (ADS)

    Hwang, DongKi; Tsukahara, Takehiko; Tanaka, Kosuke; Osaka, Masahiko; Ikeda, Yasuhisa

    2015-11-01

    In order to develop preparation method of raw metal oxide particles for low decontaminated MOX fuels by supercritical hydrothermal (SH) treatments, we have investigated behavior of aqueous solutions dissolving U(VI), Ln(III) (Ln: lanthanide = Ce, Pr, Nd, Sm, Tb), Cs(I), and Sr(II) nitrate or chloride compounds under SH conditions (temperature = 400-500 °C, pressure = 30-40 MPa). As a result, it was found that Ln(NO3)3 (Ln = Ce, Pr, Tb) compounds produce LnO2, that Ln(NO3)3 (Ln = Nd, Sm) compounds are hardly converted to their oxides, and that LnCl3 (Ln = Ce, Pr, Nd, Sm, Tb), CsNO3, and Sr(NO3)2 do not form their oxide compounds. Furthermore, HNO2 species were detected in the liquid phase obtained after treating HNO3 aqueous solutions containing Ln(NO3)3 (Ln = Ce, Pr, Tb) under SH conditions, and also NO2 and NO compounds were found to be produced by decomposition of HNO3. From these results, it was proposed that the Ln oxide (LnO2) particles are directly formed with oxidation of Ln(III) to Ln(IV) by HNO3 and HNO2 species in the SH systems. Moreover, the uranyl ions were found to form U3O8 and UO3 depending on the concentration of HNO3. From these results, it is expected that the raw metal oxide particles for low decontaminated MOX fuels are efficiently prepared by the SH method.

  5. Surface engineering on CeO2 nanorods by chemical redox etching and their enhanced catalytic activity for CO oxidation

    NASA Astrophysics Data System (ADS)

    Gao, Wei; Zhang, Zhiyun; Li, Jing; Ma, Yuanyuan; Qu, Yongquan

    2015-07-01

    Controllable surface properties of nanocerias are desired for various catalytic processes. There is a lack of efficient approaches to adjust the surface properties of ceria to date. Herein, a redox chemical etching method was developed to controllably engineer the surface properties of ceria nanorods. Ascorbic acid and hydrogen peroxide were used to perform the redox chemical etching process, resulting in a rough surface and/or pores on the surface of ceria nanorods. Increasing the etching cycles induced a steady increase of the specific surface area, oxygen vacancies and surface Ce3+ fractions. As a result, the etched nanorods delivered enhanced catalytic activity for CO oxidation, compared to the non-etched ceria nanorods. Our method provides a novel and facile approach to continuously adjust the surface properties of ceria for practical applications.Controllable surface properties of nanocerias are desired for various catalytic processes. There is a lack of efficient approaches to adjust the surface properties of ceria to date. Herein, a redox chemical etching method was developed to controllably engineer the surface properties of ceria nanorods. Ascorbic acid and hydrogen peroxide were used to perform the redox chemical etching process, resulting in a rough surface and/or pores on the surface of ceria nanorods. Increasing the etching cycles induced a steady increase of the specific surface area, oxygen vacancies and surface Ce3+ fractions. As a result, the etched nanorods delivered enhanced catalytic activity for CO oxidation, compared to the non-etched ceria nanorods. Our method provides a novel and facile approach to continuously adjust the surface properties of ceria for practical applications. Electronic supplementary information (ESI) available: Diameter distributions of as-prepared and etched samples, optical images, specific catalytic data of CO oxidation and comparison of CO oxidation. See DOI: 10.1039/c5nr01846c

  6. A novel glutamine biosensor based on zinc oxide nanorod and glutaminase enzyme from Hypocria jecorina.

    PubMed

    Albayrak, Dilruba; Karakuş, Emine

    2016-01-01

    A novel biosensor for determination of L-glutamine in pharmaceutical glutamine powder was developed via immobilizing our produced glutaminase enzyme from Hypocria jecorina onto our prepared zinc oxide (ZnO) nanorod and chitosan. ZnO nanorods were prepared as surface-dependent and surface-independent and both were used. The biosensor is specific for L-glutamine and the peculiar analytical properties (linearity range, reproducibility, and accuracy) of it were experimentally determined. The optimum operating conditions of the biosensor such as buffer concentration, buffer pH, and medium temperature effect on the response of biosensor were studied. Km and Vmax values for the our-producing glutaminase enzyme from Hypocria jecorina immobilized on the biosensor were also determined as 0.29 mM and 208.33 mV/min., respectively, from Lineweaver-Burk plot. The biosensor was then used for the determination of glutamine contained in pharmaceutical formulations.

  7. Zinc Oxide Nanorods Shielded with an Ultrathin Nickel Layer: Tailoring of Physical Properties

    PubMed Central

    Mudusu, Devika; Nandanapalli, Koteeswara Reddy; Dugasani, Sreekantha Reddy; Park, Sung Ha; Tu, Charles W.

    2016-01-01

    We report on the development of Ni-shielded ZnO nanorod (NR) structures and the impact of the Ni layer on the ZnO NR properties. We developed nickel-capped zinc oxide nanorod (ZnO/Ni NR) structures by e-beam evaporation of Ni and the subsequent annealing of the ZnO/Ni core/shell nanostructures. The core/shell NRs annealed at 400 °C showed superior crystalline and emission properties. More interestingly, with the increase of annealing temperature, the crystallinity of the Ni shells over the ZnO NRs gradually changed from polycrystalline to single crystalline. The presence of the Ni layer as a polycrystalline shell completely hindered the light emission and transmission of the ZnO NR cores. Further, the band gap of ZnO NRs continuously decreased with the increase of annealing temperature. PMID:27334555

  8. Zinc Oxide Nanorods Shielded with an Ultrathin Nickel Layer: Tailoring of Physical Properties

    NASA Astrophysics Data System (ADS)

    Mudusu, Devika; Nandanapalli, Koteeswara Reddy; Dugasani, Sreekantha Reddy; Park, Sung Ha; Tu, Charles W.

    2016-06-01

    We report on the development of Ni-shielded ZnO nanorod (NR) structures and the impact of the Ni layer on the ZnO NR properties. We developed nickel-capped zinc oxide nanorod (ZnO/Ni NR) structures by e-beam evaporation of Ni and the subsequent annealing of the ZnO/Ni core/shell nanostructures. The core/shell NRs annealed at 400 °C showed superior crystalline and emission properties. More interestingly, with the increase of annealing temperature, the crystallinity of the Ni shells over the ZnO NRs gradually changed from polycrystalline to single crystalline. The presence of the Ni layer as a polycrystalline shell completely hindered the light emission and transmission of the ZnO NR cores. Further, the band gap of ZnO NRs continuously decreased with the increase of annealing temperature.

  9. Ultra-violet Sensing Characteristic and Field Emission Properties of Vertically Aligned Aluminum Doped Zinc Oxide Nanorod Arrays

    SciTech Connect

    Mamat, M. H.; Malek, M. F.; Musa, M. Z.; Khusaimi, Z.; Rusop, M.

    2011-05-25

    Ultra-violet (UV) sensing behavior and field emission characteristic have been investigated on vertically aligned aluminum (Al) doped zinc oxide (ZnO) nanorod arrays prepared using sol-gel immersion method. Uniform and high coverage density of ZnO nanorod arrays have been successfully deposited on seeded-catalyst coated substrates. The synthesized nanorods have diameter sizes between 50 nm to 150 nm. The XRD spectra show Al doped ZnO nanorod array has high crystallinity properties with the dominancy of crystal growth along (002) plane or c-axis. UV photoresponse measurement indicates that Al doped ZnO nanorod array sensitively detects UV light as shown by conductance increment after UV illumination exposure. The nanorod array shows good field emission properties with low turn on field and threshold field at 2.1 V/{mu}m and 5.6 V/{mu}m, respectively. The result suggested that Al doped ZnO nanorod arrays prepared by low-cost sol-gel immersion method show promising result towards fabrication of multi applications especially in UV photoconductive sensor and field emission displays.

  10. Low-temperature growth of well-aligned zinc oxide nanorod arrays on silicon substrate and their photocatalytic application

    PubMed Central

    Azam, Ameer; Babkair, Saeed Salem

    2014-01-01

    Well-aligned and single-crystalline zinc oxide (ZnO) nanorod arrays were grown on silicon (Si) substrate using a wet chemical route for the photodegradation of organic dyes. Structural analysis using X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction confirmed the formation of ZnO nanorods grown preferentially oriented in the (001) direction and with a single phase nature with a wurtzite structure. Field emission scanning electron microscopy and transmission electron microscopy micrographs showed that the length and diameter of the well-aligned rods were about ~350–400 nm and ~80–90 nm, respectively. Raman scattering spectra of ZnO nanorod arrays revealed the characteristic E2 (high) mode that is related to the vibration of oxygen atoms in the wurtzite ZnO. The photodegradation of methylene blue (MB) using ZnO nanorod arrays was performed under ultraviolet light irradiation. The results of photodegradation showed that ZnO nanorod arrays were capable of degrading ~80% of MB within 60 minutes of irradiation, whereas ~92% of degradation was achieved in 120 minutes. Complete degradation of MB was observed after 270 minutes of irradiation time. Owing to enhanced photocatalytic degradation efficiency and low-temperature growth method, prepared ZnO nanorod arrays may open up the possibility for the successful utilization of ZnO nanorod arrays as a future photocatalyst for environmental remediation. PMID:24812511

  11. Position controlled and seed/catalyst free growth of ZnO nanorod arrays on reduced graphene oxide nanosheets

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Li, Jinliang; Li, Lan; Mo, Zhaojun

    2016-09-01

    A new type of seed/catalyst-free and selective-growth process is developed for in situ grown vertically-aligned ZnO nanorods on the reduced graphene oxide (rGO) nanosheets. The dense and single-crystalline ZnO nanorods have been successfully grow on rGO nanosheets with the position- and size-controlled. The effect of rGO layer on the ZnO nanorods and the growth mechanism were investigated. The position of ZnO nanorod arrays correlates well with the size and position of rGO nanosheets, which is determined by dangling bonds such as oxygen-containing groups on rGO surface. Meanwhile, ZnO nanorods could grow laterally to form a continuous arrays with a large coverage on rGO substrates, which is mainly due to the step edges in rGO boundaries. The diameter and density of ZnO nanorods were readily determined by the growth temperature, and the length was easily controlled by the growth time. The absorption and PL spectrums suggest that ZnO nanorods/rGO have a strong UV absorption ranging from 330 to 375 nm and no obvious UV PL emission at room temperature, which indicates that the ZnO nanorods/rGO nanohybrids could be an excellent candidate for application in UV photodetectors. This work represents the success in seed/catalyst-free fabrication of aligned ZnO nanorod arrays directly on rGO nanosheets and the process can be readily scaled up for industrial applications of optoelectronic devices.

  12. Carbon nanotube-induced preparation of vanadium oxide nanorods: Application as a catalyst for the partial oxidation of n-butane

    SciTech Connect

    Chen Xiaowei; Zhu Zhenping; Haevecker, Michael; Su Dangsheng . E-mail: dangsheng@fhi-berlin.mpg.de; Schloegl, Robert

    2007-02-15

    A vanadium oxide-carbon nanotube composite was prepared by solution-based hydrolysis of NH{sub 4}VO{sub 3} in the presence of carbon nanotubes. The carbon nanotubes induce the nucleation of the 1D vanadium oxide nanostructures, with the nuclei growing into long freestanding nanorods. The vanadium oxide nanorods with the lengths up to 20 {mu}m and the widths of 5-15 nm exhibit a well-ordered crystalline structure. Catalytic tests show that the composite with nanostructured vanadium oxide is active for the partial oxidation of n-butane to maleic anhydride at 300 deg. C.

  13. Surface engineering on CeO₂ nanorods by chemical redox etching and their enhanced catalytic activity for CO oxidation.

    PubMed

    Gao, Wei; Zhang, Zhiyun; Li, Jing; Ma, Yuanyuan; Qu, Yongquan

    2015-07-21

    Controllable surface properties of nanocerias are desired for various catalytic processes. There is a lack of efficient approaches to adjust the surface properties of ceria to date. Herein, a redox chemical etching method was developed to controllably engineer the surface properties of ceria nanorods. Ascorbic acid and hydrogen peroxide were used to perform the redox chemical etching process, resulting in a rough surface and/or pores on the surface of ceria nanorods. Increasing the etching cycles induced a steady increase of the specific surface area, oxygen vacancies and surface Ce(3+) fractions. As a result, the etched nanorods delivered enhanced catalytic activity for CO oxidation, compared to the non-etched ceria nanorods. Our method provides a novel and facile approach to continuously adjust the surface properties of ceria for practical applications.

  14. Lanthanide-based oxides and silicates for high-kappa gate dielectric applications

    NASA Astrophysics Data System (ADS)

    Jur, Jesse Stephen

    The ability to improve performance of the high-end metal oxide semiconductor field effect transistor (MOSFET) is highly reliant on the dimensional scaling of such a device. In scaling, a decrease in dielectric thickness results in high current leakage between the electrode and the substrate by way of direct tunneling through the gate dielectric. Observation of a high leakage current when the standard gate dielectric, SiO2, is decreased below a thickness of 1.5 nm requires engineering of a replacement dielectric that is much more scalable. This high-kappa dielectric allows for a physically thicker oxide, reducing leakage current. Integration of select lanthanide-based oxides and silicates, in particular lanthanum oxide and silicate, into MOS gate stack devices is examined. The quality of the high-kappa dielectrics is monitored electrically to determine properties such as equivalent oxide thickness, leakage current density and defect densities. In addition, analytical characterization of the dielectric and the gate stack is provided to examine the materialistic significance to the change of the electrical properties of the devices. In this work, lanthanum oxide films have been deposited by thermal evaporation on to a pre-grown chemical oxide layer on silicon. It is observed that the SiO2 interfacial layer can be consumed by a low-temperature reaction with lanthanum oxide to produce a high-quality silicate. This is opposed to depositing lanthanum oxide directly on silicon, which can possibly favor silicide formation. The importance of oxygen regulation in the surrounding environment of the La2O3-SiO2 reaction-anneal is observed. By controlling the oxygen available during the reaction, SiO2 growth can be limited to achieve high stoichiometric ratios of La2O 3 to SiO2. As a result, MOS devices with an equivalent oxide thickness (EOT) of 5 A and a leakage current density of 5.0 A/cm 2 are attained. This data equals the best value achieved in this field and is a

  15. Synthesis of supported silver nano-spheres on zinc oxide nanorods for visible light photocatalytic applications

    SciTech Connect

    Saoud, Khaled; Alsoubaihi, Rola; Bensalah, Nasr; Bora, Tanujjal; Bertino, Massimo; Dutta, Joydeep

    2015-03-15

    Highlights: • Synthesis of supported Ag NPs on ZnO nanorods using open vessel microwave reactor. • Use of the Ag/ZnO NPs as an efficient visible light photocatalyst. • Complete degradation of methylene blue in 1 h with 0.5 g/L Ag/ZnO NPs. - Abstract: We report the synthesis of silver (Ag) nano-spheres (NS) supported on zinc oxide (ZnO) nanorods through two step mechanism, using open vessel microwave reactor. Direct reduction of ZnO from zinc nitrates was followed by deposition precipitation of the silver on the ZnO nanorods. The supported Ag/ZnO nanoparticles were then characterized by electron microscopy, X-ray diffraction, FTIR, photoluminescence and UV–vis spectroscopy. The visible light photocatalytic activity of Ag/ZnO system was investigated using a test contaminant, methylene blue (MB). Almost complete removal of MB in about 60 min for doses higher than 0.5 g/L of the Ag/ZnO photocatalyst was achieved. This significant improvement in the photocatalytic efficiency of Ag/ZnO photocatalyst under visible light irradiation can be attributed to the presence of Ag nanoparticles on the ZnO nanoparticles which greatly enhances absorption in the visible range of solar spectrum enabled by surface plasmon resonance effect from Ag nanoparticles.

  16. Field emission behaviour of manganese oxide nanorods synthesized by hydrothermal method

    NASA Astrophysics Data System (ADS)

    Bankar, P. K.; Gavhane, D. S.; Kolhe, P. S.; Warule, S. S.; More, M. A.

    2016-05-01

    A facile, low temperature and single step hydrothermal method has been used to fabricate well defined manganese oxide (MnO2) nanorods over Si substrate. The structural and morphological studies reveal the formation of crystalline MnO2 nanostructures. The diameter of the MnO2 nanorods is estimated to be ~100 nm, with length in several micrometers. Field-emission properties of the as-synthesized MnO2 nanorods are investigated. The turn on field required to draw emission of 0.1 µA/cm2 current was observed to be ~ 3.2 V/μm and threshold field (corresponding to emission current density of 1 µA/cm2) was found to be 5.1 V/μm. The emission current was observed to be stable for more than three hours at a preset value 1 µA. These results are helpful for the design, fabrication and optimization of integrated field emitters using 1D nanostructure as cold cathode material.

  17. Impact of Nanosize on Supercapacitance: Study of 1D Nanorods and 2D Thin-Films of Nickel Oxide.

    PubMed

    Patil, Ranjit A; Chang, Cheng-Ping; Devan, Rupesh S; Liou, Yung; Ma, Yuan-Ron

    2016-04-20

    We synthesized unique one-dimensional (1D) nanorods and two-dimensional (2D) thin-films of NiO on indium-tin-oxide thin-films using a hot-filament metal-oxide vapor deposition technique. The 1D nanorods have an average width and length of ∼100 and ∼500 nm, respectively, and the densely packed 2D thin-films have an average thickness of ∼500 nm. The 1D nanorods perform as parallel units for charge storing. However, the 2D thin-films act as one single unit for charge storing. The 2D thin-films possess a high specific capacitance of ∼746 F/g compared to 1D nanorods (∼230 F/g) using galvanostatic charge-discharge measurements at a current density of 3 A/g. Because the 1D NiO nanorods provide more plentiful surface areas than those of the 2D thin-films, they are fully active at the first few cycles. However, the capacitance retention of the 1D nanorods decays faster than that of the 2D thin-films. Also, the 1D NiO nanorods suffer from instability due to the fast electrochemical dissolution and high nanocontact resistance. Electrochemical impedance spectroscopy verifies that the low dimensionality of the 1D NiO nanorods induces the unavoidable effects that lead them to have poor supercapacitive performances. On the other hand, the slow electrochemical dissolution and small contact resistance in the 2D NiO thin-films favor to achieve high specific capacitance and great stability.

  18. Impact of Nanosize on Supercapacitance: Study of 1D Nanorods and 2D Thin-Films of Nickel Oxide.

    PubMed

    Patil, Ranjit A; Chang, Cheng-Ping; Devan, Rupesh S; Liou, Yung; Ma, Yuan-Ron

    2016-04-20

    We synthesized unique one-dimensional (1D) nanorods and two-dimensional (2D) thin-films of NiO on indium-tin-oxide thin-films using a hot-filament metal-oxide vapor deposition technique. The 1D nanorods have an average width and length of ∼100 and ∼500 nm, respectively, and the densely packed 2D thin-films have an average thickness of ∼500 nm. The 1D nanorods perform as parallel units for charge storing. However, the 2D thin-films act as one single unit for charge storing. The 2D thin-films possess a high specific capacitance of ∼746 F/g compared to 1D nanorods (∼230 F/g) using galvanostatic charge-discharge measurements at a current density of 3 A/g. Because the 1D NiO nanorods provide more plentiful surface areas than those of the 2D thin-films, they are fully active at the first few cycles. However, the capacitance retention of the 1D nanorods decays faster than that of the 2D thin-films. Also, the 1D NiO nanorods suffer from instability due to the fast electrochemical dissolution and high nanocontact resistance. Electrochemical impedance spectroscopy verifies that the low dimensionality of the 1D NiO nanorods induces the unavoidable effects that lead them to have poor supercapacitive performances. On the other hand, the slow electrochemical dissolution and small contact resistance in the 2D NiO thin-films favor to achieve high specific capacitance and great stability. PMID:27028491

  19. Fabrication of Vertically Aligned Carbon Nanotube or Zinc Oxide Nanorod Arrays for Optical Diffraction Gratings.

    PubMed

    Kim, Jeong; Kim, Sun Il; Cho, Seong-Ho; Hwang, Sungwoo; Lee, Young Hee; Hur, Jaehyun

    2015-11-01

    We report on new fabrication methods for a transparent, hierarchical, and patterned electrode comprised of either carbon nanotubes or zinc oxide nanorods. Vertically aligned carbon nanotubes or zinc oxide nanorod arrays were fabricated by either chemical vapor deposition or hydrothermal growth, in combination with photolithography. A transparent conductive graphene layer or zinc oxide seed layer was employed as the transparent electrode. On the patterned surface defined using photoresist, the vertically grown carbon nanotubes or zinc oxides could produce a concentrated electric field under applied DC voltage. This periodic electric field was used to align liquid crystal molecules in localized areas within the optical cell, effectively modulating the refractive index. Depending on the material and morphology of these patterned electrodes, the diffraction efficiency presented different behavior. From this study, we established the relationship between the hierarchical structure of the different electrodes and their efficiency for modulating the refractive index. We believe that this study will pave a new path for future optoelectronic applications. PMID:26726580

  20. Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions

    NASA Astrophysics Data System (ADS)

    Burke, Benjamin P.; Baghdadi, Neazar; Kownacka, Alicja E.; Nigam, Shubhanchi; Clemente, Gonçalo S.; Al-Yassiry, Mustafa M.; Domarkas, Juozas; Lorch, Mark; Pickles, Martin; Gibbs, Peter; Tripier, Raphaël; Cawthorne, Christopher; Archibald, Stephen J.

    2015-09-01

    The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging.The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no

  1. Position- and orientation-controlled polarized light interaction of individual indium tin oxide nanorods

    SciTech Connect

    Choi, Daniel S.; Joh, Daniel Y.; Lee, Thomas; Milchak, Marissa; Zhou, Hebing; Kang, Yongkoo; Hahm, Jong-in

    2014-02-24

    We have systematically investigated the position, orientation, and polarization angle dependence of scattered light from well-characterized, indium tin oxide nanorods (ITO NRs) upon illumination with monochromatic light. Scattering signals from individual ITO NRs of horizontal and vertical configurations are probed quantitatively by examining signal response with respect to the analyzer angle and position along the length of the NR. Our efforts can be highly beneficial in providing fundamental understanding for the light interaction behavior of ITO NRs. Our results can provide valuable bases for comprehending optical emission from individual NRs, with their ever-growing applications in optoelectronics, photonics, and biosensing.

  2. Hydrogen Spillover between Single Gold Nanorods and Metal Oxide Supports: A Surface Plasmon Spectroscopy Study.

    PubMed

    Collins, Sean S E; Cittadini, Michela; Pecharromán, Carlos; Martucci, Alessandro; Mulvaney, Paul

    2015-08-25

    We used dark field spectroscopy to monitor the dissociation of hydrogen on single gold nanoparticles embedded in metal oxide supports. Individual gold nanorods were monitored in real time to reveal the peak position, the full width at half-maximum, and the relative intensity of the surface plasmon resonances during repeated N2-H2-N2 and air-H2-air cycles. Shifts in the spectra are shown to be due to changes in electron density and not to refractive index shifts in the environment. We demonstrate that hydrogen does not dissociate on gold nanorods (13 nm × 40 nm) at room temperature when in contact with silica and that electrons or hydrogen atoms migrate from Pt nanoparticles to Au nanoparticles through the supporting metal oxide at room temperature. However, this spillover mechanism only occurs for semiconducting oxides (anatase TiO2 and ZnO) and does not occur for Au and Pt nanoparticles embedded in silica. Finally, we show that hydrogen does dissociate directly on anatase surfaces at room temperature during air-H2-air cycles. Our results show that hydrogen spillover, surface dissociation of reactants, and surface migration of chemical intermediates can be detected and monitored in real time at the single particle level.

  3. A Zinc Oxide Nanorod Ammonia Microsensor Integrated with a Readout Circuit on-a-Chip

    PubMed Central

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2011-01-01

    A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature. PMID:22247656

  4. A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip.

    PubMed

    Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

    2011-01-01

    A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature.

  5. Characteristics of zinc oxide nanorod array/titanium oxide film heterojunction prepared by aqueous solution deposition

    NASA Astrophysics Data System (ADS)

    Lee, Ming-Kwei; Hong, Min-Hsuan; Li, Bo-Wei

    2016-07-01

    The characteristics of a ZnO nanorod array/TiO2 film heterojunction were investigated. A TiO2 film was prepared on glass by aqueous solution deposition with precursors of ammonium hexafluorotitanate and boric acid at 40 °C. Then, a ZnO seed layer was prepared on a TiO2 film/glass substrate by RF sputtering. A vertically oriented ZnO nanorod array was grown on a ZnO seed layer/TiO2 film/glass substrate by aqueous solution deposition with precursors of zinc nitrate and hexamethylenetetramine (HMT) at 70 °C. After thermal annealing in N2O ambient at 300 °C, this heterojunction used as an oxygen gas sensor shows much better rise time, decay time, and on/off current ratio than as-grown and annealed ZnO nanorods.

  6. MnO2 Nanorods Intercalating Graphene Oxide/Polyaniline Ternary Composites for Robust High-Performance Supercapacitors

    PubMed Central

    Han, Guangqiang; Liu, Yun; Zhang, Lingling; Kan, Erjun; Zhang, Shaopeng; Tang, Jian; Tang, Weihua

    2014-01-01

    New ternary composites of MnO2 nanorods, polyaniline (PANI) and graphene oxide (GO) have been prepared by a two-step process. The 100 nm-long MnO2 nanorods with a diameter ~20 nm are conformably coated with PANI layers and fastened between GO layers. The MnO2 nanorods incorporated ternary composites electrode exhibits significantly increased specific capacitance than PANI/GO binary composite in supercapacitors. The ternary composite with 70% MnO2 exhibits a highest specific capacitance reaching 512 F/g and outstanding cycling performance, with ~97% capacitance retained over 5000 cycles. The ternary composite approach offers an effective solution to enhance the device performance of metal-oxide based supercapacitors for long cycling applications. PMID:24769835

  7. A general method for preparing lanthanide oxide nanoparticles via thermal decomposition of lanthanide(III) complexes with 1-hydroxy-2-naphthoic acid and hydrazine ligands

    NASA Astrophysics Data System (ADS)

    Parimalagandhi, Karuppannan; Premkumar, Thathan; Vairam, Sundararajan

    2016-09-01

    Six new lanthanide(III) complexes (i.e., [Ln(L)2(NA)1.5]·3H2O, where Ln=La(III), Pr(III), Nd(III), Sm(III), Gd(III), and Ce(III) and L and NA indicate N2H4 and C10H6(1-O)(2-COO), respectively) with 1-hydroxy-2-naphthoic acid [C10H6(1-O)(2-COOH)] and hydrazine (N2H4) as co-ligands were characterized by elemental, FTIR, UV-visible, and XRD techniques. In the FT-IR spectra, the N-N stretching frequency in the range of 981-949 cm-1 demonstrates evidence of the presence of coordinated N2H4, indicating the bidentate bridging nature of hydrazine in the complexes. These complexes show symmetric and asymmetric COO- stretching from 1444 to 1441 cm-1 and 1582 to 1557 cm-1, respectively, indicating bidentate coordination. TG-DTA studies revealed that the compounds underwent endothermic dehydration from 98 to 110 °C. This was followed by the exothermic decomposition of oxalate intermediates to yield the respective metal oxides as the end products. From SEM images, the average size of the metal oxide particles prepared by thermal decomposition of the complexes was determined to be 39-42 nm. The powder X-ray and SEM coupled with energy dispersive X-ray (EDX) studies revealed the presence of the respective nano-sized metal oxides. The kinetic parameters of the decomposition of the complexes were calculated using the Coats-Redfern equation.

  8. Protein Biosensors Based on Polymer Nanowires, Carbon Nanotubes and Zinc Oxide Nanorods

    PubMed Central

    M., Anish Kumar; Jung, Soyoun; Ji, Taeksoo

    2011-01-01

    The development of biosensors using electrochemical methods is a promising application in the field of biotechnology. High sensitivity sensors for the bio-detection of proteins have been developed using several kinds of nanomaterials. The performance of the sensors depends on the type of nanostructures with which the biomaterials interact. One dimensional (1-D) structures such as nanowires, nanotubes and nanorods are proven to have high potential for bio-applications. In this paper we review these three different kinds of nanostructures that have attracted much attention at recent times with their great performance as biosensors. Materials such as polymers, carbon and zinc oxide have been widely used for the fabrication of nanostructures because of their enhanced performance in terms of sensitivity, biocompatibility, and ease of preparation. Thus we consider polymer nanowires, carbon nanotubes and zinc oxide nanorods for discussion in this paper. We consider three stages in the development of biosensors: (a) fabrication of biomaterials into nanostructures, (b) alignment of the nanostructures and (c) immobilization of proteins. Two different methods by which the biosensors can be developed at each stage for all the three nanostructures are examined. Finally, we conclude by mentioning some of the major challenges faced by many researchers who seek to fabricate biosensors for real time applications. PMID:22163892

  9. Magnesium-doped zinc oxide nanorod-nanotube semiconductor/p-silicon heterojunction diodes

    NASA Astrophysics Data System (ADS)

    Caglar, Yasemin; Görgün, Kamuran; Ilican, Saliha; Caglar, Mujdat; Yakuphanoğlu, Fahrettin

    2016-08-01

    Nanostructured zinc oxide material is usable in electronic device applications such as light-emitting diodes, heterojunction diode, sensors, solar cell due to its interesting electrical conductivity and optical properties. Magnesium-doped zinc oxide nanorod (NR)-nanotube (NT) films were grown by microwave-assisted chemical bath deposition to fabricate ZnO-based heterojunction diode. It is found that ZnO hexagonal nanorods turn into hexagonal nanotubes when the Mg doping ratio is increased from 1 to 10 %. The values of the optical band gap for 1 % Mg-doped ZnO NR and 10 % Mg-doped ZnO NT films are found to be 3.14 and 3.22 eV, respectively. The n-ZnO:Mg/p-Si heterojunction diodes were fabricated. The diodes exhibited a rectification behavior with ideality factor higher than unity due to the presence of surface states in the junction and series resistance. The obtained results indicate that Mg doping improves the electrical and optical properties of ZnO.

  10. Passivation of hematite nanorod photoanodes with a phosphorus overlayer for enhanced photoelectrochemical water oxidation

    NASA Astrophysics Data System (ADS)

    Xiong, Dehua; Li, Wei; Wang, Xiaoguang; Liu, Lifeng

    2016-09-01

    Hematite (i.e., α-Fe2O3) nanorod photoanodes passivated with a phosphorus overlayer have been fabricated by decomposing sodium hypophosphite (NaH2PO2) at a low temperature over the hematite nanorod surface. Extensive scanning electron microscopy, transmission electron microscopy, x-ray diffractometry and UV–vis spectroscopy characterizations confirm that conformal deposition of an amorphous phosphorus overlayer does not change the crystal structure, morphology, and optical absorption properties of hematite photoanodes. X-ray photoelectron spectroscopy reveals that phosphorus in the deposited overlayer exists in an oxidized state. Comprehensive steady-state polarization, transient photocurrent response, and impedance spectroscopy measurements as well as Mott–Schottky analysis manifest that the phosphorus overlayer is able to effectively passivate surface states and suppress electron–hole recombination, substantially enhancing the photocurrent for water oxidation. Combining the phosphorization treatment with two-step thermal activation, a photocurrent density of 1.1 mA cm‑2 is achieved at 1.23 V versus reversible hydrogen electrode under illumination of 100 mW cm‑2, ca 55 times higher than that of the non-activated pristine hematite photoanode measured under the same conditions. The simple and fast phosphorization strategy we present here can be readily applied to passivate surfaces of other semiconductor photoelectrodes to improve their photoelectrochemical performance.

  11. Passivation of hematite nanorod photoanodes with a phosphorus overlayer for enhanced photoelectrochemical water oxidation.

    PubMed

    Xiong, Dehua; Li, Wei; Wang, Xiaoguang; Liu, Lifeng

    2016-09-16

    Hematite (i.e., α-Fe2O3) nanorod photoanodes passivated with a phosphorus overlayer have been fabricated by decomposing sodium hypophosphite (NaH2PO2) at a low temperature over the hematite nanorod surface. Extensive scanning electron microscopy, transmission electron microscopy, x-ray diffractometry and UV-vis spectroscopy characterizations confirm that conformal deposition of an amorphous phosphorus overlayer does not change the crystal structure, morphology, and optical absorption properties of hematite photoanodes. X-ray photoelectron spectroscopy reveals that phosphorus in the deposited overlayer exists in an oxidized state. Comprehensive steady-state polarization, transient photocurrent response, and impedance spectroscopy measurements as well as Mott-Schottky analysis manifest that the phosphorus overlayer is able to effectively passivate surface states and suppress electron-hole recombination, substantially enhancing the photocurrent for water oxidation. Combining the phosphorization treatment with two-step thermal activation, a photocurrent density of 1.1 mA cm(-2) is achieved at 1.23 V versus reversible hydrogen electrode under illumination of 100 mW cm(-2), ca 55 times higher than that of the non-activated pristine hematite photoanode measured under the same conditions. The simple and fast phosphorization strategy we present here can be readily applied to passivate surfaces of other semiconductor photoelectrodes to improve their photoelectrochemical performance.

  12. Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions.

    PubMed

    Burke, Benjamin P; Baghdadi, Neazar; Kownacka, Alicja E; Nigam, Shubhanchi; Clemente, Gonçalo S; Al-Yassiry, Mustafa M; Domarkas, Juozas; Lorch, Mark; Pickles, Martin; Gibbs, Peter; Tripier, Raphaël; Cawthorne, Christopher; Archibald, Stephen J

    2015-09-28

    The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging. PMID:26292197

  13. Passivation of hematite nanorod photoanodes with a phosphorus overlayer for enhanced photoelectrochemical water oxidation

    NASA Astrophysics Data System (ADS)

    Xiong, Dehua; Li, Wei; Wang, Xiaoguang; Liu, Lifeng

    2016-09-01

    Hematite (i.e., α-Fe2O3) nanorod photoanodes passivated with a phosphorus overlayer have been fabricated by decomposing sodium hypophosphite (NaH2PO2) at a low temperature over the hematite nanorod surface. Extensive scanning electron microscopy, transmission electron microscopy, x-ray diffractometry and UV-vis spectroscopy characterizations confirm that conformal deposition of an amorphous phosphorus overlayer does not change the crystal structure, morphology, and optical absorption properties of hematite photoanodes. X-ray photoelectron spectroscopy reveals that phosphorus in the deposited overlayer exists in an oxidized state. Comprehensive steady-state polarization, transient photocurrent response, and impedance spectroscopy measurements as well as Mott-Schottky analysis manifest that the phosphorus overlayer is able to effectively passivate surface states and suppress electron-hole recombination, substantially enhancing the photocurrent for water oxidation. Combining the phosphorization treatment with two-step thermal activation, a photocurrent density of 1.1 mA cm-2 is achieved at 1.23 V versus reversible hydrogen electrode under illumination of 100 mW cm-2, ca 55 times higher than that of the non-activated pristine hematite photoanode measured under the same conditions. The simple and fast phosphorization strategy we present here can be readily applied to passivate surfaces of other semiconductor photoelectrodes to improve their photoelectrochemical performance.

  14. Chelator free gallium-68 radiolabelling of silica coated iron oxide nanorods via surface interactions.

    PubMed

    Burke, Benjamin P; Baghdadi, Neazar; Kownacka, Alicja E; Nigam, Shubhanchi; Clemente, Gonçalo S; Al-Yassiry, Mustafa M; Domarkas, Juozas; Lorch, Mark; Pickles, Martin; Gibbs, Peter; Tripier, Raphaël; Cawthorne, Christopher; Archibald, Stephen J

    2015-09-28

    The commercial availability of combined magnetic resonance imaging (MRI)/positron emission tomography (PET) scanners for clinical use has increased demand for easily prepared agents which offer signal or contrast in both modalities. Herein we describe a new class of silica coated iron-oxide nanorods (NRs) coated with polyethylene glycol (PEG) and/or a tetraazamacrocyclic chelator (DO3A). Studies of the coated NRs validate their composition and confirm their properties as in vivo T2 MRI contrast agents. Radiolabelling studies with the positron emitting radioisotope gallium-68 (t1/2 = 68 min) demonstrate that, in the presence of the silica coating, the macrocyclic chelator was not required for preparation of highly stable radiometal-NR constructs. In vivo PET-CT and MR imaging studies show the expected high liver uptake of gallium-68 radiolabelled nanorods with no significant release of gallium-68 metal ions, validating our innovation to provide a novel simple method for labelling of iron oxide NRs with a radiometal in the absence of a chelating unit that can be used for high sensitivity liver imaging.

  15. Electrochemical and spectroscopic studies of some less stable oxidation states of selected lanthanide and actinide elements

    SciTech Connect

    Hobart, D. E.

    1981-06-01

    Simultaneous observation of electrochemical and spectroscopic properties (spectroelectrochemistry) at optically transparent electrodes (OTE's) was used to study some less stable oxidation states of selected lanthanide and actinide elements. Cyclic voltammetry at microelectrodes was used in conjunction with spectroelectrochemistry for the study of redox couples. Additional analytical techniques were used. The formal reduction potential (E/sup 0/') values of the M(III)/M(II) redox couples in 1 M KCl at pH 6 were -0.34 +- 0.01 V for Eu, -1.18 +- 0.01 V for Yb, and -1.50 +- 0.01 V for Sm. Spectropotentiostatic determination of E/sup 0/' for the Eu(III)/Eu(II) redox couple yielded a value of -0.391 +- 0.005 V. Spectropotentiostatic measurement of the Ce(IV)/Ce(III) redox couple in concentrated carbonate solution gave E/sup 0/' equal to 0.051 +- 0.005 V, which is about 1.7 V less positive than the E/sup 0/' value in noncomplexing solution. This same difference in potential was observed for the E/sup 0/' values of the Pr(IV)/Pr(III) and Tb(IV)/Tb(III) redox couples in carbonate solution, and thus Pr(IV) and Tb(IV) were stabilized in this medium. The U(VI)/U(V)/U(IV) and U(IV)/U(III) redox couples were studied in 1 M KCl at OTE's. Spectropotentiostatic measurement of the Np(VI)/Np(V) redox couple in 1 M HClO/sub 4/ gave an E/sup 0/' value of 1.140 +- 0.005 V. An E/sup 0/' value of 0.46 +- 0.01 V for the Np(VII)/Np(VI) couple was found by voltammetry. Oxidation of Am(III) was studied in concentrated carbonate solution, and a reversible cyclic voltammogram for the Am(IV)/Am(III) couple yielded E/sup 0/' = 0.92 +- 0.01 V in this medium; this value was used to estimate the standard reduction potential (E/sup 0/) of the couple as 2.62 +- 0.01 V. Attempts to oxidize Cm(III) in concentrated carbonate solution were not successful which suggests that the predicted E/sup 0/ value for the Cm(IV)/Cm(III) redox couple may be in error.

  16. Controlled Synthesis of Ultrathin Lanthanide Oxide Nanosheets and Their Promising pH-Controlled Anticancer Drug Delivery.

    PubMed

    Zhang, Xinyu; Ge, Juan; Xue, Yumeng; Lei, Bo; Yan, Dong; Li, Na; Liu, Zhengqing; Du, Yaping; Cai, Ren

    2015-08-17

    Various lanthanide oxides (Sm2 O3 and Gd2 O3 ) nanostructures were synthesized by a facile hydrothermal method. The loss of surfactants on the nanocrystals surface, followed by the resultant assembly is responsible for the formation of ultrathin nanosheets. Owing to strong surface effects, the different morphologies of the Sm2 O3 :5 % Eu and Gd2 O3 :5 % Eu nanocrystals present unique photoluminescence properties. As a proof-of-concept application, the as-obtained Sm2 O3 and Gd2 O3 ultrathin nanosheets exhibit promising pH-controlled anticancer drug-delivery behavior.

  17. Preparation of Metal Oxide/Au Coaxial Nano-rod Membrane for Photo-energy Conversion System

    NASA Astrophysics Data System (ADS)

    Yamada, Katsumi; Kimura, Gyosuke; Shirataki, Tatsuya; Fukai, Kaoru

    Coaxial nano-rod membranes of metal oxides such as TiO2 and ZnO were prepared by low temperature electrochemical deposition from aqueous solution on Au nano-rod membrane electrode. Photogalvanic measurements showed the photocurrent at +0.4 V of a TiO2 coaxial nano-rod cell (+23.7 μA cm-2) was approximately 4.3 times larger than that of a TiO2 film on a planar Au electrode (+5.5 μA cm-2). The difference in photocurrent is not only due to the difference in the active electrode surface area, but rather from the improvements of light harvesting and/or carrier generation.

  18. Porous cobalt oxide (Co 3O 4) nanorods: Facile syntheses, optical property and application in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Xu, Rui; Wang, Jiawei; Li, Qiuyu; Sun, Guoying; Wang, Enbo; Li, Siheng; Gu, Jianmin; Ju, Mingliang

    2009-11-01

    We developed a facile synthetic route of porous cobalt oxide (Co 3O 4) nanorods via a microemulsion-based method in combination with subsequent calcination process. The porous structure was formed by controlled decomposition of the microemulsion-synthesized precursor CoC 2O 4 nanorods without destruction of the original morphology. The as-prepared Co 3O 4 nanorods, consisting of small nanoparticles with diameter of 80-150 nm, had an average diameter of 200 nm and a length of 3-5 μm. The morphology and structure of synthesized samples were characterized by transmission electron microscopy and scanning electron microscopy. The phase and composition were investigated by X-ray powder diffraction and X-ray photoelectron spectroscopy. The optical property of Co 3O 4 nanorods was investigated. Moreover, the porous Co 3O 4 nanorods exhibited high electrochemical performance when applied as cathode materials for lithium-ion batteries, which gives them good potential applications.

  19. Improving the photocatalytic activity of graphene oxide/ZnO nanorod films by UV irradiation

    NASA Astrophysics Data System (ADS)

    Rokhsat, Eliza; Akhavan, Omid

    2016-05-01

    Graphene oxide (GO) sheets with a low concentration (∼1 wt%) were deposited on surface of hydrothermally synthesized ZnO nanorod films. The deposited films were heat treated at 450 °C in order to achieve suitable GO/ZnO hybrid thin films for photocatalytic purposes. The photocatalytic activity of the nanocomposite films was investigated based on degradation of methylene blue (MB) dye which is a typical pollutant model. The GO/ZnO hybrid thin films could degrade higher MB (∼90%) than the bare ZnO nanorods (which showed only ∼75% degradation) after 450 min UV irradiation. A further significant improvement (resulting in a nearly complete degradation of MB) was achieved by exposing the GO/ZnO films to UV irradiation. The improvement was assigned to UV-assisted photocatalytic reduction of GO sheets and separation of photoexcited electron-hole pairs of ZnO by the UV-treated GO sheets. These results highlight application of UV treatment in improving the photocatalytic activity of GO-containing ZnO nanostructures.

  20. Tailoring the optical and hydrophobic property of zinc oxide nanorod by coating with amorphous graphene

    NASA Astrophysics Data System (ADS)

    Pahari, D.; Das, N. S.; Das, B.; Chattopadhyay, K. K.; Banerjee, D.

    2016-09-01

    Zinc oxide (ZnO) nanorods were synthesized at room temperature on potassium permanganate activated silicon and glass substrate by simple chemical method using zinc acetate as precursor. To modify the surface energy of the as prepared ZnO thin films the samples were coated with amorphous graphene (a-G) synthesized by un-zipping of chemically synthesized amorphous carbon nanotubes (a-CNTs). All the pure and coated samples were characterized by x-ray diffraction, field emission scanning electron microscope, Raman spectroscopy, and Fourier transformed infrared spectroscopy. The roughness analysis of the as prepared samples was done by atomic force microscopic analysis. The detail optical properties of all the samples were studied with the help of a UV-Visible spectrophotometer. The surface energy of the as prepared pure and coated samples was calculated by measuring the contact angle of two different liquids. It is seen that the water repellence of ZnO nanorods got increased after they are being coated with a-Gs. Also even after UV irradiation the contact angle remain same unlike the case for the uncoated sample where the contact angle gets decreased significantly after UV irradiation. Existing Cassie-Wenzel model has been employed along with the Owen's approach to determine the different components of surface energy.

  1. Secret lanthanides.

    PubMed

    Sturza, C M

    2014-09-15

    Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz.

  2. Secret lanthanides.

    PubMed

    Sturza, C M

    2014-09-15

    Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz. PMID:25408760

  3. Evaluation of polarization rotation in the scattering responses from individual semiconducting oxide nanorods

    PubMed Central

    Choi, Daniel S.; Singh, Manpreet; Zhou, Hebing; Milchak, Marissa; Monahan, Brian; Hahm, Jong-in

    2016-01-01

    We investigate the interaction of visible light with the solid matters of semiconducting oxide nanorods (NRs) of zinc oxide (ZnO), indium tin oxide (ITO), and zinc tin oxide (ZTO) at the single nanomaterial level. We subsequently identify an intriguing, material-dependent phenomenon of optical rotation in the electric field oscillation direction of the scattered light by systematically controlling the wavelength and polarization direction of the incident light, the NR tilt angle, and the analyzer angle. This polarization rotation effect in the scattered light is repeatedly observed from the chemically pure and highly crystalline ZnO NRs, but absent on the chemically doped NR variants of ITO and ZTO under all measurement circumstances. We further elucidate that the phenomenon of polarization rotation detected from single ZnO NRs is affected by the NR tilt angle, while the phenomenon itself occurs irrespective of the wavelength and incident polarization direction of the visible light. Combined with the widespread optical and optoelectronic use of the semiconducting oxide nanomaterials, these efforts may provide much warranted fundamental bases to tailor material-specific, single nanomaterial-driven, optically modulating functionalities which, in turn, can be beneficial for the realization of high-performance integrated photonic circuits and miniaturized bio-optical sensing devices. PMID:27158560

  4. Effects of Li and Cu dopants on structural properties of zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Ho; Jin, Zhuguang; Abe, Yoshio; Kawamura, Midori

    2015-01-01

    We fabricated undoped zinc oxide (ZnO), Li-doped zinc oxide (LZO), and Cu-doped zinc oxide (CZO) nanorods (NRs) on fluorine-doped tin oxide (FTO)-coated glass substrates using chemical solution deposition and investigated their structural properties. With the incorporation of the Li dopant, the length and crystallinity of LZO NRs increased and improved, respectively, compared to that of the ZnO NRs. The average optical transmittance of LZO NRs was slightly lower than that of the ZnO NRs, but otherwise very similar over the visible wavelength region. With the incorporation of the Cu dopant, however, the morphology of the CZO sample was remarkably different from that of the pure ZnO NRs. Rods with a length of ∼12 μm and a diameter of 0.5-1.2 μm were randomly oriented on the substrate, and copper oxide (CuO) nanocrystals were uniformly grown on the surface of substrate. This paper presents a simple way to tune the growth behaviors of the ZnO NRs by adding dopants.

  5. Evaluation of polarization rotation in the scattering responses from individual semiconducting oxide nanorods

    NASA Astrophysics Data System (ADS)

    Choi, Daniel S.; Singh, Manpreet; Zhou, Hebing; Milchak, Marissa; Monahan, Brian; Hahm, Jong-in

    2016-04-01

    We investigate the interaction of visible light with the solid matters of semiconducting oxide nanorods (NRs) of zinc oxide (ZnO), indium tin oxide (ITO), and zinc tin oxide (ZTO) at the single nanomaterial level. We subsequently identify an intriguing, material-dependent phenomenon of optical rotation in the electric field oscillation direction of the scattered light by systematically controlling the wavelength and polarization direction of the incident light, the NR tilt angle, and the analyzer angle. This polarization rotation effect in the scattered light is repeatedly observed from the chemically pure and highly crystalline ZnO NRs, but absent on the chemically doped NR variants of ITO and ZTO under all measurement circumstances. We further elucidate that the phenomenon of polarization rotation detected from single ZnO NRs is affected by the NR tilt angle, while the phenomenon itself occurs irrespective of the wavelength and incident polarization direction of the visible light. Combined with the widespread optical and optoelectronic use of the semiconducting oxide nanomaterials, these efforts may provide much warranted fundamental bases to tailor material-specific, single nanomaterial-driven, optically modulating functionalities which, in turn, can be beneficial for the realization of high-performance integrated photonic circuits and miniaturized bio-optical sensing devices.

  6. TOPICAL REVIEW: Zinc oxide nanorod based photonic devices: recent progress in growth, light emitting diodes and lasers

    NASA Astrophysics Data System (ADS)

    Willander, M.; Nur, O.; Zhao, Q. X.; Yang, L. L.; Lorenz, M.; Cao, B. Q.; Zúñiga Pérez, J.; Czekalla, C.; Zimmermann, G.; Grundmann, M.; Bakin, A.; Behrends, A.; Al-Suleiman, M.; El-Shaer, A.; Che Mofor, A.; Postels, B.; Waag, A.; Boukos, N.; Travlos, A.; Kwack, H. S.; Guinard, J.; LeSi Dang, D.

    2009-08-01

    Zinc oxide (ZnO), with its excellent luminescent properties and the ease of growth of its nanostructures, holds promise for the development of photonic devices. The recent advances in growth of ZnO nanorods are discussed. Results from both low temperature and high temperature growth approaches are presented. The techniques which are presented include metal-organic chemical vapour deposition (MOCVD), vapour phase epitaxy (VPE), pulse laser deposition (PLD), vapour-liquid-solid (VLS), aqueous chemical growth (ACG) and finally the electrodeposition technique as an example of a selective growth approach. Results from structural as well as optical properties of a variety of ZnO nanorods are shown and analysed using different techniques, including high resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), photoluminescence (PL) and cathodoluminescence (CL), for both room temperature and for low temperature performance. These results indicate that the grown ZnO nanorods possess reproducible and interesting optical properties. Results on obtaining p-type doping in ZnO micro- and nanorods are also demonstrated using PLD. Three independent indications were found for p-type conducting, phosphorus-doped ZnO nanorods: first, acceptor-related CL peaks, second, opposite transfer characteristics of back-gate field effect transistors using undoped and phosphorus doped wire channels, and finally, rectifying I-V characteristics of ZnO:P nanowire/ZnO:Ga p-n junctions. Then light emitting diodes (LEDs) based on n-ZnO nanorods combined with different technologies (hybrid technologies) are suggested and the recent electrical, as well as electro-optical, characteristics of these LEDs are shown and discussed. The hybrid LEDs reviewed and discussed here are mainly presented for two groups: those based on n-ZnO nanorods and p-type crystalline substrates, and those based on n-ZnO nanorods and p-type amorphous substrates. Promising electroluminescence

  7. Comparative electronic structure of a lanthanide and actinide diatomic oxide: Nd versus U

    NASA Astrophysics Data System (ADS)

    Krauss, M.; Stevens, W. J.

    2003-01-01

    Using a modified version of the Alchemy electronic structure code and relativistic pseudopotentials, the electronic structure of the ground and low lying excited states of UO, NdO, and NdO + have been calculated at the Hartree-Fock (HF) and multiconfiguration self-consistent field (MCSCF) levels of theory. Including results from an earlier study of UO + this provides the information for a comparative analysis of a lanthanide and an actinide diatomic oxide. UO and NdO are both described formally as M +2 O -2 and the cations as M +3 O -2 , but the HF and MCSCF calculations show that these systems are considerably less ionic due to large charge back-transfer in the πorbitals. The electronic states putatively arise from the ligand field (oxygen anion) perturbed f 4 , sf 3 , df 3 , sdf 2 , or s 2 f 2 states of M +2 and f 3 , sf 2 or df 2 states of M +3 . Molecular orbital results show a substantial stabilization of the sf 3 or s 2 f 2 configurations relative to the f 4 or df 3 configurations that are the even or odd parity ground states in the M +2 free ion. The compact f and d orbitals are more destabilized by the anion field than the diffuse s orbital. The ground states of the neutral species are dominated by orbitals arising from the M +2 sf 3 term, and all the potential energy curves arising from this configuration are similar, which allows an estimate of the vibrational frequencies for UO and NdO of 862 cm -1 and 836 cm -1 , respectively. For NdO + and UO + the excitation energies for the Ωstates were calculated with a valence configuration interaction method using ab initio effective spin-orbit operators to couple the molecular orbital configurations. The results for NdO + are very comparable with the results for UO + , and show the vibrational and electronic states to be interleaved.

  8. Gold nanoparticles coated zinc oxide nanorods as the matrix for enhanced L-lactate sensing.

    PubMed

    Zhao, Yanguang; Fang, Xiaofei; Gu, Yousong; Yan, Xiaoqin; Kang, Zhuo; Zheng, Xin; Lin, Pei; Zhao, Leichao; Zhang, Yue

    2015-02-01

    In this study, an enzymatic electrochemical biosensor for L-lactate detection was proposed. The device was developed based on gold nanoparticles (Au NPs) modified zinc oxide nanorods (ZnO NRs). The sensing performance of the device was examined by cyclic voltammetry and amperometry. Compared with pristine ZnO based biosensor, Au/ZnO based sensor exhibited higher sensitivity of 24.56 μA cm(-2) mM(-1), smaller K(M)(app) of 1.58 mM, lower detection limit of 6 μM and wider linear range of 10 μM-0.6 mM for L-lactate detection. The introduction of Au NPs enhances electro-catalytic ability and electron migration, which contributes to the improvement of the sensing performance. Hence, the results confirm the essential character of Au NPs in such semiconductor based electrochemical biosensing system. PMID:25601093

  9. Tungsten oxide nanorods: an efficient nanoplatform for tumor CT imaging and photothermal therapy.

    PubMed

    Zhou, Zhiguo; Kong, Bin; Yu, Chao; Shi, Xiangyang; Wang, Mingwei; Liu, Wei; Sun, Yanan; Zhang, Yingjian; Yang, Hong; Yang, Shiping

    2014-01-13

    We report here a facile thermal decomposition approach to creating tungsten oxide nanorods (WO2.9 NRs) with a length of 13.1 ± 3.6 nm and a diameter of 4.4 ± 1.5 nm for tumor theranostic applications. The formed WO2.9 NRs were modified with methoxypoly(ethylene glycol) (PEG) carboxyl acid via ligand exchange to have good water dispersability and biocompatibility. With the high photothermal conversion efficiency irradiated by a 980 nm laser and the better X-ray attenuation property than clinically used computed tomography (CT) contrast agent Iohexol, the formed PEGylated WO2.9 NRs are able to inhibit the growth of the model cancer cells in vitro and the corresponding tumor model in vivo, and enable effective CT imaging of the tumor model in vivo. Our "killing two birds with one stone" strategy could be extended for fabricating other nanoplatforms for efficient tumor theranostic applications.

  10. An electrochemical DNA biosensor based on gold nanorods decorated graphene oxide sheets for sensing platform.

    PubMed

    Han, Xiaowei; Fang, Xian; Shi, Anqi; Wang, Jiao; Zhang, Yuzhong

    2013-12-15

    A simple electrochemical sensor for sensitive and selective DNA detection was constructed based on gold nanorods (Au NRs) decorated graphene oxide (GO) sheets. The high-quality Au NRs-GO nanocomposite was synthesized via the electrostatic self-assembly technique, which is considered a potential sensing platform. Differential pulse voltammetry was used to monitor the DNA hybridization event using methylene blue as an electrochemical indicator. Under optimal conditions, the peak currents of methylene blue were linear with the logarithm of the concentrations of complementary DNA from 1.0 × 10(-9) to 1.0 × 10(-14)M with a detection limit of 3.5 × 10(-15)M (signal/noise=3). Moreover, the prepared electrochemical sensor can effectively distinguish complementary DNA sequences in the presence of a large amount of single-base mismatched DNA (1000:1), indicating that the biosensor has high selectivity.

  11. Paramagnetic dysprosium oxide nanoparticles and dysprosium hydroxide nanorods as T₂ MRI contrast agents.

    PubMed

    Kattel, Krishna; Park, Ja Young; Xu, Wenlong; Kim, Han Gyeol; Lee, Eun Jung; Bony, Badrul Alam; Heo, Woo Choul; Jin, Seonguk; Baeck, Jong Su; Chang, Yongmin; Kim, Tae Jeong; Bae, Ji Eun; Chae, Kwon Seok; Lee, Gang Ho

    2012-04-01

    We report here paramagnetic dysprosium nanomaterial-based T(2) MRI contrast agents. A large r(2) and a negligible r(1) is an ideal condition for T(2) MR imaging. At this condition, protons are strongly and nearly exclusively induced for T(2) MR imaging. The dysprosium nanomaterials fairly satisfy this because they are found to possess a decent r(2) but a negligible r(1) arising from L + S state 4f-electrons in Dy(III) ion ((6)H(15/2)). Their r(2) will also further increase with increasing applied field because of unsaturated magnetization at room temperature. Therefore, MR imaging and various physical properties of the synthesized d-glucuronic acid coated ultrasmall dysprosium oxide nanoparticles (d(avg) = 3.2 nm) and dysprosium hydroxide nanorods (20 × 300 nm) are investigated. These include hydrodynamic diameters, magnetic properties, MR relaxivities, cytotoxicities, and 3 tesla in vivo T(2) MR images. Here, MR imaging properties of dysprosium hydroxide nanorods have not been reported so far. These two samples show r(2)s of 65.04 and 181.57 s(-1)mM(-1), respectively, with negligible r(1)s at 1.5 tesla and at room temperature, no in vitro cytotoxicity up to 100 μM Dy, and clear negative contrast enhancements in 3 tesla in vivo T(2) MR images of a mouse liver, which will be even more improved at higher MR fields. Therefore, d-glucuronic acid coated ultrasmall dysprosium oxide nanoparticles with renal excretion can be a potential candidate as a sensitive T(2) MRI contrast agent at MR field greater than 3 tesla.

  12. Sequential growth of zinc oxide nanorod arrays at room temperature via a corrosion process: application in visible light photocatalysis.

    PubMed

    Iqbal, Danish; Kostka, Aleksander; Bashir, Asif; Sarfraz, Adnan; Chen, Ying; Wieck, Andreas D; Erbe, Andreas

    2014-11-12

    Many photocatalyst systems catalyze chemical reactions under ultraviolet (UV) illumination, because of its high photon energies. Activating inexpensive, widely available materials as photocatalyst using the intense visible part of the solar spectrum is more challenging. Here, nanorod arrays of the wide-band-gap semiconductor zinc oxide have been shown to act as photocatalysts for the aerobic photo-oxidation of organic dye Methyl Orange under illumination with red light, which is normally accessible only to narrow-band semiconductors. The homogeneous, 800-1000-nm-thick ZnO nanorod arrays show substantial light absorption (absorbances >1) throughout the visible spectral range. This absorption is caused by defect levels inside the band gap. Multiple scattering processes by the rods make the nanorods appear black. The dominantly crystalline ZnO nanorod structures grow in the (0001) direction, i.e., with the c-axis perpendicular to the surface of polycrystalline zinc. The room-temperature preparation route relies on controlled cathodic delamination of a weakly bound polymer coating from metallic zinc, an industrially produced and cheaply available substrate. Cathodic delamination is a sequential synthesis process, because it involves the propagation of a delamination front over the base material. Consequently, arbitrarily large sample surfaces can be nanostructured using this approach.

  13. Oxidative addition of zero-valent lanthanides at transition metal-halogen bonds

    SciTech Connect

    Suleimanov, G.Z.; Khandozhko, V.N.; Mekhdiev, R.Yu.; Petrovskii, P.V.; Kolobova, N.E.; Beletskaya, I.P.

    1986-11-20

    Alkyl and aryl iodides add to zero-valent lanthanides to form Grignard-like reagents RLnI. The authors have already studied the addition of Ln(0) at the Hg-I bond in HgI/sub 2/ and RHgI compounds to give bimetallic derivatives of divalent lanthanides. In the present work, preliminary results are given for a study of the reactions of rare-earth elements with metal carbonyl halides with the general formula L(OC)/sub m/M-X (I), where L(OC)/sub m/M = Cp(OC)/sub 3/Cr, Cp(OC)/sub 3/Mo, Cp(OC)/sub 3/W, (OC)/sub 5/Mn, (OC)/sub 5/Re, or Cp(OC/sub 2/)Fe and X = Cl, BR, or I.

  14. Unique Temporal and Spatial Biomolecular Emission Profile on Individual Zinc Oxide Nanorods

    PubMed Central

    Singh, Manpreet; Song, Sheng; Hahm, Jong-in

    2013-01-01

    Zinc oxide nanorods (ZnO NRs) have emerged in recent years as extremely useful, optical signal-enhancing platforms in DNA and protein detection. Although the use of ZnO NRs in biodetection has been demonstrated so far in systems involving many ZnO NRs per detection element, their future applications will likely take place in a miniaturized setting while exploiting single ZnO NRs in a low-volume, high-throughput bioanalysis. In this paper, we investigate temporal and spatial characteristics of biomolecular fluorescence on individual ZnO NR systems. Quantitative and qualitative examinations of biomolecular intensity and photostability are carried out as a function of two important criteria, time and position along the long axis (length) of NRs. Photostability profiles are also measured with respect to the position on NRs and compared to those characteristics of biomolecules on polymeric control platforms. Unlike uniformly distributed signal observed on the control platforms, both fluorescence intensity and photostability are position-dependent on individual ZnO NRs. We have identified a unique phenomenon of highly localized, fluorescence intensification on the nanorod ends (FINE) of well-characterized, individual ZnO nanostructures. When compared to the polymeric controls, biomolecular fluorescence intensity and photostability are determined to be higher on individual ZnO NRs regardless of the position on NRs. We have also carried out finite-difference time-domain simulations whose results agree well with the observed FINE. The outcomes of our investigation will offer a much needed basis for signal interpretation for biodetection devices and platforms consisting of single ZnO NRs and, at the same time, contribute significantly to provide insight in understanding biomolecular fluorescence observed from ZnO NR ensemble-based systems. PMID:24193145

  15. Secret Lanthanides

    PubMed Central

    Sturza, CM

    2014-01-01

    Abstract Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz. PMID:25408760

  16. Partially reduced graphene oxide-gold nanorods composite based bioelectrode of improved sensing performance.

    PubMed

    Nirala, Narsingh R; Abraham, Shiju; Kumar, Vinod; Pandey, Shobhit A; Yadav, Umakant; Srivastava, Monika; Srivastava, S K; Singh, Vidya Nand; Kayastha, Arvind M; Srivastava, Anchal; Saxena, Preeti S

    2015-11-01

    The present work proposes partially reduced graphene oxide-gold nanorods supported by chitosan (CH-prGO-AuNRs) as a potential bioelectrode material for enhanced glucose sensing. Developed on ITO substrate by immobilizing glucose oxidase on CH-prGO-AuNRs composite, these CH-prGO-AuNRs/ITO bioelectrodes demonstrate high sensitivity of 3.2 µA/(mg/dL)/cm(2) and linear range of 25-200 mg/dL with an ability to detect as low as 14.5 mg/dL. Further, these CH-prGO-AuNRs/ITO based electrodes attest synergistiacally enhanced sensing properties when compared to simple graphene oxide based CH-GO/ITO electrode. This is evident from one order higher electron transfer rate constant (Ks) value in case of CH-prGO-AuNRs modified electrode (12.4×10(-2) cm/s), in contrast to CH-GO/ITO electrode (6×10(-3) cm/s). Additionally, very low Km value [15.4 mg/dL(0.85 mM)] ensures better binding affinity of enzyme to substrate which is desirable for good biosensor stability and resistance to environmental interferences. Hence, with better loading capacity, kinetics and stability, the proposed CH-prGO-AuNRs composite shows tremendous potential to detect several bio-analytes in the coming future. PMID:26452886

  17. Amperometric Non-Enzymatic Hydrogen Peroxide Sensor Based on Aligned Zinc Oxide Nanorods

    PubMed Central

    Al-Hardan, Naif H.; Abdul Hamid, Muhammad Azmi; Shamsudin, Roslinda; Othman, Norinsan Kamil; Kar Keng, Lim

    2016-01-01

    Zinc oxide (ZnO) nanorods (NRs) have been synthesized via the hydrothermal process. The NRs were grown over a conductive glass substrate. A non-enzymatic electrochemical sensor for hydrogen peroxide (H2O2), based on the prepared ZnO NRs, was examined through the use of current-voltage measurements. The measured currents, as a function of H2O2 concentrations ranging from 10 μM to 700 μM, revealed two distinct behaviours and good performance, with a lower detection limit (LOD) of 42 μM for the low range of H2O2 concentrations (first region), and a LOD of 143.5 μM for the higher range of H2O2 concentrations (second region). The prepared ZnO NRs show excellent electrocatalytic activity. This enables a measurable and stable output current. The results were correlated with the oxidation process of the H2O2 and revealed a good performance for the ZnO NR non-enzymatic H2O2 sensor. PMID:27367693

  18. In situ reduced graphene oxide interlayer for improving electrode performance in ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Venkatesan, A.; Ramesha, C. K.; Kannan, E. S.

    2016-06-01

    The effect of reduced graphene oxide (RGO) thin film on the transport characteristics of vertically aligned zinc oxide nanorods (ZnO NRs) grown on ITO substrate was studied. GO was uniformly drop casted on ZnO NRs as a passivation layer and then converted into RGO by heating it at 60 °C prior to metal electrode deposition. This low temperature reduction is facilitated by the thermally excited electrons from ZnI interstitial sites (~30 meV). Successful reduction of GO was ascertained from the increased disorder band (D) intensity in the Raman spectra. Temperature (298 K-10 K) dependent transport measurements of RGO-ZnO NRs indicate that the RGO layer not only acts as a short circuiting inhibitor but also reduces the height of the potential barrier for electron tunneling. This is confirmed from the temperature dependent electrical characteristics which revealed a transition of carrier transport from thermionic emission at high temperature (T  >  100 K) to tunneling at low temperature (T  <  100 K) across the interface. Our technique is the most promising approach for making reliable electrical contacts on vertically aligned ZnO NRs and improving the reproducibility of device characteristics.

  19. Effect of thicknesses of copper catalyst and oxide sublayer on morphology of ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Lyanguzov, N. V.; Kaydashev, V. E.; Kaidashev, E. M.; Abdulvakhidov, K. G.

    2011-03-01

    The influence of thicknesses of a ZnO sublayer and a copper catalyst film on the morphology of ZnO nanorods grown by carbothermal synthesis on α-Al2O3(11-20) substrates has been studied. An increase in the Cu catalyst film thickness leads to a growth in the diameters, heights, and surface density of nanorods. As the ZnO sublayer thickness is increased, the average diameter of nanorods also increases, while their lengths and surface density decrease. The effect of elevated temperatures on the thermal decomposition of ultrathin Cu films deposited on α-Al2O3 substrates has been studied. The photoluminescence characteristics of nanorod arrays have been measured at high levels of optical pumping. An increase in the pumping level to 250-280 kW/cm2 leads to superluminescence of the nanorods.

  20. Colloidal luminescent silicon nanorods.

    PubMed

    Lu, Xiaotang; Hessel, Colin M; Yu, Yixuan; Bogart, Timothy D; Korgel, Brian A

    2013-07-10

    Silicon nanorods are grown by trisilane decomposition in hot squalane in the presence of tin (Sn) nanocrystals and dodecylamine. Sn induces solution-liquid-solid nanorod growth with dodecylamine serving as a stabilizing ligand. As-prepared nanorods do not luminesce, but etching with hydrofluoric acid to remove residual surface oxide followed by thermal hydrosilylation with 1-octadecene induces bright photoluminescence with quantum yields of 4-5%. X-ray photoelectron spectroscopy shows that the ligands prevent surface oxidation for months when stored in air. PMID:23731184

  1. High dielectric constant, low loss, and low percolation threshold dielectric composites based on polyvinylidene fluoride and ferroferric oxide nanorods

    NASA Astrophysics Data System (ADS)

    Li, Lili; Fu, Qiong; Li, Ya; Li, Weiping

    2016-08-01

    Dielectric super-capacitors call the excellent dielectric materials with high dielectric constant and low dielectric loss, both of which are not easy to obtain at the same time. The work synthesized the high aspect ratio and good crystalline ferroferric oxide (Fe3O4) nanorods by the hydrothermal process and used them as the filler to effectively reduce the percolation threshold value. It was found that the composites here based on the polyvinylidene fluoride (PVDF) polymer and these Fe3O4 nanorods exhibited ultra-high dielectric constant (>3000) and very low loss (<0.04) at very low filler fraction (0.35%). It was also proved that the high aspect ratio filler could help to improve the dielectric constant and suppress the dielectric loss in the percolative composites.

  2. Ultrafast switching of tunable infrared plasmons in indium tin oxide nanorod arrays with large absolute amplitude

    NASA Astrophysics Data System (ADS)

    Guo, Peijun; Schaller, Richard D.; Ketterson, John B.; Chang, Robert P. H.

    2016-04-01

    All-optical control of plasmons can enable optical switches with high speeds, small footprints and high on/off ratios. Here we demonstrate ultrafast plasmon modulation in the near-infrared (NIR) to mid-infrared (MIR) range by intraband pumping of indium tin oxide nanorod arrays (ITO-NRAs). We observe redshifts of localized surface plasmon resonances arising from a change of the plasma frequency of ITO, which is governed by the conduction band non-parabolicity. We generalize the plasma frequency for non-parabolic bands, quantitatively model the fluence-dependent plasma frequency shifts, and show that different from noble metals, the lower electron density in ITO enables a remarkable change of electron distributions, yielding a significant plasma frequency modulation and concomitant large transient bleaches and induced absorptions, which can be tuned spectrally by tailoring the ITO-NRA geometry. The low electron heat capacity explains the sub-picosecond kinetics that is much faster than noble metals. Our work demonstrates a new scheme to control infrared plasmons for optical switching, telecommunications and sensing.

  3. Sol-gel synthesized zinc oxide nanorods and their structural and optical investigation for optoelectronic application.

    PubMed

    Foo, Kai Loong; Hashim, Uda; Muhammad, Kashif; Voon, Chun Hong

    2014-01-01

    Nanostructured zinc oxide (ZnO) nanorods (NRs) with hexagonal wurtzite structures were synthesized using an easy and low-cost bottom-up hydrothermal growth technique. ZnO thin films were prepared with the use of four different solvents, namely, methanol, ethanol, isopropanol, and 2-methoxyethanol, and then used as seed layer templates for the subsequent growth of the ZnO NRs. The influences of the different solvents on the structural and optical properties were investigated through scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and photoluminescence. The obtained X-ray diffraction patterns showed that the synthesized ZnO NRs were single crystals and exhibited a preferred orientation along the (002) plane. In addition, the calculated results from the specific models of the refractive index are consistent with the experimental data. The ZnO NRs that grew from the 2-methoxyethanol seeded layer exhibited the smallest grain size (39.18 nm), largest diffracted intensities on the (002) plane, and highest bandgap (3.21 eV).

  4. Gigahertz Acoustic Vibrations of Elastically Anisotropic Indium-Tin-Oxide Nanorod Arrays.

    PubMed

    Guo, Peijun; Schaller, Richard D; Ocola, Leonidas E; Ketterson, John B; Chang, Robert P H

    2016-09-14

    Active control of light is important for photonic integrated circuits, optical switches, and telecommunications. Coupling light with acoustic vibrations in nanoscale optical resonators offers optical modulation capabilities with high bandwidth and small footprint. Instead of using noble metals, here we introduce indium-tin-oxide nanorod arrays (ITO-NRAs) as the operating media and demonstrate optical modulation covering the visible spectral range (from 360 to 700 nm) with ∼20 GHz bandwidth through the excitation of coherent acoustic vibrations in ITO-NRAs. This broadband modulation results from the collective optical diffraction by the dielectric ITO-NRAs, and a high differential transmission modulation up to 10% is achieved through efficient near-infrared, on-plasmon-resonance pumping. By combining the frequency signatures of the vibrational modes with finite-element simulations, we further determine the anisotropic elastic constants for single-crystalline ITO, which are not known for the bulk phase. This technique to determine elastic constants using coherent acoustic vibrations of uniform nanostructures can be generalized to the study of other inorganic materials.

  5. Gigahertz Acoustic Vibrations of Elastically Anisotropic Indium-Tin-Oxide Nanorod Arrays.

    PubMed

    Guo, Peijun; Schaller, Richard D; Ocola, Leonidas E; Ketterson, John B; Chang, Robert P H

    2016-09-14

    Active control of light is important for photonic integrated circuits, optical switches, and telecommunications. Coupling light with acoustic vibrations in nanoscale optical resonators offers optical modulation capabilities with high bandwidth and small footprint. Instead of using noble metals, here we introduce indium-tin-oxide nanorod arrays (ITO-NRAs) as the operating media and demonstrate optical modulation covering the visible spectral range (from 360 to 700 nm) with ∼20 GHz bandwidth through the excitation of coherent acoustic vibrations in ITO-NRAs. This broadband modulation results from the collective optical diffraction by the dielectric ITO-NRAs, and a high differential transmission modulation up to 10% is achieved through efficient near-infrared, on-plasmon-resonance pumping. By combining the frequency signatures of the vibrational modes with finite-element simulations, we further determine the anisotropic elastic constants for single-crystalline ITO, which are not known for the bulk phase. This technique to determine elastic constants using coherent acoustic vibrations of uniform nanostructures can be generalized to the study of other inorganic materials. PMID:27526053

  6. Importance of Plasmonic Heating on Visible Light Driven Photocatalysis of Gold Nanoparticle Decorated Zinc Oxide Nanorods

    NASA Astrophysics Data System (ADS)

    Bora, Tanujjal; Zoepfl, David; Dutta, Joydeep

    2016-05-01

    Herein we explore the role of localized plasmonic heat generated by resonantly excited gold (Au) NPs on visible light driven photocatalysis process. Au NPs are deposited on the surface of vertically aligned zinc oxide nanorods (ZnO NRs). The localized heat generated by Au NPs under 532 nm continuous laser excitation (SPR excitation) was experimentally probed using Raman spectroscopy by following the phonon modes of ZnO. Under the resonant excitation the temperature at the surface of the Au-ZnO NRs reaches up to about 300 °C, resulting in almost 6 times higher apparent quantum yield (AQY) for photocatalytic degradation of methylene blue (MB) compared to the bare ZnO NRs. Under solar light irradiation the Au-ZnO NRs demonstrated visible light photocatalytic activity twice that of what was achieved with bare ZnO NRs, while significantly reduced the activation energy required for the photocatalytic reactions allowing the reactions to occur at a faster rate.

  7. Importance of Plasmonic Heating on Visible Light Driven Photocatalysis of Gold Nanoparticle Decorated Zinc Oxide Nanorods

    PubMed Central

    Bora, Tanujjal; Zoepfl, David; Dutta, Joydeep

    2016-01-01

    Herein we explore the role of localized plasmonic heat generated by resonantly excited gold (Au) NPs on visible light driven photocatalysis process. Au NPs are deposited on the surface of vertically aligned zinc oxide nanorods (ZnO NRs). The localized heat generated by Au NPs under 532 nm continuous laser excitation (SPR excitation) was experimentally probed using Raman spectroscopy by following the phonon modes of ZnO. Under the resonant excitation the temperature at the surface of the Au-ZnO NRs reaches up to about 300 °C, resulting in almost 6 times higher apparent quantum yield (AQY) for photocatalytic degradation of methylene blue (MB) compared to the bare ZnO NRs. Under solar light irradiation the Au-ZnO NRs demonstrated visible light photocatalytic activity twice that of what was achieved with bare ZnO NRs, while significantly reduced the activation energy required for the photocatalytic reactions allowing the reactions to occur at a faster rate. PMID:27242172

  8. Tungsten Oxide Nanorods: An Efficient Nanoplatform for Tumor CT Imaging and Photothermal Therapy

    PubMed Central

    Zhou, Zhiguo; Kong, Bin; Yu, Chao; Shi, Xiangyang; Wang, Mingwei; Liu, Wei; Sun, Yanan; Zhang, Yingjian; Yang, Hong; Yang, Shiping

    2014-01-01

    We report here a facile thermal decomposition approach to creating tungsten oxide nanorods (WO2.9 NRs) with a length of 13.1 ± 3.6 nm and a diameter of 4.4 ± 1.5 nm for tumor theranostic applications. The formed WO2.9 NRs were modified with methoxypoly(ethylene glycol) (PEG) carboxyl acid via ligand exchange to have good water dispersability and biocompatibility. With the high photothermal conversion efficiency irradiated by a 980 nm laser and the better X-ray attenuation property than clinically used computed tomography (CT) contrast agent Iohexol, the formed PEGylated WO2.9 NRs are able to inhibit the growth of the model cancer cells in vitro and the corresponding tumor model in vivo, and enable effective CT imaging of the tumor model in vivo. Our “killing two birds with one stone” strategy could be extended for fabricating other nanoplatforms for efficient tumor theranostic applications. PMID:24413483

  9. Importance of Plasmonic Heating on Visible Light Driven Photocatalysis of Gold Nanoparticle Decorated Zinc Oxide Nanorods.

    PubMed

    Bora, Tanujjal; Zoepfl, David; Dutta, Joydeep

    2016-01-01

    Herein we explore the role of localized plasmonic heat generated by resonantly excited gold (Au) NPs on visible light driven photocatalysis process. Au NPs are deposited on the surface of vertically aligned zinc oxide nanorods (ZnO NRs). The localized heat generated by Au NPs under 532 nm continuous laser excitation (SPR excitation) was experimentally probed using Raman spectroscopy by following the phonon modes of ZnO. Under the resonant excitation the temperature at the surface of the Au-ZnO NRs reaches up to about 300 °C, resulting in almost 6 times higher apparent quantum yield (AQY) for photocatalytic degradation of methylene blue (MB) compared to the bare ZnO NRs. Under solar light irradiation the Au-ZnO NRs demonstrated visible light photocatalytic activity twice that of what was achieved with bare ZnO NRs, while significantly reduced the activation energy required for the photocatalytic reactions allowing the reactions to occur at a faster rate. PMID:27242172

  10. Self-decontaminating photocatalytic zinc oxide nanorod coatings for prevention of marine microfouling: a mesocosm study.

    PubMed

    Sathe, Priyanka; Richter, Jutta; Myint, Myo Tay Zar; Dobretsov, Sergey; Dutta, Joydeep

    2016-01-01

    The antifouling (AF) properties of zinc oxide (ZnO) nanorod coated glass substrata were investigated in an out-door mesocosm experiment under natural sunlight (14:10 light: dark photoperiod) over a period of five days. The total bacterial density (a six-fold reduction) and viability (a three-fold reduction) was significantly reduced by nanocoatings in the presence of sunlight. In the absence of sunlight, coated and control substrata were colonized equally by bacteria. MiSeq Illumina sequencing of 16S rRNA genes revealed distinct bacterial communities on the nanocoated and control substrata in the presence and absence of light. Diatom communities also varied on nanocoated substrata in the presence and the absence of light. The observed AF activity of the ZnO nanocoatings is attributed to the formation of reactive oxygen species (ROS) through photocatalysis in the presence of sunlight. These nanocoatings are a significant step towards the production of an environmentally friendly AF coating that utilizes a sustainable supply of sunlight.

  11. Piezoelectric nanogenerator based on zinc oxide nanorods grown on textile cotton fabric

    NASA Astrophysics Data System (ADS)

    Khan, Azam; Ali Abbasi, Mazhar; Hussain, Mushtaque; Hussain Ibupoto, Zafar; Wissting, Jonas; Nur, Omer; Willander, Magnus

    2012-11-01

    This investigation explores piezoelectricity generation from ZnO nanorods, which were grown on silver coated textile cotton fabrics using the low temperature aqueous chemical growth method. The morphology and crystal structure studies were carried out by x-ray diffraction, scanning electron microscopic and high resolution transmission electron microscopic techniques, respectively. ZnO nanorods were highly dense, well aligned, uniform in spatial distribution and exhibited good crystal quality. The generation of piezoelectricity from fabricated ZnO nanorods grown on textile cotton fabrics was measured using contact mode atomic force microscopy. The average output voltage generated from ZnO nanorods was measured to be around 9.5 mV. This investigation is an important achievement regarding the piezoelectricity generation on textile cotton fabric substrate. The fabrication of this device provides an alternative approach for a flexible substrate to develop devices for energy harvesting and optoelectronic technology on textiles.

  12. Zinc oxide nanorod growth on gold islands prepared by microsphere lithography on silicon and quartz.

    PubMed

    Blackledge, Charles W; Szarko, Jodi M; Dupont, Aurélie; Chan, George H; Read, Elizabeth L; Leone, Stephen R

    2007-09-01

    Gold islands, vapor deposited on silicon and quartz by microsphere lithography patterning, are used to nucleate arrays of ZnO nanorods. ZnO is grown on approximately 0.32 microm2 Au islands by carbothermal reduction in a tube furnace. Scanning electron microscopy (SEM) and energy dispersive atomic X-ray spectroscopy (EDS) confirm that the gold effectively controls the sites of nucleation of ZnO. Atomic force microscopy (AFM) shows that approximately 30 nm diameter nanorods grow horizontally, along the surface. Alloy droplets that are characteristic of the vapor-liquid-solid (VLS) mechanism are observed at the tips of the nanorods. The spatial growth direction of VLS catalyzed ZnO nanorods is along the substrate when they nucleate from gold islands on silicon and quartz. The energy of adhesion of the VLS droplet to the surface can account for the horizontal growth. PMID:18019171

  13. Comparison of the toxicity of aluminum oxide nanorods with different aspect ratio.

    PubMed

    Park, Eun-Jung; Lee, Gwang-Hee; Shim, Jae-Hun; Cho, Myung-Haing; Lee, Byoung-Seok; Kim, Yong-Bum; Kim, Jae-Ho; Kim, Younghun; Kim, Dong-Wan

    2015-10-01

    Aluminum oxide nanoparticles are listed among 14 high-priority nanomaterials published by the Organization for Economic Co-operation and Development, but limited information is available on their potential hazards. In this study, we compared the toxicity of two different aluminum oxide nanorods (AlNRs) commercially available in vivo and in vitro. Considering aspect ratio, one was 6.2 ± 0.6 (long-AlNRs) and the other was 2.1 ± 0.4 (short-AlNRs). In mice, long-AlNRs induced longer and stronger inflammatory responses than short-AlNRs, and the degree reached the maximum on day 7 for both types and decreased with time. In addition, in vitro tests were performed on six cell lines derived from potential target organs for AlNPs, HEK-293 (kidney), HACAT (skin), Chang (liver), BEAS-2B (lung), T98G (brain), and H9C2 (heart), using MTT assay, ATP assay, LDH release, and xCELLigence system. Long-AlNRs generally produced stronger toxicity than short-AlNRs, and HEK-293 cells were the most sensitive for both AlNRs, followed by BEAS-2B cells, although results from 4 kinds of toxicity tests conflicted among the cell lines. Based on these results, we suggest that toxicity of AlNRs may be related to aspect ratio (and resultant surface area). Furthermore, novel in vitro toxicity testing methods are needed to resolve questionable results caused by the unique properties of nanoparticles.

  14. Nanorod and nanoparticle shells in concentration gradient core-shell lithium oxides for rechargeable lithium batteries.

    PubMed

    Yoon, Sung-June; Myung, Seung-Taek; Noh, Hyung-Joo; Lu, Jun; Amine, Khalil; Sun, Yang-Kook

    2014-12-01

    The structure, electrochemistry, and thermal stability of concentration gradient core-shell (CGCS) particles with different shell morphologies were evaluated and compared. We modified the shell morphology from nanoparticles to nanorods, because nanorods can result in a reduced surface area of the shell such that the outer shell would have less contact with the corrosive electrolyte, resulting in improved electrochemical properties. Electron microscopy studies coupled with electron probe X-ray micro-analysis revealed the presence of a concentration gradient shell consisting of nanoparticles and nanorods before and after thermal lithiation at high temperature. Rietveld refinement of the X-ray diffraction data and the chemical analysis results showed no variations of the lattice parameters and chemical compositions of both produced CGCS particles except for the degree of cation mixing (or exchange) in Li and transition metal layers. As anticipated, the dense nanorods present in the shell gave rise to a high tap density (2.5 g cm(-3) ) with a reduced pore volume and surface area. Intimate contact among the nanorods is likely to improve the resulting electric conductivity. As a result, the CGCS Li[Ni0.60 Co0.15 Mn0.25 ]O2 with the nanorod shell retained approximately 85.5% of its initial capacity over 150 cycles in the range of 2.7-4.5 V at 60 °C. The charged electrode consisting of Li0.16 [Ni0.60 Co0.15 Mn0.25 ]O2 CGCS particles with the nanorod shell also displayed a main exothermic reaction at 279.4 °C releasing 751.7 J g(-1) of heat. Due to the presence of the nanorod shell in the CGCS particles, the electrochemical and thermal properties are substantially superior to those of the CGCS particles with the nanoparticle shell.

  15. Nanorod and nanoparticle shells in concentration gradient core-shell lithium oxides for rechargeable lithium batteries.

    PubMed

    Yoon, Sung-June; Myung, Seung-Taek; Noh, Hyung-Joo; Lu, Jun; Amine, Khalil; Sun, Yang-Kook

    2014-12-01

    The structure, electrochemistry, and thermal stability of concentration gradient core-shell (CGCS) particles with different shell morphologies were evaluated and compared. We modified the shell morphology from nanoparticles to nanorods, because nanorods can result in a reduced surface area of the shell such that the outer shell would have less contact with the corrosive electrolyte, resulting in improved electrochemical properties. Electron microscopy studies coupled with electron probe X-ray micro-analysis revealed the presence of a concentration gradient shell consisting of nanoparticles and nanorods before and after thermal lithiation at high temperature. Rietveld refinement of the X-ray diffraction data and the chemical analysis results showed no variations of the lattice parameters and chemical compositions of both produced CGCS particles except for the degree of cation mixing (or exchange) in Li and transition metal layers. As anticipated, the dense nanorods present in the shell gave rise to a high tap density (2.5 g cm(-3) ) with a reduced pore volume and surface area. Intimate contact among the nanorods is likely to improve the resulting electric conductivity. As a result, the CGCS Li[Ni0.60 Co0.15 Mn0.25 ]O2 with the nanorod shell retained approximately 85.5% of its initial capacity over 150 cycles in the range of 2.7-4.5 V at 60 °C. The charged electrode consisting of Li0.16 [Ni0.60 Co0.15 Mn0.25 ]O2 CGCS particles with the nanorod shell also displayed a main exothermic reaction at 279.4 °C releasing 751.7 J g(-1) of heat. Due to the presence of the nanorod shell in the CGCS particles, the electrochemical and thermal properties are substantially superior to those of the CGCS particles with the nanoparticle shell. PMID:25044175

  16. Reduced graphene oxide-induced recrystallization of NiS nanorods to nanosheets and the improved Na-storage properties.

    PubMed

    Pan, Qin; Xie, Jian; Zhu, Tiejun; Cao, Gaoshao; Zhao, Xinbing; Zhang, Shichao

    2014-04-01

    Preparation of two-dimensional (2D) graphene-like materials is currently an emerging field in materials science since the discovery of single-atom-thick graphene prepared by mechanical cleavage. In this work, we proposed a new method to prepare 2D NiS, where reduced graphene oxide (rGO) was found to induce the recrystallization of NiS from nanorods to nanosheets in a hydrothermal process. The process and mechanism of recrystallization have been clarified by various characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) mapping, and X-ray photoelectron spectroscopy (XPS). The characterization of ex situ NiS/rGO products by SEM and EDS mapping indicates that the recrystallization of NiS from nanorods to nanosheets is realized actually through an exfoliation process, while the characterization of in situ NiS/rGO products by SEM, TEM, and EDS mapping reveals the exfoliation process. The XPS result demonstrates that hydrothermally assisted chemical bonding occurs between NiS and rGO, which induces the exfoliation of NiS nanorods into nanosheets. The obtained NiS/rGO composite shows promising Na-storage properties.

  17. Amplified photoacoustic performance and enhanced photothermal stability of reduced graphene oxide coated gold nanorods for sensitive photoacoustic imaging.

    PubMed

    Moon, Hyungwon; Kumar, Dinesh; Kim, Haemin; Sim, Changbeom; Chang, Jin-Ho; Kim, Jung-Mu; Kim, Hyuncheol; Lim, Dong-Kwon

    2015-03-24

    We report a strongly amplified photoacoustic (PA) performance of the new functional hybrid material composed of reduced graphene oxide and gold nanorods. Due to the excellent NIR light absorption properties of the reduced graphene oxide coated gold nanorods (r-GO-AuNRs) and highly efficient heat transfer process through the reduced graphene oxide layer, r-GO-AuNRs exhibit excellent photothermal stability and significantly higher photoacoustic amplitudes than those of bare-AuNRs, nonreduced graphene oxide coated AuNRs (GO-AuNRs), or silica-coated AuNR, as demonstrated in both in vitro and in vivo systems. The linear response of PA amplitude from reduced state controlled GO on AuNR indicates the critical role of GO for a strong photothermal effect of r-GO-AuNRs. Theoretical studies with finite-element-method lab-based simulation reveal that a 4 times higher magnitude of the enhanced electromagnetic field around r-GO-AuNRs can be generated compared with bare AuNRs or GO-AuNRs. Furthermore, the r-GO-AuNRs are expected to be a promising deep-tissue imaging probe because of extraordinarily high PA amplitudes in the 4-11 MHz operating frequency of an ultrasound transducer. Therefore, the r-GO-AuNRs can be a useful imaging probe for highly sensitive photoacoustic images and NIR sensitive therapeutics based on a strong photothermal effect. PMID:25751167

  18. Amplified photoacoustic performance and enhanced photothermal stability of reduced graphene oxide coated gold nanorods for sensitive photoacoustic imaging.

    PubMed

    Moon, Hyungwon; Kumar, Dinesh; Kim, Haemin; Sim, Changbeom; Chang, Jin-Ho; Kim, Jung-Mu; Kim, Hyuncheol; Lim, Dong-Kwon

    2015-03-24

    We report a strongly amplified photoacoustic (PA) performance of the new functional hybrid material composed of reduced graphene oxide and gold nanorods. Due to the excellent NIR light absorption properties of the reduced graphene oxide coated gold nanorods (r-GO-AuNRs) and highly efficient heat transfer process through the reduced graphene oxide layer, r-GO-AuNRs exhibit excellent photothermal stability and significantly higher photoacoustic amplitudes than those of bare-AuNRs, nonreduced graphene oxide coated AuNRs (GO-AuNRs), or silica-coated AuNR, as demonstrated in both in vitro and in vivo systems. The linear response of PA amplitude from reduced state controlled GO on AuNR indicates the critical role of GO for a strong photothermal effect of r-GO-AuNRs. Theoretical studies with finite-element-method lab-based simulation reveal that a 4 times higher magnitude of the enhanced electromagnetic field around r-GO-AuNRs can be generated compared with bare AuNRs or GO-AuNRs. Furthermore, the r-GO-AuNRs are expected to be a promising deep-tissue imaging probe because of extraordinarily high PA amplitudes in the 4-11 MHz operating frequency of an ultrasound transducer. Therefore, the r-GO-AuNRs can be a useful imaging probe for highly sensitive photoacoustic images and NIR sensitive therapeutics based on a strong photothermal effect.

  19. Boiling Method-Based Zinc Oxide Nanorods for Enhancement of Adipose-Derived Stem Cell Proliferation.

    PubMed

    Jin, Su-Eon; Ahn, Hyo-Sun; Kim, Ji Hye; Arai, Yoshie; Lee, Soo-Hong; Yoon, Tae-Jong; Hwang, Sung-Joo; Sung, Jong-Hyuk

    2016-09-01

    Adipose-derived stem cells (ASCs) are typically expanded to acquire large numbers of cells for therapeutic applications. Diverse stimuli such as sphingosylphosphocholine and vitamin C have been used to increase the production yield and regenerative potential of ASCs. In the present study, we hypothesized that ZnO nanorods have promising potential for the enhancement of ASC proliferation. ZnO nanorods were prepared using three different methods: grinding and boiling at low temperature with and without surfactant. The physicochemical properties of the nanorods such as their crystallinity, morphology, size, and solvent compatibility were evaluated, and then, the ability of the synthesized ZnO nanorods to enhance ASC proliferation was investigated. Scanning electron microscopy images of all of the ZnO powders showed rod-shaped nanoflakes with lengths of 200-500 nm. Notably, although ZnO-G produced by the grinding method was well dispersed in ethanol, atomic force microscopy images of dispersions of both ZnO-B from boiling methods and ZnO-G indicated the presence of clusters of ZnO nanorods. In contrast, ZnO-B was freely dispersible in 5% dextrose of water and dimethyl sulfoxide, whereas ZnO-G and ZnO-M, produced by boiling with ethanolamine, were not. All three types of ZnO nanorods increased the proliferation of ASCs in a dose-dependent manner. These results collectively suggest that ZnO nanorods have promising potential for use as an agent for the enhancement of ASC proliferation. PMID:27464704

  20. Boiling Method-Based Zinc Oxide Nanorods for Enhancement of Adipose-Derived Stem Cell Proliferation.

    PubMed

    Jin, Su-Eon; Ahn, Hyo-Sun; Kim, Ji Hye; Arai, Yoshie; Lee, Soo-Hong; Yoon, Tae-Jong; Hwang, Sung-Joo; Sung, Jong-Hyuk

    2016-09-01

    Adipose-derived stem cells (ASCs) are typically expanded to acquire large numbers of cells for therapeutic applications. Diverse stimuli such as sphingosylphosphocholine and vitamin C have been used to increase the production yield and regenerative potential of ASCs. In the present study, we hypothesized that ZnO nanorods have promising potential for the enhancement of ASC proliferation. ZnO nanorods were prepared using three different methods: grinding and boiling at low temperature with and without surfactant. The physicochemical properties of the nanorods such as their crystallinity, morphology, size, and solvent compatibility were evaluated, and then, the ability of the synthesized ZnO nanorods to enhance ASC proliferation was investigated. Scanning electron microscopy images of all of the ZnO powders showed rod-shaped nanoflakes with lengths of 200-500 nm. Notably, although ZnO-G produced by the grinding method was well dispersed in ethanol, atomic force microscopy images of dispersions of both ZnO-B from boiling methods and ZnO-G indicated the presence of clusters of ZnO nanorods. In contrast, ZnO-B was freely dispersible in 5% dextrose of water and dimethyl sulfoxide, whereas ZnO-G and ZnO-M, produced by boiling with ethanolamine, were not. All three types of ZnO nanorods increased the proliferation of ASCs in a dose-dependent manner. These results collectively suggest that ZnO nanorods have promising potential for use as an agent for the enhancement of ASC proliferation.

  1. Dissolution of metal oxides and separation of uranium from lanthanides and actinides in supercritical carbon dioxide

    SciTech Connect

    Quach, D.L.; Wai, C.M.; Mincher, B.J.

    2013-07-01

    This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO{sub 2}) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO{sub 2} modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO{sub 2} modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO{sub 2} and counter current stripping columns is presented. (authors)

  2. Dissolution of cerium(IV)-lanthanide(III) oxides: comparative effect of chemical composition, temperature, and acidity.

    PubMed

    Horlait, D; Clavier, N; Szenknect, S; Dacheux, N; Dubois, V

    2012-03-19

    The dissolution of Ce(1-x)Ln(x)O(2-x/2) solid solutions was undertaken in various acid media in order to evaluate the effects of several physicochemical parameters such as chemical composition, temperature, and acidity on the reaction kinetics. The normalized dissolution rates (R(L,0)) were found to be strongly modified by the trivalent lanthanide incorporation rate, due to the presence of oxygen vacancies decreasing the samples cohesion. Conversely, the nature of the trivalent cation considered only weakly impacted the R(L,0) values. The dependence of the normalized dissolution rates on the temperature then appeared to be of the same order of magnitude than that of chemical composition. Moreover, it allowed determining the corresponding activation energy (E(A) ≈ 60-85 kJ·mol(-1)) which accounts for a dissolution driven by surface-controlled reactions. A similar conclusion was made regarding the acidity of the solution: the partial order related to (H(3)O(+)) reaching about 0.7. Finally, the prevailing effect of the incorporation of aliovalent cations in the fluorite-type CeO(2) matrix on the dissolution kinetics precluded the observation of slight effects such as those linked to the complexing agents or to the crystal structure of the samples.

  3. DISSOLUTION OF METAL OXIDES AND SEPARATION OF URANIUM FROM LANTHANIDES AND ACTINIDES IN SUPERCRITICAL CARBON DIOXIDE

    SciTech Connect

    Donna L. Quach; Bruce J. Mincher; Chien M. Wai

    2013-10-01

    This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO2) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO2 modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO2 modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO2 and counter current stripping columns is presented.

  4. Dissolution of cerium(IV)-lanthanide(III) oxides: Comparative effect of chemical composition, temperature, and acidity

    SciTech Connect

    Horlait, D.; Clavier, N.; Szenknect, S.; Dacheux, N.; Dubois, V.

    2012-03-15

    The dissolution of Ce{sub 1-x}Ln{sub x}O{sub 2-x/2} solid solutions was undertaken in various acid media in order to evaluate the effects of several physicochemical parameters such as chemical composition, temperature, and acidity on the reaction kinetics. The normalized dissolution rates (R{sub L,0}) were found to be strongly modified by the trivalent lanthanide incorporation rate, due to the presence of oxygen vacancies decreasing the samples cohesion. Conversely, the nature of the trivalent cation considered only weakly impacted the R{sub L,0} values. The dependence of the normalized dissolution rates on the temperature then appeared to be of the same order of magnitude than that of chemical composition. Moreover, it allowed determining the corresponding activation energy (E{sub A} ≅ 60-85 kJ.mol{sup -1}) which accounts for a dissolution driven by surface-controlled reactions. A similar conclusion was made regarding the acidity of the solution: the partial order related to (H{sub 3}O{sup +}) reaching about 0.7. Finally, the prevailing effect of the incorporation of aliovalent cations in the fluorite-type CeO{sub 2} matrix on the dissolution kinetics precluded the observation of slight effects such as those linked to the complexing agents or to the crystal structure of the samples. (authors)

  5. Self-assembly and dynamics of oxide nano-rods on NiAl(110).

    SciTech Connect

    Pierce, John P.; McCarty, Kevin F.

    2004-10-01

    We observe the spontaneous formation of parallel oxide rods upon exposing a clean NiAl(110) surface to oxygen at elevated temperatures (850-1350 K). By following the self-assembly of individual nanorods in real time with low-energy electron microscopy (LEEM), we are able to investigate the processes by which the rods lengthen along their axes and thicken normal to the surface of the substrate. At a fixed temperature and O{sub 2} pressure, the rods lengthen along their axes at a constant rate. The exponential temperature dependence of this rate yields an activation energy for growth of 1.2 {+-} 0.1 eV. The rod growth rates do not change as their ends pass in close proximity (<40 nm) to each other, which suggests that they do not compete for diffusing flux in order to elongate. Both LEEM and scanning tunneling microscopy (STM) studies show that the rods can grow vertically in layer-by-layer fashion. The heights of the rods are extremely bias dependent in STM images, but occur in integer multiples of approximately 2-{angstrom}-thick oxygen-cation layers. As the rods elongate from one substrate terrace to the next, we commonly see sharp changes in their rates of elongation that result from their tendency to gain (lose) atomic layers as they descend (climb) substrate steps. Diffraction analysis and dark-field imaging with LEEM indicate that the rods are crystalline, with a lattice constant that is well matched to that of the substrate along their length. We discuss the factors that lead to the formation of these highly anisotropic structures.

  6. Ultraviolet photodetectors based on ZnO nanorods-seed layer effect and metal oxide modifying layer effect

    NASA Astrophysics Data System (ADS)

    Zhou, Hai; Fang, Guojia; Liu, Nishuang; Zhao, Xingzhong

    2011-12-01

    Pt/ZnO nanorod (NR) and Pt/modified ZnO NR Schottky barrier ultraviolet (UV) photodetectors (PDs) were prepared with different seed layers and metal oxide modifying layer materials. In this paper, we discussed the effect of metal oxide modifying layer on the performance of UV PDs pre- and post-deposition annealing at 300°C, respectively. For Schottky barrier UV PDs with different seed layers, the MgZnO seed layer-PDs without metal oxide coating showed bigger responsivity and larger detectivity ( D λ*) than those of PDs with ZnO seed layer, and the reason was illustrated through energy band theory and the electron transport mechanism. Also the ratio of D 254* to D 546* was calculated above 8 × 102 for all PDs, which demonstrated that our PDs showed high selectivity for detecting UV light with less influence of light with long wavelength.

  7. Well-aligned zinc oxide nanorods and nanowires prepared without catalyst

    NASA Astrophysics Data System (ADS)

    Liu, F.; Cao, P. J.; Zhang, H. R.; Shen, C. M.; Wang, Z.; Li, J. Q.; Gao, H. J.

    2005-01-01

    Without catalyst and at a low temperature (550 °C), well-aligned ZnO nanorods and nanowires were prepared on porous silicon substrates using a simple method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results confirm that both the nanorods and the nanowires are perfect single crystals with the wurtzite structure. The diameters range from 40 to 100 nm. The growth directions are along the [0 0 0 1] axis. Photoluminescence (PL) spectra show that the UV emission shifts slightly to low frequency and the intensity of green emission decreases with the improvement of ZnO crystallization.

  8. Structures and Properties of the Products of the Reaction of Lanthanide Atoms with H 2 O: Dominance of the +II Oxidation State

    DOE PAGESBeta

    Mikulas, Tanya C.; Chen, Mingyang; Fang, Zongtang; Peterson, Kirk A.; Andrews, Lester; Dixon, David A.

    2016-01-07

    We studied, lanthanides and H2O reactions using density functional theory with the B3LYP functional. H2O forms an initial Lewis acid-base complex with the lanthanides exothermically with interaction energies from -2 to -20 kcal/mol. For most of the Ln, formation of HLnOH is more exothermic than formation of H2LnO, HLnO + H, and LnOH + H. Moreover, the reactions to produce HLnOH are exothermic from -25 to -75 kcal/mol. The formation of LnO + H2 for La and Ce is slightly more exothermic than formation of HLnOH and is less or equally exothermic for the rest of the lanthanides. The Lnmore » in HLnOH and LnOH are in the formal +II and +I oxidation states, respectively. The Ln in H2LnO is mostly in the +III formal oxidation state with either Ln-O-/Ln-H- or Ln-(H2)-/Ln= O2- bonding interactions. A few of the H2LnO have the Ln in the +IV or mixed +III/+IV formal oxidation states with Ln=O2-/Ln-H- bonding interactions. The Ln in HLnO are generally in the +III oxidation state with the exception of Yb in the +II state. The orbital populations calculated within the natural bond orbital (NBO) analysis are consistent with the oxidation states and reaction energies. The more exothermic reactions to produce HLnOH are always associated with more backbonding from the O(H) and H characterized by more population in the 6s and 5d in Ln and the formation of a stronger Ln-O(H) bond. Overall, the calculations are consistent with the experiments in terms of reaction energies and vibrational frequencies.« less

  9. Structures and Properties of the Products of the Reaction of Lanthanide Atoms with H2O: Dominance of the +II Oxidation State.

    PubMed

    Mikulas, Tanya C; Chen, Mingyang; Fang, Zongtang; Peterson, Kirk A; Andrews, Lester; Dixon, David A

    2016-02-11

    The reactions of lanthanides with H2O have been studied using density functional theory with the B3LYP functional. H2O forms an initial Lewis acid-base complex with the lanthanides exothermically with interaction energies from -2 to -20 kcal/mol. For most of the Ln, formation of HLnOH is more exothermic than formation of H2LnO, HLnO + H, and LnOH + H. The reactions to produce HLnOH are exothermic from -25 to -75 kcal/mol. The formation of LnO + H2 for La and Ce is slightly more exothermic than formation of HLnOH and is less or equally exothermic for the rest of the lanthanides. The Ln in HLnOH and LnOH are in the formal +II and +I oxidation states, respectively. The Ln in H2LnO is mostly in the +III formal oxidation state with either Ln-O(-)/Ln-H(-) or Ln-(H2)(-)/Ln=O(2-) bonding interactions. A few of the H2LnO have the Ln in the +IV or mixed +III/+IV formal oxidation states with Ln=O(2-)/Ln-H(-) bonding interactions. The Ln in HLnO are generally in the +III oxidation state with the exception of Yb in the +II state. The orbital populations calculated within the natural bond orbital (NBO) analysis are consistent with the oxidation states and reaction energies. The more exothermic reactions to produce HLnOH are always associated with more backbonding from the O(H) and H characterized by more population in the 6s and 5d in Ln and the formation of a stronger Ln-O(H) bond. Overall, the calculations are consistent with the experiments in terms of reaction energies and vibrational frequencies.

  10. Understanding the Chemistry of Uncommon Americium Oxidation States for Application to Actinide/Lanthanide Separations

    SciTech Connect

    Leigh Martin; Bruce J. Mincher; Nicholas C. Schmitt

    2007-09-01

    A spectroscopic study of the stability of Am(V) and Am(VI) produced by oxidizing Am(III) with sodium bismuthate is presented, varying the initial americium concentration, temperature and length of the oxidation was seen to have profound effects on the resultant solutions.

  11. Hydra as a model organism to decipher the toxic effects of copper oxide nanorod: Eco-toxicogenomics approach

    PubMed Central

    Murugadas, Anbazhagan; Zeeshan, Mohammed; Thamaraiselvi, Kaliannan; Ghaskadbi, Surendra; Akbarsha, Mohammad Abdulkader

    2016-01-01

    Nanotechnology has emerged as a powerful field of applied research. However, the potential toxicity of nano-materials is a cause of concern. A thorough toxicological investigation is required before a nanomaterial is evaluated for application of any kind. In this context, there is concerted effort to find appropriate test systems to assess the toxicity of nanomaterials. Toxicity of a nanomaterial greatly depends on its physicochemical properties and the biological system with which it interacts. The present research was carried out with a view to generate data on eco-toxicological impacts of copper oxide nanorod (CuO NR) in Hydra magnipapillata 105 at organismal, cellular and molecular levels. Exposure of hydra to CuO NR resulted in severe morphological alterations in a concentration- as well as duration-dependent manner. Impairment of feeding, population growth, and regeneration was also observed. In vivo and in vitro analyses revealed induction of oxidative stress, genotoxicity, and molecular machinery of apoptotic cell death, accompanied by disruption of cell cycle progression. Taken together, CuO nanorod is potentially toxic to the biological systems. Also, hydra offers potential to be used as a convenient model organism for aquatic ecotoxicological risk assessment of nanomaterials. PMID:27417574

  12. Role of bonding mechanisms during transfer hydrogenation reaction on heterogeneous catalysts of platinum nanoparticles supported on zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Al-Alawi, Reem A.; Laxman, Karthik; Dastgir, Sarim; Dutta, Joydeep

    2016-07-01

    For supported heterogeneous catalysis, the interface between a metal nanoparticle and the support plays an important role. In this work the dependency of the catalytic efficiency on the bonding chemistry of platinum nanoparticles supported on zinc oxide (ZnO) nanorods is studied. Platinum nanoparticles were deposited on ZnO nanorods (ZnO NR) using thermal and photochemical processes and the effects on the size, distribution, density and chemical state of the metal nanoparticles upon the catalytic activities are presented. The obtained results indicate that the bonding at Pt-ZnO interface depends on the deposition scheme which can be utilized to modulate the surface chemistry and thus the activity of the supported catalysts. Additionally, uniform distribution of metal on the catalyst support was observed to be more important than the loading density. It is also found that oxidized platinum Pt(IV) (platinum hydroxide) provided a more suitable surface for enhancing the transfer hydrogenation reaction of cyclohexanone with isopropanol compared to zero valent platinum. Photochemically synthesized ZnO supported nanocatalysts were efficient and potentially viable for upscaling to industrial applications.

  13. Hydra as a model organism to decipher the toxic effects of copper oxide nanorod: Eco-toxicogenomics approach

    NASA Astrophysics Data System (ADS)

    Murugadas, Anbazhagan; Zeeshan, Mohammed; Thamaraiselvi, Kaliannan; Ghaskadbi, Surendra; Akbarsha, Mohammad Abdulkader

    2016-07-01

    Nanotechnology has emerged as a powerful field of applied research. However, the potential toxicity of nano-materials is a cause of concern. A thorough toxicological investigation is required before a nanomaterial is evaluated for application of any kind. In this context, there is concerted effort to find appropriate test systems to assess the toxicity of nanomaterials. Toxicity of a nanomaterial greatly depends on its physicochemical properties and the biological system with which it interacts. The present research was carried out with a view to generate data on eco-toxicological impacts of copper oxide nanorod (CuO NR) in Hydra magnipapillata 105 at organismal, cellular and molecular levels. Exposure of hydra to CuO NR resulted in severe morphological alterations in a concentration- as well as duration-dependent manner. Impairment of feeding, population growth, and regeneration was also observed. In vivo and in vitro analyses revealed induction of oxidative stress, genotoxicity, and molecular machinery of apoptotic cell death, accompanied by disruption of cell cycle progression. Taken together, CuO nanorod is potentially toxic to the biological systems. Also, hydra offers potential to be used as a convenient model organism for aquatic ecotoxicological risk assessment of nanomaterials.

  14. Hydra as a model organism to decipher the toxic effects of copper oxide nanorod: Eco-toxicogenomics approach.

    PubMed

    Murugadas, Anbazhagan; Zeeshan, Mohammed; Thamaraiselvi, Kaliannan; Ghaskadbi, Surendra; Akbarsha, Mohammad Abdulkader

    2016-01-01

    Nanotechnology has emerged as a powerful field of applied research. However, the potential toxicity of nano-materials is a cause of concern. A thorough toxicological investigation is required before a nanomaterial is evaluated for application of any kind. In this context, there is concerted effort to find appropriate test systems to assess the toxicity of nanomaterials. Toxicity of a nanomaterial greatly depends on its physicochemical properties and the biological system with which it interacts. The present research was carried out with a view to generate data on eco-toxicological impacts of copper oxide nanorod (CuO NR) in Hydra magnipapillata 105 at organismal, cellular and molecular levels. Exposure of hydra to CuO NR resulted in severe morphological alterations in a concentration- as well as duration-dependent manner. Impairment of feeding, population growth, and regeneration was also observed. In vivo and in vitro analyses revealed induction of oxidative stress, genotoxicity, and molecular machinery of apoptotic cell death, accompanied by disruption of cell cycle progression. Taken together, CuO nanorod is potentially toxic to the biological systems. Also, hydra offers potential to be used as a convenient model organism for aquatic ecotoxicological risk assessment of nanomaterials. PMID:27417574

  15. Synthesis and optical characteristics of yttrium-doped zinc oxide nanorod arrays grown by hydrothermal method.

    PubMed

    Park, Hyunggil; Kim, Younggyu; Ji, Iksoo; Lee, Sang-Heon; Kim, Jin Soo; Kim, Jin Soo; Leem, Jae-Young

    2014-11-01

    Yttrium-doped ZnO (YZO) nanorods were synthesized by hydrothermal growth on a quartz substrate with various post-annealing temperatures. To investigate the effects of post-annealing on the optical properties and parameters of the nanorods, X-ray diffractometry (XRD), photoluminescence (PL) measurement, and ultraviolet (UV)-visible spectroscopy were used. From the XRD investigation, the full width at half maximum (FWHM) and the dislocation density of the nanorods was found to increase with an increase in the post-annealing temperature. In the PL spectra, the intensity of the near band edge (NBE) emission peak in the UV region also increases with an increase in the temperature of post-annealing. The deep level emission (DLE) peak in the visible region changes with various post-annealing temperatures, and its intensity increases remarkably with post-annealing at 800 degrees C. In this paper, changes in the optical parameters of the nanorods caused by variation in the behavior of Y during post-annealing was investigated, with properties such as absorption coefficients, refractive indices, and dispersion parameters being obtained from transmittance and reflectance analysis.

  16. Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods

    PubMed Central

    Fulati, Alimujiang; Ali, Syed M.Usman; Riaz, Muhammad; Amin, Gul; Nur, Omer; Willander, Magnus

    2009-01-01

    ZnO nanotubes and nanorods grown on gold thin film were used to create pH sensor devices. The developed ZnO nanotube and nanorod pH sensors display good reproducibility, repeatability and long-term stability and exhibit a pH-dependent electrochemical potential difference versus an Ag/AgCl reference electrode over a large dynamic pH range. We found the ZnO nanotubes provide sensitivity as high as twice that of the ZnO nanorods, which can be ascribed to the fact that small dimensional ZnO nanotubes have a higher level of surface and subsurface oxygen vacancies and provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods, thus affording the ZnO nanotube pH sensor a higher sensitivity. Experimental results indicate ZnO nanotubes can be used in pH sensor applications with improved performance. Moreover, the ZnO nanotube arrays may find potential application as a novel material for measurements of intracellular biochemical species within single living cells. PMID:22291545

  17. Lanthanide-doped nanocrystals: synthesis, optical-magnetic properties, and applications.

    PubMed

    Wang, Guofeng; Peng, Qing; Li, Yadong

    2011-05-17

    Because of the potential applications of lanthanide-doped nanocrystals in display devices, optical communication, solid-state lasers, catalysis, and biological labeling, the controlled synthesis of these new nanomaterials has sparked considerable interest. Nanosized phosphorescent or optoelectronic devices usually exhibit novel properties, depending on their structures, shapes, and sizes, such as tunable wavelengths, rapid responses, and high efficiencies. Thus, the development of facile synthetic methods towards high-quality lanthanide-doped nanocrystals with uniform size and shape appears to be of key importance both for the exploration of their materials properties and for potential applications. This Account focuses on the recent development in our laboratory of the synthesis and applications of lanthanide-doped nanocrystals. Since 2005, when we proposed a general strategy for nanocrystal synthesis via a liquid-solid-solution process, a range of monodisperse and colloidal lanthanide-doped fluoride, oxide, hydroxide, orthovanadate, thiooxide, borate, and phosphate nanocrystals have been successfully prepared. By rationally tuning the reaction conditions, we have readily synthesized nanostructures, such as hollow microspheres, nanorods, nanowires, hexagonal nanoplates, and nanobelts. By adjusting the different colloidal nanocrystal mixtures, we fabricated unique binary nanostructures with novel dual-mode luminescence properties through a facile ultrasonic method. By tridoping with lanthanide ions that had different electronic structures, we successfully achieved β-NaYF(4) nanorods that were paramagnetic with tuned upconversion luminescence. We have also used NaYF(4):Yb(3+)/Er(3+) conbined with magnetite nanoparticles as a sensitive detection system for DNA: NaYF(4):Yb(3+)/Er(3+) and Fe(3)O(4) nanoparticles were modified with two different DNA sequences. Then, the modified NaYF(4):Yb(3+)/Er(3+) nanoparticles were conjugated to the modified Fe(3)O(4) nanoparticles

  18. N,N-dimethyldodecylamine oxide self-organization in the presence of lanthanide ions in aqueous and aqueous-decanol solutions.

    PubMed

    Selivanova, Natalia M; Galeeva, Aliya I; Sukhanov, Andrey A; Gnezdilov, Oleg I; Chachkov, Denis V; Galyametdinov, Yury G

    2013-05-01

    The article represents the results of research in self-organization of new lanthanide systems in water-decanol medium. The systems are based on N,N-dimethyldodecylamine oxide, a zwitterionic surfactant. The study covers the complex formation of lanthanide ions with C12DMAO molecules and the influence of Ln(III) ions and medium composition on surfactant association in diluted solutions. The analysis of adsorption isotherms was carried out on the basis of the combination of Gibbs and Langmuir adsorption equations. The results were used to determine physicochemical properties and parameters of a monomolecular adsorption layer. The research objects were various lanthanide ions with identical coordination centers. A number of spectroscopic methods (UV, NMR self-diffusion, EPR, dynamic light scattering (DLS), and fluorescent analysis) were involved in the research for comparative estimations of molecular dynamics, critical micellization concentration, geometry, sizes, and aggregation numbers of micellar aggregates. Micelle structure simulation revealed good agreement between experimental data and quantum chemical calculations. PMID:23557206

  19. Micromechanical model for self-organized secondary phase oxide nanorod arrays in epitaxial YBa2Cu3O7-δ films

    NASA Astrophysics Data System (ADS)

    Shi, Jack J.; Wu, Judy Z.

    2012-08-01

    A micromechanical model based on the theory of elasticity has been developed to study the configuration of self-assembled secondary phase oxide nanostructures in high-temperature superconducting YBa2Cu3O7-δ films. With the calculated equilibrium strain and elastic energy of the impurity doped film, a phase diagram of lattice mismatches vs. elastic constants of the dopant was obtained that predicts the energetically preferred orientation of secondary phase nanorods. The calculation of the nanorod orientation and the film lattice deformation has yielded excellent agreement with experimental measurements.

  20. Tailoring the Optoelectronic Properties of Nano-Metal Oxides Using Anthocyanins and Lanthanide.

    PubMed

    Al Rez, Mohammed Fayez; Choudhury, Trisha; Islam, J; Fouad, H; Umar, Ahmad; Khan, A A; Ansari, S G; Ansari, Z A

    2015-12-01

    Here we report a simple and effective method in tailoring the optoelectronic properties of semi-conducting metal oxide for suitable device application. Sol-gel synthesis was used to synthesize manganese doped TiO2 nanopowder and commercially available TiO2 nanopowder was used as reference material. Thick films of these powder were screen printed on FTO coated glass and annealed at 450 degrees C in ambient air. Separately, 60 μL of neodymium chloride prepared from neodymium oxide, 60 μL of ruthenium based commercial dye (N719) and 60 μL of extracts of calendula orange and dog flower were used as sensitizer to improve the photoconductance properties. Elemental analysis confirmed synthesis of composite material of Mn and TiO2. Morphological observation showed a uniform particles of 25 to 50 nm diameter. Optoelectronic properties were studied by using thick films of these powders as working electrode as a function of wavelength from 430 to 750 nm and the cyclic voltammogram were obtained by scanning potential from -1.5 V to +1.5 V at the illumination intensity of 1000 Wm(-2). Sensitization resulted in additional absorption and functional bands. Oxidation peak current was found decreasing with increasing wavelength. Sensitization with flower extract resulted in increased oxidation current at higher wavelength indicating the improved photoconduction in comparison with N719 and neodymium. PMID:26682377

  1. Strongly coupled metal oxide nanorod arrays with graphene nanoribbons and nanosheets enable novel solid-state hybrid cells

    NASA Astrophysics Data System (ADS)

    Xiao, Junwu; Xi, Jiangbo; Xu, Yangyang; Yang, Shihe; Jin, Yunxia; Xiao, Fei; Wang, Shuai

    2015-06-01

    Electrochemical capacitors and rechargeable batteries are still limited in applications by the low energy and power densities they can deliver, respectively, holding back their deployment in electric vehicles. Here we develop a type of solid-state hybrid cells (SHCs) composed of graphene nanoribbons and nanosheets-coated metal oxide nanorod arrays ((MOx/GNR)@GNS). GNR and GNS are deposited on the surface of MOx nanorod arrays to improve the electron transport characteristic, and thus enhance the energy storage performance. The (MOx/GNR)@GNS-based SHCs can achieve a maximum volumetric energy density of 0.9 mWh cm-3, and still retain 0.4 mWh cm-3 even at 0.1 W cm-3. The energy storage performance is much better than the electrochemical capacitors reported previously, and can even rival the commercial Li thin-film battery but with a significantly higher power density, lower cost and higher safety. Also demonstrated is the good long-term cycle life with only ∼17% loss after 2500 cycles. These salient features make the (MOx/GNR)@GNS composites-based SHCs a strong contender for electrochemical energy storage.

  2. A new nano-worm structure from gold-nanoparticle mediated random curving of zinc oxide nanorods.

    PubMed

    Perumal, Veeradasan; Hashim, Uda; Gopinath, Subash C B; Haarindraprasad, R; Poopalan, P; Liu, Wei-Wen; Ravichandran, M; Balakrishnan, S R; Ruslinda, A R

    2016-04-15

    Creating novel nanostructures is a primary step for high-performance analytical sensing. Herein, a new worm like nanostructure with Zinc Oxide-gold (ZnO/Au) hybrid was fabricated through an aqueous hydrothermal method, by doping Au-nanoparticle (AuNP) on the growing ZnO lattice. During ZnO growth, fine tuning the solution temperature expedites random curving of ZnO nanorods and forms nano-worms. The nano-worms which were evidenced by morphological, physical and structural analyses, revealed elongated structures protruding from the surface (length: 1 µm; diameter: ~100 nm). The appropriate peaks for the face centred cubic gold were (111) and (200), as seen from X-ray diffractogram. The strong interrelation between Au and ZnO was manifested by X-ray photoelectron spectroscopy. The combined surface area increment from the nanoparticle radii and ZnO nanorod random curving gives raise an enhancement in detection sensitivity by increasing bio-loading. 'Au-decorated hybrid nano-worm' was immobilized with a probe DNA from Vibrio Cholera and duplexed with a target which was revealed by Fourier Transform Infrared Spectroscopy. Our novel Au-decorated hybrid nano-worm is suitable for high-performance bio-sensing, as evidenced by impedance spectroscopy, having higher-specificity and attained femtomolar (10 fM) sensitivity. Further, higher stability, reproducibility and regeneration on this sensing surface were demonstrated.

  3. A new nano-worm structure from gold-nanoparticle mediated random curving of zinc oxide nanorods.

    PubMed

    Perumal, Veeradasan; Hashim, Uda; Gopinath, Subash C B; Haarindraprasad, R; Poopalan, P; Liu, Wei-Wen; Ravichandran, M; Balakrishnan, S R; Ruslinda, A R

    2016-04-15

    Creating novel nanostructures is a primary step for high-performance analytical sensing. Herein, a new worm like nanostructure with Zinc Oxide-gold (ZnO/Au) hybrid was fabricated through an aqueous hydrothermal method, by doping Au-nanoparticle (AuNP) on the growing ZnO lattice. During ZnO growth, fine tuning the solution temperature expedites random curving of ZnO nanorods and forms nano-worms. The nano-worms which were evidenced by morphological, physical and structural analyses, revealed elongated structures protruding from the surface (length: 1 µm; diameter: ~100 nm). The appropriate peaks for the face centred cubic gold were (111) and (200), as seen from X-ray diffractogram. The strong interrelation between Au and ZnO was manifested by X-ray photoelectron spectroscopy. The combined surface area increment from the nanoparticle radii and ZnO nanorod random curving gives raise an enhancement in detection sensitivity by increasing bio-loading. 'Au-decorated hybrid nano-worm' was immobilized with a probe DNA from Vibrio Cholera and duplexed with a target which was revealed by Fourier Transform Infrared Spectroscopy. Our novel Au-decorated hybrid nano-worm is suitable for high-performance bio-sensing, as evidenced by impedance spectroscopy, having higher-specificity and attained femtomolar (10 fM) sensitivity. Further, higher stability, reproducibility and regeneration on this sensing surface were demonstrated. PMID:26584078

  4. Zinc oxide nanorod mediated visible light photoinactivation of model microbes in water

    NASA Astrophysics Data System (ADS)

    Sapkota, Ajaya; Anceno, Alfredo J.; Baruah, Sunandan; Shipin, Oleg V.; Dutta, Joydeep

    2011-05-01

    The inactivation of model microbes in aqueous matrix by visible light photocatalysis as mediated by ZnO nanorods was investigated. ZnO nanorods were grown on glass substrate following a hydrothermal route and employed in the inactivation of gram-negative Escherichia coli and gram-positive Bacillus subtilis in MilliQ water. The concentration of Zn2 + ions in the aqueous matrix, bacterial cell membrane damage, and DNA degradation at post-exposure were also studied. The inactivation efficiencies for both organisms under light conditions were about two times higher than under dark conditions across the cell concentrations assayed. Anomalies in supernatant Zn2 + concentration were observed under both conditions as compared to control treatments, while cell membrane damage and DNA degradation were observed only under light conditions. Inactivation under dark conditions was hence attributed to the bactericidal effect of Zn2 + ions, while inactivation under light conditions was due to the combined effects of Zn2 + ions and photocatalytically mediated electron injection. The reduction of pathogenic bacterial densities by the photocatalytically active ZnO nanorods in the presence of visible light implies potential ex situ application in water decontamination at ambient conditions under sunlight.

  5. Development of superhydrophilic and superhydrophobic polyester fabric by growing zinc oxide nanorods.

    PubMed

    Ashraf, Munir; Campagne, Christine; Perwuelz, Anne; Champagne, Philippe; Leriche, Anne; Courtois, Christian

    2013-03-15

    ZnO nanorods were grown on microfibers of Polyethylene terephthalate (PET) fabric by seeding method to develop hierarchical roughness structure. XRD and XPS analysis show the presence of crystalline ZnO and chemical Zn species at the fiber surface at each stage of the process. Five series of samples with different seed concentrations have been realized, and their surface morphology and topography were characterized by AFM and SEM. Increasing seed concentrations lead to samples with superhydrophilic properties. Not only the water contact angle at fabric surface tends to zero but also the water capillary diffusion inside fabric is faster. Nanostructuration affects the structure inside the fabric, and further experiments with decane liquid have been made to get a better understanding of this effect. To study the superhydrophobicity, nanorods treated samples were modified with octadecyltrimethoxysilane (ODS) by two method; solution deposition and vapor deposition. The superhydrophobicity was characterized by measuring the water contact angle and water sliding angle with 5 μl water droplet. The samples modified with ODS by vapor deposition showed higher water contact angles and low water sliding angle than the ones modified with solution method. The lotus effect has been well correlated with the surface morphology of the nanorods structured fibers. The application of the Cassie-Baxter equation is discussed.

  6. Nanorod niobium oxide as powerful catalysts for an all vanadium redox flow battery.

    PubMed

    Li, Bin; Gu, Meng; Nie, Zimin; Wei, Xiaoliang; Wang, Chongmin; Sprenkle, Vincent; Wang, Wei

    2014-01-01

    A powerful low-cost electrocatalyst, nanorod Nb2O5, is synthesized using the hydrothermal method with monoclinic phases and simultaneously deposited on the surface of a graphite felt (GF) electrode in an all vanadium flow battery (VRB). Cyclic voltammetry (CV) study confirmed that Nb2O5 has catalytic effects toward redox couples of V(II)/V(III) at the negative side and V(IV)/V(V) at the positive side to facilitate the electrochemical kinetics of the vanadium redox reactions. Because of poor conductivity of Nb2O5, the performance of the Nb2O5 loaded electrodes is strongly dependent on the nanosize and uniform distribution of catalysts on GF surfaces. Accordingly, an optimal amount of W-doped Nb2O5 nanorods with minimum agglomeration and improved distribution on GF surfaces are established by adding water-soluble compounds containing tungsten (W) into the precursor solutions. The corresponding energy efficiency is enhanced by ∼10.7% at high current density (150 mA·cm(-2)) as compared with one without catalysts. Flow battery cyclic performance also demonstrates the excellent stability of the as prepared Nb2O5 catalyst enhanced electrode. These results suggest that Nb2O5-based nanorods, replacing expensive noble metals, uniformly decorating GFs holds great promise as high-performance electrodes for VRB applications.

  7. Nanorod niobium oxide as powerful catalysts for an all vanadium redox flow battery.

    PubMed

    Li, Bin; Gu, Meng; Nie, Zimin; Wei, Xiaoliang; Wang, Chongmin; Sprenkle, Vincent; Wang, Wei

    2014-01-01

    A powerful low-cost electrocatalyst, nanorod Nb2O5, is synthesized using the hydrothermal method with monoclinic phases and simultaneously deposited on the surface of a graphite felt (GF) electrode in an all vanadium flow battery (VRB). Cyclic voltammetry (CV) study confirmed that Nb2O5 has catalytic effects toward redox couples of V(II)/V(III) at the negative side and V(IV)/V(V) at the positive side to facilitate the electrochemical kinetics of the vanadium redox reactions. Because of poor conductivity of Nb2O5, the performance of the Nb2O5 loaded electrodes is strongly dependent on the nanosize and uniform distribution of catalysts on GF surfaces. Accordingly, an optimal amount of W-doped Nb2O5 nanorods with minimum agglomeration and improved distribution on GF surfaces are established by adding water-soluble compounds containing tungsten (W) into the precursor solutions. The corresponding energy efficiency is enhanced by ∼10.7% at high current density (150 mA·cm(-2)) as compared with one without catalysts. Flow battery cyclic performance also demonstrates the excellent stability of the as prepared Nb2O5 catalyst enhanced electrode. These results suggest that Nb2O5-based nanorods, replacing expensive noble metals, uniformly decorating GFs holds great promise as high-performance electrodes for VRB applications. PMID:24279888

  8. Synthesis and Coordination Properties of Trifluoromethyl Decorated Derivatives of 2,6-Bis[(diphenylphosphinoyl)methyl]pyridine N-Oxide Ligands with Lanthanide Ions

    SciTech Connect

    Pailloux, Sylvie; Shirima, Cornel Edicome; Ray, Alicia D.; Duesler, Eileen N.; Paine, Robert T.; Klaehn, John D.; McIlwain, Michael E; Hay, Benjamin

    2009-01-01

    Phosphinoyl Grignard-based substitutions on 2,6-bis(chloromethyl)pyridine followed by N-oxidation of the intermediate 2,6-bis(phosphinoyl)methyl pyridine compounds with mCPBA give the target trifunctional ligands 2,6-bis[bis-(2-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine 1-oxide (2a) and 2,6-bis[bis-(3,5-bis-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine 1-oxide (2b) in high yields. The ligands have been spectroscopically characterized, the molecular structures confirmed by single crystal X-ray diffraction methods and the coordination chemistry surveyed with lanthanide nitrates. Single crystal X-ray diffraction analyses are described for the coordination complexes Nd(2a)(NO3)3, Nd(2a)(NO3)3 (CH3CN)0.5, Eu(2a)(NO3)3 and Nd(2b)(NO3)3 (H2O)1.25; in each case the ligand binds in a tridentate mode to the Ln(III) cation. These structures are compared with the structures found for lanthanide coordination complexes of the parent NOPOPO ligand, [Ph2P(O)CH2]2C5H3NO.

  9. Novel lanthanide-labeled metal oxide nanoparticles improve the measurement of in vivo clearance and translocation.

    PubMed

    Abid, Aamir D; Anderson, Donald S; Das, Gautom K; Van Winkle, Laura S; Kennedy, Ian M

    2013-01-01

    The deposition, clearance and translocation of europium-doped gadolinium oxide nanoparticles in a mouse lung were investigated experimentally. Nanoparticles were synthesized by spray flame pyrolysis. The particle size, crystallinity and surface properties were characterized. Following instillation, the concentrations of particles in organs were determined with inductively coupled plasma mass spectrometry. The protein corona coating the nanoparticles was found to be similar to the coating on more environmentally relevant nanoparticles such as iron oxide. Measurements of the solubility of the nanoparticles in surrogates of biological fluids indicated very little propensity for dissolution, and the elemental ratio of particle constituents did not change, adding further support to the contention that intact nanoparticles were measured. The particles were intratracheally instilled into the mouse lung. After 24 hours, the target organs were harvested, acid digested and the nanoparticle mass in each organ was measured by inductively coupled plasma mass spectrometry (ICP-MS). The nanoparticles were detected in all the studied organs at low ppb levels; 59% of the particles remained in the lung. A significant amount of particles was also detected in the feces, suggesting fast clearance mechanisms. The nanoparticle system used in this work is highly suitable for quantitatively determining deposition, transport and clearance of nanoparticles from the lung, providing a quantified measure of delivered dose. PMID:23305071

  10. Novel lanthanide-labeled metal oxide nanoparticles improve the measurement of in vivo clearance and translocation.

    PubMed

    Abid, Aamir D; Anderson, Donald S; Das, Gautom K; Van Winkle, Laura S; Kennedy, Ian M

    2013-01-10

    The deposition, clearance and translocation of europium-doped gadolinium oxide nanoparticles in a mouse lung were investigated experimentally. Nanoparticles were synthesized by spray flame pyrolysis. The particle size, crystallinity and surface properties were characterized. Following instillation, the concentrations of particles in organs were determined with inductively coupled plasma mass spectrometry. The protein corona coating the nanoparticles was found to be similar to the coating on more environmentally relevant nanoparticles such as iron oxide. Measurements of the solubility of the nanoparticles in surrogates of biological fluids indicated very little propensity for dissolution, and the elemental ratio of particle constituents did not change, adding further support to the contention that intact nanoparticles were measured. The particles were intratracheally instilled into the mouse lung. After 24 hours, the target organs were harvested, acid digested and the nanoparticle mass in each organ was measured by inductively coupled plasma mass spectrometry (ICP-MS). The nanoparticles were detected in all the studied organs at low ppb levels; 59% of the particles remained in the lung. A significant amount of particles was also detected in the feces, suggesting fast clearance mechanisms. The nanoparticle system used in this work is highly suitable for quantitatively determining deposition, transport and clearance of nanoparticles from the lung, providing a quantified measure of delivered dose.

  11. Novel lanthanide-labeled metal oxide nanoparticles improve the measurement of in vivo clearance and translocation

    PubMed Central

    2013-01-01

    The deposition, clearance and translocation of europium-doped gadolinium oxide nanoparticles in a mouse lung were investigated experimentally. Nanoparticles were synthesized by spray flame pyrolysis. The particle size, crystallinity and surface properties were characterized. Following instillation, the concentrations of particles in organs were determined with inductively coupled plasma mass spectrometry. The protein corona coating the nanoparticles was found to be similar to the coating on more environmentally relevant nanoparticles such as iron oxide. Measurements of the solubility of the nanoparticles in surrogates of biological fluids indicated very little propensity for dissolution, and the elemental ratio of particle constituents did not change, adding further support to the contention that intact nanoparticles were measured. The particles were intratracheally instilled into the mouse lung. After 24 hours, the target organs were harvested, acid digested and the nanoparticle mass in each organ was measured by inductively coupled plasma mass spectrometry (ICP-MS). The nanoparticles were detected in all the studied organs at low ppb levels; 59% of the particles remained in the lung. A significant amount of particles was also detected in the feces, suggesting fast clearance mechanisms. The nanoparticle system used in this work is highly suitable for quantitatively determining deposition, transport and clearance of nanoparticles from the lung, providing a quantified measure of delivered dose. PMID:23305071

  12. Mechanical and piezoelectric properties of zinc oxide nanorods grown on conductive textile fabric as an alternative substrate

    NASA Astrophysics Data System (ADS)

    Khan, Azam; Hussain, Mushtaque; Nur, Omer; Willander, Magnus

    2014-08-01

    The present research is devoted to understanding the mechanism and causes of variation in the piezoelectric potential generated from vertically aligned zinc oxide (ZnO) nanorods (NRs), which were grown on a conductive textile fabric as an alternative substrate by using the aqueous chemical growth method. The piezoelectric voltage was harvested from vertically aligned ZnO NRs having different physical parameters by using atomic force microscopy in contact mode and the variation in the generated piezoelectricity was investigated. The generated output potential indicates that different physical parameters such aspect ratio, crystal size and lattice internal crystal strain have a strong influence on the piezoelectric properties of vertically aligned ZnO NRs, which were grown on a textile fabric. Presented results indicate that textiles can be used as an alternative substrate just like the other conventional substrates, because our results are similar/better than many reported works on conventional substrates.

  13. Polystyrene-catalytic indium–tin–oxide nanorods grown on green light-emitting diodes for enhancing light extraction

    NASA Astrophysics Data System (ADS)

    Gong, Zhina; Li, Qiang; Li, Yufeng; Xiong, Han; Liu, Hao; Wang, Shuai; Zhang, Ye; Guo, Maofeng; Yun, Feng

    2016-08-01

    A novel technique for fabricating indium–tin–oxide (ITO) nanorods (NRs) on hexagonal-pyramid-surface green vertical light-emitting diodes (VLEDs) is demonstrated using electron-beam deposition with polystyrene spheres catalysis. The ITO NRs have high optical transmittance (>90%) in green wavelength and good crystal quality with a cubic structure. The VLED with ITO NRs has a 31% enhancement of light output power at 200 mA, compared with those without ITO NRs. Finite-difference time-domain simulations suggest that the power enhancement is attributed to the gradient refractive indices of the ITO NRs, and that the light extraction enhancement is caused by changes in ITO NR heights.

  14. Polystyrene-catalytic indium-tin-oxide nanorods grown on green light-emitting diodes for enhancing light extraction

    NASA Astrophysics Data System (ADS)

    Gong, Zhina; Li, Qiang; Li, Yufeng; Xiong, Han; Liu, Hao; Wang, Shuai; Zhang, Ye; Guo, Maofeng; Yun, Feng

    2016-08-01

    A novel technique for fabricating indium-tin-oxide (ITO) nanorods (NRs) on hexagonal-pyramid-surface green vertical light-emitting diodes (VLEDs) is demonstrated using electron-beam deposition with polystyrene spheres catalysis. The ITO NRs have high optical transmittance (>90%) in green wavelength and good crystal quality with a cubic structure. The VLED with ITO NRs has a 31% enhancement of light output power at 200 mA, compared with those without ITO NRs. Finite-difference time-domain simulations suggest that the power enhancement is attributed to the gradient refractive indices of the ITO NRs, and that the light extraction enhancement is caused by changes in ITO NR heights.

  15. Facile and Mild Strategy to Construct Mesoporous CeO2-CuO Nanorods with Enhanced Catalytic Activity toward CO Oxidation.

    PubMed

    Chen, Guozhu; Xu, Qihui; Yang, Ying; Li, Cuncheng; Huang, Taizhong; Sun, Guoxin; Zhang, Shuxiang; Ma, Dongling; Li, Xu

    2015-10-28

    CeO2-CuO nanorods with mesoporous structure were synthesized by a facile and mild strategy, which involves an interfacial reaction between Ce2(SO4)3 precursor and NaOH ethanol solution at room temperature to obtain mesoporous CeO2 nanorods, followed by a solvothermal treatment of as-prepared CeO2 and Cu(CH3COO)2. Upon solvothermal treatment, CuO species is highly dispersed onto the CeO2 nanorod surface to form CeO2-CuO composites, which still maintain the mesoporous feature. A preliminary CO catalytic oxidation study demonstrated that the CeO2-CuO samples exhibited strikingly high catalytic activity, and a high CO conversion rate was observed without obvious loss in activity even after thermal treatment at a high temperature of 500 °C. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and hydrogen temperature-programmed reduction (H2-TPR) analysis revealed that there is a strong interaction between CeO2 and CuO. Moreover, it was found that the introduction of CuO species into CeO2 generates oxygen vacancies, which is highly likely to be responsible for high catalytic activity toward CO oxidation of the mesoporous CeO2-CuO nanorods.

  16. Harnessing the Cancer Radiation Therapy by Lanthanide-Doped Zinc Oxide Based Theranostic Nanoparticles.

    PubMed

    Ghaemi, Behnaz; Mashinchian, Omid; Mousavi, Tayebeh; Karimi, Roya; Kharrazi, Sharmin; Amani, Amir

    2016-02-10

    In this paper, doping of europium (Eu) and gadolinium (Gd) as high-Z elements into zinc oxide (ZnO) nanoparticles (NPs) was designed to optimize restricted energy absorption from a conventional radiation therapy by X-ray. Gd/Eu-doped ZnO NPs with a size of 9 nm were synthesized by a chemical precipitation method. The cytotoxic effects of Eu/Gd-doped ZnO NPs were determined using MTT assay in L929, HeLa, and PC3 cell lines under dark conditions as well as exposure to ultraviolet, X-ray, and γ radiation. Doped NPs at 20 μg/mL concentration under an X-ray dose of 2 Gy were as efficient as 6 Gy X-ray radiation on untreated cells. It is thus suggested that the doped NPs may be used as photoinducers to increase the efficacy of X-rays within the cells, consequently, cancer cell death. The doped NPs also could reduce the received dose by normal cells around the tumor. Additionally, we evaluated the diagnostic efficacy of doped NPs as CT/MRI nanoprobes. Results showed an efficient theranostic nanoparticulate system for simultaneous CT/MR imaging and cancer treatment.

  17. Ergonomic Synthesis Suitable for Industrial Production of Silver-Festooned Zinc Oxide Nanorods

    NASA Astrophysics Data System (ADS)

    Khan, G. R.; Khan, R. A.

    2015-07-01

    For maximizing productivity, minimizing cost, time-boxing process and optimizing human effort, a single-step, cost-effective, ultra-fast and environmentally benign synthesis suitable for industrial production of nanocrystalline ZnO, and Ag-doped ZnO has been reported in this paper. The synthesis based on microwave-supported aqueous solution method used zinc acetate dehydrate and silver nitrate as precursors for fabrication of nanorods. The synthesized products were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and UV-Vis-NIR spectroscopy. The undoped and Ag-doped ZnO nanorods crystallized in a hexagonal wurtzite structure having spindle-like morphology. The blue shift occurred at absorption edge of Ag-doped ZnO around 260 nm compared to 365 nm of bulk ZnO. The red shift occurred at Raman peak site of 434 cm-1 compared to characteristic wurtzite phase peak of ZnO (437 cm-1). The bandgap energies were found to be 3.10 eV, 3.11 eV and 3.18 eV for undoped, 1% Ag-doped, and 3% Ag-doped ZnO samples, respectively. The TEM results provided average particle sizes of 17 nm, 15 nm and 13 nm for undoped, and 1% and 3% Ag-doped ZnO samples, respectively.

  18. Branched zinc oxide nanorods arrays modified paper electrode for electrochemical immunosensing by combining biocatalytic precipitation reaction and competitive immunoassay mode.

    PubMed

    Sun, Guoqiang; Yang, Hongmei; Zhang, Yan; Yu, Jinghua; Ge, Shenguang; Yan, Mei; Song, Xianrang

    2015-12-15

    Branched zinc oxide nanorods (BZR) arrays, an array with high charge carries collection efficiency and specific surface area, are grown on the reduced graphene oxide-paper working electrode for the first time to construct a paper-based electrochemical (EC) immunosensor. Typically, the BZR are fabricated via a simple hydrothermal process, which can provide abundant sites for antibodies loading. By combining the large surface area of porous zinc oxide (PZS) and good biocompatibility of gold nanoparticles (AuNPs), PZS-AuNPs (PZS@Au) nanocomposites are designed to label horseradish peroxide (HRP) and antigens. After a competitive reaction between antigens and PZS@Au nanocomposites labeled antigens, the signal labels are introduced into the immunosensor, in which, HRP participate in biocatalytic precipitation process. The produced precipitate reduces the electrode surface area and hinders the electron transfer. With the increase of concentration of antigens, the signal labels introduced into the sensor decrease, thus, a signal-on immunoassay for α-fetoprotein detection is constructed. The proposed paper-based EC immunosensor combines enzymatic biocatalytic precipitation reaction and competitive immunoassay mode for the first time, and possesses a wide linear range from 0.2 pg mL(-1) to 500 ng mL(-1) with a detection limit of 0.08 pg mL(-1). In addition, the proposed method is simple, sensitive and specific and can be a promising platform for other protein detection.

  19. Microbundles of zinc oxide nanorods: Assembly in ionic liquid [EMIM]{sup +}[BF{sub 4}]{sup -}, photoluminescence and photocatalytic properties

    SciTech Connect

    Wang Li; Xu Shenzhi; Li Huijun; Chang Lixian; Zhisu; Zeng Minghua; Wang Lina; Huang Yineng

    2011-03-15

    A simple, efficient and low-temperature approach for the assembly of hierarchical Zinc oxide (ZnO) microstructures in ionic liquid [EMIM]{sup +}[BF{sub 4}]{sup -} is reported. The as-obtained ZnO superstructures are composed of microbundles of nanorods from the center points, with the diameter and length in the range of 100-150 nm and 2-4 {mu}m, which have been characterized by X-ray diffraction, scanning and transmission electron microscopy, and photoluminescence spectroscopy. The ZnO microstructures exhibit significant defect-related green-yellow emission and high photodegradation of dye Methyl Orange (5x10{sup -5} mol/L) under UV excitation within 80 min. -- Graphical abstract: Easy formation of microbundles of ZnO nanorods were accomplished in low temperature with [EMIM]{sup +}[BF{sub 4}]{sup -} (1-ethyl-3-methylimidazolium tetrafluoroborate) ionic liquid, which exhibit significant green-yellow photoluminescence property and high photodegradation of Methyl Orange dye. Display Omitted Research highlights: {yields} Ionic liquid assisted solid-state route was introduced into synthesis of ZnO nanorods. {yields} The distinctive microbundles ZnO nanorod assembles was evidenced by SEM and TEM. {yields} ZnO nano-material exhibited high efficiency in photodegradation of Methyl Orange.

  20. Features of the Thermodynamics of Trivalent Lanthanide/Actinide Distribution Reactions by Tri-n-Octylphosphine Oxide and Bis(2-EthylHexyl) Phosphoric Acid

    SciTech Connect

    Travis S. Grimes; Peter R. Zalupski

    2014-11-01

    A new methodology has been developed to study the thermochemical features of the biphasic transfer reactions of trisnitrato complexes of lanthanides and americium by a mono-functional solvating ligand (tri-n-octyl phosphine oxide - TOPO). Stability constants for successive nitrato complexes (M(NO3)x3-x (aq) where M is Eu3+, Am3+ or Cm3+) were determined to assist in the calculation of the extraction constant, Kex, for the metal ions under study. Enthalpies of extraction (?Hextr) for the lanthanide series (excluding Pm3+) and Am3+ by TOPO have been measured using isothermal titration calorimetry. The observed ?Hextr were found to be constant at ~29 kJ mol-1across the series from La3+-Er3+, with a slight decrease observed from Tm3+-Lu3+. These heats were found to be consistent with enthalpies determined using van ’t Hoff analysis of temperature dependent extraction studies. A complete set of thermodynamic parameters (?G, ?H, ?S) was calculated for Eu(NO3)3, Am(NO3)3 and Cm(NO3)3 extraction by TOPO and Am3+ and Cm3+ extraction by bis(2-ethylhexyl) phosphoric acid (HDEHP). A discussion comparing the energetics of these systems is offered. The measured biphasic extraction heats for the transplutonium elements, ?Hextr, presented in these studies are the first ever direct measurements offered using two-phase calorimetric techniques.

  1. Lanthanides in silicate glasses: A vibrational spectroscopic study

    NASA Astrophysics Data System (ADS)

    Ellison, Adam J. G.; Hess, Paul C.

    1990-09-01

    Parallel- and perpendicular-polarized Raman and KBr pellet transmission IR spectra of quenched 10K2O-50SiO2-nR2O3 (R = La, Gd, Yb; n = 0, 1, 5, 10 mol) glasses are presented. Increasing lanthanide oxide concentration produces partially-polarized high-frequency bands at 1030, 940, and 860 cm-1, assigned to the symmetric stretching modes of SiO4 tetrahedra containing 1, 2, and 4 nonbridging oxygen, respectively, in which the nonbridging oxygen coordinate primarily with lanthanides. Lanthanides therefore form silicate anions that are depolymerized relative to the bulk liquid and which have no counterparts in R2O3-SiO2 binary systems. The spectra indicate that there is little sharing of nonbridging oxygen by K and lanthanides. The spectra of glasses containing different lanthanides at the same concentration are qualitatively and quantitatively very similar. Lanthanides have energetically unfavorable interactions with the network structure of polymerized liquids compared to cations of lower valence. If lanthanides coordinate nonbridging oxygen without the aid of K, then lanthanide saturation concentrations will show modest increases with increasing (Na,K)/Al in peralkaline liquids, except in liquids in which P2O5 concentration is comparable to the total lanthanide concentration. Since differences in lanthanide ionic radii have small effects upon the spectra, lanthanide solution mechanisms in silicate glasses (and by inference silicate liquids) are probably very similar.

  2. Hybrid Zinc Oxide Nanorods/Carbon Nanotubes Composite for Nitrogen Dioxide Gas Sensing

    NASA Astrophysics Data System (ADS)

    Oweis, Rami J.; Albiss, B. A.; Al-Widyan, M. I.; Al-Akhras, M.-Ali

    2014-09-01

    This study reports on the synthesis and fabrication of hybrid nanocomposite based on single-walled carbon nanotubes-ZnO nanorods (SWCNT-ZnONR) as resistive gas sensors for NO2 detection. The sensor was prepared using the standard simple and cost-effective hydrothermal process. The sensor was characterized by x-ray diffraction (XRD) and scanning electron microscopy. The findings revealed enhanced porous SWCNT-ZnONR nanocomposites due to the high porosity of the SWCNT. It was also found that the sensor exhibited average response and recovery times of about 70 s and 100 s, respectively. The XRD peak at 26° indicated that the SWCNT pattern was not disturbed, while sensitivity increased with temperature up to 150°C, at which the sensitivity was maximum. Similarly, the sensor sensitivity increased with NO2 concentration at all levels examined. Moreover, the results indicate that the sensor shows significant promise for NO2 gas sensing applications.

  3. Immobilization of a Molecular Ruthenium Catalyst on Hematite Nanorod Arrays for Water Oxidation with Stable Photocurrent.

    PubMed

    Fan, Ke; Li, Fusheng; Wang, Lei; Daniel, Quentin; Chen, Hong; Gabrielsson, Erik; Sun, Junliang; Sun, Licheng

    2015-10-12

    Photoelectrochemical (PEC) cells for light-driven water splitting are prepared using hematite nanorod arrays on conductive glass as the photoanode. These devices improve the photocurrent of the hematite-based photoanode for water splitting, owing to fewer surface traps and decreased electron recombination resulting from the one-dimensional structure. By employing a molecular ruthenium co-catalyst, which contains a strong 2,6-pyridine-dicarboxylic acid anchoring group at the hematite photoanode, the photocurrent of the PEC cell is enhanced with high stability for over 10 000 s in a 1 m KOH solution. This approach can pave a route for combining one-dimensional nanomaterials and molecular catalysts to split water with high efficiency and stability. PMID:26315677

  4. Materials discovery by crystal growth: Lanthanide metal containing oxides of the platinum group metals (Ru, Os, Ir, Rh, Pd, Pt) from molten alkali metal hydroxides

    SciTech Connect

    Mugavero, Samuel J.; Gemmill, William R.; Roof, Irina P.; Loye, Hans-Conrad zur

    2009-07-15

    This review addresses the process of materials discovery via crystal growth, specifically of lanthanide metal containing oxides of the platinum group metals (Ru, Os, Ir, Rh, Pd, Pt). It provides a detailed overview of the use of hydroxide fluxes for crystal growth. The melt chemistry of hydroxide fluxes, specifically, the extensive acid base chemistry, the metal cation solubility, and the ability of hydroxide melts to oxidize metals are described. Furthermore, a general methodology for the successful crystal growth of oxides is provided, including a discussion of experimental considerations, suitable reaction vessels, reaction profiles and temperature ranges. Finally, a compilation of complex platinum group metal oxides recently synthesized using hydroxide melts, focusing on their crystal growth and crystal structures, is included. - Graphical abstract: A review that addresses the process of materials discovery via crystal growth using hydroxide fluxes. It provides a detailed overview of the use of hydroxide fluxes for crystal growth and describes the melt chemistry of hydroxide fluxes, specifically, the extensive acid base chemistry, the metal cation solubility, and the ability of hydroxide melts to oxidize metals. In addition, a compilation of complex platinum group metal oxides recently synthesized using hydroxide melts is included.

  5. Controllable growth of vertically aligned Bi-doped TiO2 nanorod arrays for all-oxide solid-state DSSCs

    NASA Astrophysics Data System (ADS)

    Asemi, Morteza; Ghanaatshoar, Majid

    2016-09-01

    In this study, vertically aligned Bi-doped TiO2 nanorod arrays as photoanodes were successfully grown on the fluorine-doped tin oxide by hydrothermal method. Structural analysis showed that bismuth was successfully incorporated into the TiO2 lattice at low concentration, but at higher concentration, phase segregation of Bi2O3 in the TiO2 matrix was occurred. TiO2 nanorods with 3 % bismuth concentration had minimum electrical resistivity. As the solid-state electrolyte, Mg-doped CuCrO2 nanoparticles with p-type conductivity were synthesized by sol-gel method. The fabricated all-oxide solid-state dye-sensitized solar cells with Bi-doped TiO2 nanorods displayed better photovoltaic performance due to the presence of Bi. The improved cell performance was correlated with the higher dye loading, slower charge recombination rate and the higher electrical conductivity of the photoanodes. After mechanical pressing, the all-oxide solid-state DSSC exhibited enhanced photovoltaic performance due to the formation of the large neck between adjacent nanoparticles by mechanical sintering. The open-circuit photovoltage decay measurement of the devices and electrical conductivity of the nanoparticles before and after pressing revealed that the mechanical pressing technique reduces charge recombination rate and facilitates electron transport through the interconnected nanoparticles.

  6. Fabrication of hydroxyapatite and TiO 2 nanorods on microarc-oxidized titanium surface using hydrothermal treatment

    NASA Astrophysics Data System (ADS)

    Song, Ho-Jun; Kim, Ji-Woo; Kook, Min-Suk; Moon, Won-Jin; Park, Yeong-Joon

    2010-09-01

    AC-type microarc oxidation (MAO) and hydrothermal treatment techniques were used to enhance the bioactivity of commercially pure titanium (CP-Ti). The porous TiO 2 layer fabricated by the MAO treatment had a dominant anatase structure and contained Ca and P ions. The MAO-treated specimens were treated hydrothermally to form HAp crystallites on the titanium oxide layer in an alkaline aqueous solution (OH-solution) or phosphorous-containing alkaline solution (POH-solution). A small number of micro-sized hydroxyapatite (HAp) crystallites and a thin layer composed of nano-sized HAps were formed on the Ti-MAO-OH group treated hydrothermally in an OH-solution, whereas a large number of micro-sized HAp crystallites and dense anatase TiO 2 nanorods were formed on the Ti-MAO-POH group treated hydrothermally in a POH-solution. The layer of bone-like apatite that formed on the surface of the POH-treated sample after soaking in a modified simulated body fluid was thicker than that on the OH-treated samples.

  7. Physiological investigation of gold nanorods toward watermelon.

    PubMed

    Wan, Yujie; Li, Junli; Ren, Hongxuan; Huang, Jin; Yuan, Hong

    2014-08-01

    The objective of the present study was to evaluate the phytotoxicity and oxidant stress of the gold nanorods toward watermelon, and hence give a quantitative risk assessment of both seeds and plants phase. The seed germination, the activity of antioxidant enzymes, and the contents of soluble protein and malondialdehyde (MDA) have been measured while the plant roots were observed by transmission electron microscopy (TEM). It was found that the gold nanorods significantly promoted the root elongation. Furthermore, the results on the enzymes activities of plant indicated that oxidative stress happened in the plant treated with gold nanorods. However, the gold nanorods resulted in the phytotoxicity toward plant especially at high concentration. The TEM images of the plant roots with and without the treatment of gold nanorods showed the significant different size of starch granules. In conclusion, significant physiological changes of plant occurred after treatment with the gold nanorods. PMID:25936063

  8. Role of sensitivity of zinc oxide nanorods (ZnO-NRs) based photosensitizers in hepatocellular site of biological tissue

    NASA Astrophysics Data System (ADS)

    Atif, M.; Fakhar-E-Alam, M.; Alsalhi, M. S.

    2011-11-01

    Zinc oxide nanorods (ZnO-NRs) with high surface to volume ratio and bio compatibility are used as an efficient photosensitizer carrier system for achievement of Hepatocellular cancer cell (HepG2) necrosis within few minutes. Present study highlights the role of effectiveness of ZnO-NRs in photodynamic therapy (PDT). We have grown the ZnO-NRs on the tip of borosilicate glass capillaries (0.5 μm diameter). The grown ZnO-NRs were conjugated using Photofrin® and ALA for the efficient intracellular drug delivery, which produces reactive oxygen species (ROS) via photochemical reactions leading to cell death within few minutes after exposing UV light (240 nm). Viability of controlled and treated HepG2 cells with optimum dose of light (UV-visible) has been assessed by neutral red assay (NRA). The results were verified by staining of mitochondria using Mitotracker® red as an efficient dye as well as ROS detection. ZnO-NRs based Phogem® (PG) treated normal liver tissues of Sprague-Dawley rats were used as comparative experimental model. Morphological apoptotic changes in liver tissue of Sprague-Dawley rats before and after ZnO-NRs conjugated with photosensitizer (PS)-mediated PDT were investigated by microscopic examination.

  9. Effect of platinum-nanodendrite modification on the glucose-sensing properties of a zinc-oxide-nanorod electrode

    NASA Astrophysics Data System (ADS)

    Abdul Razak, Khairunisak; Neoh, Soo Huan; Ridhuan, N. S.; Mohamad Nor, Noorhashimah

    2016-09-01

    The properties of ZnO nanorods (ZnONRs) decorated with platinum nanodendrites (PtNDs) were studied. Various sizes of PtNDs were synthesized and spin coated onto ZnONRs, which were grown on indium-titanium-oxide (ITO) substrates through a low-temperature hydrothermal method. Scanning electron microscopy and X-ray diffraction analyses were conducted to analyze the morphology and structural properties of the electrodes. The effects of PtND size, glucose concentration, and Nafion amount on glucose-sensing properties were investigated. The glucose-sensing properties of electrodes with immobilized glucose oxidase (GOx) were measured using cyclic voltammetry. The bio-electrochemical properties of Nafion/GOx/42 nm PtNDs/ZnONRs/ITO glucose sensor was observed with linear range within 1-18 mM, with a sensitivity value of 5.85 μA/mM and a limit of detection of 1.56 mM. The results of this study indicate that PtNDs/ZnONRs/ITO has potential in glucose sensor applications.

  10. Facile one pot synthesis of zinc oxide nanorods and statistical evaluation for photocatalytic degradation of a diazo dye.

    PubMed

    Dutta, Suvanka; Ghosh, Ananya; Kabir, Humayun; Saha, Rajnarayan

    2016-01-01

    In the present work zinc oxide nanorods (ZNRs) have been synthesized to estimate its photocatalytic degradation potential on an industrially used diazo dye and optimization of the total treatment process has been designed. Response surface methodology (RSM) has been used to model the operational parameters for this photocatalytic degradation. The crystallite size (101 plane) of the synthesized ZNR has been found to be 20.99 nm having a band gap energy of 3.45 eV. At elevated pH, the rate of degradation of the photocatalyst was found to be higher than that of acidic pH. The independent variables of the model are time (9.6-122 min), pH (2-12.2), catalyst dose (0.2-0.4 g/L) and dye concentration (88-512 mg/L). It was seen that the degradation efficiency was significantly affected by the initial dye concentration and the pH, the optimal values of the parameters being a pH of 10.67, an initial concentration of 150 mg/L and ZnO dose of 0.37 g/L, the time taken being 88.52 min. The actual degradation efficiency of the dye reached 96.9% at optimized condition, which is quite close to the predicted value of 98.07%. PMID:27508375

  11. Synthesis of praseodymium hydroxide (Pr(OH)3) and praseodymium oxide (Pr6O11) nanorods via room temperature aging.

    PubMed

    Dodd, Aaron

    2013-02-15

    In this study, room-temperature aging has been investigated as an alternative to high-temperature hydrothermal processing for manufacturing Pr(OH)(3) nanorods. It was found that a simple process consisting of precipitation, washing, and room-temperature aging results in the formation of Pr(OH)(3) nanorods that are structurally different to those synthesized by hydrothermal processing. Rather than single crystals, the nanorods were found to consist of crystals viewed down the [12¯10] and [11¯00] axes sharing a common [0001] growth direction. Subsequent calcination yielded Pr(6)O(11) nanorods consisting of cubic crystals viewed down the [11¯0] and [11¯2¯] directions. The constituent crystals shared a common [110] direction parallel with the longitudinal rod axis.

  12. Features of the thermodynamics of trivalent lanthanide/actinide distribution reactions by tri-n-octylphosphine oxide and bis(2-ethylhexyl) phosphoric acid.

    PubMed

    Grimes, Travis S; Zalupski, Peter R; Martin, Leigh R

    2014-11-01

    A new methodology has been developed to study the thermochemical features of the biphasic transfer reactions of trisnitrato complexes of lanthanides and americium by a monofunctional solvating ligand (tri-n-octylphosphine oxide, TOPO). Stability constants for successive nitrato complexes (M(NO3)x(3-x)(aq) where M is Eu(3+), Am(3+), or Cm(3+)) were determined to assist in the calculation of the extraction constant, K(ex), for the metal ions under study. Enthalpies of extraction (ΔH(extr)) for the lanthanide series (excluding Pm(3+)) and Am(3+) by TOPO have been measured using isothermal titration calorimetry. The observed ΔH(extr) were found to be constant at ~29 kJ mol(-1) across the series from La(3+) to Er(3+), with a slight decrease observed from Tm(3+) to Lu(3+). These heats were found to be consistent with enthalpies determined using van't Hoff analysis of temperature dependent extraction studies. A complete set of thermodynamic parameters (ΔG, ΔH, ΔS) was calculated for Eu(NO3)3, Am(NO3)3, and Cm(NO3)3 extraction by TOPO and Am(3+) and Cm(3+) extraction by bis(2-ethylhexyl) phosphoric acid (HDEHP). A discussion comparing the energetics of these systems is offered. The measured biphasic extraction heats for the transplutonium elements, ΔH(extr), presented in these studies are the first ever direct measurements offered using two-phase calorimetric techniques. PMID:25315891

  13. Improved method for extracting lanthanides and actinides from acid solutions

    DOEpatents

    Horwitz, E.P.; Kalina, D.G.; Kaplan, L.; Mason, G.W.

    1983-07-26

    A process for the recovery of actinide and lanthanide values from aqueous acidic solutions uses a new series of neutral bi-functional extractants, the alkyl(phenyl)-N,N-dialkylcarbamoylmethylphosphine oxides. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high-level nuclear reprocessing waste solutions.

  14. Zinc oxide nanorod assisted rapid single-step process for the conversion of electrospun poly(acrylonitrile) nanofibers to carbon nanofibers with a high graphitic content

    NASA Astrophysics Data System (ADS)

    Nain, Ratyakshi; Singh, Dhirendra; Jassal, Manjeet; Agrawal, Ashwini K.

    2016-02-01

    The effect of incorporation of rigid zinc oxide (ZnO) nanostructures on carbonization behavior of electrospun special acrylic fiber grade poly(acrylonitrile) (PAN-SAF) nanofibers was investigated. ZnO nanorods with high aspect ratios were incorporated into a PAN-N,N-dimethylformamide system and the composite nanofibers reinforced with aligned ZnO rods up to 50 wt% were successfully electrospun, and subsequently, carbonized. The morphology and the structural analysis of the resultant carbon nanofibers revealed that the rigid ZnO nanorods, present inside the nanofibers, possibly acted as scaffolds (temporary support structures) for immobilization of polymer chains and assisted in uniform heat distribution. This facilitated rapid and efficient conversion of the polymer structure to the ladder, and subsequently, the graphitized structure. At the end of the process, the ZnO nanorods were found to completely separate from the carbonized fibers yielding pure carbon nanofibers with a high graphitic content and surface area. The approach could be used to eliminate the slow, energy intensive stabilization step and achieve fast conversion of randomly laid carbon nanofiber webs in a single step to carbon nanofibers without the application of external tension or internal templates usually employed to achieve a high graphitic content in such systems.The effect of incorporation of rigid zinc oxide (ZnO) nanostructures on carbonization behavior of electrospun special acrylic fiber grade poly(acrylonitrile) (PAN-SAF) nanofibers was investigated. ZnO nanorods with high aspect ratios were incorporated into a PAN-N,N-dimethylformamide system and the composite nanofibers reinforced with aligned ZnO rods up to 50 wt% were successfully electrospun, and subsequently, carbonized. The morphology and the structural analysis of the resultant carbon nanofibers revealed that the rigid ZnO nanorods, present inside the nanofibers, possibly acted as scaffolds (temporary support structures) for

  15. Exceptional performance of photoelectrochemical water oxidation of single-crystal rutile TiO2 nanorods dependent on the hole trapping of modified chloride

    NASA Astrophysics Data System (ADS)

    Zhang, Xuliang; Cui, Haiqin; Humayun, Muhammad; Qu, Yang; Fan, Naiying; Sun, Xiaojun; Jing, Liqiang

    2016-02-01

    It is highly desired to effectively trap photogenerated holes for efficient photoelectrochemical (PEC) water oxidation to evolve O2 on oxide semiconductors. Herein, it is found for the first time mainly based on the time-resolved- and atmosphere-controlled- surface photovoltage responses that the modified chloride would effectively trap photogenerated holes so as to prolong the charge lifetime and hence promote charge separation of single-crystal rutile TiO2 nanorods. Its strong capacity to trap holes, comparable to the widely-used methanol and Co(II) phosphate, is well responsible for the exceptional photoactivities for PEC water oxidation to evolve O2 on rutile nanorods with a proper amount of chloride modified, about 2.5-time high as that on the resulting anatase nanoparticles, even 10-time if the surface area is considered. Moreover, it is suggested that the hole trapping role of chemically-adsorbed chloride is related to its lonely-pair electrons, and to the subsequently-produced intermediate Cl atoms with proper electronegativity for evolving O2. Interestingly, this finding is also applicable to the chloride-modified anatase TiO2. This work will provide a feasible strategy to design high-activity nanostructured semiconductor photoanodes for PEC water oxidation, even for overall water splitting.

  16. Exceptional performance of photoelectrochemical water oxidation of single-crystal rutile TiO2 nanorods dependent on the hole trapping of modified chloride

    PubMed Central

    Zhang, Xuliang; Cui, Haiqin; Humayun, Muhammad; Qu, Yang; Fan, Naiying; Sun, Xiaojun; Jing, Liqiang

    2016-01-01

    It is highly desired to effectively trap photogenerated holes for efficient photoelectrochemical (PEC) water oxidation to evolve O2 on oxide semiconductors. Herein, it is found for the first time mainly based on the time-resolved- and atmosphere-controlled- surface photovoltage responses that the modified chloride would effectively trap photogenerated holes so as to prolong the charge lifetime and hence promote charge separation of single-crystal rutile TiO2 nanorods. Its strong capacity to trap holes, comparable to the widely-used methanol and Co(II) phosphate, is well responsible for the exceptional photoactivities for PEC water oxidation to evolve O2 on rutile nanorods with a proper amount of chloride modified, about 2.5-time high as that on the resulting anatase nanoparticles, even 10-time if the surface area is considered. Moreover, it is suggested that the hole trapping role of chemically-adsorbed chloride is related to its lonely-pair electrons, and to the subsequently-produced intermediate Cl atoms with proper electronegativity for evolving O2. Interestingly, this finding is also applicable to the chloride-modified anatase TiO2. This work will provide a feasible strategy to design high-activity nanostructured semiconductor photoanodes for PEC water oxidation, even for overall water splitting. PMID:26906953

  17. Ultratrace Level Determination and Quantitative Analysis of Kidney Injury Biomarkers in Patient Samples Attained by Zinc Oxide Nanorods

    PubMed Central

    Singh, Manpreet; Alabanza, Anginelle; Gonzalez, Lorelis E.; Wang, Weiwei; Reeves, W. Brian; Hahm, Jong-in

    2016-01-01

    Determining ultratrace amounts of protein biomarkers in patient samples in a straightforward and quantitative manner is extremely important for early disease diagnosis and treatment. Here, we successfully demonstrate the novel use of zinc oxide nanorods (ZnO NRs) in the ultrasensitive and quantitative detection of two acute kidney injury (AKI)-related protein biomarkers, tumor necrosis factor (TNF)-α and interleukin (IL)-8, directly from patient samples. We first validate the ZnO NRs-based IL-8 results via comparison with those obtained from using a conventional enzyme-linked immunosorbent method in samples from 38 individuals. We further assess the full detection capability of the ZnO NRs-based technique by quantifying TNF-α, whose levels in human urine are often below the detection limits of conventional methods. Using the ZnO NR platforms, we determine the TNF-α concentrations of all 46 patient samples tested, down to the fg/mL level. Subsequently, we screen for TNF-α levels in approximately 50 additional samples collected from different patient groups in order to demonstrate a potential use of the ZnO NRs-based assay in assessing cytokine levels useful for further clinical monitoring. Our research efforts demonstrate that ZnO NRs can be straightforwardly employed in the rapid, ultrasensitive, quantitative, and simultaneous detection of multiple AKI-related biomarkers directly in patient urine samples, providing an unparalleled detection capability beyond those of conventional analysis methods. Additional key advantages of the ZnO NRs-based approach include a fast detection speed, low-volume assay condition, multiplexing ability, and easy automation/integration capability to existing fluorescence instrumentation. Therefore, we anticipate that our ZnO NRs-based detection method will be highly beneficial for overcoming the frequent challenges in early biomarker development and treatment assessment, pertaining to the facile and ultrasensitive quantification of

  18. Ultratrace level determination and quantitative analysis of kidney injury biomarkers in patient samples attained by zinc oxide nanorods.

    PubMed

    Singh, Manpreet; Alabanza, Anginelle; Gonzalez, Lorelis E; Wang, Weiwei; Reeves, W Brian; Hahm, Jong-in

    2016-02-28

    Determining ultratrace amounts of protein biomarkers in patient samples in a straightforward and quantitative manner is extremely important for early disease diagnosis and treatment. Here, we successfully demonstrate the novel use of zinc oxide nanorods (ZnO NRs) in the ultrasensitive and quantitative detection of two acute kidney injury (AKI)-related protein biomarkers, tumor necrosis factor (TNF)-α and interleukin (IL)-8, directly from patient samples. We first validate the ZnO NRs-based IL-8 results via comparison with those obtained from using a conventional enzyme-linked immunosorbent method in samples from 38 individuals. We further assess the full detection capability of the ZnO NRs-based technique by quantifying TNF-α, whose levels in human urine are often below the detection limits of conventional methods. Using the ZnO NR platforms, we determine the TNF-α concentrations of all 46 patient samples tested, down to the fg per mL level. Subsequently, we screen for TNF-α levels in approximately 50 additional samples collected from different patient groups in order to demonstrate a potential use of the ZnO NRs-based assay in assessing cytokine levels useful for further clinical monitoring. Our research efforts demonstrate that ZnO NRs can be straightforwardly employed in the rapid, ultrasensitive, quantitative, and simultaneous detection of multiple AKI-related biomarkers directly in patient urine samples, providing an unparalleled detection capability beyond those of conventional analysis methods. Additional key advantages of the ZnO NRs-based approach include a fast detection speed, low-volume assay condition, multiplexing ability, and easy automation/integration capability to existing fluorescence instrumentation. Therefore, we anticipate that our ZnO NRs-based detection method will be highly beneficial for overcoming the frequent challenges in early biomarker development and treatment assessment, pertaining to the facile and ultrasensitive quantification

  19. Separation of actinides from lanthanides

    DOEpatents

    Smith, Barbara F.; Jarvinen, Gordon D.; Ryan, Robert R.

    1989-01-01

    An organic extracting solution and an extraction method useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form. The extracting solution consists of a primary ligand and a secondary ligand, preferably in an organic solvent. The primary ligand is a substituted monothio-1,3-dicarbonyl, which includes a substituted 4-acyl-2-pyrazolin-5-thione, such as 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT). The secondary ligand is a substituted phosphine oxide, such as trioctylphosphine oxide (TOPO).

  20. Superior asymmetric supercapacitor based on Ni-Co oxide nanosheets and carbon nanorods

    PubMed Central

    Wang, Rutao; Yan, Xingbin

    2014-01-01

    Nickel and cobalt (Ni-Co) binary oxide nanosheets with mesoporous structure are prepared by a facile approach based on the formation and disassociation of nickel/cobalt-citrate complex, and they show an ultra-high Faradaic capacitance up to 1846 F g−1 and excellent rate capability. On this basic, advanced aqueous asymmetric supercapacitors (AASs) are successfully built by using the Ni-Co oxide as the positive electrode and three kinds of activated carbons respectively as the negative electrode. As-made AASs are able to work reversibly in a full operated voltage region of 0–1.6 V and exhibit outstanding electrochemical performance. Among them, activated polyaniline-derived carbon (APDC)//Ni-Co oxide AASs shows the highest specific capacitance of 202 F g−1, the maximum energy density of 71.7 Wh kg−1, and superior combination of high energy and power density (a energy density of 41.6 Wh kg−1 at a high power density of 16 kW kg−1). PMID:24429842

  1. Ionization Energies of Lanthanides

    ERIC Educational Resources Information Center

    Lang, Peter F.; Smith, Barry C.

    2010-01-01

    This article describes how data are used to analyze the pattern of ionization energies of the lanthanide elements. Different observed pathways of ionization between different ground states are discussed, and the effects of pairing, exchange, and orbital interactions on ionization energies of the lanthanides are evaluated. When all the above…

  2. Pressure Regulations on the Surface Properties of CeO2 Nanorods and Their Catalytic Activity for CO Oxidation and Nitrile Hydrolysis Reactions.

    PubMed

    Li, Jing; Zhang, Zhiyun; Gao, Wei; Zhang, Sai; Ma, Yuanyuan; Qu, Yongquan

    2016-09-01

    Surface properties of nanoscale CeO2 catalysts in terms of the surface Ce(3+) fraction and concentration of oxygen vacancy can affect their catalytic performance significantly. Continual adjustment on surface properties of CeO2 with the morphological preservation has not been realized by synthetic methods. The revisited studies show that surface properties of CeO2 nanorods can be effectively regulated by synthetic pressures while the rodlike morphology is well-preserved. Such phenomena are ascribed to the contact possibility between Ce(3+) species and dissolved O2, which is balanced by the rapidly increased and gradually saturated dissolution/recrystallization rate of Ce(OH)3 and linearly increased concentration of dissolved O2 with the increase of total air pressure or partial pressure of O2. Surface-property-dependent catalytic activity of CeO2 nanorods synthesized under various pressures was also demonstrated in two benchmark reactions-catalytic oxidation of CO and hydrolysis of nitrile. Such a finding of the pressure regulation on the reducible metal oxides provides an effective approach to rationally design novel catalysts for specific reactions, where ceria are supports, promoters, or actives.

  3. Preparation of thin hexagonal highly-ordered anodic aluminum oxide (AAO) template onto silicon substrate and growth ZnO nanorod arrays by electrodeposition

    NASA Astrophysics Data System (ADS)

    Chahrour, Khaled M.; Ahmed, Naser M.; Hashim, M. R.; Elfadill, Nezar G.; Qaeed, M. A.; Bououdina, M.

    2014-12-01

    In this study, anodic aluminum oxide (AAO) templates of Aluminum thin films onto Ti-coated silicon substrates were prepared for growth of nanostructure materials. Hexagonally highly ordered thin AAO templates were fabricated under controllable conditions by using a two-step anodization. The obtained thin AAO templates were approximately 70 nm in pore diameter and 250 nm in length with 110 nm interpore distances within an area of 3 cm2. The difference between first and second anodization was investigated in details by in situ monitoring of current-time curve. A bottom barrier layer of the AAO templates was removed during dropping the voltage in the last period of the anodization process followed by a wet etching using phosphoric acid (5 wt%) for several minutes at ambient temperature. As an application, Zn nanorod arrays embedded in anodic alumina (AAO) template were fabricated by electrodeposition. Oxygen was used to oxidize the electrodeposited Zn nanorods in the AAO template at 700 °C. The morphology, structure and photoluminescence properties of ZnO/AAO assembly were analyzed using Field-emission scanning electron microscope (FESEM), Energy dispersive X-ray spectroscopy (EDX), Atomic force microscope (AFM), X-ray diffraction (XRD) and photoluminescence (PL).

  4. Synthesis of hierarchical NiCo2O4 hollow nanorods via sacrificial-template accelerate hydrolysis for electrochemical glucose oxidation.

    PubMed

    Yang, Jiao; Cho, Misuk; Lee, Youngkwan

    2016-01-15

    Hierarchical NiCo2O4 hollow nanorods (HR) were directly grown on stainless steel via a sacrificial template accelerated hydrolysis and post calcination using ZnO nanorod as a template. The composition of the NiCo2O4 HR electrode was determined using X-ray diffraction and X-ray photoelectron spectroscopy. The morphology of the NiCo2O4 HR is comprised of nanoflakes that were characterized with scanning electron microscopy and transmission electron microscopy. The mixed-valence metal oxide and hollow structure provided high chemical reactivity and a large surface area for glucose oxidation in an alkaline solution. Under an optimal applied potential of +0.6 V, the developed NiCo2O4 HR electrode showed a broad detection range of 0.0003–1.0 mM, a sensitivity of 1685.1 μA mM−1 cm−2, and a low detection limit of 0.16 μM. These results represent a significant improvement over both NiO and Co3O4 HR. The developed NiCo2O4 HR electrode not only demonstrated excellent selectivity in the presence of several electro-active species, but also exhibited high stability following a 200 cycles voltammetry test. PMID:26281005

  5. Pressure Regulations on the Surface Properties of CeO2 Nanorods and Their Catalytic Activity for CO Oxidation and Nitrile Hydrolysis Reactions.

    PubMed

    Li, Jing; Zhang, Zhiyun; Gao, Wei; Zhang, Sai; Ma, Yuanyuan; Qu, Yongquan

    2016-09-01

    Surface properties of nanoscale CeO2 catalysts in terms of the surface Ce(3+) fraction and concentration of oxygen vacancy can affect their catalytic performance significantly. Continual adjustment on surface properties of CeO2 with the morphological preservation has not been realized by synthetic methods. The revisited studies show that surface properties of CeO2 nanorods can be effectively regulated by synthetic pressures while the rodlike morphology is well-preserved. Such phenomena are ascribed to the contact possibility between Ce(3+) species and dissolved O2, which is balanced by the rapidly increased and gradually saturated dissolution/recrystallization rate of Ce(OH)3 and linearly increased concentration of dissolved O2 with the increase of total air pressure or partial pressure of O2. Surface-property-dependent catalytic activity of CeO2 nanorods synthesized under various pressures was also demonstrated in two benchmark reactions-catalytic oxidation of CO and hydrolysis of nitrile. Such a finding of the pressure regulation on the reducible metal oxides provides an effective approach to rationally design novel catalysts for specific reactions, where ceria are supports, promoters, or actives. PMID:27534804

  6. Enhanced thermal stability of Ag nanorods through capping

    SciTech Connect

    Bachenheimer, Lou; Elliott, Paul; Stagon, Stephen; Huang, Hanchen

    2014-11-24

    Ag nanorods may serve as sensors in the detection of trace amounts of chemical agents, even single molecules, through surface enhanced Raman spectroscopy (SERS). However, thermal coarsening of Ag nanorods near room temperature limits their applications. This letter proposes the use of a thin oxide capping layer to enhance the thermal stability of Ag nanorods beyond 100 °C. Using electron microscopy characterization and SERS tests, the authors show that the proposed method is effective in stabilizing both morphology and sensitivity of Ag nanorods. The results of this work extend the applicability of Ag nanorods as chemical sensors to higher temperatures.

  7. The Lanthanide Contraction Revisited

    SciTech Connect

    Seitz, Michael; Oliver, Allen G.; Raymond, Kenneth N.

    2007-04-19

    A complete, isostructural series of lanthanide complexes (except Pm) with the ligand TREN-1,2-HOIQO has been synthesized and structurally characterized by means of single-crystal X-ray analysis. All complexes are 1D-polymeric species in the solid state, with the lanthanide being in an eight-coordinate, distorted trigonal-dodecahedral environment with a donor set of eight unique oxygen atoms. This series constitutes the first complete set of isostructural lanthanide complexes with a ligand of denticity greater than two. The geometric arrangement of the chelating moieties slightly deviates across the lanthanide series, as analyzed by a shape parameter metric based on the comparison of the dihedral angles along all edges of the coordination polyhedron. The apparent lanthanide contraction in the individual Ln-O bond lengths deviates considerably from the expected quadratic decrease that was found previously in a number of complexes with ligands of low denticity. The sum of all bond lengths around the trivalent metal cation, however, is more regular, showing an almost ideal quadratic behavior across the entire series. The quadratic nature of the lanthanide contraction is derived theoretically from Slater's model for the calculation of ionic radii. In addition, the sum of all distances along the edges of the coordination polyhedron show exactly the same quadratic dependency as the Ln-X bond lengths. The universal validity of this coordination sphere contraction, concomitant with the quadratic decrease in Ln-X bond lengths, was confirmed by reexamination of four other, previously published, almost complete series of lanthanide complexes. Due to the importance of multidentate ligands for the chelation of rare-earth metals, this result provides a significant advance for the prediction and rationalization of the geometric features of the corresponding lanthanide complexes, with great potential impact for all aspects of lanthanide coordination.

  8. Surfactant controlled synthesis of crystalline phosphovanadate nanorods

    SciTech Connect

    Asnani, Minakshi; Thomas, Jency; Sen, Prasenjit; Ramanan, Arunachalam . E-mail: aramanan@chemistry.iitd.ac.in

    2007-04-12

    Phosphovanadate nanorods were obtained in a reaction of vanadium (V) oxide as a precursor and a cationic surfactant, dodecylpyridinium chloride, as structure directing template at pH {approx}3 at room temperature. The composition and morphology of the nanorods was established by powder X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), fourier transform infra-red spectroscopy (FTIR), thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and atomic force microscopy (AFM). The obtained nanorods have diameters of 40-60 nm with lengths up to 1 {mu}m. The effect of reaction parameters such as concentration of surfactant and pH of the solution on the growth of nanorods has been investigated. A plausible mechanism involving the coalescence of nanoparticle 'seeds' leading to one-dimensional nanorods is also discussed. The same reaction when performed under hydrothermal condition, keeping other reaction parameters unchanged, resulted in the formation of phosphovanadate nanospheres of diameter 10-15 nm.

  9. Ultratrace level determination and quantitative analysis of kidney injury biomarkers in patient samples attained by zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Singh, Manpreet; Alabanza, Anginelle; Gonzalez, Lorelis E.; Wang, Weiwei; Reeves, W. Brian; Hahm, Jong-In

    2016-02-01

    Determining ultratrace amounts of protein biomarkers in patient samples in a straightforward and quantitative manner is extremely important for early disease diagnosis and treatment. Here, we successfully demonstrate the novel use of zinc oxide nanorods (ZnO NRs) in the ultrasensitive and quantitative detection of two acute kidney injury (AKI)-related protein biomarkers, tumor necrosis factor (TNF)-α and interleukin (IL)-8, directly from patient samples. We first validate the ZnO NRs-based IL-8 results via comparison with those obtained from using a conventional enzyme-linked immunosorbent method in samples from 38 individuals. We further assess the full detection capability of the ZnO NRs-based technique by quantifying TNF-α, whose levels in human urine are often below the detection limits of conventional methods. Using the ZnO NR platforms, we determine the TNF-α concentrations of all 46 patient samples tested, down to the fg per mL level. Subsequently, we screen for TNF-α levels in approximately 50 additional samples collected from different patient groups in order to demonstrate a potential use of the ZnO NRs-based assay in assessing cytokine levels useful for further clinical monitoring. Our research efforts demonstrate that ZnO NRs can be straightforwardly employed in the rapid, ultrasensitive, quantitative, and simultaneous detection of multiple AKI-related biomarkers directly in patient urine samples, providing an unparalleled detection capability beyond those of conventional analysis methods. Additional key advantages of the ZnO NRs-based approach include a fast detection speed, low-volume assay condition, multiplexing ability, and easy automation/integration capability to existing fluorescence instrumentation. Therefore, we anticipate that our ZnO NRs-based detection method will be highly beneficial for overcoming the frequent challenges in early biomarker development and treatment assessment, pertaining to the facile and ultrasensitive quantification

  10. Ultratrace level determination and quantitative analysis of kidney injury biomarkers in patient samples attained by zinc oxide nanorods

    NASA Astrophysics Data System (ADS)

    Singh, Manpreet; Alabanza, Anginelle; Gonzalez, Lorelis E.; Wang, Weiwei; Reeves, W. Brian; Hahm, Jong-In

    2016-02-01

    Determining ultratrace amounts of protein biomarkers in patient samples in a straightforward and quantitative manner is extremely important for early disease diagnosis and treatment. Here, we successfully demonstrate the novel use of zinc oxide nanorods (ZnO NRs) in the ultrasensitive and quantitative detection of two acute kidney injury (AKI)-related protein biomarkers, tumor necrosis factor (TNF)-α and interleukin (IL)-8, directly from patient samples. We first validate the ZnO NRs-based IL-8 results via comparison with those obtained from using a conventional enzyme-linked immunosorbent method in samples from 38 individuals. We further assess the full detection capability of the ZnO NRs-based technique by quantifying TNF-α, whose levels in human urine are often below the detection limits of conventional methods. Using the ZnO NR platforms, we determine the TNF-α concentrations of all 46 patient samples tested, down to the fg per mL level. Subsequently, we screen for TNF-α levels in approximately 50 additional samples collected from different patient groups in order to demonstrate a potential use of the ZnO NRs-based assay in assessing cytokine levels useful for further clinical monitoring. Our research efforts demonstrate that ZnO NRs can be straightforwardly employed in the rapid, ultrasensitive, quantitative, and simultaneous detection of multiple AKI-related biomarkers directly in patient urine samples, providing an unparalleled detection capability beyond those of conventional analysis methods. Additional key advantages of the ZnO NRs-based approach include a fast detection speed, low-volume assay condition, multiplexing ability, and easy automation/integration capability to existing fluorescence instrumentation. Therefore, we anticipate that our ZnO NRs-based detection method will be highly beneficial for overcoming the frequent challenges in early biomarker development and treatment assessment, pertaining to the facile and ultrasensitive quantification

  11. Extraction of trivalent lanthanides and actinides by ``CMPO-like`` calixarenes

    SciTech Connect

    Delmau, L.H.; Simon, N.; Schwing-Weill, M.J.

    1999-04-01

    Extractive properties of calix[4]arenes bearing carbamoylmethylphosphine oxide moieties on their upper rim toward trivalent lanthanide and actinide cations were investigated. The study revealed that these molecules selectively extract light lanthanides and actinides from heavy lanthanides. All parameters present in the extraction system were varied to determine the origin of the selectivity. It was found that this selectivity requires a calix[4]arene platform and acetamidophosphine oxide groups containing phenyl substituents on the four phosphorus atoms.

  12. Enhancement in ion adsorption rate and desalination efficiency in a capacitive deionization cell through improved electric field distribution using electrodes composed of activated carbon cloth coated with zinc oxide nanorods.

    PubMed

    Laxman, Karthik; Myint, Myo Tay Zar; Bourdoucen, Hadj; Dutta, Joydeep

    2014-07-01

    Electrodes composed of activated carbon cloth (ACC) coated with zinc oxide (ZnO) nanorods are compared with plain ACC electrodes, with respect to their desalination efficiency of a 17 mM NaCl solution at different applied potentials. Polarization of the ZnO nanorods increased the penetration depth and strength of the electric field between the electrodes, leading to an increase in the capacitance and charge efficiency at reduced input charge ratios. Uniform distribution of the electric field lines between two electrodes coated with ZnO nanorods led to faster ion adsorption rates, reduced the electrode saturation time, and increased the average desalination efficiency by ∼45% for all applied potentials. The electrodes were characterized for active surface area, capacitance from cyclic voltammetry, theoretical assessment of surface area utilization, and the magnitude of electric field force acting on an ion of unit charge for each potential.

  13. Near-Infrared and Ultraviolet Photodetector Based on p-n Homojunction of Undoped and Phosphorus-Doped Zinc Oxide Nanorods.

    PubMed

    Tuico, Anthony; Copa, Vernalyn; Ferrolino, John Paul; Vergara, Christopher Jude; Abrenica, Jefferson; Salvador, Arnel; Somintac, Armando

    2016-06-01

    The application of a p-n homojunction based on zinc oxide (ZnO) nanorods as photodetector is presented in this study. The homojunctions were grown via chemical bath deposition for 6, 9, and 12 hours per layer of the junction. X-ray diffraction and scanning electron micrographs confirmed the material composition, structure, and morphology of the grown device. Current-voltage (I-V) measurements were done to verify the diode-like behavior of the ZnO p-n homojunction. Upon illumination, it is observed through I-V curves and through photocurrent measurements that the fabricated device is sensitive to ultraviolet and near-infrared light, respectively. The peak sensitivities in the photocurrent spectrum were found tunable based on the observed red shift as the length of the nanorods is increased. In addition to this, upon applying a positive voltage bias, the response of the device was observed to enhance by 5 orders of magnitude. In general, the device was successfully proven to have a great potential for applications in photodetection. PMID:27427690

  14. Studies on the structural and optical properties of zinc oxide nanobushes and Co-doped ZnO self-aggregated nanorods synthesized by simple thermal decomposition route

    SciTech Connect

    Freedsman, Joseph J.; Kennedy, L. John; Kumar, R. Thinesh; Sekaran, G.; Vijaya, J. Judith

    2010-10-15

    Pure and Co-doped zinc oxide nanomaterials were prepared by a simple low temperature synthesis and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution-transmission electron microscopy (HR-TEM), diffused reflectance spectroscopy (DRS) and electron paramagnetic resonance (EPR) techniques. The results showed the formation of nanobushes that consists of several nanowires for pure ZnO and the nanorods formed by self-aggregation for Co-doped ZnO. The presence of Co{sup 2+} ions replacing some of the Zn{sup 2+} in the ZnO lattice was confirmed by EPR and DRS studies. The mechanism for the formation of self-aggregated and self-aligned ZnO rods after the incorporation of cobalt in the lattice by the building block units is discussed in this study. Morphological studies were carried out using SEM and HR-TEM, which supports the validity of the proposed mechanism for the formation of ZnO nanobushes and Co-doped ZnO nanorods. The synthesized nanomaterials were found to have good optoelectronic properties.

  15. Development of diamond-lanthanide metal oxide affinity composites for the selective capture of endogenous serum phosphopeptides.

    PubMed

    Hussain, Dilshad; Musharraf, Syed Ghulam; Najam-ul-Haq, Muhammad

    2016-02-01

    Development of affinity materials for the selective enrichment of phosphopeptides has attracted attention during the last decade. In this work, diamond-lanthanum oxide and diamond-samarium oxide composites have been fabricated via the hydrothermal method. The composites are characterized by scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDAX), and atomic force microscopy (AFM). The analyses confirm the size and composition of the nanocomposites. They have been applied to selectively capture phosphorylated peptides from standard proteins (β-casein and BSA). Selectivity is calculated as 1:3000 and 1:1500 while sensitivity down to 1 and 20 fmol for diamond-lanthanum oxide and diamond-samarium oxide nanocomposites, respectively. Enrichment efficiency has also been evaluated for non-fat milk digest where 18 phosphopeptides are enriched. Total of 213 and 187 phosphopeptides are captured from tryptic digest of HeLa cells extracted proteins by diamond-lanthanum oxide and diamond-samarium oxide, respectively. Finally, human serum, without any pre-treatment, is applied and nanocomposites capture the endogenous serum phosphopeptides.

  16. An electrochemical biosensor with nanointerface for lactate detection based on lactate dehydrogenase immobilized on zinc oxide nanorods.

    PubMed

    Nesakumar, Noel; Thandavan, Kavitha; Sethuraman, Swaminathan; Krishnan, Uma Maheswari; Rayappan, John Bosco Balaguru

    2014-01-15

    Hepatic immaturity is observed particularly in children whose age is under three, when the lactate concentration is greater than the normal level in blood. An electrochemical lactate biosensor was developed by immobilizing lactate dehydrogenase (LDH) on to ZnO nanorods at pH 7.4 via chitosan. Growth of polycrystalline ZnO nanorods towards (101) plane was confirmed using XRD. The FE-SEM study revealed the formation of ZnO nanorods with an aspect ratio of 3.24. Immobilization of LDH on ZnO nanorods was confirmed using FTIR spectra and surface coverage. Electrochemical studies were carried out through cyclic voltammetry and amperometry using three electrode system with Au/NanoZnO/LDH as working electrode, Ag/AgCl in 0.1 M KCl as reference electrode and Pt wire as counter electrode. The sensitivity of the biosensor was found to be 1.832 μA μmol(-1) L exhibiting linearity 0.2-0.8 μmol L(-1) with the detection and quantification limits of 4.73 and 15.75 nmol L(-1) respectively. The response time of Au/NanoZnO/LDH bioelectrode was found to be <1 s. Prediction band for net current was framed to enhance specificity. Michaelis-Menten constant (KM(app)) and maximum rate (Imax) values for immobilized LDH were found to be 0.38 μmol L(-1) and 2.798 μA respectively. Repeatability and reproducibility of LDH biosensor were also reported. PMID:24231089

  17. Making sense of lanthanide luminescence.

    PubMed

    Werts, Martinus H V

    2005-01-01

    The luminescence of trivalent lanthanide ions has found applications in lighting, lasers, optical telecommunications, medical diagnostics, and various other fields. This introductory review presents the basics of organic and inorganic luminescent materials containing lanthanide ions, their applications, and some recent developments. After a brief history of the discovery, purification and early spectroscopic studies of the lanthanides, the radiative and nonradiative transitions of the 4f electrons in lanthanide ions are discussed. Lanthanide-doped phosphors, glasses and crystals as well as luminescent lanthanide complexes with organic ligands receive attention with respect to their preparation and their applications. Finally, two recent developments in the field of luminescent materials are addressed: near-infrared luminescent lanthanide complexes and lanthanide-doped nano-particles.

  18. In vivo toxicity studies of europium hydroxide nanorods in mice

    SciTech Connect

    Patra, Chitta Ranjan Abdel Moneim, Soha S.; Wang, Enfeng; Dutta, Shamit; Patra, Sujata; Eshed, Michal; Mukherjee, Priyabrata; Gedanken, Aharon; Shah, Vijay H.; Mukhopadhyay, Debabrata

    2009-10-01

    Lanthanide nanoparticles and nanorods have been widely used for diagnostic and therapeutic applications in biomedical nanotechnology due to their fluorescence and pro-angiogenic properties to endothelial cells, respectively. Recently, we have demonstrated that europium (III) hydroxide [Eu{sup III}(OH){sub 3}] nanorods, synthesized by the microwave technique and characterized by several physico-chemical techniques, can be used as pro-angiogenic agents which introduce future therapeutic treatment strategies for severe ischemic heart/limb disease, and peripheral ischemic disease. The toxicity of these inorganic nanorods to endothelial cells was supported by several in vitro assays. To determine the in vivo toxicity, these nanorods were administered to mice through intraperitoneal injection (IP) everyday over a period of seven days in a dose dependent (1.25 to 125 mg kg{sup -1} day{sup -1}) and time dependent manner (8-60 days). Bio-distribution of europium elements in different organs was analyzed by inductively coupled plasma mass spectrometry (ICPMS). Short-term (S-T) and long-term (L-T) toxicity studies (mice euthanized on days 8 and 60 for S-T and L-T, respectively) show normal blood hematology and serum clinical chemistry with the exception of a slight elevation of liver enzymes. Histological examination of nanorod-treated vital organs (liver, kidney, spleen and lungs) showed no or only mild histological changes that indicate mild toxicity at the higher dose of nanorods.

  19. Magnetic and transport studies of core-shell nanorods based on metallic oxide ferromagnet SrRuO3

    NASA Astrophysics Data System (ADS)

    Zheng, M.; Li, X. Y.; Zhu, Q. X.; Li, H. R.; Shi, L.; Li, X. M.; Zheng, R. K.

    2016-01-01

    This study presents the synthesis of perovskite metal-semiconductor core-shell heterostructures by sputtering SrRuO3 (SRO) shell layer on vertically aligned hydrothermally produced ZnO nanorods. Compared to the two-dimensional SRO films, the magnetic behaviors of the SRO shells on ZnO nanorods are morphology and thickness dependent, as reflected by the magnetic isotropy effects and the appearance of double-step magnetic hysteresis loops caused by nanograin-induced disorder and uncompensated spin at the surface and interface. The appearance of low-temperature resistance minimum and the good fitting of the low-temperature resistance data to a theoretical model establish the emergence of weak localization effect in the SRO shells, whose strength can be reinforced by a magnetic field. In addition, an apparent low-resistance Ohmic contact was realized in the ZnO/SRO heterojunctions due to the lower work function of the SRO. This, together with the absence of the Schottky barrier at the interface, demonstrates that the ZnO/SRO nanostructures could hold great promise for applications in advanced electron field emitters.

  20. Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents

    SciTech Connect

    Tkachenko, L.; Babain, V.; Alyapyshev, M.; Vizniy, A.; Il'in, A.; Shadrin, A.

    2013-07-01

    Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

  1. Luminescent macrocyclic lanthanide complexes

    DOEpatents

    Raymond, Kenneth N.; Corneillie, Todd M.; Xu, Jide

    2012-05-08

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  2. Luminescent macrocyclic lanthanide complexes

    DOEpatents

    Raymond, Kenneth N; Corneillie, Todd M; Xu, Jide

    2014-05-20

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  3. New trend for synthesizing of magnetic nanorods with titanomaghemite structure

    NASA Astrophysics Data System (ADS)

    Saber, Osama

    2016-07-01

    This research aims at developing magnetic and optical materials through fabrication of uniform nanorods by facile and novel technique. In this trend, titanium and iron were successfully combined together forming nanorods without template or high temperature by urea hydrolysis. TEM images showed uniform and homogeneous nanorods with dimensions; 10 nm in width and 50 nm in length. In the same time, fine nanoparticles were observed around the nanorods. With further treatment for the nanorods at high temperature and pressure, FESEM images revealed that the dimensions of the rods slightly increased to be 70 nm in length and 12 nm in width with a complete disappearance of the nanoparticles. Using X-ray diffraction, thermal analyses and infrared spectra in addition to the results of the electron microscopy, the oriented attachment mechanism was suggested for the formation of titanium iron oxides nanorods. The magnetic measurements revealed that the prepared nanorods possess ferromagnetic behavior and exhibit high saturation magnetization. Also, the optical properties showed that the nanorods have high absorption in the visible region and possess low band gap energy. Finally, we concluded that it is probably the first time to prepare nanorods by urea hydrolysis. The advanced optical and magnetic properties give the prepared nanorods relevance to use as building blocks in functional nanoscale devices.

  4. A molecular approach to Cu doped ZnO nanorods with tunable dopant content.

    PubMed

    Pashchanka, Mikhail; Hoffmann, Rudolf C; Gurlo, Aleksander; Swarbrick, Janine C; Khanderi, Jayaprakash; Engstler, Jörg; Issanin, Alexander; Schneider, Jörg J

    2011-04-28

    A novel molecular approach to the synthesis of polycrystalline Cu-doped ZnO rod-like nanostructures with variable concentrations of introduced copper ions in ZnO host matrix is presented. Spectroscopic (PLS, variable temperature XRD, XPS, ELNES, HERFD) and microscopic (HRTEM) analysis methods reveal the +II oxidation state of the lattice incorporated Cu ions. Photoluminescence spectra show a systematic narrowing (tuning) of the band gap depending on the amount of Cu(II) doping. The advantage of the template assembly of doped ZnO nanorods is that it offers general access to doped oxide structures under moderate thermal conditions. The doping content of the host structure can be individually tuned by the stoichiometric ratio of the molecular precursor complex of the host metal oxide and the molecular precursor complex of the dopant, Di-aquo-bis[2-(methoxyimino)-propanoato]zinc(II) 1 and -copper(II) 2. Moreover, these keto-dioximato complexes are accessible for a number of transition metal and lanthanide elements, thus allowing this synthetic approach to be expanded into a variety of doped 1D metal oxide structures.

  5. In vitro cytotoxicity of gold nanorods in A549 cells.

    PubMed

    Tang, Ying; Shen, Yafeng; Huang, Libin; Lv, Gaojian; Lei, Changhai; Fan, Xiaoyan; Lin, Fangxing; Zhang, Yuxia; Wu, Lihui; Yang, Yongji

    2015-03-01

    Gold nanoparticles, which have unique physicochemical characteristics, are being used for an increasingly wide range of applications in biomedical research. In this study, gold nanorods (width of 25 nm, length of 52 nm) were found to be internalized by A549 cells and were primarily localized in the lysosomes and membranous vesicles. The integrity of the membranes of A549 cells exposed to gold nanorods for 4h was damaged, as indicated by laser scanning confocal microscopy (LSCM). Increased lactate dehydrogenase (LDH) leakage and decreased cell viability further indicated the concentration-dependent cytotoxicity of the gold nanorods to the A549 cells. Reactive oxygen species (ROS) production was induced in the A549 cells by the gold nanorods, and this effect was positively correlated with the concentration of the gold nanorods. The results of this study indicated that exposure to gold nanorods caused dose-dependent cytotoxicity in A549 cells and that oxidative stress may be the main factor causing cytotoxicity.

  6. Cerium oxide as a promoter for the electro-oxidation reaction of ethanol: in situ XAFS characterization of the Pt nanoparticles supported on CeO2 nanoparticles and nanorods.

    PubMed

    Corchado-García, Juan; Betancourt, Luis E; Vélez, Carlos A; Senanayake, Sanjaya D; Stacchiola, Dario; Sasaki, Kotaro; Guinel, Maxime J-F; Zhou, Yunyun; Cheung, Chin Li; Cabrera, Carlos R

    2015-12-28

    In this study we probe the electrocatalytic activity of Pt nanoparticles supported on ceria nanoparticles (NPs) and nanorods (NRs) in the ethanol oxidation reaction (EOR) in alkaline media. The goal of this study was to relate morphology, support structure and composition to the EOR catalytic activity by using in situ X-ray absorption fine structure (XAFS) studies. Cyclic voltammetry experiments showed that both ceria supported catalysts (NP vs. NR) had similar peak current densities at fast scan rates, however at slow scan rates, the ceria NR catalyst showed superior catalytic activity. In situ XAFS studies in KOH showed that both ceria supported catalysts had more electron density in their d-band (with the ceria NR having more electron density overall) than ceria - free Pt/Vulcan standard. However, in an ethanol solution the ceria NR catalyst had the least electron density. We propose that this change is due to the increased charge transfer efficiency between the ceria nanorod support and platinum. In the KOH solution, the increased electron density makes the platinum less electrophilic and hinders Pt-OH bond formation. In the EtOH solution, platinum's increased nucleophilicity facilitates the bond formation between Pt and the electron deficient carbon in ethanol which in turn withdraws the electron density from platinum and increases the white line intensity as observed in the XAS measurements.

  7. Design of lanthanide fingers: compact lanthanide-binding metalloproteins.

    PubMed

    am Ende, Christopher W; Meng, Hai Yun; Ye, Mao; Pandey, Anil K; Zondlo, Neal J

    2010-08-16

    Lanthanides have interesting chemical properties; these include luminescent, magnetic, and catalytic functions. Toward the development of proteins incorporating novel functions, we have designed a new lanthanide-binding motif, lanthanide fingers. These were designed based on the Zif268 zinc finger, which exhibits a beta beta alpha structural motif. Lanthanide fingers utilize an Asp(2)Glu(2) metal-coordination environment to bind lanthanides through a tetracarboxylate peptide ligand. The iterative design of a general lanthanide-binding peptide incorporated the following key elements: 1) residues with high alpha-helix and beta-sheet propensities in the respective secondary structures; 2) an optimized big box alpha-helix N-cap; 3) a Schellman alpha-helix C-cap motif; and 4) an optional D-Pro-Ser type II' beta-turn in the beta-hairpin. The peptides were characterized for lanthanide binding by circular dichroism (CD), NMR, and fluorescence spectroscopy. In all instances, stabilization of the peptide secondary structures resulted in an increase in metal affinity. The optimized protein design was a 25-residue peptide that was a general lanthanide-binding motif; this binds all lanthanides examined in a competitive aqueous environment, with a dissociation constant of 9.3 microM for binding Er(3+). CD spectra of the peptide-lanthanide complexes are similar to those of zinc fingers and other beta beta alpha proteins. Metal binding involves residues from the N-terminal beta-hairpin and the C terminal alpha-helical segments of the peptide. NMR data indicated that metal binding induced a global change in the peptide structure. The D-Pro-Ser type II' beta-turn motif could be replaced by Thr-Ile to generate genetically encodable lanthanide fingers. Replacement of the central Phe with Trp generated genetically encodable lanthanide fingers that exhibited terbium luminescence greater than that of an EF-hand peptide.

  8. Ultrasound and modulation assisted synthesis of {[Cu2(BDC-NH2)2(dabco)]DMF.3H2O} nanostructures: new precursor to prepare nanorods and nanotubes of copper(II) oxide.

    PubMed

    Alavi, Mohammad Amin; Morsali, Ali; Joo, Sang Woo; Min, Bong-Ki

    2015-01-01

    Nanostructures of porous coordination polymer {[Cu2(BDC-NH2)2(dabco)]DMF.3H2O} (1) have been synthesized in the presence of acetic acid as a modulator via sonochemical method. Different concentrations of metal ions, organic linkers, modulator reagent and also different sonication times were held to improve the quality and distribution of nanostructures. Ultrasound irradiation helps to nucleation step of the oriented attachment of modulation method and nanorods of compound 1 has been prepared. Compound 1 was calcinated at 500°C to prepare nanorods and nanotubes of copper(II) oxide. Compound 1 and CuO nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HR-TEM), X-ray powder diffraction (XRD) and thermal gravimetric analysis (TGA). PMID:24853108

  9. Effect of precursor solutions stirring on deep level defects concentration and spatial distribution in low temperature aqueous chemical synthesis of zinc oxide nanorods

    SciTech Connect

    Alnoor, Hatim Chey, Chan Oeurn; Pozina, Galia; Willander, Magnus; Nur, Omer; Liu, Xianjie; Khranovskyy, Volodymyr

    2015-08-15

    Hexagonal c-axis oriented zinc oxide (ZnO) nanorods (NRs) with 120-300 nm diameters are synthesized via the low temperature aqueous chemical route at 80 °C on silver-coated glass substrates. The influence of varying the precursor solutions stirring durations on the concentration and spatial distributions of deep level defects in ZnO NRs is investigated. Room temperature micro-photoluminesnce (μ-PL) spectra were collected for all samples. Cathodoluminescence (CL) spectra of the as-synthesized NRs reveal a significant change in the intensity ratio of the near band edge emission (NBE) to the deep-level emission (DLE) peaks with increasing stirring durations. This is attributed to the variation in the concentration of the oxygen-deficiency with increasing stirring durations as suggested from the X-ray photoelectron spectroscopy analysis. Spatially resolved CL spectra taken along individual NRs revealed that stirring the precursor solutions for relatively short duration (1-3 h), which likely induced high super saturation under thermodynamic equilibrium during the synthesis process, is observed to favor the formation of point defects moving towards the tip of the NRs. In contrary, stirring for longer duration (5-15 h) will induce low super saturation favoring the formation of point defects located at the bottom of the NRs. These findings demonstrate that it is possible to control the concentration and spatial distribution of deep level defects in ZnO NRs by varying the stirring durations of the precursor solutions.

  10. Sequential Drug Release and Enhanced Photothermal and Photoacoustic Effect of Hybrid Reduced Graphene Oxide-Loaded Ultrasmall Gold Nanorod Vesicles for Cancer Therapy.

    PubMed

    Song, Jibin; Yang, Xiangyu; Jacobson, Orit; Lin, Lisen; Huang, Peng; Niu, Gang; Ma, Qingjie; Chen, Xiaoyuan

    2015-09-22

    We report a hybrid reduced graphene oxide (rGO)-loaded ultrasmall plasmonic gold nanorod vesicle (rGO-AuNRVe) (∼65 nm in size) with remarkably amplified photoacoustic (PA) performance and photothermal effects. The hybrid vesicle also exhibits a high loading capacity of doxorubicin (DOX), as both the cavity of the vesicle and the large surface area of the encapsulated rGO can be used for loading DOX, making it an excellent drug carrier. The loaded DOX is released sequentially: near-infrared photothermal heating induces DOX release from the vesicular cavity, and an intracellular acidic environment induces DOX release from the rGO surface. Positron emission tomography imaging showed high passive U87MG tumor accumulation of (64)Cu-labeled rGO-AuNRVes (∼9.7% ID/g at 24 h postinjection) and strong PA signal in the tumor region. Single intravenous injection of rGO-AuNRVe-DOX followed by low-power-density 808 nm laser irradiation (0.25 W/cm(2)) revealed effective inhibition of tumor growth due to the combination of chemo- and photothermal therapies. The rGO-AuNRVe-DOX capable of sequential DOX release by laser light and acid environment may have the potential for clinical translation to treat cancer patients with tumors accessible by light. PMID:26308265

  11. Polyethylenimine-Mediated Electrostatic Assembly of MnO2 Nanorods on Graphene Oxides for Use as Anodes in Lithium-Ion Batteries.

    PubMed

    Chae, Changju; Kim, Ki Woong; Yun, Young Jun; Lee, Daehee; Moon, Jooho; Choi, Youngmin; Lee, Sun Sook; Choi, Sungho; Jeong, Sunho

    2016-05-11

    In recent years, the development of electrochemically active materials with excellent lithium storage capacity has attracted tremendous attention for application in high-performance lithium-ion batteries. MnO2-based composite materials have been recognized as one of promising candidates owing to their high theoretical capacity and cost-effectiveness. In this study, a previously unrecognized chemical method is proposed to induce intra-stacked assembly from MnO2 nanorods and graphene oxide (GO), which is incorporated as an electrically conductive medium and a structural template, through polyethylenimine (PEI)-derived electrostatic modulation between both constituent materials. It is revealed that PEI, a cationic polyelectrolyte, is capable of effectively forming hierarchical, two-dimensional MnO2-RGO composites, enabling highly reversible capacities of 880, 770, 630, and 460 mA·h/g at current densities of 0.1, 1, 3, and 5 A/g, respectively. The role of PEI in electrostatically assembled composite materials is clarified through electrochemical impedance spectroscopy-based comparative analysis. PMID:27082880

  12. Polyethylenimine-Mediated Electrostatic Assembly of MnO2 Nanorods on Graphene Oxides for Use as Anodes in Lithium-Ion Batteries.

    PubMed

    Chae, Changju; Kim, Ki Woong; Yun, Young Jun; Lee, Daehee; Moon, Jooho; Choi, Youngmin; Lee, Sun Sook; Choi, Sungho; Jeong, Sunho

    2016-05-11

    In recent years, the development of electrochemically active materials with excellent lithium storage capacity has attracted tremendous attention for application in high-performance lithium-ion batteries. MnO2-based composite materials have been recognized as one of promising candidates owing to their high theoretical capacity and cost-effectiveness. In this study, a previously unrecognized chemical method is proposed to induce intra-stacked assembly from MnO2 nanorods and graphene oxide (GO), which is incorporated as an electrically conductive medium and a structural template, through polyethylenimine (PEI)-derived electrostatic modulation between both constituent materials. It is revealed that PEI, a cationic polyelectrolyte, is capable of effectively forming hierarchical, two-dimensional MnO2-RGO composites, enabling highly reversible capacities of 880, 770, 630, and 460 mA·h/g at current densities of 0.1, 1, 3, and 5 A/g, respectively. The role of PEI in electrostatically assembled composite materials is clarified through electrochemical impedance spectroscopy-based comparative analysis.

  13. Influence of morphological transformation on luminescence properties of europium-doped gadolinium oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Dondapati, Hareesh; Holloway, Terence; Cao, Wei; Kar, Arik; Patra, Amitava; Pradhan, Aswini K.

    2010-09-01

    Low dimensional europium (Eu3+)-doped gadolinium oxide (Gd2O3) lanthanide nanostructures are synthesized by an effective and simple coprecipitation process followed by subsequent heat treatments. Transmission electron microscope (TEM) images indicate Eu3+-doped Gd2O3 nanostructures undergo significant morphological changes from nanorods to nanoparticles during thermal treatments. Nanostructures with different morphology, including nanotubes, strongly influence the photoluminescence properties. The dependence of luminescence lifetime on morphological nature of the nanostructures demonstrates that the one dimensional nanostructures such as nanorods and nanotubes have higher emission intensity with shorter lifetime. Our analysis suggests that the morphological transformation of the nanostructures plays the most important role in the behavior of radiative and nonradiative relaxation mechanisms, resulting in the overall photoluminescence properties.

  14. Tailoring lanthanide nanocrystals for nanomedicine

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Tan, Timothy T. Y.

    2013-02-01

    Lanthanide nanocrystals have demonstrated strong potentials in nanomedicine due to its up-conversion and strong magnetic properties, and low toxicity. This talk will focus on strategies in lanthanide nanostructure tailoring to achieve up-conversion color emission tuning, MRI T1 and T2 contrast tuning, and the use of up-conversion fluorescence in drug delivery and cancer cells ablation.

  15. Aromatic triamide-lanthanide complexes

    DOEpatents

    Raymond, Kenneth N; Petoud, Stephane; Xu, Jide

    2013-10-08

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  16. Fungus-promoted transformation of lanthanides during the biooxidation of divalent manganese

    NASA Astrophysics Data System (ADS)

    Yu, Qianqian; Ohnuki, Toshihiko; Tanaka, Kazuya; Kozai, Naofumi; Yamasaki, Shinya; Sakamoto, Fuminori; Tani, Yukinori

    2016-02-01

    Although microorganisms possess high sorption capability for lanthanides, the effect of their biological response on lanthanides migration is unclear. Using active fungus Acremonium strictum KR21-2, supplied with nutrients, this study compared the transformation of lanthanides during the biooxidation of Mn(II) in the absence and presence of trisodium citrate. In the absence of trisodium citrate, lanthanides were rapidly sorbed on fungal cells within 24 h, followed by the preferential desorption of Ce over other lanthanides as Mn oxide formed. Most of the desorbed Ce was in the colloidal phase and associated with a biomolecule produced by the active fungus. In contrast, neither desorption of Ce nor release of this biomolecule occurred in the presence of trisodium citrate. Most importantly, the Ce-binding biomolecule was not found to associate with any other trivalent lanthanides tested or with Fe. The biomolecule was characterized as c.a. 4700 Da in size, and it contains saccharides that differed from those non-nuclide-specific organic substances released from resting cells, as reported previously. This study highlights the importance of biotic reactions between lanthanides and microbial cells, which may affect the migration of lanthanides at the water-Mn oxide interface.

  17. Graded core/shell semiconductor nanorods and nanorod barcodes

    DOEpatents

    Alivisatos, A. Paul; Scher, Erik C.; Manna, Liberato

    2013-03-26

    Graded core/shell semiconductor nanorods and shapped nanorods are disclosed comprising Group II-VI, Group III-V and Group IV semiconductors and methods of making the same. Also disclosed are nanorod barcodes using core/shell nanorods where the core is a semiconductor or metal material, and with or without a shell. Methods of labeling analytes using the nanorod barcodes are also disclosed.

  18. Graded core/shell semiconductor nanorods and nanorod barcodes

    DOEpatents

    Alivisatos, A. Paul; Scher, Erik C.; Manna, Liberato

    2010-12-14

    Graded core/shell semiconductor nanorods and shaped nanorods are disclosed comprising Group II-VI, Group III-V and Group IV semiconductors and methods of making the same. Also disclosed are nanorod barcodes using core/shell nanorods where the core is a semiconductor or metal material, and with or without a shell. Methods of labeling analytes using the nanorod barcodes are also disclosed.

  19. Surface plasmon spectroscopy study of electron exchange between single gold nanorods and metal oxide matrix during hydrogen gas sensing (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Cittadini, Michela; Collins, Sean; Mulvaney, Paul; Martucci, Alessandro

    2015-08-01

    The direct optical monitoring of electron exchange on single plasmonic nanoparticles, involved in chemical reactions with gas molecules, is one of the main challenges in the heterogeneous catalysis and gas sensing fields. Catalysts are substances that speed up reactions by providing an alternative pathway with lower activation energy than that required for the uncatalysed reaction. A lot of research, both fundamental and applied, has been carried out to investigate how catalysts work and to increase their efficiency. The present work shows how the use of Dark Field Microscopy (DFM) coupled with surface plasmon spectroscopy, enables the direct observation of the kinetics of H2 gas interaction with single gold nanorods (NR) coupled with Pt nanoparticles (NPs) and/or with metal oxide matrices. The plasmonic particles, gold NRs, act as optical probes, and enable the monitoring of the electron exchange through the measurement of their surface plasmon resonance (SPR) band shift. To improve the redox reaction kinetics, the Au NRs have been coupled with Pt NPs and embedded also into a TiO2 or ZnO low scattering matrix. The Au NRs, the Pt, TiO2 and ZnO NPs have been synthetized by colloid chemistry. Several samples made of bare Au NRs, or Au NRs coupled with only Pt NPs or with Pt and TiO2 NPs or with Pt and TiO2 have been deposited by spin coating on silica substrates. The longitudinal Au SPR band shift has been monitored by DFM looking at the variation of the scattering spectrum of a single Au NRs in the presence of H2. Time-resolved measurements have been also conducted at fixed wavelength in order to monitor the kinetics of the H2 reaction. With such measurements it was possible to elucidate the importance of the adsorbed oxygen and the TiO2 matrix on the H2 reaction with the Pt NPs.

  20. An electrochemical nanobiosensor for plasma miRNA-155, based on graphene oxide and gold nanorod, for early detection of breast cancer.

    PubMed

    Azimzadeh, Mostafa; Rahaie, Mahdi; Nasirizadeh, Navid; Ashtari, Khadijeh; Naderi-Manesh, Hossein

    2016-03-15

    Circulating miRNAs are emerging as novel reliable biomarkers for early detection of cancer diseases. Through combining the advantages of electrochemical methods and nanomaterials with the selectivity of the oligo-hybridization-based biosensors, a novel electrochemical nanobiosensor for plasma miR-155 detection have demonstrated here, based on thiolated probe-functionalized gold nanorods (GNRs) decorated on the graphene oxide (GO) sheet on the surface of the glassy carbon electrode (GCE). The reduction signals of a novel intercalating label Oracet Blue (OB), were measured by differential pulse voltammetry (DPV) method. The transmission electron microscope (TEM) imaging, UV-vis spectrophotometry, cyclic voltammetry (CV), field emission scanning electron microscope (FE-SEM) imaging and energy dispersive spectroscopy (EDS) were proved the right synthesis of the GNRs and correct assembly of the modified electrode. The electrochemical signal had a linear relationship with the concentration of the target miRNA ranging from 2.0 fM to 8.0 pM, and the detection limit was 0.6 fM. Furthermore, the nanobiosensor showed high Specificity, and was able to discriminate sharply between complementary target miRNA, single-, three-base mismatch, and non-complementary miRNA. Alongside the outstanding sensitivity and selectivity, this nanobiosensor had great storage ability, reproducibility, and showed a decent response in the real sample analysis with plasma. In conclusion, the proposed electrochemical nanobiosensor could clinically be used in the early detection of the breast cancer, by direct detection of the plasma miR-155 in real clinical samples, without a need for sample preparation, RNA extraction and/or amplification.

  1. Core-Shell Structural CdS@SnO₂ Nanorods with Excellent Visible-Light Photocatalytic Activity for the Selective Oxidation of Benzyl Alcohol to Benzaldehyde.

    PubMed

    Liu, Ya; Zhang, Ping; Tian, Baozhu; Zhang, Jinlong

    2015-07-01

    Core-shell structural CdS@SnO2 nanorods (NRs) were fabricated by synthesizing SnO2 nanoparticles with a solvent-assisted interfacial reaction and further anchoring them on the surface of CdS NRs under ultrasonic stirring. The morphology, composition, and microstructures of the obtained samples were characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and nitrogen adsorption-desorption. It was found that SnO2 nanoparticles can be tightly anchored on the surface of CdS NRs, and the thickness of SnO2 shells can be conveniently adjusted by simply changing the addition amount of SnO2 quantum dots. UV-vis diffuse reflectance spectrum indicated that SnO2 shell layer also can enhance the visible light absorption of CdS NRs to a certain extent. The results of transient photocurrents and photoluminescence spectra revealed that the core-shell structure can effectively promote the separation rate of electron-hole pairs and prolong the lifetime of electrons. Compared with the single CdS NRs, the core-shell structural CdS@SnO2 exhibited a remarkably enhanced photocatalytic activity for selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) under visible light irradiation, attributed to the more efficient separation of electrons and holes, improved surface area, and enhanced visible light absorption of core-shell structure. The radical scavenging experiments proved that in acetonitrile solution, ·O2- and holes are the main reactive species responsible for BA to BAD transformation, and the lack of ·OH radicals is favorable to obtaining high reaction selectivity.

  2. Enzyme-mimetic effects of gold@platinum nanorods on the antioxidant activity of ascorbic acid

    NASA Astrophysics Data System (ADS)

    Zhou, Yu-Ting; He, Weiwei; Wamer, Wayne G.; Hu, Xiaona; Wu, Xiaochun; Lo, Y. Martin; Yin, Jun-Jie

    2013-01-01

    Au@Pt nanorods were prepared by growing platinum nanodots on gold nanorods. Using electron spin resonance (ESR), we determined that the mechanisms for oxidation of ascorbic acid (AA) by Au@Pt nanorods and ascorbic acid oxidase (AAO) were kinetically similar and yielded similar products. In addition we observed that Au@Pt nanorods were stable with respect to temperature and pH. Using UV-VIS spectroscopy, the apparent kinetics of enzyme-mimetic activity of Au@Pt nanorods were studied and compared with the activity of AAO. With the help of ESR, we found that Au@Pt nanorods did not scavenge hydroxyl radicals but inhibited the antioxidant ability of AA for scavenging hydroxyl radicals produced by photoirradiating solutions containing titanium dioxide and zinc oxide. Moreover, the Au@Pt nanorods reduced the ability of AA to scavenge DPPH radicals and superoxide radicals. These results demonstrate that Au@Pt nanorods can reduce the antioxidant activity of AA. Therefore, it is necessary to consider the effects of using Pt nanoparticles together with other reducing agents or antioxidants such as AA due to the oxidase-like property of Au@Pt nanorods.Au@Pt nanorods were prepared by growing platinum nanodots on gold nanorods. Using electron spin resonance (ESR), we determined that the mechanisms for oxidation of ascorbic acid (AA) by Au@Pt nanorods and ascorbic acid oxidase (AAO) were kinetically similar and yielded similar products. In addition we observed that Au@Pt nanorods were stable with respect to temperature and pH. Using UV-VIS spectroscopy, the apparent kinetics of enzyme-mimetic activity of Au@Pt nanorods were studied and compared with the activity of AAO. With the help of ESR, we found that Au@Pt nanorods did not scavenge hydroxyl radicals but inhibited the antioxidant ability of AA for scavenging hydroxyl radicals produced by photoirradiating solutions containing titanium dioxide and zinc oxide. Moreover, the Au@Pt nanorods reduced the ability of AA to scavenge

  3. Aerosol-assisted chemical vapor deposition of tungsten oxide films and nanorods from oxo tungsten(VI) fluoroalkoxide precursors.

    PubMed

    Kim, Hankook; Bonsu, Richard O; O'Donohue, Christopher; Korotkov, Roman Y; McElwee-White, Lisa; Anderson, Timothy J

    2015-02-01

    Aerosol-assisted chemical vapor deposition (AACVD) of WOx was demonstrated using the oxo tungsten(VI) fluoroalkoxide single-source precursors, WO[OCCH3(CF3)2]4 and WO[OC(CH3)2CF3]4. Substoichiometric amorphous tungsten oxide thin films were grown on indium tin oxide (ITO) substrates in nitrogen at low deposition temperature (100-250 °C). At growth temperatures above 300 °C, the W18O49 monoclinic crystalline phase was observed. The surface morphology and roughness, visible light transmittance, electrical conductivity, and work function of the tungsten oxide materials are reported. The solvent and carrier gas minimally affected surface morphology and composition at low deposition temperature; however, material crystallinity varied with solvent choice at higher temperatures. The work function of the tungsten oxide thin films grown between 150 and 250 °C was determined to be in the range 5.0 to 5.7 eV, according to ultraviolet photoelectron spectroscopy (UPS). PMID:25569472

  4. A TRUEX-based separation of americium from the lanthanides

    SciTech Connect

    Bruce J. Mincher; Nicholas C. Schmitt; Mary E. Case

    2011-03-01

    Abstract: The inextractability of the actinide AnO2+ ions in the TRUEX process suggests the possibility of a separation of americium from the lanthanides using oxidation to Am(V). The only current method for the direct oxidation of americium to Am(V) in strongly acidic media is with sodium bismuthate. We prepared Am(V) over a wide range of nitric acid concentrations and investigated its solvent extraction behavior for comparison to europium. While a separation is achievable in principal, the presence of macro amounts of cerium competes for the sparingly soluble oxidant and the oxidant itself competes for CMPO complexation. These factors conspire to reduce the Eu/Am separation factor from ~40 using tracer solutions to ~5 for extractions from first cycle raffinate simulant solution. To separate pentavalent americium directly from the lanthanides using the TRUEX process, an alternative oxidizing agent will be necessary.

  5. Buffer layer effect on ZnO nanorods growth alignment

    NASA Astrophysics Data System (ADS)

    Zhao, Dongxu; Andreazza, Caroline; Andreazza, Pascal; Ma, Jiangang; Liu, Yichun; Shen, Dezhen

    2005-06-01

    Vertical aligned ZnO nanorods array was fabricated on Si with introducing a ZnO thin film as a buffer layer. Two different nucleation mechanisms were found in growth process. With using Au catalyst, Zn vapor could diffuse into Au nanoclusters with forming a solid solution. Then the ZnO nucleation site is mainly on the catalyst by oxidation of Au/Zn alloy. Without catalyst, nucleation could occur directly on the surface of buffer layer by homoepitaxy. The density and the size of ZnO nanorods could be governed by morphological character of catalyst and buffer layer. The nanorods growth is followed by vapor-solid mechanism.

  6. Fabrication and photoluminescence studies of porous ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Cho, Min Young; Kim, Min Su; Kim, Soaram; Leem, Jae-Young; Kim, Do Yeob; Kim, Sung-O.; Nam, Giwoong

    2012-07-01

    Zinc-oxide (ZnO) nanorods were grown using the hydrothermal method, and nanosized pores were formed on their surfaces by thermal annealing at 700 °C for 20 min under an argon atmosphere. The structural and the optical properties of the porous ZnO nanorods were investigated using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and temperature-dependent photoluminescence. The average diameter and density of the nanosized pores were 32 nm and 7 × 1010 cm-2, respectively. The crystal quality, stoichiometry, and optical properties of the porous ZnO nanorods were enhanced in comparison with those of the as-prepared ZnO nanorods. The activation energies for the exciton with increasing temperature in the as-prepared and the porous ZnO nanorods were 27.0 and 37.8 meV, respectively. At temperatures of 50 K < T < 125 K, the free exciton emission peak energy of the porous ZnO nanorods exhibited an anomalous behavior. The values of the fitting parameters in Varshni's empirical formula were α = 1 × 10-3 eV/K and β = 720 K for the as-prepared ZnO nanorods and α = 1 × 10-3 eV/K and β = 710 K for the porous ZnO nanorods. With increasing temperature, the exciton radiative lifetime of the porous ZnO nanorods exhibited an inverted S-shape while that of the as-prepared ZnO nanorods increased linearly.

  7. The separation of lanthanides and actinides in supercritical fluid carbon dioxide

    SciTech Connect

    Mincher, Bruce J.; Wai, Chien M.; Fox, Robert V.; Baek, Donna L.; Yen, Clive; Case, Mary E.

    2015-10-28

    Supercritical fluid carbon dioxide presents an attractive alternative to conventional solvents for recovery of the actinides and lanthanides. Carbon dioxide is a good solvent for fluorine and phosphate-containing ligands, including the traditional tributylphosphate ligand used in process-scale uranium separations. Actinide and lanthanide oxides may even be directly dissolved in carbon dioxide containing the complexes formed between these ligands and mineral acids, obviating the need for large volumes of acids for leaching and dissolution, and the corresponding organic liquid–liquid solvent extraction solutions. As a result, examples of the application of this novel technology for actinide and lanthanide separations are presented.

  8. Selective Alkane Oxidation by Manganese Oxide: Site Isolation of MnOx Chains at the Surface of MnWO4 Nanorods.

    PubMed

    Li, Xuan; Lunkenbein, Thomas; Pfeifer, Verena; Jastak, Mateusz; Nielsen, Pia Kjaer; Girgsdies, Frank; Knop-Gericke, Axel; Rosowski, Frank; Schlögl, Robert; Trunschke, Annette

    2016-03-14

    The electronic and structural properties of vanadium-containing phases govern the formation of isolated active sites at the surface of these catalysts for selective alkane oxidation. This concept is not restricted to vanadium oxide. The deliberate use of hydrothermal techniques can turn the typical combustion catalyst manganese oxide into a selective catalyst for oxidative propane dehydrogenation. Nanostructured, crystalline MnWO4 serves as the support that stabilizes a defect-rich MnOx surface phase. Oxygen defects can be reversibly replenished and depleted at the reaction temperature. Terminating MnOx zigzag chains on the (010) crystal planes are suspected to bear structurally site-isolated oxygen defects that account for the unexpectedly good performance of the catalyst in propane activation. PMID:26913704

  9. Involvement of lanthanides in the free radicals homeostasis.

    PubMed

    Valcheva-Traykova, Maria; Saso, Luciano; Kostova, Irena

    2014-01-01

    Lanthanides are group of rare-earth elements with growing applications both in the industry and healthcare. Their unique properties impose various possibilities for involvement in electron transfer reactions essential for the cellular survival and health on general. The intensified contact of people with lanthanides and the expanding medicinal applications of their compounds insist more profound knowledge on the involvement in biologically relevant electron transfer reactions. It is well known that the balance between formation and elimination of free radicals in a living body is essential for its health and survival. Any internal or environmental factor that alters this balance alters the homeostasis and this way altering the health status. In the present review, the possibilities of changing the balance between formation and elimination of free radicals, due to introduction of different lanthanides and their complexes with organic ligands, were explored, based on the available information in the literature. It was observed that lanthanides may act either as antioxidants or pro-oxidants, depending on the environment, the nature of the bonding in their compounds, and concentration in the tissues. The opportunities for their application in medicine were related with the abilities to control over their involvement in the overall oxidative status of the body.

  10. Calibration beads containing luminescent lanthanide ion complexes

    EPA Science Inventory

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  11. The Lanthanide Contraction beyond Coordination Chemistry.

    PubMed

    Ferru, Geoffroy; Reinhart, Benjamin; Bera, Mrinal K; Olvera de la Cruz, Monica; Qiao, Baofu; Ellis, Ross J

    2016-05-10

    The lanthanide contraction is conceptualized traditionally through coordination chemistry. Here we break this mold in a structural study of lanthanide ions dissolved in an amphiphilic liquid. The lanthanide contraction perturbs the weak interactions between molecular aggregates that drive mesoscale assembly and emergent behavior. The weak interactions correlate with lanthanide ion transport properties, suggesting new strategies for rare-earth separation that exploit forces outside of the coordination sphere.

  12. Vapor phase growth and photoluminescence of oriented-attachment Zn2GeO4 nanorods array

    NASA Astrophysics Data System (ADS)

    Tang, Haiping; Zhu, Xingda; He, Haiping

    2016-10-01

    We carry out one-step vapor phase growth of high quality Zn2GeO4 nanorods array to provide insights into the growth mechanism of such ternary oxide nanostructures. The morphology and microstructure of these nanorods are investigated carefully. Under certain conditions, the nanorods follow the oriented-attachment growth which is unusual in vapor-based growth. Each nanorod consists of many nanocrystals aligned along the [110] direction. The nanorods show strong deep ultraviolet absorption around 260 nm and broad longlife green luminescence around 490 nm.

  13. Watching single gold nanorods grow.

    PubMed

    Wei, Zhongqing; Qi, Hua; Li, Min; Tang, Bochong; Zhang, Zhengzheng; Han, Ruiling; Wang, Jiaojiao; Zhao, Yuliang

    2012-05-01

    The consecutive evolution process of single gold nanorods is monitored using atomic force microscopy (AFM). The single-crystal gold nanorods investigated are grown directly on surfaces to which gold seed particles are covalently linked. The growth kinetics for single nanorods is derived from the 3D information recorded by AFM. A better understanding of the seed-mediated growth mechanism may ultimately lead to the direct growth of aligned nanorods on surfaces. PMID:22378704

  14. Kinetics-controlled growth of bimetallic RhAg on Au nanorods and their catalytic properties

    NASA Astrophysics Data System (ADS)

    Ye, Wei; Guo, Xia; Xie, Fang; Zhu, Rui; Zhao, Qing; Yang, Jian

    2014-03-01

    Controlled growth of hybrid metallic nanocomposites for a desirable structure in a combination of selected components is highly important for their applications. Herein, the controllable growth of RhAg on the gold nanorods is achieved from the dumbbell-like RhAg-tipped nanorods to the brushy RhAg-coated nanorods, or the rod-like Au@Ag-Rh nanorattles. These different growth modes of RhAg on the gold nanorods are correlated with the reducing kinetics of RhCl3 and AgNO3. In view of the promising catalytic properties of Rh, the gold nanorods modified by RhAg in different structures are examined as catalysts for the oxidation of o-phenylenediamine. It is found that brushy RhAg-coated nanorods present a higher catalytic efficiency than dumbbell-like RhAg-tipped nanorods and rod-like Au@Ag-Rh nanorattles. These results would benefit the overgrowth control on the one-dimensional metallic nanorods and the rational design of new generation heterogeneous catalysts and optical devices.Controlled growth of hybrid metallic nanocomposites for a desirable structure in a combination of selected components is highly important for their applications. Herein, the controllable growth of RhAg on the gold nanorods is achieved from the dumbbell-like RhAg-tipped nanorods to the brushy RhAg-coated nanorods, or the rod-like Au@Ag-Rh nanorattles. These different growth modes of RhAg on the gold nanorods are correlated with the reducing kinetics of RhCl3 and AgNO3. In view of the promising catalytic properties of Rh, the gold nanorods modified by RhAg in different structures are examined as catalysts for the oxidation of o-phenylenediamine. It is found that brushy RhAg-coated nanorods present a higher catalytic efficiency than dumbbell-like RhAg-tipped nanorods and rod-like Au@Ag-Rh nanorattles. These results would benefit the overgrowth control on the one-dimensional metallic nanorods and the rational design of new generation heterogeneous catalysts and optical devices. Electronic

  15. Lanthanide Hydroxide Nanoparticles Induce Angiogenesis via ROS-Sensitive Signaling.

    PubMed

    Zhao, Haishan; Osborne, Olivia J; Lin, Sijie; Ji, Zhaoxia; Damoiseux, Robert; Wang, Yuqiang; Nel, André E; Lin, Shuo

    2016-08-01

    Recent studies suggest that the nanorods consisting of europium hydroxide could promote angiogenesis. In this study, it is sought to determine if additional types of nanoparticles are capable of enhancing angiogenesis and in addition, understand the underlying mechanisms. For this reason, a method is employed that combines a high throughput in vitro cell based screen coupled with an in vivo validation using vascular specific green fluorescent protein reporter transgenic zebrafish for examining proangiogenesis activity. After screening multiple types of nanoparticles, it is discovered that four of them, Eu(III) (OH)3 rods (Eu rods), Eu(III) (OH)3 spheres (Eu spheres), Tb(III) (OH)3 rods (Tb rods), and Tb(III) (OH)3 spheres (Tb spheres), are the most effective in promoting angiogenesis. It is also showed that ionic forms of europium nitrate [Eu(NO3 )3 ] (Eu) and terbium nitrate [Tb(NO3 )3 ] (Tb), the two lanthanide elements for these four nanoparticles, are also capable of enhancing angiogenesis. However, this effect is further enhanced by nanoparticle synthesis. Finally, it is demonstrated that reactive oxygen species H2 O2 is a key factor in the process of proangiogenesis by lanthanide elemental nanoparticles. PMID:27383397

  16. Lanthanides: New life metals?

    PubMed

    Chistoserdova, Ludmila

    2016-08-01

    Lanthanides (Ln(3+)) that are Rare Earth Elements, until recently thought to be biologically inert, have recently emerged as essential metals for activity and expression of a special type of methanol dehydrogenase, XoxF. As XoxF enzyme homologs are encoded in a wide variety of microbes, including microbes active in important environmental processes such as methane and methanol metabolism, Ln(3+) may represent some of the key biogeochemical drivers in cycling of carbon and other elements. However, significant gaps in understanding the role of Ln(3+) in biological systems remain as the functions of most of the proteins potentially dependent of Ln(3+) and their roles in specific metabolic networks/respective biogeochemical cycles remain unknown. Moreover, enzymes dependent on Ln(3+) but not related to XoxF enzymes may exist, and these so far have not been recognized. Through connecting the recently uncovered genetic divergence and phylogenetic distribution of XoxF-like enzymes and through elucidation of their activities, metal and substrate specificities, along with the biological contexts of respective biochemical pathways, most parsimonious scenarios for their evolution could be uncovered. Generation of such data will firmly establish the role of Ln(3+) in the biochemistry of Life inhabiting this planet. PMID:27357406

  17. Tetrathiafulvalene-amido-2-pyridine-N-oxide as efficient charge-transfer antenna ligand for the sensitization of Yb(III) luminescence in a series of lanthanide paramagnetic coordination complexes.

    PubMed

    Pointillart, Fabrice; Cauchy, Thomas; Maury, Olivier; Le Gal, Yann; Golhen, Stéphane; Cador, Olivier; Ouahab, Lahcène

    2010-10-18

    The tetrathiafulvalene-amido-2-pyridine-N-oxide (L) ligand has been employed to coordinate 4f elements. The architecture of the complexes mainly depends on the ionic radii of the lanthanides. Thus, the reaction of L in the same experimental protocol leads to three different molecular structure series. Binuclear [Ln(2)(hfac)(5)(O(2)CPhCl)(L)(3)]·2 H(2)O (hfac(-)=1,1,1,5,5,5-hexafluoroacetylacetonate anion, O(2)CPhCl(-)=3-chlorobenzoate anion) and mononuclear [Ln(hfac)(3)(L)(2)] complexes were obtained by using rare-earth ions with either large (Ln(III)=Pr, Gd) or small (Ln(III)=Y, Yb) ionic radius, respectively, whereas the use of Tb(III) that possesses an intermediate ionic radius led to the formation of a binuclear complex of formula [Tb(2)(hfac)(4)(O(2)CPhCl)(2)(L)(2)]. Antiferromagnetic interactions have been observed in the three dinuclear compounds by using an extended empirical method. Photophysical properties of the coordination complexes have been studied by solid-state absorption spectroscopy, whereas time-dependent density functional theory (TD-DFT) calculations have been carried out on the diamagnetic Y(III) derivative to build a molecular orbital diagram and to reproduce the absorption spectrum. For the [Yb(hfac)(3)(L)(2)] complex, the excitation at 19,600 cm(-1) of the HOMO→LUMO+1/LUMO+2 charge-transfer transition induces both line-shape emissions in the near-IR spectral range assigned to the (2)F(5/2)→(2)F(7/2) (9860 cm(-1)) ytterbium-centered transition and a residual charge-transfer emission around 13,150 cm(-1). An efficient antenna effect that proceeds through energy transfer from the singlet excited state of the tetrathiafulvalene-amido-2-pyridine-N-oxide chromophore is evidence of the Yb(III) sensitization.

  18. Three-dimensional nitrogen-doped graphene frameworks anchored with bamboo-like tungsten oxide nanorods as high performance anode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Gu, Xinyuan; Wu, Feilong; Lei, Bingbing; Wang, Jing; Chen, Ziliang; Xie, Kai; Song, Yun; Sun, Dalin; Sun, Lixian; Zhou, Huaiying; Fang, Fang

    2016-07-01

    Bamboo-like WO3 nanorods were anchored on three-dimensional nitrogen-doped graphene frameworks (r-WO3/3DNGF) by a facile one-step hydrothermal synthesis plus heating processes. There is a strong dependence of the obtained r-WO3/3DNGF nanostructures on the content of 3DNGF. The composite with 20 wt% 3DNGF content shows the most favorable structure where bamboo-like WO3 nanorods lie flat on the surface of fungus-like 3DNGF, and exhibits a high discharge capacity of 828 mAh g-1 over 100 cycles at 80 mA g-1 with the largest capacity retention of 73.9% for WO3 and excellent rate capacities of 719, 665, 573, 453 and 313 mAh g-1 at 80, 160, 400, 800 and 1600 mA g-1, respectively. The electrochemical performance is better than most of reported WO3-based carbonaceous composites, which can be attributed to the synergistic effects of the following actions: i) WO3 nanorods effectively shorten the diffusion path of Li+; ii) mechanically strong 3DNGF alleviates the huge volume change of WO3 upon Li+ intercalation/extraction; and iii) nitrogen-doping in 3D graphene frameworks improves electronic conductivity and provides large numbers of lithium ion diffusion channels.

  19. Photophysical studies of chromium sensitizers designed for excited state hole transfer to semiconductors and sequential hole/electron transfers from photoexcited cadmium sulfide nanorods to mononuclear ruthenium water-oxidation catalysts

    NASA Astrophysics Data System (ADS)

    Tseng, Huan-Wei

    a photoexcited cadmium sulfide nanorod and [Ru(diethyl 2,2'-bipyridine-4,4'-dicarboxylate)(2,2':6',2"-terpyridine)Cl] +, a mononuclear water-oxidation catalyst. Upon photoexcitation, hole transfer from the cadmium sulfide nanorod oxidizes the catalyst (Ru 2+ → Ru3+) on a 100 ps to 1 ns timescale. This is followed by electron transfer (10-100 ns) from the nanorod to reduce the Ru3+ center. The relatively slow electron transfer dynamics may provide opportunities for the accumulation of multiple holes at the catalyst, which is required for water oxidation.

  20. Hydrodynamic fabrication of structurally gradient ZnO nanorods.

    PubMed

    Kim, Hyung Min; Youn, Jae Ryoun; Song, Young Seok

    2016-02-26

    We studied a new approach where structurally gradient nanostructures were fabricated by means of hydrodynamics. Zinc oxide (ZnO) nanorods were synthesized in a drag-driven rotational flow in a controlled manner. The structural characteristics of nanorods such as orientation and diameter were determined by momentum and mass transfer at the substrate surface. The nucleation of ZnO was induced by shear stress which plays a key role in determining the orientation of ZnO nanorods. The nucleation and growth of such nanostructures were modeled theoretically and analyzed numerically to understand the underlying physics of the fabrication of nanostructures controlled by hydrodynamics. The findings demonstrated that the precise control of momentum and mass transfer enabled the formation of ZnO nanorods with a structural gradient in diameter and orientation. PMID:26807679

  1. Novel nanorods based on PANI / PEO polymers using electrospinning method

    NASA Astrophysics Data System (ADS)

    Al-Hazeem, Nabeel Z.; Ahmed, Naser M.; Matjafri, M. Z.; Sabah, Fayroz A.; Rasheed, Hiba S.

    2016-07-01

    In this work, we fabricated nanorods by applying an electric potential on poly (ethylene oxide) (PEO) and polyaniline (PANI) as a polymeric solution by electrospinning method. Testing was conducted on the samples by field emission scanning Electron microscope (FE-SEM), X-ray diffraction (XRD) and Photoluminescence. And the results showed the emergence of nanorods in the sample within glass substrate. Diameters of nanorods have ranged between (52.78-122.40)nm And a length of between (1.15 - 1.32)μm. The emergence of so the results are for the first time, never before was the fabrication of nanorods for polymers using the same method used in this research.

  2. The Crystal Structure of Lanthanide Zirconates

    NASA Astrophysics Data System (ADS)

    Clements, Richard; Kennedy, Brendan; Ling, Christopher; Stampfl, Anton P. J.

    2010-03-01

    The lanthanide zirconates of composition Ln2Zr2O7 (Ln = La-Gd) are of interest for use in inert matrix fuels and nuclear wasteforms. The series undergoes a pyrochlore to fluorite phase transition as a function of the Ln atomic radii. The phase transition has been attributed to disordering of both the cation and the anion [1]. We have undertaken a synthesis of the lanthanide zirconate series Ln2Zr2O7 (Ln = La-Gd), Ln0.2Zr0.8O1.9 (Ln = Tb-Yb) and NdxHo2-xZr2O7 (0oxide technique. We have performed neutron powder diffraction on selections of the series, using ANSTO's new high resolution powder diffractometer Echidna, in order to obtain accurate data on atomic displacement parameters and O 48f position across the series. These results will be presented, along with details of the analysis and synthetic techniques used.

  3. The TRUSPEAK Concept: Combining CMPO and HDEHP for Separating Trivalent Lanthanides from the Transuranic Elements

    SciTech Connect

    Lumetta, Gregg J.; Gelis, Artem V.; Braley, Jenifer C.; Carter, Jennifer C.; Pittman, Jonathan W.; Warner, Marvin G.; Vandegrift, George F.

    2013-04-08

    Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO) and bis-(2-ethylhexyl) phosphoric acid (HDEHP) into a single process solvent for separating transuranic elements from liquid high-level waste is explored. Co-extraction of americium and the lanthanide elements from nitric acid solution is possible with a solvent mixture consisting of 0.1-M CMPO plus 1-M HDEHP in n-dodecane. Switching the aqueous-phase chemistry to a citrate-buffered solution of diethylene triamine pentaacetic acid (DTPA) allows for selective stripping of americium, separating it from the lanthanide elements. Potential strategies for managing molybdenum and zirconium (both of which co-extract with americium and the lanthanides) have been developed. The work presented here demonstrates the feasibility of combining CMPO and HDEHP into a single extraction solvent for recovering americium from high-level waste and its separation from the lanthanides.

  4. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements.

  5. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements. PMID:20547408

  6. Improvement of photocatalytic activity of brookite titanium dioxide nanorods by surface modification using chemical etching

    NASA Astrophysics Data System (ADS)

    Zhang, Linjie; Menendez-Flores, Victor M.; Murakami, Naoya; Ohno, Teruhisa

    2012-05-01

    Surface morphology of brookite titanium dioxide (TiO2) nanorods was modified by chemical etching with aqueous hydrogen (H2O2)-ammonia (NH3) or sulfuric acid (H2SO4) solution. The brookite nanorods after chemical etching were characterized by TEM, SAED, FE-SEM, XRD and specific surface area measurements. Brookite nanorods after chemical etching with H2O2-NH3 solution exposed new crystal faces in the tips, and nanorods with sharper tips were observed. On the other hand, etching with H2SO4 at 200 °C induced morphological changes in the tip faces and broadened the angle between tip faces as a result of dissolution along the [0 0 1] direction, though brookite nanorods were only slightly etched after etching with H2SO4 at room temperature. Photocatalytic activity of brookite nanorods was tested by toluene decomposition in gas phase under ultraviolet irradiation. Brookite nanorods etched with H2O2-NH3 solution showed higher photocatalytic activity than that of brookite nanorods before etching. In the case of H2SO4 etching at 200 °C, brookite nanorods after etching exhibited lower photocatalytic activity. One reason for this may be that the formation of newly exposed crystal faces by H2O2-NH3 etching improved separation of redox sites due to their strong oxidation ability.

  7. Enhancement of Anion Binding in Lanthanide Optical Sensors

    PubMed Central

    Cable, Morgan L.; Kirby, James P.; Gray, Harry B.; Ponce, Adrian

    2013-01-01

    be established from the ionization energy of Ln3+ → Ln4+. These results account for the order Tb3+ > Dy3+ > Eu3+ ≈ Sm3+. As with many lanthanide properties, ranging from hydration enthalpy to vaporization energy, this AL-induced enhancement shows a large discrepancy between Tb3+ and Eu3+ despite their similarity in size, a phenomenon known as the ‘gadolinium break.’ This discrepancy, based on the unusual stabilities of the Eu2+ and Tb4+ oxidation states, results from the half-shell effect, as both of these ions have half-filled 4f-shells. The high polarizability of Tb3+ explains the extraordinarily large increase in the binding affinity of anions for terbium compared to other lanthanides. We recommend that researchers consider this AL-induced enhancement when designing lanthanide-macrocycle optical sensors. Ancillary ligands also can reduce the impact of interfering species such as phosphate) commonly found in environmental and physiological samples. PMID:24032446

  8. Photochemical synthesis of gold nanorods.

    PubMed

    Kim, Franklin; Song, Jae Hee; Yang, Peidong

    2002-12-01

    Gold nanorods have been synthesized by photochemically reducing gold ions within a micellar solution. The aspect ratio of the rods can be controlled with the addition of silver ions. This process reported here is highly promising for producing uniform nanorods, and more importantly it will be useful in resolving the growth mechanism of anisotropic metal nanoparticles due to its simplicity and the relatively slow growth rate of the nanorods. PMID:12452700

  9. Investigation of Gravity Lanthanide Separation Chemistry

    SciTech Connect

    Payne, Rosara F.; Schulte, Shannon M.; Douglas, Matthew; Friese, Judah I.; Farmer, Orville T.; Finn, Erin C.

    2011-03-01

    Lanthanides are common fission products and the ability to separate and quantify these elements is critical to rapid radiochemistry applications. Published lanthanide separations using Eichrom Ln Spec resin utilize an HCl gradient. Here it is shown that the efficacy and resolution of the separation is improved when a nitric acid gradient is used instead. The described method allows parallel processing of many samples in 1.5 hours followed by 60 minute counting for quantification of 9 isotopes of 7 lanthanide elements.

  10. Lanthanide transport in stabilized zirconias: interrelation between ionic radius and diffusion coefficient.

    PubMed

    Kilo, Martin; Taylor, Marcela A; Argirusis, Christos; Borchardt, Günter; Weber, Sylvain; Scherrer, Hubert; Jackson, Robert A

    2004-09-15

    The diffusion of all stable lanthanides was measured both in calcia stabilized zirconia (CSZ) and in yttria stabilized zirconia (YSZ) in the temperature range between 1,286 and 1,600 degrees C. The lanthanide diffusion coefficients obtained increase with increasing ionic radius. The experimental activation enthalpy of diffusion is near 6 eV for CSZ and between 4 and 5 eV for YSZ and is not strongly affected by the type of lanthanide. The results were correlated with defect energy calculations of the lanthanide diffusion enthalpy using the Mott-Littleton approach. An association enthalpy of cation vacancies with oxygen vacancies of about 1 eV (96 kJ/mol) was deduced in the case of CSZ, while there is no association in the case of YSZ. Furthermore, the change in diffusion coefficients can be correlated to the interaction parameter for the interaction between the lanthanide oxide with zirconia: The higher the interaction parameter, the higher the lanthanide diffusion coefficient.

  11. Lanthanide transport in stabilized zirconias: Interrelation between ionic radius and diffusion coefficient

    NASA Astrophysics Data System (ADS)

    Kilo, Martin; Taylor, Marcela A.; Argirusis, Christos; Borchardt, Günter; Weber, Sylvain; Scherrer, Hubert; Jackson, Robert A.

    2004-09-01

    The diffusion of all stable lanthanides was measured both in calcia stabilized zirconia (CSZ) and in yttria stabilized zirconia (YSZ) in the temperature range between 1286 and 1600 °C. The lanthanide diffusion coefficients obtained increase with increasing ionic radius. The experimental activation enthalpy of diffusion is near 6 eV for CSZ and between 4 and 5 eV for YSZ and is not strongly affected by the type of lanthanide. The results were correlated with defect energy calculations of the lanthanide diffusion enthalpy using the Mott-Littleton approach. An association enthalpy of cation vacancies with oxygen vacancies of about 1 eV (96 kJ/mol) was deduced in the case of CSZ, while there is no association in the case of YSZ. Furthermore, the change in diffusion coefficients can be correlated to the interaction parameter for the interaction between the lanthanide oxide with zirconia: The higher the interaction parameter, the higher the lanthanide diffusion coefficient.

  12. Facile preparation of hybrid core-shell nanorods for photothermal and radiation combined therapy

    NASA Astrophysics Data System (ADS)

    Deng, Yaoyao; Li, Erdong; Cheng, Xiaju; Zhu, Jing; Lu, Shuanglong; Ge, Cuicui; Gu, Hongwei; Pan, Yue

    2016-02-01

    The hybrid platinum@iron oxide core-shell nanorods with high biocompatibility were synthesized and applied for combined therapy. These hybrid nanorods exhibit a good photothermal effect on cancer cells upon irradiation with a NIR laser. Furthermore, due to the presence of a high atomic number element (platinum core), the hybrid nanorods show a synergistic effect between photothermal and radiation therapy. Therefore, the as-prepared core-shell nanorods could play an important role in facilitating synergistic therapy between photothermal and radiation therapy to achieve better therapeutic efficacy.The hybrid platinum@iron oxide core-shell nanorods with high biocompatibility were synthesized and applied for combined therapy. These hybrid nanorods exhibit a good photothermal effect on cancer cells upon irradiation with a NIR laser. Furthermore, due to the presence of a high atomic number element (platinum core), the hybrid nanorods show a synergistic effect between photothermal and radiation therapy. Therefore, the as-prepared core-shell nanorods could play an important role in facilitating synergistic therapy between photothermal and radiation therapy to achieve better therapeutic efficacy. Electronic supplementary information (ESI) available: Details of general experimental procedures. See DOI: 10.1039/c5nr09102k

  13. Fracture-resistant lanthanide scintillators

    DOEpatents

    Doty, F. Patrick

    2011-01-04

    Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (<3% FWHM energy resolutions at 662 keV). However brittle fracture of these materials upon cooling hinders the growth of large volume crystals. Efforts to improve the strength through non-lanthanide alloy substitution, while preserving scintillation, have been demonstrated. Isovalent alloys having nominal compositions of comprising Al, Ga, Sc, Y, and In dopants as well as aliovalent alloys comprising Ca, Sr, Zr, Hf, Zn, and Pb dopants were prepared. All of these alloys exhibit bright fluorescence under UV excitation, with varying shifts in the spectral peaks and intensities relative to pure CeBr.sub.3. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed to .sup.137Cs gamma rays.

  14. ZnO nanorods/plates on Si substrate grown by low-temperature hydrothermal reaction

    NASA Astrophysics Data System (ADS)

    Gao, S. Y.; Li, H. D.; Yuan, J. J.; Li, Y. A.; Yang, X. X.; Liu, J. W.

    2010-02-01

    The zinc oxide (ZnO) nanorods/plates are obtained via hydrothermal method assisted by etched porous Al film on Si substrate. The products consist of nanorods with average diameter of 100 nm and nanoplates with thickness of 200-300 nm, which are uniformly distributed widely and grown perpendicularly to the substrate. The ZnO nanoplates with thickness of 150-300 nm were grown on Si substrate coated with a thin continuous Al film (without etching) in the same aqueous solution. The growth mechanism and room temperature photoluminescence (PL) properties of ZnO nanorods/plates and nanoplates were investigated. It is found that the introduction of the etched Al film plays a key role in the formation of ZnO nanorods/plates. The annealing process is favorable to enhance the UV PL emissions of the ZnO nanorods/plates.

  15. Characterization of individual barium titanate nanorods and their assessment as building blocks of new circuit architectures.

    PubMed

    Zagar, Kristina; Hernandez-Ramirez, Francisco; Prades, Joan Daniel; Morante, Joan Ramon; Rečnik, Aleksander; Ceh, Miran

    2011-09-23

    In this work, we report on the integration of individual BaTiO(3) nanorods into simple circuit architectures. Polycrystalline BaTiO(3) nanorods were synthesized by electrophoretic deposition (EPD) of barium titanate sol into aluminium oxide (AAO) templates and subsequent annealing. Transmission electron microscopy (TEM) observations revealed the presence of slabs of hexagonal polymorphs intergrown within cubic grains, resulting from the local reducing atmosphere during the thermal treatment. Electrical measurements performed on individual BaTiO(3) nanorods revealed resistivity values between 10 and 100 Ω cm, which is in good agreement with typical values reported in the past for oxygen-deficient barium titanate films. Consequently the presence of oxygen vacancies in their structure was indirectly validated. Some of these nanorods were tested as proof-of-concept humidity sensors. They showed reproducible responses towards different moisture concentrations, demonstrating that individual BaTiO(3) nanorods may be integrated in complex circuit architectures with functional capacities.

  16. Modulation of field emission properties of znO nanorods during arc discharge.

    PubMed

    Fang, F; Kennedy, J; Carder, D A; Futter, J; Murmu, P; Markwitz, A

    2010-12-01

    Zinc oxide (ZnO) nanorods have been synthesized via the arc discharge method. Different oxygen partial pressures were applied in the arc discharge chamber to modulate the field emission properties of the as-synthesized ZnO nanorods. Scanning electron microscopy (SEM) was carried out to analyze the morphology of the ZnO nanorods. The ion beam analysis technique of proton induced X-ray emission (PIXE) was performed to probe the impurities in ZnO nanorods. SEM images clearly revealed the formation of randomly oriented ZnO nanorods with diameters between 10-50 nm. It was found that the morphology and the electrical properties of the ZnO nanorods were dependent on the oxygen partial pressure during arc discharge. In addition enhanced UV-sensitive photoconductivity was found for ZnO nanorods synthesized at high oxygen partial pressure during arc discharge. The field emission properties of the nanorods were studied. The turn-on field, which is defined at a current density of 10 microA cm(-2), was about 3 V microm(-1) for ZnO nanorods synthesized at 99% oxygen partial pressure during arc discharge. The turn-on field for ZnO nanorods increased with the decrease of oxygen partial pressure during arc discharge. The simplicity of the synthesis route coupled with the modulation of field emission properties due to the arc discharge method make the ZnO nanorods a promising candidate for a low cost and compact cold cathode material. PMID:21121322

  17. Development of a physical and electronic model for RuO 2 nanorod rectenna devices

    NASA Astrophysics Data System (ADS)

    Dao, Justin

    Ruthenium oxide (RuO2) nanorods are an emergent technology in nanostructure devices. As the physical size of electronics approaches a critical lower limit, alternative solutions to further device miniaturization are currently under investigation. Thin-film nanorod growth is an interesting technology, being investigated for use in wireless communications, sensor systems, and alternative energy applications. In this investigation, self-assembled RuO2 nanorods are grown on a variety of substrates via a high density plasma, reactive sputtering process. Nanorods have been found to grow on substrates that form native oxide layers when exposed to air, namely silicon, aluminum, and titanium. Samples were analyzed with Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. Conductive Atomic Force Microscopy (C-AFM) measurements were performed on single nanorods to characterize structure and electrical conductivity. The C-AFM probe tip is placed on a single nanorod and I-V characteristics are measured, potentially exhibiting rectifying capabilities. An analysis of these results using fundamental semiconductor physics principles is presented. Experimental data for silicon substrates was most closely approximated by the Simmons model for direct electron tunneling, whereas that of aluminum substrates was well approximated by Fowler-Nordheim tunneling. The native oxide of titanium is regarded as a semiconductor rather than an insulator and its ability to function as a rectifier is not strong. An electronic model for these nanorods is described herein.

  18. Synthesis and magnetic properties of single-crystalline Na2-xMn8O16 nanorods

    PubMed Central

    2011-01-01

    The synthesis of single-crystalline hollandite-type manganese oxides Na2-xMn8O16 nanorods by a simple molten salt method is reported for the first time. The nanorods were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and a superconducting quantum interference device magnetometer. The magnetic measurements indicated that the nanorods showed spin glass behavior and exchange bias effect at low temperatures. The low-temperature magnetic behaviors can be explained by the uncompensated spins on the surface of the nanorods. PMID:21711626

  19. Nanorod Material Developed for Use as an Optical Sensor Platform

    NASA Technical Reports Server (NTRS)

    Bencic, Timothy J.

    2005-01-01

    Optical sensors are becoming increasingly important in the development of new nonintrusive or embedded sensors. The use of light and material optical properties helps us measure unknown parameters such as temperature, pressure, flow, or chemical species. The focus of this work is to develop new nanostructure platforms upon which optical sensors can be constructed. These nanorods are synthesized oxides that form a base structure to which luminescent sensing dyes or dopants can be attached or embedded. The nanorod structure allows for a much greater open area than closed or polymer-based sensors do, enabling a much faster contact of the measured species with the luminescent sensor and, thus, a potentially faster measurement.

  20. Enantioselective catalysis using lanthanide Schiff base complexes

    SciTech Connect

    Watkin, J.G.

    1996-10-01

    The use of lanthanide-based catalysts to facilitate organic transformations is currently an area of rapid growth, in particular the application of lanthanide alkoxide and triflate derivatives as effective Lewis-acidic catalysts for Michael additions and aldol reactions, and bis-pentamethylcyclopentadienyl derivatives as extremely active catalysts for hydrogenation and enantioselective hydroamination reactions. We have begun an investigation into the use of lanthanide complexes containing chiral alkoxide ligands as Lewis-acidic catalysts for enantioselective organic reactions. Since the large ionic radii of the lanthanide +III metal centers can often lead to oligomerization of simple alkoxide species, we have also examined the use of multidentate, chelating Schiff base ligands to provide an asymmetric environment about a lanthanide metal center. Structural investigations of the catalysts will be described, together with the use of these catalysts in enantioselective Meerwein-Ponndorf-Verley reduction of ketones and nitroaldol reactions.

  1. Facet Control of Gold Nanorods.

    PubMed

    Zhang, Qingfeng; Han, Lili; Jing, Hao; Blom, Douglas A; Lin, Ye; Xin, Huolin L; Wang, Hui

    2016-02-23

    While great success has been achieved in fine-tuning the aspect ratios and thereby the plasmon resonances of cylindrical Au nanorods, facet control with atomic level precision on the highly curved nanorod surfaces has long been a significantly more challenging task. The intrinsic structural complexity and lack of precise facet control of the nanorod surfaces remain the major obstacles for the atomic-level elucidation of the structure-property relationships that underpin the intriguing catalytic performance of Au nanorods. Here we demonstrate that the facets of single-crystalline Au nanorods can be precisely tailored using cuprous ions and cetyltrimethylammonium bromide as a unique pair of surface capping competitors to guide the particle geometry evolution during nanorod overgrowth. By deliberately maneuvering the competition between cuprous ions and cetyltrimethylammonium bromide, we have been able to create, in a highly controllable and selective manner, an entire family of nanorod-derived anisotropic multifaceted geometries whose surfaces are enclosed by specific types of well-defined high-index and low-index facets. This facet-controlled nanorod overgrowth approach also allows us to fine-tune the particle aspect ratios while well-preserving all the characteristic facets and geometric features of the faceted Au nanorods. Taking full advantage of the combined structural and plasmonic tunability, we have further studied the facet-dependent heterogeneous catalysis on well-faceted Au nanorods using surface-enhanced Raman spectroscopy as an ultrasensitive spectroscopic tool with unique time-resolving and molecular finger-printing capabilities. PMID:26795706

  2. Facet control of gold nanorods

    DOE PAGESBeta

    Zhang, Qingfeng; Han, Lili; Jing, Hao; Blom, Douglas A.; Lin, Ye; Xin, Huolin L.; Wang, Hui

    2016-01-21

    While great success has been achieved in fine-tuning the aspect ratios and thereby the plasmon resonances of cylindrical Au nanorods, facet control with atomic level precision on the highly curved nanorod surfaces has long been a significantly more challenging task. The intrinsic structural complexity and lack of precise facet control of the nanorod surfaces remain the major obstacles for the atomic-level elucidation of the structure–property relationships that underpin the intriguing catalytic performance of Au nanorods. Here we demonstrate that the facets of single-crystalline Au nanorods can be precisely tailored using cuprous ions and cetyltrimethylammonium bromide as a unique pair ofmore » surface capping competitors to guide the particle geometry evolution during nanorod overgrowth. By deliberately maneuvering the competition between cuprous ions and cetyltrimethylammonium bromide, we have been able to create, in a highly controllable and selective manner, an entire family of nanorod-derived anisotropic multifaceted geometries whose surfaces are enclosed by specific types of well-defined high-index and low-index facets. This facet-controlled nanorod overgrowth approach also allows us to fine-tune the particle aspect ratios while well-preserving all the characteristic facets and geometric features of the faceted Au nanorods. Furthermore, taking full advantage of the combined structural and plasmonic tunability, we have further studied the facet-dependent heterogeneous catalysis on well-faceted Au nanorods using surface-enhanced Raman spectroscopy as an ultrasensitive spectroscopic tool with unique time-resolving and molecular finger-printing capabilities.« less

  3. Photoelectrochemical and photosensing behaviors of hydrothermally grown ZnO nanorods

    SciTech Connect

    Majumder, T.; Hmar, J. J. L.; Roy, J. N.; Mondal, S. P. E-mail: suvra.phy@nita.ac.in; Debnath, K.; Gogurla, N.; Ray, S. K.

    2014-07-21

    ZnO nanorods have been grown on indium-tin-oxide coated glass substrates by a low cost chemical process. Current-voltage characteristics have been studied using ZnO nanorods as photoanode in an electrochemical cell. The flat band voltage shift and depletion width of ZnO nanorods/electrolyte interface have been estimated from Mott-Schottky (MS) characteristics. The electrochemical impedance measurements have been carried out to study the charge transport mechanism at the semiconductor-electrolyte interface under dark and white light (100 mW/cm{sup 2}) illumination. The doping concentration of nanorods has been extracted from MS plot. Photoresponse behavior of ZnO nanorods is found to be enhanced than seed layers with the incident of white light. Spectral dependent photovoltage of ZnO nanorods has been carried out using monochromatic light of wavelength 250–600 nm. The photopotential recovery time has been estimated for nanorods and seed layers. The stability of ZnO nanorods as a photoanode has been investigated.

  4. Directed self-assembly of nanorod networks: bringing the top down to the bottom up

    NASA Astrophysics Data System (ADS)

    Einsle, Joshua F.; Scheunert, Gunther; Murphy, Antony; McPhillips, John; Zayats, Anatoly V.; Pollard, Robert; Bowman, Robert M.

    2012-12-01

    Self-assembled electrodeposited nanorod materials have been shown to offer an exciting landscape for a wide array of research ranging from nanophotonics through to biosensing and magnetics. However, until now, the scope for site-specific preparation of the nanorods on wafers has been limited to local area definition. Further there is little or no lateral control of nanorod height. In this work we present a scalable method for controlling the growth of the nanorods in the vertical direction as well as their lateral position. A focused ion beam pre-patterns the Au cathode layer prior to the creation of the anodized aluminium oxide (AAO) template on top. When the pre-patterning is of the same dimension as the pore spacing of the AAO template, lines of single nanorods are successfully grown. Further, for sub-200 nm wide features, a relationship between the nanorod height and distance from the non-patterned cathode can be seen to follow a quadratic growth rate obeying Faraday’s law of electrodeposition. This facilitates lateral control of nanorod height combined with localized growth of the nanorods.

  5. Effective PEGylation of gold nanorods

    NASA Astrophysics Data System (ADS)

    Schulz, F.; Friedrich, W.; Hoppe, K.; Vossmeyer, T.; Weller, H.; Lange, H.

    2016-03-01

    Standard procedures to coat gold nanorods (AuNR) with poly(ethylene glycol) (PEG)-based ligands are not reliable and high PEG-grafting densities are not achieved. In this work, the ligand exchange of AuNR with PEGMUA, a tailored PEG-ligand bearing a C10 alkylene spacer, is studied. PEGMUA provides AuNR with very high stability against oxidative etching with cyanide. This etching reaction is utilized to study the ligand exchange in detail. Ligand exchange is faster, less ligand consuming and more reproducible with assisting chloroform extraction. Compared to PEG ligands commonly used, PEGMUA provides much higher colloidal and chemical stability. Further analyses based on NMR-, IR- and UV/Vis-spectroscopy reveal that significantly higher PEG-grafting densities, up to ~3 nm-2, are obtained with PEGMUA. This demonstrates how the molecular structure of the PEG ligand can be used to dramatically improve the ligand exchange and to synthesize PEGylated AuNR with high chemical and colloidal stability and high PEG grafting densities. Such AuNR are especially interesting for applications in nanomedicine.Standard procedures to coat gold nanorods (AuNR) with poly(ethylene glycol) (PEG)-based ligands are not reliable and high PEG-grafting densities are not achieved. In this work, the ligand exchange of AuNR with PEGMUA, a tailored PEG-ligand bearing a C10 alkylene spacer, is studied. PEGMUA provides AuNR with very high stability against oxidative etching with cyanide. This etching reaction is utilized to study the ligand exchange in detail. Ligand exchange is faster, less ligand consuming and more reproducible with assisting chloroform extraction. Compared to PEG ligands commonly used, PEGMUA provides much higher colloidal and chemical stability. Further analyses based on NMR-, IR- and UV/Vis-spectroscopy reveal that significantly higher PEG-grafting densities, up to ~3 nm-2, are obtained with PEGMUA. This demonstrates how the molecular structure of the PEG ligand can be used to

  6. CeO2 nanorods and gold nanocrystals supported on CeO2 nanorods as catalyst.

    PubMed

    Huang, P X; Wu, F; Zhu, B L; Gao, X P; Zhu, H Y; Yan, T Y; Huang, W P; Wu, S H; Song, D Y

    2005-10-20

    The formation mechanism of uniform CeO2 structure at the nanometer scale via a wet-chemical reaction is of great interest in fundamental study as well as a variety of applications. In this work, large-scale well-crystallized CeO2 nanorods with uniform diameters in the range of 20-30 nm and lengths up to tens of micrometers are first synthesized through a hydrothermal synthetic route in 5 M KOH solution at 180 degrees C for 45 h without any templates and surfactants. The nanorod formation involves dehydration of CeO2 nanoparticles and orientation growth along the 110 direction in KOH solution. Subsequently, gold nanoparticles with crystallite sizes between 10 and 20 nm are loaded on the surface of CeO2 nanorods using HAuCl4 solution as the gold source and NaBH4 solution as a reducing agent. The synthesized Au/CeO2 nanorods demonstrate a higher catalytic activity in CO oxidation than the pure CeO2 nanorods. PMID:16853472

  7. Semiconductor nanorod liquid crystals

    SciTech Connect

    Li, Liang-shi; Walda, Joost; Manna, Liberato; Alivisatos, A. Paul

    2002-01-28

    Rodlike molecules form liquid crystalline phases with orientational order and positional disorder. The great majority of materials in which liquid crystalline phases have been observed are comprised of organic molecules or polymers, even though there has been continuing and growing interest in inorganic liquid crystals. Recent advances in the control of the sizes and shapes of inorganic nanocrystals allow for the formation of a broad class of new inorganic liquid crystals. Here we show the formation of liquid crystalline phases of CdSe semiconductor nanorods. These new liquid crystalline phases may have great importance for both application and fundamental study.

  8. How Robust are Semiconductor Nanorods? Investigating the Stability and Chemical Decomposition Pathways of Photoactive Nanocrystals

    SciTech Connect

    Reichert, Malinda D; Lin, Chia-Cheng; Vela, Javier

    2014-07-08

    Anisotropic II–VI semiconductor nanostructures are important photoactive materials for various energy conversion and optical applications. However, aside from the many available surface chemistry studies and from their ubiquitous photodegradation under continuous illumination, the general chemical reactivity and thermal stability (phase and shape transformations) of these materials are poorly understood. Using CdSe and CdS nanorods as model systems, we have investigated the behavior of II–VI semiconductor nanorods against various conditions of extreme chemical and physical stress (acids, bases, oxidants, reductants, and heat). CdSe nanorods react rapidly with acids, becoming oxidized to Se or SeO2. In contrast, CdSe nanorods remain mostly unreactive when treated with bases or strong oxidants, although bases do partially etch the tips of the nanorods (along their axis). Roasting (heating in air) of CdSe nanorods results in rock-salt CdO, but neither CdSe nor CdO is easily reduced by hydrogen (H2). Another reductant, n-BuLi, reduces CdSe nanorods to metallic Cd. Variable temperature X-ray diffraction experiments show that axial annealing and selective axial melting of the nanorods precede particle coalescence. Furthermore, thermal analysis shows that the axial melting of II–VI nanorods is a ligand-dependent process. In agreement with chemical reactivity and thermal stability observations, silica-coating experiments show that the sharpest (most curved) II–VI surfaces are most active against heterogeneous nucleation of a silica shell. These results provide valuable insights into the fate and possible ways to enhance the stability and improve the use of II–VI semiconductor nanostructures in the fields of optics, magnetism, and energy conversion.

  9. Plasmon Modes Induced by Anisotropic Gap Opening in Au@Cu2 O Nanorods.

    PubMed

    Zhang, Shouren; Jiang, Ruibin; Guo, Yanzhen; Yang, Baocheng; Chen, Xiao-Lan; Wang, Jianfang; Zhao, Yufen

    2016-08-01

    Integration of semiconductors with noble metals to form heteronanostructures can give rise to many interesting plasmonic and electronic properties. A number of such heteronanostructures have been demonstrated comprising noble metals and n-type semiconductors, such as TiO2 , ZnO, SnO2 , Fe3 O4 , and CuO. In contrast, reports on heteronanostructures made of noble metals and p-type semiconductors are scarce. Cu2 O is an unintentional p-type semiconductor with unique properties. Here, the uniform coating of Cu2 O on two types of Au nanorods and systematic studies of the plasmonic properties of the resultant core-shell heteronanostructures are reported. One type of Au nanorods is prepared by seed-mediated growth, and the other is obtained by oxidation of the as-prepared Au nanorods. The (Au nanorod)@Cu2 O nanostructures produced from the as-prepared nanorods exhibit two transverse plasmon peaks, whereas those derived from the oxidized nanorods display only one transverse plasmon peak. Through electrodynamic simulations the additional transverse plasmon peak is found to originate from a discontinuous gap formed at the side of the as-prepared nanorods. The existence of the gap is verified and its formation mechanism is unraveled with additional experiments. The results will be useful for designing metal-semiconductor heteronanostructures with desired plasmonic properties and therefore also for exploring plasmon-enhanced applications in photocatalysis, solar-energy harvesting, and biotechnologies.

  10. Plasmon Modes Induced by Anisotropic Gap Opening in Au@Cu2 O Nanorods.

    PubMed

    Zhang, Shouren; Jiang, Ruibin; Guo, Yanzhen; Yang, Baocheng; Chen, Xiao-Lan; Wang, Jianfang; Zhao, Yufen

    2016-08-01

    Integration of semiconductors with noble metals to form heteronanostructures can give rise to many interesting plasmonic and electronic properties. A number of such heteronanostructures have been demonstrated comprising noble metals and n-type semiconductors, such as TiO2 , ZnO, SnO2 , Fe3 O4 , and CuO. In contrast, reports on heteronanostructures made of noble metals and p-type semiconductors are scarce. Cu2 O is an unintentional p-type semiconductor with unique properties. Here, the uniform coating of Cu2 O on two types of Au nanorods and systematic studies of the plasmonic properties of the resultant core-shell heteronanostructures are reported. One type of Au nanorods is prepared by seed-mediated growth, and the other is obtained by oxidation of the as-prepared Au nanorods. The (Au nanorod)@Cu2 O nanostructures produced from the as-prepared nanorods exhibit two transverse plasmon peaks, whereas those derived from the oxidized nanorods display only one transverse plasmon peak. Through electrodynamic simulations the additional transverse plasmon peak is found to originate from a discontinuous gap formed at the side of the as-prepared nanorods. The existence of the gap is verified and its formation mechanism is unraveled with additional experiments. The results will be useful for designing metal-semiconductor heteronanostructures with desired plasmonic properties and therefore also for exploring plasmon-enhanced applications in photocatalysis, solar-energy harvesting, and biotechnologies. PMID:27374920

  11. Nanoparticles of lanthanide oxysulfate/oxysulfide for improved oxygen storage/release.

    PubMed

    Zhang, Wuyuan; Arends, Isabel W C E; Djanashvili, Kristina

    2016-09-28

    Lanthanide oxysulfates have the ability to store and release large volumes of oxygen under oxidizing/reducing conditions, rendering them interesting as automotive catalysts. Herein we demonstrate a remarkable improvement of both processes by utilization of nanoparticles compared to the bulk materials. A further improvement of the catalytic activity was achieved by cost-effective doping with 1.9 wt% of Ni.

  12. Method for extracting lanthanides and actinides from acid solutions by modification of Purex solvent

    DOEpatents

    Horwitz, E.P.; Kalina, D.G.

    1984-05-21

    A process has been developed for the extraction of multivalent lanthanide and actinide values from acidic waste solutions, and for the separation of these values from fission product and other values, which utilizes a new series of neutral bi-functional extractants, the alkyl(phenyl)-N, N-dialkylcarbamoylmethylphosphine oxides, in combination with a phase modifier to form an extraction solution. The addition of the extractant to the Purex process extractant, tri-n-butylphosphate in normal paraffin hydrocarbon diluent, will permit the extraction of multivalent lanthanide and actinide values from 0.1 to 12.0 molar acid solutions.

  13. Active modulation of nanorod plasmons.

    PubMed

    Khatua, Saumyakanti; Chang, Wei-Shun; Swanglap, Pattanawit; Olson, Jana; Link, Stephan

    2011-09-14

    Confining visible light to nanoscale dimensions has become possible with surface plasmons. Many plasmonic elements have already been realized. Nanorods, for example, function as efficient optical antennas. However, active control of the plasmonic response remains a roadblock for building optical analogues of electronic circuits. We present a new approach to modulate the polarized scattering intensities of individual gold nanorods by 100% using liquid crystals with applied voltages as low as 4 V. This novel effect is based on the transition from a homogeneous to a twisted nematic phase of the liquid crystal covering the nanorods. With our method it will be possible to actively control optical antennas as well as other plasmonic elements.

  14. Crystallographic, luminescence and photoconductive characteristics of chemically tailored ZnO nanorods

    SciTech Connect

    Bayan, Sayan Chakraborty, Purushottam

    2014-04-24

    The optoelectronic properties of zinc oxide (ZnO) nanorods synthesized using two different chemical methods have been explored in the light of microstructural features. The presence/absence of band edge emission in the luminescence spectra of the nanorods is found to be governed by the crystallographic properties. Moreover, we observed a pronounced effect of variation in crystallite size on the UV photoconductivity of the nanorods. Understanding the influence of microstructural aspects on the optical and electronic properties of the nanostructures may help in the fabrication of prototype, miniaturized optoelectronic devices.

  15. Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

    PubMed Central

    Witkowski, Bartlomiej Slawomir; Luka, Grzegorz; Wachnicki, Lukasz; Gieraltowska, Sylwia; Kopalko, Krzysztof; Zielony, Eunika; Bieganski, Piotr; Placzek-Popko, Ewa; Godlewski, Marek

    2014-01-01

    Summary Selected properties of photovoltaic (PV) structures based on n-type zinc oxide nanorods grown by a low temperature hydrothermal method on p-type silicon substrates (100) are investigated. PV structures were covered with thin films of Al doped ZnO grown by atomic layer deposition acting as transparent electrodes. The investigated PV structures differ in terms of the shapes and densities of their nanorods. The best response is observed for the structure containing closely-spaced nanorods, which show light conversion efficiency of 3.6%. PMID:24605282

  16. Pt-content-controlled synthesis of Pd nanohollows/Pt nanorods core/shell composites with enhanced electrocatalytic activities for the methanol oxidation reaction

    NASA Astrophysics Data System (ADS)

    Lai, Shiqin; Fu, Chenglin; Chen, Yongxiang; Yu, Xiang; Lai, Xuandi; Ye, Cui; Hu, Jianqiang

    2015-01-01

    Pd nanohollows/Pt nanorods (PdNHs/PtNRs) core/shell composites have been synthesized by a multistep crystalline growth method, in which Pt NRs grow on the exterior surface of hollow Pd nanospheres in order. Moreover, the size and quantity of the Pt NRs in the PdNHs/PtNRs can be easily tailored and thus ameliorate Pt utilization efficiency through varying H2PtCl6 concentrations. By comparing with Pt NPs and commercial Pt/C (JM), the PdNHs/PtNRs prepared using 2.50 mL 0.02 M H2PtCl6 have larger surface area, better anti-CO poisoning ability and more excellent catalytic performance. Moreover, the catalytic properties of the PdNHs/PtNRs can be well tunable by modifying the Pt contents. Our studies indicate that the PdNHs/PtNRs prepared using 2.50 mL 0.02 M H2PtCl6, in which Pd NHs are nearly completely covered with Pt NRs, have the largest surface area, best antitoxic ability and most excellent catalytic performance, indicative of high Pt utilization efficiency of the PdNHs/PtNRs relative to Pt/C (JM), Pt NPs and other PdNHs/PtNRs prepared using other H2PtCl6 concentrations. Therefore, the strategy to the size and content control of the PdNHs/PtNRs nanocomposites can facilitate optimized design of Pt-based catalysts for direct methanol fuel cells.

  17. Electrical conduction and NO2 gas sensing properties of ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Şahin, Yasin; Öztürk, Sadullah; Kılınç, Necmettin; Kösemen, Arif; Erkovan, Mustafa; Öztürk, Zafer Ziya

    2014-06-01

    Thermally stimulated current (TSC), photoresponse and gas sensing properties of zinc oxide (ZnO) nanorods were investigated depending on heating rates, illumination and dark aging times with using sandwich type electrode system. Vertically aligned ZnO nanorods were grown on indium tin oxide (ITO) coated glass substrate by hydrothermal process. TSC measurements were performed at different heating rates under constant potential. Photoresponse and gas sensing properties were investigated in dry air ambient at 200 °C. For gas sensing measurements, ZnO nanorods were exposed to NO2 (100 ppb to 1 ppm) in dark and illuminated conditions and the resulting resistance transient was recorded. It was found from dark electrical measurements that the dependence of the dc conductivity on temperature followed Mott's variable range hopping (VRH) model. In addition, response time and recovery times of ZnO nanorods to NO2 gas decreased by exposing to white light.

  18. Non-enzymatic electrochemical glucose sensor based on NiMoO₄ nanorods.

    PubMed

    Wang, Dandan; Cai, Daoping; Huang, Hui; Liu, Bin; Wang, Lingling; Liu, Yuan; Li, Han; Wang, Yanrong; Li, Qiuhong; Wang, Taihong

    2015-04-10

    A non-enzymatic glucose sensor based on the NiMoO4 nanorods has been fabricated for the first time. The electrocatalytic performance of the NiMoO4 nanorods' modified electrode toward glucose oxidation was evaluated by cyclic voltammetry and amperometry. The NiMoO4 nanorods' modified electrode showed a greatly enhanced electrocatalytic property toward glucose oxidation, as well as an excellent anti-interference and a good stability. Impressively, good accuracy and high precision for detecting glucose concentration in human serum samples were obtained. These excellent sensing properties, combined with good reproducibility and low cost, indicate that NiMoO4 nanorods are a promising candidate for non-enzymatic glucose sensors. PMID:25772142

  19. Analysis of multinuclear lanthanide-induced shifts. 4. Some consequences of the lanthanide contraction

    NASA Astrophysics Data System (ADS)

    Peters, Joop A.

    The effects of the lanthanide contraction on lanthanide-induced shifts are estimated using simulated structures for a set of lanthanide chelates. The variations of the Ln-donor distances cause small conformational changes in the coordination polyhedron of the Ln(III) cation, and the induced pseudocontact shifts for a series of Ln complexes vary gradually going from La(III) to Lu(III). As a result of data manipulation these gradual variations may sometimes show up as an abrupt break in the middle of the lanthanide series.

  20. Controllable vertically aligned ZnO nanorods on flexible polyethylene naphthalate (PEN) substrate using chemical bath deposition synthesis

    NASA Astrophysics Data System (ADS)

    Shabannia, R.; Abu Hassan, H.

    2014-02-01

    Zinc oxide (ZnO) nanorods were successfully grown on polyethylene naphthalate substrates with a seed layer using a wet chemical bath deposition method at a low temperature. Using various precursor concentrations, the diameter, length, and density of the ZnO nanorods were controlled, and their optical and crystallinity properties were investigated. X-ray diffraction and field emission scanning electron microscopy were used to examine the structure and morphology of the ZnO nanorods. The obtained ZnO nanorods were hexagonal and grew vertically from the substrate in the (002) direction along the c-axis. The low compressive strain values confirmed the high-quality crystal structure of the synthesized ZnO nanorods. A 0.050 M precursor concentration resulted in nanorods with a uniform diameter along their entire length and diameters ranging from 10 nm to 40 nm. The photoluminescence results indicated that the ZnO nanorods grown using a 0.050 M precursor concentration exhibited the sharpest and most intense PL peaks in the UV range compared with the other samples. Therefore, the precursor concentration considerably influenced the growth of the ZnO nanorods. These ZnO nanorods can be greatly applied for the development of flexible, elastic electronic, and optoelectronic devices.

  1. Plasmonic Fano resonances in metallic nanorod complexes.

    PubMed

    Yang, Zhong-Jian; Hao, Zhong-Hua; Lin, Hai-Qing; Wang, Qu-Quan

    2014-05-21

    Plasmonic Fano resonances (FRs) in nanostructures have been extensively studied in recent years. Nanorod-based complexes for FRs have also attracted much attention. The basic optical properties and fabrication technology of different kinds of plasmonic nanorods have been greatly developed over the last several years. The mutipole plasmon resonances and their flexible adjustment ranges on nanorods make them promising for FR modifications and structure diversity. In this paper, we review some recently studied plasmonic nanorod based nanostructures for FRs, including single nanorods, dimers, mutipole rods and nanorod-nanoparticle hybrids. The corresponding applications of the FRs are also briefly discussed.

  2. A Selective Blocking Method To Control the Overgrowth of Pt on Au Nanorods

    PubMed Central

    2013-01-01

    A method for the preparation of smooth deposits of Pt on Au nanorods is described, involving sequential deposition steps with selective blocking of surface sites that reduces Pt-on-Pt deposition. The Au–Pt nanorods prepared by this method have higher long-term stability than those prepared by standard Pt deposition. Electrochemical data show that the resulting structure has more extended regions of Pt surface and enhanced activity toward the carbon monoxide oxidation and oxygen reduction reactions. PMID:23594230

  3. Sorption speciation of lanthanides/actinides on minerals by TRLFS, EXAFS and DFT studies: a review.

    PubMed

    Tan, Xiaoli; Fang, Ming; Wang, Xiangke

    2010-11-17

    Lanthanides/actinides sorption speciation on minerals and oxides by means of time resolved laser fluorescence spectroscopy (TRLFS), extended X-ray absorption fine structure spectroscopy (EXAFS) and density functional theory (DFT) is reviewed in the field of nuclear disposal safety research. The theoretical aspects of the methods are concisely presented. Examples of recent research results of lanthanide/actinide speciation and local atomic structures using TRLFS, EXAFS and DFT are discussed. The interaction of lanthanides/actinides with oxides and minerals as well as their uptake are also of common interest in radionuclide chemistry. Especially the sorption and inclusion of radionuclides into several minerals lead to an improvement in knowledge of minor components in solids. In the solid-liquid interface, the speciation and local atomic structures of Eu(III), Cm(III), U(VI), and Np(IV/VI) in several natural and synthetic minerals and oxides are also reviewed and discussed. The review is important to understand the physicochemical behavior of lanthanides/actinides at a molecular level in the natural environment.

  4. Luminescent lanthanide chelates and methods of use

    DOEpatents

    Selvin, Paul R.; Hearst, John

    1997-01-01

    The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

  5. The role of lanthanides in optical materials

    SciTech Connect

    Weber, M.J.

    1995-05-01

    A survey is presented of the use of the lanthanides as chemical components in transmitting optical materials and as activators in materials for luminescent, electro-optic, magneto-optic, and various photosensitive applications.

  6. Synthesis of non-aggregated nicotinic acid coated magnetite nanorods via hydrothermal technique

    NASA Astrophysics Data System (ADS)

    Attallah, Olivia A.; Girgis, E.; Abdel-Mottaleb, Mohamed M. S. A.

    2016-02-01

    Non-aggregated magnetite nanorods with average diameters of 20-30 nm and lengths of up to 350 nm were synthesized via in situ, template free hydrothermal technique. These nanorods capped with different concentrations (1, 1.5, 2 and 2.5 g) of nicotinic acid (vitamin B3); possessed good magnetic properties and easy dispersion in aqueous solutions. Our new synthesis technique maintained the uniform shape of the nanorods even with increasing the coating material concentration. The effect of nicotinic acid on the shape, particle size, chemical structure and magnetic properties of the prepared nanorods was evaluated using different characterization methods. The length of nanorods increased from 270 nm to 350 nm in nicotinic acid coated nanorods. Goethite and magnetite phases with different ratios were the dominant phases in the coated samples while a pure magnetite phase was observed in the uncoated one. Nicotinic acid coated magnetic nanorods showed a significant decrease in saturation magnetization than uncoated samples (55 emu/g) reaching 4 emu/g in 2.5 g nicotinic acid coated sample. The novel synthesis technique proved its potentiality to prepare coated metal oxides with one dimensional nanostructure which can function effectively in different biological applications.

  7. Cathodoluminescence spectra of gallium nitride nanorods

    PubMed Central

    2011-01-01

    Gallium nitride [GaN] nanorods grown on a Si(111) substrate at 720°C via plasma-assisted molecular beam epitaxy were studied by field-emission electron microscopy and cathodoluminescence [CL]. The surface topography and optical properties of the GaN nanorod cluster and single GaN nanorod were measured and discussed. The defect-related CL spectra of GaN nanorods and their dependence on temperature were investigated. The CL spectra along the length of the individual GaN nanorod were also studied. The results reveal that the 3.2-eV peak comes from the structural defect at the interface between the GaN nanorod and Si substrate. The surface state emission of the single GaN nanorod is stronger as the diameter of the GaN nanorod becomes smaller due to an increased surface-to-volume ratio. PMID:22168896

  8. LANTHANIDE ENHANCE LUMINESCENCE (LEL) WITH ONE AND TWO PHOTON EXCITATION OF QUANTUM DYES LANTHANIDE (III) - MACROCYCLES

    EPA Science Inventory

    Title: Lanthanide Enhance Luminescence (LEL) with one and two photon excitation of Quantum Dyes? Lanthanide(III)-Macrocycles
    Principal Author:
    Robert C. Leif, Newport Instruments
    Secondary Authors:
    Margie C. Becker, Phoenix Flow Systems
    Al Bromm, Virginia Commonw...

  9. Lanthanide concentrations in freshwater plants and molluscs, related to those in surface water, pore water and sediment. A case study in The Netherlands.

    PubMed

    Weltje, Lennart; Heidenreich, Heike; Zhu, Wangzhao; Wolterbeek, Hubert Th; Korhammer, Siegfried; de Goeij, Jeroen J M; Markert, Bernd

    2002-03-01

    Industrial emissions of lanthanides to aquatic ecosystems increase, but knowledge of the environmental fate of these metals is limited. Here we focus attention upon the distribution of lanthanides in freshwater ecosystems, describing lanthanide partitioning between sediment, water and biota. Since lanthanides are often used as oxidation-state analogues for actinides, their distribution can reflect long-term behaviour of the radioactive transuranics. Concentrations of all 14 naturally occurring lanthanides were measured by ICP-MS in Sago pondweed (Potamogeton pectinatus), common duckweed (Lemna minor), seven different mollusc species (tissue and shell), two sediment fractions (< 2 mm and < 63 microm), surface water and sediment pore water from five locations in The Netherlands. In all samples, the typical 'saw-tooth' lanthanide pattern was observed, which implies that lanthanides are transported as a coherent group through aquatic ecosystems. Typical deviations from this pattern were found for Ce and Eu and could be explained by their redox chemistry. The variation in concentrations in abiotic fractions was limited, i.e. within one order of magnitude. However, variations of up to three orders of magnitude were observed in biotic samples, suggesting different affinities among organisms for lanthanides as a group, with significant differences only among molluscs and pondweed samples in relation to sampling location. For P. pectinatus it was shown that pore water was the most important lanthanide source, and for snails, food (plants) seems to be the dominant lanthanide source. Lanthanides were not equally distributed between mollusc shell and tissue and the ratio of lanthanide concentrations in shell and tissue were dependent on the sampling location. Shells contained much lower concentrations and were relatively enriched in Eu, and to a lesser extent in Ce. Bioconcentration factors for lanthanides in plants and snails relative to surface water were typically between

  10. Purification of lanthanides for double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Tretyak, V. I.

    2013-08-01

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain 238U, 226Ra and 232,228Th typically on the level of ˜ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO2, Nd2O3 and Gd2O3. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R&D of the methods to remove the pollutions with improved efficiency is in progress.

  11. Purification of lanthanides for double beta decay experiments

    SciTech Connect

    Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Danevich, F. A.; Mokina, V. M.; Poda, D. V.; Tretyak, V. I.; Cappella, F.; Incicchitti, A.; Cerulli, R.; Laubenstein, M.; Nisi, S.

    2013-08-08

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain {sup 238}U, {sup 226}Ra and {sup 232,228}Th typically on the level of ∼ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO{sub 2}, Nd{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R and D of the methods to remove the pollutions with improved efficiency is in progress.

  12. Nonaqueous method for dissolving lanthanide and actinide metals

    DOEpatents

    Crisler, L.R.

    1975-11-11

    Lanthanide and actinide beta-diketonate complex molecular compounds are produced by reacting a beta-diketone compound with a lanthanide or actinide element in the elemental metallic state in a mixture of carbon tetrachloride and methanol.

  13. Preparation and electrochemical characterization of manganese dioxide-zirconia nanorods

    NASA Astrophysics Data System (ADS)

    Muthuchudarkodi, R. R.; Vedhi, C.

    2015-04-01

    MnO2-ZrO2 nanorods were prepared by wet chemical method by mixing the solutions of MnSO4 and ZrOCl2 varying in the range (0.05-0.45 M) in aqueous NaOH at an elevated temperature. The morphologies of the synthesized products are characterized by scanning electron microscopy and transmission electron microscopy (TEM). X-ray diffraction (XRD) and energy-dispersive spectroscopic measurements were also employed for the characterization of the nanostructures. The synthesized nanoparticles were also characterized by ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, electrochemical impedance and cyclic voltammetric studies. The morphological studies of the nanoparticles revealed particle distribution with uniform rod-like structure. Energy-dispersive analysis indicated the presence of Mn, Zr and O. The nanostructures of the product were characterized by TEM studies and the mixed rod and granular structure that was found clearly indicated the presence of MnO2-ZrO2 mixed oxide. The size of the synthesized nanorod was found to be 20 nm. From XRD studies the size of the nanorods was found to be in the range 39-56 nm calculated by Debye-Scherrer's formula. Thermal stability of the nanorods was characterized by thermogravimetric and differential scanning colorimetric analysis. Cyclic voltammetric studies exhibit good adherent behavior on electrode surface and good electroactivity at a pH value of 1.0.

  14. Au sensitized ZnO nanorods for enhanced liquefied petroleum gas sensing properties

    NASA Astrophysics Data System (ADS)

    Nakate, U. T.; Bulakhe, R. N.; Lokhande, C. D.; Kale, S. N.

    2016-05-01

    The zinc oxide (ZnO) nanorods have grown on glass substrate by spray pyrolysis deposition (SPD) method using zinc acetate solution. The phase formation, surface morphology and elemental composition of ZnO films have been investigated using X-ray diffraction, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX) techniques. The liquefied petroleum gas (LPG) sensing response was remarkably improved by sensitization of gold (Au) surface noble metal on ZnO nanorods film. Maximum LPG response of 21% was observed for 1040 ppm of LPG, for pure ZnO nanorods sample. After Au sensitization on ZnO nanorods film sample, the LPG response greatly improved up to 48% at operating temperature 623 K. The improved LPG response is attributed Au sensitization with spill-over mechanism. Proposed model for LPG sensing mechanism discussed.

  15. Synthesis and characterization of high-ordered CdTe nanorods

    NASA Astrophysics Data System (ADS)

    Ma, Ligang; Wei, Zelu; Zhang, Fengming; Wu, Xiaoshan

    2015-12-01

    Cadmium telluride (CdTe) materials are an important absorbed layer and development solar energy conversion devices based on nano-fabrication techniques have attracted considerable interest in fabricating optoelectronic devices. Herein, through close-space sublimation method, vertically high-aligned CdTe nanorods are successfully obtained for the first time, with the help of Anodic Aluminum Oxide (AAO) template, which can perfectly control the morphology, diameter, and spacing among the CdTe nanorods. Its the crystal structure and optical properties are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering, and photoluminescence. The results indicate that CdTe nanorods are textured polycrystalline with the cubic phase and bear good crystallinity. In addition, this deposition technique is a clean, inexpensive, high-throughput, versatile and reproducible for obtaining vertically aligned CdTe nanorod, which shows the potential applications in the future for the preparation of CdTe-based nanostructure solar cells.

  16. Gold Nanobipyramid-Directed Growth of Length-Variable Silver Nanorods with Multipolar Plasmon Resonances.

    PubMed

    Zhuo, Xiaolu; Zhu, Xingzhong; Li, Qian; Yang, Zhi; Wang, Jianfang

    2015-07-28

    We report on a method for the preparation of uniform and length-variable Ag nanorods through anisotropic Ag overgrowth on high-purity Au nanobipyramids. The rod diameters can be roughly tailored from ∼20 nm to ∼50 nm by judicious selection of differently sized Au nanobipyramids. The rod lengths can be tuned from ∼150 nm to ∼550 nm by varying the Ag precursor amount during the overgrowth process and/or by anisotropic shortening through mild oxidation. The controllable aspect ratios, high purity, and high dimensional uniformity of these Ag nanorods enable the observation of Fabry-Pérot-like multipolar plasmon resonance modes in the colloidal suspensions at the ensemble level, which has so far been demonstrated only on Au nanorods prepared electrochemically with anodic aluminum oxide templates. Depending on the mode order and geometry of the Ag nanorods, the multipolar plasmon wavelengths can be readily tailored over a wide spectral range from the visible to near-infrared region. We have further elucidated the relationships between the multipolar plasmon wavelengths and the geometric dimensions of the Ag nanorods at both the ensemble and single-particle levels. Our results indicate that the Au nanobipyramid-directed, dimensionally controllable Ag nanorods will be an attractive and promising candidate for developing multipolar plasmon-based devices and applications.

  17. Hydrothermal Synthesis and Photocatalytic Property of β-Ga2O3 Nanorods

    NASA Astrophysics Data System (ADS)

    Reddy, L. Sivananda; Ko, Yeong Hwan; Yu, Jae Su

    2015-09-01

    Gallium oxide (Ga2O3) nanorods were facilely prepared by a simple hydrothermal synthesis, and their morphology and photocatalytic property were studied. The gallium oxide hydroxide (GaOOH) nanorods were formed in aqueous growth solution containing gallium nitrate and ammonium hydroxide at 95 °C of growth temperature. Through the calcination treatment at 500 and 1000 °C for 3 h, the GaOOH nanorods were converted into single crystalline α-Ga2O3 and β-Ga2O3 phases. From X-ray diffraction analysis, it could be confirmed that a high crystalline quality of β-Ga2O3 nanorods was achieved by calcinating at 1000 °C. The thermal behavior of the Ga2O3 nanorods was also investigated by differential thermal analysis, and their vibrational bands were identified by Fourier transform infrared spectroscopy. In order to examine the photocatalytic activity of samples, the photodegradation of Rhodamine B solution was observed under UV light irradiation. As a result, the α-Ga2O3 and β-Ga2O3 nanorods exhibited high photodegeneration efficiencies of 62 and 79 %, respectively, for 180 min of UV irradiation time.

  18. Gold Nanobipyramid-Directed Growth of Length-Variable Silver Nanorods with Multipolar Plasmon Resonances.

    PubMed

    Zhuo, Xiaolu; Zhu, Xingzhong; Li, Qian; Yang, Zhi; Wang, Jianfang

    2015-07-28

    We report on a method for the preparation of uniform and length-variable Ag nanorods through anisotropic Ag overgrowth on high-purity Au nanobipyramids. The rod diameters can be roughly tailored from ∼20 nm to ∼50 nm by judicious selection of differently sized Au nanobipyramids. The rod lengths can be tuned from ∼150 nm to ∼550 nm by varying the Ag precursor amount during the overgrowth process and/or by anisotropic shortening through mild oxidation. The controllable aspect ratios, high purity, and high dimensional uniformity of these Ag nanorods enable the observation of Fabry-Pérot-like multipolar plasmon resonance modes in the colloidal suspensions at the ensemble level, which has so far been demonstrated only on Au nanorods prepared electrochemically with anodic aluminum oxide templates. Depending on the mode order and geometry of the Ag nanorods, the multipolar plasmon wavelengths can be readily tailored over a wide spectral range from the visible to near-infrared region. We have further elucidated the relationships between the multipolar plasmon wavelengths and the geometric dimensions of the Ag nanorods at both the ensemble and single-particle levels. Our results indicate that the Au nanobipyramid-directed, dimensionally controllable Ag nanorods will be an attractive and promising candidate for developing multipolar plasmon-based devices and applications. PMID:26135608

  19. Two-stage epitaxial growth of vertically-aligned SnO2 nano-rods on (001) ceria

    SciTech Connect

    Solovyov, VF; Wu, LJ; Rupich, MW; Sathyamurthy, S; Li, XP; Li, Q

    2014-12-15

    Growth of high-aspect ratio oriented tin oxide, SnO2, nano-rods is complicated by a limited choice of matching substrates. We show that a (001) cerium oxide, CeO2, surface uniquely enables epitaxial growth of tin-oxide nano-rods via a two-stage process. First, (100) oriented nano-wires coat the ceria surface by lateral growth, forming a uniaxially-textured SnO2 deposit. Second, vertical SnO2 nano-rods nucleate on the deposit by homoepitaxy. We demonstrate growth of vertically oriented 1-2 mu m long nano-rods with an average diameter of approximate to 20 nm. 2014 Elsevier B.V. All rights reserved.

  20. Two-stage epitaxial growth of vertically-aligned SnO2 nano-rods on(001) ceria

    DOE PAGESBeta

    Solovyov, Vyacheslav F.; Wu, Li-jun; Rupich, Martin W.; Sathyamurthy, Srivatsan; Li, Xiaoping; Li, Qiang

    2014-09-20

    Growth of high-aspect ratio oriented tin oxide, SnO2, nano-rods is complicated by a limited choice of matching substrates. We show that a (001) cerium oxide, CeO2, surface uniquely enables epitaxial growth of tin-oxide nano-rods via a two-stage process. First, (100) oriented nano-wires coat the ceria surface by lateral growth, forming a uniaxially-textured SnO2 deposit. Second, vertical SnO2nano-rods nucleate on the deposit by homoepitaxy. We demonstrate growth of vertically oriented 1-2 μm long nano-rods with an average diameter of ≈20 nm.

  1. Low temperature plasma synthesis of mesoporous Fe3O4 nanorods grafted on reduced graphene oxide for high performance lithium storage.

    PubMed

    Zhou, Quan; Zhao, Zongbin; Wang, Zhiyu; Dong, Yanfeng; Wang, Xuzhen; Gogotsi, Yury; Qiu, Jieshan

    2014-02-21

    Transition metal oxide coupling with carbon is an effective method for improving electrical conductivity of battery electrodes and avoiding the degradation of their lithium storage capability due to large volume expansion/contraction and severe particle aggregation during the lithium insertion and desertion process. In our present work, we develop an effective approach to fabricate the nanocomposites of porous rod-shaped Fe3O4 anchored on reduced graphene oxide (Fe3O4/rGO) by controlling the in situ nucleation and growth of β-FeOOH onto the graphene oxide (β-FeOOH/GO) and followed by dielectric barrier discharge (DBD) hydrogen plasma treatment. Such well-designed hierarchical nanostructures are beneficial for maximum utilization of electrochemically active matter in lithium ion batteries and display superior Li uptake with high reversible capacity, good rate capability, and excellent stability, maintaining 890 mA h g(-1) capacity over 100 cycles at a current density of 500 mA g(-1). PMID:24413631

  2. Low temperature plasma synthesis of mesoporous Fe3O4 nanorods grafted on reduced graphene oxide for high performance lithium storage.

    PubMed

    Zhou, Quan; Zhao, Zongbin; Wang, Zhiyu; Dong, Yanfeng; Wang, Xuzhen; Gogotsi, Yury; Qiu, Jieshan

    2014-02-21

    Transition metal oxide coupling with carbon is an effective method for improving electrical conductivity of battery electrodes and avoiding the degradation of their lithium storage capability due to large volume expansion/contraction and severe particle aggregation during the lithium insertion and desertion process. In our present work, we develop an effective approach to fabricate the nanocomposites of porous rod-shaped Fe3O4 anchored on reduced graphene oxide (Fe3O4/rGO) by controlling the in situ nucleation and growth of β-FeOOH onto the graphene oxide (β-FeOOH/GO) and followed by dielectric barrier discharge (DBD) hydrogen plasma treatment. Such well-designed hierarchical nanostructures are beneficial for maximum utilization of electrochemically active matter in lithium ion batteries and display superior Li uptake with high reversible capacity, good rate capability, and excellent stability, maintaining 890 mA h g(-1) capacity over 100 cycles at a current density of 500 mA g(-1).

  3. High Resolution Fluorescence Imaging of Cancers Using Lanthanide Ion-Doped Upconverting Nanocrystals

    PubMed Central

    Naccache, Rafik; Rodríguez, Emma Martín; Bogdan, Nicoleta; Sanz-Rodríguez, Francisco; de la Cruz, Maria del Carmen Iglesias; de la Fuente, Ángeles Juarranz; Vetrone, Fiorenzo; Jaque, Daniel; Solé, José García; Capobianco, John A.

    2012-01-01

    During the last decade inorganic luminescent nanoparticles that emit visible light under near infrared (NIR) excitation (in the biological window) have played a relevant role for high resolution imaging of cancer. Indeed, semiconductor quantum dots (QDs) and metal nanoparticles, mostly gold nanorods (GNRs), are already commercially available for this purpose. In this work we review the role which is being played by a relatively new class of nanoparticles, based on lanthanide ion doped nanocrystals, to target and image cancer cells using upconversion fluorescence microscopy. These nanoparticles are insulating nanocrystals that are usually doped with small percentages of two different rare earth (lanthanide) ions: The excited donor ions (usually Yb3+ ion) that absorb the NIR excitation and the acceptor ions (usually Er3+, Ho3+ or Tm3+), that are responsible for the emitted visible (or also near infrared) radiation. The higher conversion efficiency of these nanoparticles in respect to those based on QDs and GNRs, as well as the almost independent excitation/emission properties from the particle size, make them particularly promising for fluorescence imaging. The different approaches of these novel nanoparticles devoted to “in vitro” and “in vivo” cancer imaging, selective targeting and treatment are examined in this review. PMID:24213500

  4. In vitro selection of a new lanthanide-dependent DNAzyme for ratiometric sensing lanthanides.

    PubMed

    Huang, Po-Jung Jimmy; Vazin, Mahsa; Liu, Juewen

    2014-10-01

    Developing biosensors for lanthanides is an important but challenging analytical task. To address this problem, in vitro selection of RNA-cleaving DNAzymes was carried out using a library containing a region of 35 random nucleotides in the presence of Lu(3+), since Lu(3+) was reported to be the most efficient lanthanide for RNA cleavage. The resulting DNA sequences can be aligned to a single family with two conserved stretches of nucleotides. One of the representative DNAzymes (named Lu12) was further studied. Lu12 is more active with smaller lanthanides and has the lowest activity in the presence of the largest lanthanide (lutetium). Its cleavage rate is 0.12 min(-1) in the presence of 10 μM Nd(3+) at pH 6.0. This is a new DNAzyme, and a catalytic beacon sensor is designed by attaching a fluorophore/quencher pair, detecting Nd(3+) down to 0.4 nM (72 parts-per-trillion). This DNAzyme is highly selective for lanthanides as well, showing cleavage only with two nonlanthanide ions: Y(3+) and Pb(2+). We previously reported a DNAzyme named Ce13d, which has similar responses to all the trivalent lanthanides. Combining these two allows for a ratiometric assay that identifies a few large lanthanides.

  5. Electronic Structure of Small Lanthanide Containing Molecules

    NASA Astrophysics Data System (ADS)

    Kafader, Jared O.; Ray, Manisha; Topolski, Josey E.; Chick Jarrold, Caroline

    2016-06-01

    Lanthanide-based materials have unusual electronic properties because of the high number of electronic degrees of freedom arising from partial occupation of 4f orbitals, which make these materials optimal for their utilization in many applications including electronics and catalysis. Electronic spectroscopy of small lanthanide molecules helps us understand the role of these 4f electrons, which are generally considered core-like because of orbital contraction, but are energetically similar to valence electrons. The spectroscopy of small lanthanide-containing molecules is relatively unexplored and to broaden this understanding we have completed the characterization of small cerium, praseodymium, and europium molecules using photoelectron spectroscopy coupled with DFT calculations. The characterization of PrO, EuH, EuO/EuOH, and CexOy molecules have allowed for the determination of their electron affinity, the assignment of numerous anion to neutral state transitions, modeling of anion/neutral structures and electron orbital occupation.

  6. Separations of actinides, lanthanides and other metals

    DOEpatents

    Smith, Barbara F.; Jarvinen, Gordon D.; Ensor, Dale D.

    1995-01-01

    An organic extracting solution comprised of a bis(acylpyrazolone or a substituted bis(acylpyrazolone) and an extraction method useful for separating certain elements of the actinide series of the periodic table having a valence of four from one other, and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also useful for separating hexavalent actinides from one or more of the substances in a group consisting of trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals.

  7. Curvature of the Lanthanide Contraction: An Explanation

    SciTech Connect

    Raymond, Kenneth; Wellman, Daniel; Sgarlata, Carmelo; Hill, Aru

    2009-12-21

    A number of studies have shown that for isostructural series of the lanthanides (elements La through Lu), a plot of equivalent metal-ligand bond lengths versus atomic number differs significantly from linearity and can be better fit as a quadratic equation. However, for hydrogen type wave functions, it is the inverse of the average distance of the electron from the nucleus (an estimate of size) that varies linearly with effective nuclear charge. This generates an apparent quadratic dependence of radius with atomic number. Plotting the inverse of lanthanide ion radii (the observed distance minus the ligand size) as a function of effective nuclear charge gives very good linear fits for a variety of lanthanide complexes and materials. Parameters obtained from this fit are in excellent agreement with the calculated Slater shielding constant, k.

  8. Actinide Lanthanide Separation Process – ALSEP

    SciTech Connect

    Gelis, Artem V.; Lumetta, Gregg J.

    2014-01-29

    Separation of the minor actinides (Am, Cm) from the lanthanides at an industrial scale remains a significant technical challenge for closing the nuclear fuel cycle. To increase the safety of used nuclear fuel (UNF) reprocessing, as well as reduce associated costs, a novel solvent extraction process has been developed. The process allows for partitioning minor actinides, lanthanides and fission products following uranium/plutonium/neptunium removal; minimizing the number of separation steps, flowsheets, chemical consumption, and waste. This new process, Actinide Lanthanide SEParation (ALSEP), uses an organic solvent consisting of a neutral diglycolamide extractant, either N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) or N,N,N',N'-tetraoctyldiglycolamide (TODGA), and an acidic extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]), dissolved in an aliphatic diluent (e.g. n-dodecane). The An/Ln co-extraction is conducted from moderate-to-strong nitric acid, while the selective stripping of the minor actinides from the lanthanides is carried out using a polyaminocarboxylic acid/citrate buffered solution at pH anywhere between 3 and 4.5. The extraction and separation of the actinides from the fission products is very effective in a wide range of HNO3 concentrations and the minimum separation factors for lanthanide/Am exceed 30 for Nd/Am, reaching > 60 for Eu/Am under some conditions. The experimental results presented here demonstrate the great potential for a combined system, consisting of a neutral extractant such as T2EHDGA or TODGA, and an acidic extractant such as HEH[EHP], for separating the minor actinides from the lanthanides.

  9. Valence determination of rare earth elements in lanthanide silicates by L 3-XANES spectroscopy

    NASA Astrophysics Data System (ADS)

    Kravtsova, Antonina N.; Guda, Alexander A.; Goettlicher, Joerg; Soldatov, Alexander V.; Taroev, Vladimir K.; Kashaev, Anvar A.; Suvorova, Lyudmila F.; Tauson, Vladimir L.

    2016-05-01

    Lanthanide silicates have been hydrothermally synthesized using Cu and Ni containers. Chemical formulae of the synthesized compounds correspond to K3Eu[Si6O15] 2H2O, HK6Eu[Si10O25], K7Sm3[Si12O32], K2Sm[AlSi4O12] 0.375H2O, K4Yb2[Si8O21], K4Ce2[Al2Si8O24]. The oxidation state of lanthanides (Eu, Ce, Tb, Sm, Yb) in these silicates has been determined using XANES spectroscopy at the Eu, Ce, Tb, Sm, Yb, L 3- edges. The experimental XANES spectra were recorded using the synchrotron radiation source ANKA (Karlsruhe Institute of Technology) and the X-ray laboratory spectrometer Rigaku R- XAS. By comparing the absorption edge energies and white line intensities of the silicates with the ones of reference spectra the oxidation state of lanthanides Eu, Ce, Tb, Sm, Yb has been found to be equal to +3 in all investigated silicates except of the Ce-containing silicate from the run in Cu container where the cerium oxidation state ranges from +3 (Ce in silicate apatite and in a KCe silicate with Si12O32 layers) to +4 (starting CeO2 or oxidized Ce2O3).

  10. Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone

    SciTech Connect

    Hassan, S.S.M.; Mahmoud, W.H.

    1982-02-01

    Sensitive and reasonably selective methods are described for the spectrophotometric, potentiometric, and gravimetric determination of lanthanides using peri-dihydroxynaphthindenone as a novel chromogenic and precipitating reagent. The reagent forms a stable 1:2 (metal:reagent) type of complex with light lanthanides at pH 2-7 in 1:1 ethanol-water mixture. Low metal concentrations (<10 ..mu..g/mL) develop colored species (lambda/sub max/ 580 to 590 nm, epsilon/sub max/ (4-6) x 10/sup 4/ L mol/sup -1/ cm/sup -1/) which obey Beer's law. Quantitative precipitation of the complexes from metal solutions of concentrations > 100 ..mu..g/mL permits both gravimetric quantitation by igniting the precipitates to the metal oxides and potentiometric titration of the excess reagent. Results with an average recovery of 98% (standard deviation 0.7%) are obtainable for 0.1 ..mu..g to 200 mg of all light lanthanides. Many foreign ions naturally occurring or frequently associated with lanthanides do not interfere or can be tolerated.

  11. MxaY regulates the lanthanide-mediated methanol dehydrogenase switch in Methylomicrobium buryatense

    PubMed Central

    Chu, Frances; Beck, David A.C.

    2016-01-01

    Many methylotrophs, microorganisms that consume carbon compounds lacking carbon–carbon bonds, use two different systems to oxidize methanol for energy production and biomass accumulation. The MxaFI methanol dehydrogenase (MDH) contains calcium in its active site, while the XoxF enzyme contains a lanthanide in its active site. The genes encoding the MDH enzymes are differentially regulated by the presence of lanthanides. In this study, we found that the histidine kinase MxaY controls the lanthanide-mediated switch in Methylomicrobium buryatense 5GB1C. MxaY controls the transcription of genes encoding MxaFI and XoxF at least partially by controlling the transcript levels of the orphan response regulator MxaB. We identify a constitutively active version of MxaY, and identify the mutated residue that may be involved in lanthanide sensing. Lastly, we find evidence to suggest that tight control of active MDH production is required for wild-type growth rates.

  12. MxaY regulates the lanthanide-mediated methanol dehydrogenase switch in Methylomicrobium buryatense

    PubMed Central

    Chu, Frances; Beck, David A.C.

    2016-01-01

    Many methylotrophs, microorganisms that consume carbon compounds lacking carbon–carbon bonds, use two different systems to oxidize methanol for energy production and biomass accumulation. The MxaFI methanol dehydrogenase (MDH) contains calcium in its active site, while the XoxF enzyme contains a lanthanide in its active site. The genes encoding the MDH enzymes are differentially regulated by the presence of lanthanides. In this study, we found that the histidine kinase MxaY controls the lanthanide-mediated switch in Methylomicrobium buryatense 5GB1C. MxaY controls the transcription of genes encoding MxaFI and XoxF at least partially by controlling the transcript levels of the orphan response regulator MxaB. We identify a constitutively active version of MxaY, and identify the mutated residue that may be involved in lanthanide sensing. Lastly, we find evidence to suggest that tight control of active MDH production is required for wild-type growth rates. PMID:27651996

  13. MxaY regulates the lanthanide-mediated methanol dehydrogenase switch in Methylomicrobium buryatense.

    PubMed

    Chu, Frances; Beck, David A C; Lidstrom, Mary E

    2016-01-01

    Many methylotrophs, microorganisms that consume carbon compounds lacking carbon-carbon bonds, use two different systems to oxidize methanol for energy production and biomass accumulation. The MxaFI methanol dehydrogenase (MDH) contains calcium in its active site, while the XoxF enzyme contains a lanthanide in its active site. The genes encoding the MDH enzymes are differentially regulated by the presence of lanthanides. In this study, we found that the histidine kinase MxaY controls the lanthanide-mediated switch in Methylomicrobium buryatense 5GB1C. MxaY controls the transcription of genes encoding MxaFI and XoxF at least partially by controlling the transcript levels of the orphan response regulator MxaB. We identify a constitutively active version of MxaY, and identify the mutated residue that may be involved in lanthanide sensing. Lastly, we find evidence to suggest that tight control of active MDH production is required for wild-type growth rates. PMID:27651996

  14. Shear viscosity coefficient of liquid lanthanides

    SciTech Connect

    Patel, H. P. Thakor, P. B. Prajapati, A. V.; Sonvane, Y. A.

    2015-05-15

    Present paper deals with the computation of shear viscosity coefficient (η) of liquid lanthanides. The effective pair potential v(r) is calculated through our newly constructed model potential. The Pair distribution function g(r) is calculated from PYHS reference system. To see the influence of local field correction function, Hartree (H), Tailor (T) and Sarkar et al (S) local field correction function are used. Present results are compared with available experimental as well as theoretical data. Lastly, we found that our newly constructed model potential successfully explains the shear viscosity coefficient (η) of liquid lanthanides.

  15. Method bacterial endospore quantification using lanthanide dipicolinate luminescence

    NASA Technical Reports Server (NTRS)

    Ponce, Adrian (Inventor); Venkateswaran, Kasthuri J. (Inventor); Kirby, James Patrick (Inventor)

    2007-01-01

    A lanthanide is combined with a medium to be tested for endospores. The dipicolinic acid released from the endospores binds the lanthanides, which have distinctive emission (i.e., luminescence) spectra, and are detected using photoluminescence. The concentration of spores is determined by preparing a calibration curve generated from photoluminescence spectra of lanthanide complex mixed with spores of a known concentration. A lanthanide complex is used as the analysis reagent, and is comprised of lanthanide ions bound to multidentate ligands that increase the dipicolinic acid binding constant through a cooperative binding effect with respect to lanthanide chloride. The resulting combined effect of increasing the binding constant and eliminating coordinated water and multiple equilibria increase the sensitivity of the endospore assay by an estimated three to four orders of magnitude over prior art of endospore detection based on lanthanide luminescence.

  16. Preparation of Lanthanide-Polymer Composite Material via Click Chemistry.

    PubMed

    Chen, Bin; Wen, Guian; Wu, Jiajie; Feng, Jiachun

    2015-10-01

    Covalently attaching lanthanide complexes to the polymer backbone can effectively reduce the clustering of lanthanides and thus become an important strategy to fully unleash their potential. In this Communication, a metal-free click reaction is used for the first time to link a lanthanide complex to the polymer matrix. A diene-bearing copolymer with anthracenylmethyl methacrylate as a monomer and a dienophile-bearing lanthanide complex with 5-maleimido-1,10-phenanthroline as the second ligand are synthesized and coupled together through a Diels-Alder cycloaddition (DA). A comparative investigation demonstrates that the composite material prepared by DA click reaction shows the highest quantum yields in the same lanthanide concentration as compared to materials prepared by widely used "directly doping" and "in situ coordinating lanthanide ions with macromolecular ligand" approaches. This work suggests that the "metal-free" DA click reaction can be a promising tool in the synthesis of high efficient lanthanide functionalized polymeric materials.

  17. Hydrothermal synthesis of highly crystalline ZnO nanorod arrays: Dependence of morphology and alignment on growth conditions

    NASA Astrophysics Data System (ADS)

    Azzez, Shrook A.; Hassan, Z.; Hassan, J. J.; Alimanesh, M.; Rasheed, Hiba S.; Sabah, Fayroz A.; Abdulateef, Sinan A.

    2016-07-01

    Highly oriented zinc oxide nanorod were successfully grown on seeded p-type silicone substrate by hydrothermal methode. The morphology and the crystallinty of ZnO c-axis (002) arrays were systematically studied using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) methods. The effect of seed layer pre-annealing on nanorods properties was explained according to the nucleation site of ZnO nanoparticles on silicon substrate. In addition, the variation of the equal molarity of zinc nitrate hexahydrate and hexamine concentrations in the reaction vessel play a crucial role related to the ZnO nanorods.

  18. Low-temperature growth and optical properties of Ce-doped ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Yang, Jinghai; Gao, Ming; Yang, Lili; Zhang, Yongjun; Lang, Jihui; Wang, Dandan; Wang, Yaxin; Liu, Huilian; Fan, Hougang

    2008-12-01

    Ce-doped ZnO nanorods were prepared by sol-gel method with low annealing temperature of 500 °C. The effects of Ce doping on the structural and optical properties of ZnO nanorods were investigated in detail. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and Raman-scattering spectroscopy measurements. The XRD results showed that Ce was doped into ZnO nanorods because of no diffraction peaks of Ce or cerium oxide in the pattern. The synthesis temperature of Ce-doped ZnO nanorods decreased from 900 to 500 °C compared to that of pure ZnO nanorods. Compared with pure ZnO, UV peaks shifted towards the blue color and the intensity of visible peaks decreased after Ce doping. The PL properties of Ce-doped ZnO nanorods depend on both the synthesis temperatures and the dopant. In Raman spectra of doped samples, some classical modes, such as A 1 and E 1 modes, disappear, and the E 2 modes blue shift.

  19. ZnO Nanorod-Based Non-Enzymatic Optical Glucose Biosensor.

    PubMed

    Sarangi, Sachindra Nath; Nozaki, Shinji; Sahu, Surendra Nath

    2015-06-01

    The highly sensitive, interference-free and non-enzymatic optical sensing of glucose has been made possible for the first time using the hydrothermally synthesized ZnO nanorods. The UV irradiation of glucose-treated ZnO nanorods decomposes glucose into hydrogen peroxide (H2O2) and gluconic acid by UV oxidation. The ZnO nanorods play the role of a catalyst similar to the oxidase used in the enzymatic glucose sensors. The photoluminescence (PL) intensity of the near-band edge emission of the ZnO nanorods linearly decreased with the increased concentration of H2O2. Therefore, the glucose concentration is monitored over the wide range of 0.5-30 mM, corresponding to 9-540 mg/dL. The concentration range of the linear region in the calibration curve is suitable for its clinical use as a glucose sensor, because the glucose concentration of human serum is typically in the range of 80-120 mg/dL. In addition, the optical glucose sensor made of the ZnO nanorods is free from interference by bovin serum albumin, ascorbic acid or uric acid, which are also present in human blood. The non-enzymatic ZnO-nanorod sensor has been demonstrated with human serum samples from both normal persons and diabetic patients. There is a good agreement between the glucose concentrations measured by the PL quenching and standard clinical methods. PMID:26353588

  20. Photocatalytic activity of 6.5 MeV electron-irradiated ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Sapnar, K. B.; Ghule, L. A.; Bhoraskar, S. V.; Garadkar, K. M.; Dhole, S. D.; Bhoraskar, V. N.

    2012-04-01

    The microwave-synthesized zinc-oxide (ZnO) nanonorods of average length of ∼ 1500 nm and diameter ∼ 100 nm were irradiated with 6.5 meV electrons. From sample to sample, the electron fluence was varied over the range 5×1014 to 2.5×1015 e-cm-2. The pre- and post-electron-irradiated ZnO nanorods were characterized by X-ray diffraction, UV-VIS, EDAX, scanning electron microscopy, transmission electron microscopy, and BET methods. The results show that after electron irradiation, the ZnO nanorods could retain the hexagonal phase with the wurtzite structure; however, the average length of the ZnO nanorods reduced to ∼ 800 nm. Moreover, the oxygen atoms from a fraction of ZnO molecules were dislodged, and the process contributed to the formation of Zn-ZnO mixed phase, with increased zinc to oxygen ratio. In the photo-degradation of Rhodamine-B, a significant enhancement in the photocatalytic activity of the electron-irradiated ZnO nanorods was observed. This could be attributed to the induced defects, reduced dimensions, and increased surface area of the ZnO nanorods, in addition to the formation of the Zn-ZnO phase. All these could collectively contribute to the effective separation of the photogenerated electrons from the holes on the ZnO nanorods, and therefore enhance the photocatalytic activity under UV exposure.

  1. Growth mechanism, structure and IR photoluminescence studies of indium nitride nanorods

    NASA Astrophysics Data System (ADS)

    Lan, Z. H.; Wang, W. M.; Sun, C. L.; Shi, S. C.; Hsu, C. W.; Chen, T. T.; Chen, K. H.; Chen, C. C.; Chen, Y. F.; Chen, L. C.

    2004-08-01

    High-quality single crystal indium nitride nanorods were grown on Si substrates by catalytic chemical vapor deposition. Both Raman and high resolution transmission electron microscopic analyses suggested that even a minute amount of oxygen, from the residual oxygen in the growth environment and/or native oxide on the Si, would effectively help the growth of InN nanorods. The In 2O 3 formed on Au nanoparticles helped dissolve nitrogen as a catalyst with the subsequent growth of InN nanorods. Variations in the apparent color and photoluminescence (PL) spectra of the InN nanorods were observed. For the optically brown InN nanorods that exhibited diameters in the range of 30-50 nm, the PL study showed a peak at 1.9 eV, the possible origins of which are discussed. In contrast, for the optically black InN nanorods that exhibited diameters in the range of 50-100 nm, the PL peak at approximately 0.766 eV measured at 20 K was attributed to band edge emission.

  2. Conjugation of antibodies to gold nanorods through Fc portion: synthesis and molecular specific imaging

    PubMed Central

    Joshi, Pratixa P.; Yoon, Soon Joon; Hardin, William G.; Emelianov, Stanislav; Sokolov, Konstantin V.

    2013-01-01

    Anisotropic gold nanorods provide a convenient combination of properties, such as tunability of plasmon resonances and strong extinction cross-sections in the near-infrared to red spectral region. These properties have created significant interest in the development of antibody conjugation methods for synthesis of targeted nanorods for a number of biomedical applications, including molecular specific imaging and therapy. Previously published conjugation approaches have achieved molecular specificity. However, the current conjugation methods have several downsides including low stability and potential cytotoxicity of bioconjugates that are produced by electrostatic interactions as well as lack of control over antibody orientation during covalent conjugation. Here we addressed these shortcomings by introducing directional antibody conjugation to the gold nanorod surface. The directional conjugation is achieved through the carbohydrate moiety, which is located on one of the heavy chains of the Fc portion of most antibodies. The carbohydrate is oxidized under mild conditions to a hydrazide reactive aldehyde group. Then, a heterofunctional linker with hydrazide and dithiol groups is used to attach antibodies to gold nanorods. The directional conjugation approach was characterized using electron microscopy, zeta potential and extinction spectra. We also determined spectral changes associated with nanorod aggregation; these spectral changes can be used as a convenient quality control of nanorod bioconjugates. Molecular specificity of the synthesized antibody targeted nanorods was demonstrated using hyperspectral optical and photoacoustic imaging of cancer cell culture models. Additionally, we observed characteristic changes in optical spectra of molecular specific nanorods after their interactions with cancer cells; the observed spectral signatures can be explored for sensitive cancer detection. PMID:23631707

  3. In situ fabrication and characterization of cobalt ferrite nanorods/graphene composites

    SciTech Connect

    Fu, Min; Jiao, Qingze; Zhao, Yun

    2013-12-15

    Cobalt ferrite nanorods/graphene composites were prepared by a one-step hydrothermal process using NaHSO{sub 3} as the reducing agent and 1-propyl-3-hexadecylimidazolium bromide as the structure growth-directing template. The reduction of graphene oxide and the in situ formation of cobalt ferrite nanorods were accomplished in a one-step reaction. The structure and morphology of as-obtained composites were characterized by field emission scanning electron microscopy, transmission electron microscopy, high resolution transmission electron microscopy, atomic force microscope, X-ray diffractometer, Fourier transform infrared spectra, X-ray photoelectron spectroscopy and Raman spectroscopy. Uniform rod-like cobalt ferrites with diameters of about 100 nm and length of about 800 nm were homogeneously distributed on the graphene sheets. The hybrid materials showed a saturation magnetization of 42.5 emu/g and coercivity of 495.1 Oe at room temperature. The electromagnetic parameters were measured using a vector network analyzer. A minimum reflection loss (RL) of − 25.8 dB was observed at 16.1 GHz for the cobalt ferrite nanorods/graphene composites with a thickness of 2 mm, and the effective absorption frequency (RL < − 10 dB) ranged from 13.5 to 18.0 GHz. The composites exhibited better absorbing properties than the cobalt ferrite nanorods and the mixture of cobalt ferrite nanorods and graphene. - Highlights: • Reduction of GO and formation of ferrites were accomplished in a one-step reaction. • Ionic liquid was used to control 1D growth of ferrite nanorods for the first time. • Cobalt ferrite nanorods/graphene composites showed dielectric and magnetic loss. • Cobalt ferrite nanorods/graphene composites exhibited better absorbing properties.

  4. Novel Biomimatic Synthesis of ZnO Nanorods Using Egg White (Albumen) and Their Antibacterial Studies.

    PubMed

    Ahmed, Faheem; Arshi, Nishat; Jeong, Yeong Seung; Anwar, M S; Dwivedi, Saurabh; Alsharaeh, Edreese; Koo, B H

    2016-06-01

    Zinc oxide (ZnO) is well-recognized as a biocompatible multifunctional material with outstanding properties as well as low toxicity and biodegradability. In this work, a simple and versatile technique was developed to prepare highly crystalline ZnO nanorods by introducing egg white to a bio-inspired approach. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern results indicated that the ZnO nanorods have single phase nature with the wurtzite structure. Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) results showed the nanometer dimension of the nanorods. Raman, FTIR, and TGA/DTA analyses revealed the formation of wurtzite ZnO. The antibacterial properties of ZnO nanorods were investigated using both Gram-positive and Gram-negative microorganisms. These studies demonstrate that ZnO nanorods have a wide range of antibacterial activities toward various microorganisms that are commonly found in environmental settings. Survival ratio of bacteria decreased with increasing powder concentration, i.e., increase in antibacterial activity. The antibacterial activity of the ZnO nanorods toward Pseudomonas aeruginosa was stronger than that of Escherichia coli and Staphylococcus aureus. Surprisingly, the antibacterial activity did not require specific UV activation using artificial lamps, rather activation was achieved under ambient lighting conditions. Overall, the experimental results suggest that ZnO nanorods could be developed as antibacterial agents against a wide range of microorganisms to control and prevent the spreading and persistence of bacterial infections. This research introduces a new concept to synthesize ZnO nanorods by using egg white as a biological template for various applications including food science, animal science, biochemistry, microbiology and medicine.

  5. Novel Biomimatic Synthesis of ZnO Nanorods Using Egg White (Albumen) and Their Antibacterial Studies.

    PubMed

    Ahmed, Faheem; Arshi, Nishat; Jeong, Yeong Seung; Anwar, M S; Dwivedi, Saurabh; Alsharaeh, Edreese; Koo, B H

    2016-06-01

    Zinc oxide (ZnO) is well-recognized as a biocompatible multifunctional material with outstanding properties as well as low toxicity and biodegradability. In this work, a simple and versatile technique was developed to prepare highly crystalline ZnO nanorods by introducing egg white to a bio-inspired approach. X-ray diffraction (XRD) and selected area electron diffraction (SAED) pattern results indicated that the ZnO nanorods have single phase nature with the wurtzite structure. Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) results showed the nanometer dimension of the nanorods. Raman, FTIR, and TGA/DTA analyses revealed the formation of wurtzite ZnO. The antibacterial properties of ZnO nanorods were investigated using both Gram-positive and Gram-negative microorganisms. These studies demonstrate that ZnO nanorods have a wide range of antibacterial activities toward various microorganisms that are commonly found in environmental settings. Survival ratio of bacteria decreased with increasing powder concentration, i.e., increase in antibacterial activity. The antibacterial activity of the ZnO nanorods toward Pseudomonas aeruginosa was stronger than that of Escherichia coli and Staphylococcus aureus. Surprisingly, the antibacterial activity did not require specific UV activation using artificial lamps, rather activation was achieved under ambient lighting conditions. Overall, the experimental results suggest that ZnO nanorods could be developed as antibacterial agents against a wide range of microorganisms to control and prevent the spreading and persistence of bacterial infections. This research introduces a new concept to synthesize ZnO nanorods by using egg white as a biological template for various applications including food science, animal science, biochemistry, microbiology and medicine. PMID:27427657

  6. An efficient methodology for measurement of the average electrical properties of single one-dimensional NiO nanorods.

    PubMed

    Patil, Ranjit A; Devan, Rupesh S; Lin, Jin-Han; Liou, Yung; Ma, Yuan-Ron

    2013-01-01

    We utilized a metal tantalum (Ta) ball-probe to measure the electrical properties of vertical-aligned one-dimensional (1D) nickel-oxide (NiO) nanorods. The 1D NiO nanorods (on average, ~105 nm wide and ~700 nm long) are synthesized using the hot-filament metal-oxide vapor deposition (HFMOVD) technique, and they are cubic phased and have a wide bandgap of 3.68 eV. When the 1D NiO nanorods are arranged in a large-area array in ohmic-contact with the Ta ball-probe, they acted as many parallel resistors. By means of a rigorous calculation, we can easily acquire the average resistance RNR and resistivity ρNR of a single NiO nanorod, which were approximately 3.1 × 10(13) Ω and 4.9 × 10(7) Ω.cm, respectively.

  7. Electrodeposition of Pd Nanowires and Nanorods on Carbon Nanoparticles

    SciTech Connect

    Bliznakov, S.; Vukmirovic, M.; Sutter, E.; Adzic, R.

    2011-06-01

    We report on the method for synthesizing palladium nanowires and nanorods involving the electrodeposition on oxidized amorphous carbon nanoparticles from chloride containing solutions. The effect of the deposition overpotential and the concentration of palladium ions on the morphology of the Pd electrodeposits have been established. Palladium grows predominately in the shape of nanowires if electrodeposited at potentials in the H underpotential deposition potential (UPD) range, where chloride ions are adsorbed only at the edges of nucleated monolayer-thick clusters on the carbon surface. The effect of the concentration of palladium ions on deposits morphology is also discussed. The mechanism of electrodeposition of Pd nanowires and nanorods in the H UPD potential range has been proposed.

  8. Copper nanorod array assisted silicon waveguide polarization beam splitter.

    PubMed

    Kim, Sangsik; Qi, Minghao

    2014-04-21

    We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology.

  9. Copper nanorod array assisted silicon waveguide polarization beam splitter

    PubMed Central

    Kim, Sangsik; Qi, Minghao

    2014-01-01

    We present the design of a three-dimensional (3D) polarization beam splitter (PBS) with a copper nanorod array placed between two silicon waveguides. The localized surface plasmon resonance (LSPR) of a metal nanorod array selectively cross-couples transverse electric (TE) mode to the coupler waveguide, while transverse magnetic (TM) mode passes through the original input waveguide without coupling. An ultra-compact and broadband PBS compared to all-dielectric devices is achieved with the LSPR. The output ports of waveguides are designed to support either TM or TE mode only to enhance the extinction ratios. Compared to silver, copper is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology. PMID:24787839

  10. Nanoparticles of lanthanide oxysulfate/oxysulfide for improved oxygen storage/release.

    PubMed

    Zhang, Wuyuan; Arends, Isabel W C E; Djanashvili, Kristina

    2016-09-28

    Lanthanide oxysulfates have the ability to store and release large volumes of oxygen under oxidizing/reducing conditions, rendering them interesting as automotive catalysts. Herein we demonstrate a remarkable improvement of both processes by utilization of nanoparticles compared to the bulk materials. A further improvement of the catalytic activity was achieved by cost-effective doping with 1.9 wt% of Ni. PMID:27515224

  11. The preparation of concentric-tubular composite microstructures and nanorod sols using template synthesis

    NASA Astrophysics Data System (ADS)

    Cepak, Veronica Marie

    1998-12-01

    Membrane-based template synthesis has been employed in the fabrication of concentric-tubular composite microstructures and nanorod organosols of two materials, metals and semiconductors. This type of template synthesis is unique because the cylindrical pores of filtration membranes were used as templates to prepare these materials. Insulating polymer nanofibrils and microtubules were prepared by template-assisted deposition. This method entailed filtering a polymer solution through a filtration membrane. Insulating microtubules that were obtained were further used to prepare concentric-tubular composite microstructure arrays consisting of an outer tubule of polystyrene surrounding an inner fibril of the conductive polymer, polypyrrole. The preparation and characterization of insulating polymer structures along with this microcomposite array was discussed. In addition, template synthesis has also been used to prepare a variety of other types of concentric-tubular microcomposite structures. Examples prepared consisted of Au/poly(phenylene oxide)/polypyrrole, Au/TiO2, and Au/ZnO to demonstrate the versatility of this method. These examples used the following chemistries: the electroless deposition of Au, electrochemical deposition of conductive and insulating polymers, electrodeposition of semiconductors, and sol-gel methods. Membrane-based template synthesis has also been used to prepare metal and semiconductor nanorod sols in organic solvents. Nanorods were prepared in the polycarbonate membrane's pores by electrochemical deposition of metals or semiconductors. The nanorod organosols were then prepared by immersing a nanorod/membrane composite into either CHCl3 or hexafluoroisopropanol. These organic solvents dissolved the template membrane and simultaneously dispersed the nanorods to form a sol. Ag, Au, CdS, and ZnO nanorod sols were prepared in this fashion. The metal nanorod sols were investigated by visible absorption spectroscopy. The position of the plasmon

  12. Large hexagonal arrays of aligned ZnO nanorods

    NASA Astrophysics Data System (ADS)

    Banerjee, D.; Rybczynski, J.; Huang, J. Y.; Wang, D. Z.; Kempa, K.; Ren, Z. F.

    2005-02-01

    Large-scale truly periodic arrays of vertically aligned zinc oxide nanorods were grown on pre-patterned and pre-annealed gold dots on a-plane sapphire substrates via the vapor liquid solid mechanism. Periodic arrays of triangular gold islands were first patterned on the a-plane sapphire substrates by the nanosphere self-assembly technique. Zinc has been found to be an effective interfacial modifier between gold and sapphire to form single catalytic dots from triangular islands. The successful fabrication of zinc oxide nanowires in truly periodic arrays opens up the possibility of achieving enhanced room-temperature ultraviolet lasing and photonic crystal based devices and sensors.

  13. High temperature structural and magnetic properties of cobalt nanorods

    SciTech Connect

    Ait Atmane, Kahina; Zighem, Fatih; Soumare, Yaghoub; Ibrahim, Mona; Boubekri, Rym; Maurer, Thomas; Margueritat, Jeremie; Piquemal, Jean-Yves; Ott, Frederic; Chaboussant, Gregory; Schoenstein, Frederic; Jouini, Noureddine; Viau, Guillaume

    2013-01-15

    We present in this paper the structural and magnetic properties of high aspect ratio Co nanoparticles ({approx}10) at high temperatures (up to 623 K) using in-situ X ray diffraction (XRD) and SQUID characterizations. We show that the anisotropic shapes, the structural and texture properties are preserved up to 500 K. The coercivity can be modelled by {mu}{sub 0}H{sub C}=2(K{sub MC}+K{sub shape})/M{sub S} with K{sub MC} the magnetocrystalline anisotropy constant, K{sub shape} the shape anisotropy constant and M{sub S} the saturation magnetization. H{sub C} decreases linearly when the temperature is increased due to the loss of the Co magnetocrystalline anisotropy contribution. At 500 K, 50% of the room temperature coercivity is preserved corresponding to the shape anisotropy contribution only. We show that the coercivity drop is reversible in the range 300-500 K in good agreement with the absence of particle alteration. Above 525 K, the magnetic properties are irreversibly altered either by sintering or by oxidation. - Graphical abstract: We present in this paper the structural and magnetic properties of high aspect ratio Co nanorods ({approx}10) at high temperatures (up to 623 K) using in-situ X-ray diffraction and SQUID characterizations. We show that the anisotropic shapes, the structural and texture properties are preserved up to 500 K. Above 525 K, the magnetic properties are irreversibly altered either by sintering or by oxidation. Highlights: Black-Right-Pointing-Pointer Ferromagnetic Co nanorods are prepared using the polyol process. Black-Right-Pointing-Pointer The structural and texture properties of the Co nanorods are preserved up to 500 K. Black-Right-Pointing-Pointer The magnetic properties of the Co nanorods are irreversibly altered above 525 K.

  14. Biological and Clinical Aspects of Lanthanide Coordination Compounds

    PubMed Central

    Misra, Sudhindra N.; M., Indira Devi; Shukla, Ram S.

    2004-01-01

    The coordinating chemistry of lanthanides, relevant to the biological, biochemical and medical aspects, makes a significant contribution to understanding the basis of application of lanthanides, particularly in biological and medical systems. The importance of the applications of lanthanides, as an excellent diagnostic and prognostic probe in clinical diagnostics, and an anticancer material, is remarkably increasing. Lanthanide complexes based X-ray contrast imaging and lanthanide chelates based contrast enhancing agents for magnetic resonance imaging (MRI) are being excessively used in radiological analysis in our body systems. The most important property of the chelating agents, in lanthanide chelate complex, is its ability to alter the behaviour of lanthanide ion with which it binds in biological systems, and the chelation markedly modifies the biodistribution and excretion profile of the lanthanide ions. The chelating agents, especially aminopoly carboxylic acids, being hydrophilic, increase the proportion of their complex excreted from complexed lanthanide ion form biological systems. Lanthanide polyamino carboxylate-chelate complexes are used as contrast enhancing agents for Magnetic Resonance Imaging. Conjugation of antibodies and other tissue specific molecules to lanthanide chelates has led to a new type of specific MRI contrast agents and their conjugated MRI contrast agents with improved relaxivity, functioning in the body similar to drugs. Many specific features of contrast agent assisted MRI make it particularly effective for musculoskeletal and cerebrospinal imaging. Lanthanide-chelate contrast agents are effectively used in clinical diagnostic investigations involving cerebrospinal diseases and in evaluation of central nervous system. Chelated lanthanide complexes shift reagent aided 23Na NMR spectroscopic analysis is used in cellular, tissue and whole organ systems. PMID:18365075

  15. Template-free formation of vertically oriented TiO2 nanorods with uniform distribution for organics-sensing application.

    PubMed

    Mu, Qinghui; Li, Yaogang; Zhang, Qinghong; Wang, Hongzhi

    2011-04-15

    High-density arrays of vertically oriented TiO(2) nanorods with uniform distribution on Ti foil have been formed through template-free oxidation of Ti in hydrogen peroxide solutions. Subsequent thermal treatment was applied for growing mixed crystal structures to pursue higher performance. Morphology characterization using field emission scanning electron microscopy (FESEM) shows a nanorod diameter in the range of 20-50 nm with a length of 1.5 μm. X-ray diffraction (XRD) measurement demonstrates the crystallization of the TiO(2) nanorods prior to thermal treatment and the formation of anatase and rutile mixed phase after thermal treatment. The mixed crystal TiO(2) nanorods show a much higher performance than pure anatase in photoelectrochemical experiments. Steady-state photocurrent resulted from photocatalytic oxidation of organic compounds by TiO(2) nanorods is employed as response signal in determination of the organics to yield a linear range of 0-1.1mM for glucose. For other organics, an excellent linear relationship between the net steady-state photocurrent and the concentration of electrons transferred in exhaustive oxidation for these organics is obtained, which empowers the mixed crystal TiO(2) nanorods to serve as versatile material in organics-sensing application.

  16. X-ray spectral diagnostics of synthetic lanthanide silicates

    NASA Astrophysics Data System (ADS)

    Kravtsova, A. N.; Guda, A. A.; Soldatov, A. V.; Goettlicher, J.; Taroev, V. K.; Kashaev, A. A.; Suvorova, L. F.; Tauson, V. L.

    2015-12-01

    Potassium and rare-earth (Eu, Sm, Yb, Ce) silicate and aluminosilicate crystals are hydrothermally synthesized under isothermal conditions at 500°C and a pressure of 100 MPa. The chemical and structural formulas of the synthesized compounds HK6Eu[Si10O25], K7Sm3[Si12O32], K2Sm[AlSi4O12] · 0.375H2O, K4Yb2[Si8O21], and K4Ce2[Al2Si8O24] are determined. In addition, a synthesis product with Eu, in which the dominant phase is assumed to be K3Eu3+[Si6O15] · 2H2O, is studied. The oxidation state of lanthanides in the silicates under study is determined based on X-ray absorption near-edge structure spectroscopy. The Eu L 3-, Sm L 3-, Yb L 3-, and Ce L 3-edge X-ray absorption spectra of the studied silicates and reference samples are recorded using a Rigaku R-XAS laboratory spectrometer. As reference samples, Eu2+S, Eu3+F3, Eu 2 3+ O3, Sm 2 3+ O3, Yb 2 3+ O3, Yb3+F3, Yb3+Cl3, Ce 2 3+ O3, and Ce4+O2 are used. Comparison of the absorption edge energies of lanthanide silicates and reference samples shows that Eu, Sm, Yb, and Ce in all the samples studied are in the oxidation state 3+. The synthesized silicates will supplement our knowledge of possible rare-earth minerals existing in hydrothermal systems, which is important for analyzing the distribution spectra of rare elements, which are widely used for diagnostics of geochemical processes and determination of sources of ore materials.

  17. Enhanced dual contrast agent, Co(2+)-doped NaYF4:Yb(3+),Tm(3+) nanorods, for near infrared-to-near infrared upconversion luminescence and magnetic resonance imaging.

    PubMed

    Xia, Ao; Zhang, Xiaofeng; Zhang, Jun; Deng, Yunyun; Chen, Qiang; Wu, Shishan; Huang, Xiaohua; Shen, Jian

    2014-11-01

    Dual-modality imaging with magnetic resonance (MR) and upconversion luminescence (UCL) is a promising technique for molecular imaging in biomedical research. Multifunctional lanthanide-based nanoparticles have been widely investigated as agents for contrast enhanced MR and fluorescence imaging. However, the use of rare earth fluoride nanoparticles for dual-modality imaging of T2-weighted MR and UCL is rarely reported. We find that NaYF4:Yb(3+),Tm(3+),Co(2+) (MUC) nanorods can be applied as a high-performance dual contrast agent for both T2-weighted MR and UCL dual-modality imaging. After modification with 6-O-carboxymethyl chitosan (OCC), MUC nanorods can be endocytosed by cells without showing signs of cytotoxicity. High-quality UCL images of living cells incubated with MUC-OCC nanorods were acquired on a near-infrared (NIR) confocal microscopy under the excitation at 980 nm. Moreover, MUC-OCC nanorods display high transverse (r2) relaxivities in vitro. The application of low-dose MUC-OCC nanorods for NIR-to-NIR UCL and MR dual-modality in vivo imaging was also carried out successfully. In addition, the toxicity of MUC-OCC nanorods was evaluated by MTT assay, serological tests and histological analysis of visceral organs.

  18. Single inorganic-organic hybrid photovoltaic nanorod

    NASA Astrophysics Data System (ADS)

    Yoo, Sang-Hoon; Liu, Lichun; Ku, Tea-Woong; Hong, Soonchang; Whang, Dongmok; Park, Sungho

    2013-09-01

    We demonstrate that single photovoltaic (PV) nanorods can be readily fabricated by electrochemical processing in solution-phase under ambient conditions. A porous Au nanorod electrode in the core of the PV nanorod was central to both its structural formation and superior performance. We examined an intrinsically conducting polymer (polypyrrole) and an inorganic semiconductor (cadmium selenide) as precursor materials. Through an extremely simple and cost-effective fashioning process (solution-phase, room temperature), unadorned PV nanorods with up to 1.1% power conversion efficiency were obtained.

  19. Graded core/shell semiconductor nanorods and nanorod barcodes

    DOEpatents

    Alivisatos, A. Paul; Scher, Erik C.; Manna, Liberato

    2009-05-19

    Disclosed herein is a graded core/shell semiconductor nanorod having at least a first segment of a core of a Group II-VI, Group III-V or a Group IV semiconductor, a graded shell overlying the core, wherein the graded shell comprises at least two monolayers, wherein the at least two monolayers each independently comprise a Group II-VI, Group III-V or a Group IV semiconductor.

  20. Acetone Sensing with In2O3-Coated Nb2O5 Nanorod Sensors.

    PubMed

    Park, Sunghoon; Kim, Soohyun; Jung, Jihwan; Lee, Chongmu

    2016-03-01

    Nb2O5-core/In2O3-shell nanorods were synthesized by thermal oxidation of Nb foil followed by sputter deposition of In2O3. The 1D nanostructures exhibited a rod-like morphology with widths and lengths ranging from 20 to 70 nm and 10 to 20 /jm, respectively. The sensing properties of Nb2O5-core/In2O3-shell nanorod sensors toward acetone gas were examined. The pristine Nb2O5 nanorods showed responses ranging from -121 to -253% to CH3COCH3 concentrations of 200-1,000 ppm. In contrast, Nb2O5-core/In2O3-shell nanorods showed responses ranging from -167 to -563% over the same concentration range. These responses are comparable or superior to other metal oxide semiconductor gas sensors in the literature. The underlying mechanism of the enhanced sensing properties of Nb2O5-core/In2O3-shell nanorods toward CH3COCH3 is also discussed.

  1. Surface Engineered Doping of Hematite Nanorod Arrays for Improved Photoelectrochemical Water Splitting

    PubMed Central

    Shen, Shaohua; Zhou, Jigang; Dong, Chung-Li; Hu, Yongfeng; Tseng, Eric Nestor; Guo, Penghui; Guo, Liejin; Mao, Samuel S.

    2014-01-01

    Given the narrow band gap enabling excellent optical absorption, increased charge carrier density and accelerated surface oxidation reaction kinetics become the key points for improved photoelectrochemical performances for water splitting over hematite (α-Fe2O3) photoanodes. In this study, a facile and inexpensive method was demonstrated to develop core/shell structured α-Fe2O3 nanorod arrays. A thin, Ag-doped overlayer of ~2–3 nm thickness was formed along α-Fe2O3 nanorods via ultrasonication treatment of solution-based β-FeOOH nanorods in Ag precursor solution followed by high temperature annealing. The obtained α-Fe2O3/AgxFe2−xO3 core/shell nanorod films demonstrated much higher photoelectrochemical performances as photoanodes than the pristine α-Fe2O3 nanorod film, especially in the visible light region; the incident photon-to-current efficiency (IPCE) at 400 nm was increased from 2.2% to 8.4% at 1.23 V vs. RHE (Reversible hydrogen electrode). Mott-Schottky analysis and X-ray absorption spectra revealed that the Ag-doped overlayer not only increased the carrier density in the near-surface region but also accelerated the surface oxidation reaction kinetics, synergistically contributing to the improved photoelectrochemical performances. These findings provide guidance for the design and optimization of nanostructured photoelectrodes for efficient solar water splitting. PMID:25316219

  2. Multifunctional particles: Magnetic nanocrystals and gold nanorods coated with fluorescent dye-doped silica shells

    SciTech Connect

    Heitsch, Andrew T.; Smith, Danielle K.; Patel, Reken N.; Ress, David; Korgel, Brian A.

    2008-07-15

    Multifunctional colloidal core-shell nanoparticles of magnetic nanocrystals (of iron oxide or FePt) or gold nanorods encapsulated in silica shells doped with the fluorescent dye, Tris(2,2'-bipyridyl)dichlororuthenium(II) hexahydrate (Rubpy) were synthesized. The as-prepared magnetic nanocrystals are initially hydrophobic and were coated with silica using a microemulsion approach, while the as-prepared gold nanorods are hydrophilic and were coated with silica using a Stoeber type of process. Each approach yielded monodisperse nanoparticles with uniform fluorescent dye-doped silica shells. These colloidal heterostructures have the potential to be used as dual-purpose tags-exhibiting a fluorescent signal that could be combined with either dark-field optical contrast (in the case of the gold nanorods), or enhanced contrast in magnetic resonance images (in the case of magnetic nanocrystal cores). The optical and magnetic properties of the fluorescent silica-coated gold nanorods and magnetic nanocrystals are reported. - Graphical abstract: Colloidal gold nanorods and iron platinum and iron oxide nanocrystals were encapsulated with fluorescent dye-doped silica shells using a generic coating strategy. These heterostructures are promising contrast agents for dual-mode medical imaging. Their optical and magnetic properties were studied and are reported here.

  3. Comparative study of photocatalytic activities of hydrothermally grown ZnO nanorod on Si(001) wafer and FTO glass substrates.

    PubMed

    Jeon, Eun Hee; Yang, Sena; Kim, Yeonwoo; Kim, Namdong; Shin, Hyun-Joon; Baik, Jaeyoon; Kim, Hyun Sung; Lee, Hangil

    2015-12-01

    ZnO nanorods have been grown on Si(001) wafer and fluorine-doped tin oxide (FTO) glass substrates for 1 and 4 h with the hydrothermal methods. The morphologies and photocatalytic activities of the ZnO nanorods were found to depend on the substrates. We investigated their properties by using spectroscopic analysis and demonstrated that the shape of nanorod and the ratios of external defects can be controlled by varying the substrates. Our experiments revealed that the nanorods grown on Si(001) have a single-crystalline wurtzite structure with (002) facets and that the number of surface oxygen defects increases with their length as the growth time increases. The nanorods grown on Si(001) have different facets, in particular wider (002) facets, and a higher ratio of the oxygen defect than the nanorods on FTO glass substrate. Moreover, the photocatalytic activities with respect to 2-aminothiophenol (2-ATP) of these nanorods were investigated with high-resolution photoemission spectroscopy (HRPES). We demonstrated that their photocatalytic activity is influenced by the ratios of surface oxygen defects, which varies with the substrate surface.

  4. Comparative study of photocatalytic activities of hydrothermally grown ZnO nanorod on Si(001) wafer and FTO glass substrates

    NASA Astrophysics Data System (ADS)

    Jeon, Eun Hee; Yang, Sena; Kim, Yeonwoo; Kim, Namdong; Shin, Hyun-Joon; Baik, Jaeyoon; Kim, Hyun Sung; Lee, Hangil

    2015-09-01

    ZnO nanorods have been grown on Si(001) wafer and fluorine-doped tin oxide (FTO) glass substrates for 1 and 4 h with the hydrothermal methods. The morphologies and photocatalytic activities of the ZnO nanorods were found to depend on the substrates. We investigated their properties by using spectroscopic analysis and demonstrated that the shape of nanorod and the ratios of external defects can be controlled by varying the substrates. Our experiments revealed that the nanorods grown on Si(001) have a single-crystalline wurtzite structure with (002) facets and that the number of surface oxygen defects increases with their length as the growth time increases. The nanorods grown on Si(001) have different facets, in particular wider (002) facets, and a higher ratio of the oxygen defect than the nanorods on FTO glass substrate. Moreover, the photocatalytic activities with respect to 2-aminothiophenol (2-ATP) of these nanorods were investigated with high-resolution photoemission spectroscopy (HRPES). We demonstrated that their photocatalytic activity is influenced by the ratios of surface oxygen defects, which varies with the substrate surface.

  5. Fabrication, characterization and antibacterial effect of novel electrospun TiO2 nanorods on a panel of pathogenic bacteria.

    PubMed

    Hassan, M Shamshi; Amna, Touseef; Mishra, Amrita; Yun, Soon-Il; Kim, Hyun-Chel; Kim, Hak-Yong; Khil, Myung-Seob

    2012-06-01

    This study is aimed at the synthesis and characterization of novel Titania nanorods by sol-gel electrospinning technique. The physicochemical properties of the synthesized nanorods were determined by FE-SEM, EDX, TEM, TGA and XRD. We investigated the photocatalytic activity of Titania nanorods for degrading Rhodamine 6G dye and discussed the antibacterial activity and interaction mechanism against four pathogenic bacteria viz., S. aureus, E. coli, S. typhimurium and K. pneumoniae by taking five different concentrations (5-45 microg/mL). The antibacterial effect of electrospun Titania nanorods was tested both in liquid culture and on agar plates. Our investigation reveals that the lowest concentration of Titania nanorods solution inhibiting the growth of microbial strain was found to be 5 microg/mL for all the tested pathogens. The photocatalytic activity of TiO2 nanorods showed better performance for dye degradation than commercially available P25. Moreover, Bio-TEM examination demonstrated that the exposure of the selected microbial strains to the Titania nanorods led to disruption of the cell membranes and leakage of the cytoplasm which cause bacteria to die eventually. Our results point the oxidative attack from exterior to the interior of the bacteria by hydroxyl radicals as the primary mechanism of photocatalytic inactivation.

  6. Morphological and structural characterization of single-crystal ZnO nanorod arrays on flexible and non-flexible substrates

    PubMed Central

    Farhat, Omar F; Halim, Mohd M; Abdullah, Mat J; Ali, Mohammed K M

    2015-01-01

    Summary We report a facile synthesis of zinc oxide (ZnO) nanorod arrays using an optimized, chemical bath deposition method on glass, PET and Si substrates. The morphological and structural properties of the ZnO nanorod arrays were investigated using various techniques such as field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) measurements, which revealed the formation of dense ZnO nanorods with a single crystal, hexagonal wurtzite structure. The aspect ratio of the single-crystal ZnO nanorods and the growth rate along the (002) direction was found to be sensitive to the substrate type. The lattice constants and the crystallite size of the fabricated ZnO nanorods were calculated based on the XRD data. The obtained results revealed that the increase in the crystallite size is strongly associated with the growth conditions with a minor dependence on the type of substrate. The Raman spectroscopy measurements confirmed the existence of a compressive stress in the fabricated ZnO nanorods. The obtained results illustrated that the growth of high quality, single-crystal ZnO nanorods can be realized by adjusting the synthesis conditions. PMID:25821712

  7. Characterization and adsorption performance of Pb(II) on CuO nanorods synthesized by the hydrothermal method

    SciTech Connect

    Arfaoui, Lobna; Kouass, Salah; Dhaouadi, Hassouna; Jebali, Raouf; Touati, Fathi

    2015-10-15

    Highlights: • The nanorods of CuO were synthesized by a hydrothermal route without any surfactant. • X-ray diffraction showed monoclinic structure with space group C{sub 2/c}. • The nanorods show relatively high adsorption capacity for the removal of Pb(II). • The adsorption kinetics could be fitted well by the pseudo-second-order model. • The equilibrium data can be fitted well using the Langmuir isotherm model - Abstract: Copper oxide (CuO) nanorods were synthesized by hydrothermal method. The detailed structural, compositional and optical characterization of this material was also evaluated with XRD, FT-IR, EDS, and UV–vis spectroscopy, which confirmed that the obtained nanorods are well-crystallized CuO and possess good optical properties. SEM and TEM studies revealed that the as-synthesized CuO nanorods are uniform with an average diameter of 17 nm. The adsorption activity of the CuO nanostructures was studied. The adsorption results showed that the CuO nanorods are an effective and efficient adsorbent for the removal of Pb(II) ions. The influence of various operational parameters such as the pH of the solution, the contact time and the initial concentrations were also studied and the results were discussed. The estimated maximum lead ion adsorption capacity of the CuO nanorods was found to be 188.67 mg g{sup −1} at an optimum pH of 6.

  8. Infrared Resonances in Plasmonic Nanorod and Nanoarc Antennas

    NASA Astrophysics Data System (ADS)

    Lawson, Andrew; Ellis, Chase; Tischler, Joseph; Rabin, Oded

    Tunability of the frequency and polarization of localized surface plasmon resonances (LSPR) of nanostructures is crucial for their implementation in nanophotonics applications such as photovoltaics, chiroptical spectroscopy, and infrared detection. We report spectroscopic data of plasmonic nanorods and nanoarcs collected by polarized Fourier transform infrared reflectance spectroscopy (FTIR). The effects of the nanostructure material, geometry and substrate material are investigated by patterning gold and aluminum structures with varying length on silicon and glass substrates, as well as on anodic aluminum oxide, a cost effective alternative to standard transparent substrates. By varying such parameters for straight rods and arcs, we find that the measured LSPR frequencies of our nanostructures span the mid-infrared spectral range (λ=2-12 microns). However, we find that bending the nanostructures (i.e., forming arcs rather than straight rods) results in additional resonances with unique polarizations not observed in straight nanorods. We find that the nanorods exhibit half-wave antenna behavior which can be modeled using antenna theory with a linearly scaled effective wavelength which accounts for structure dimensions and material.

  9. Experimental Findings On Minor Actinide And Lanthanide Separations Using Ion Exchange

    SciTech Connect

    Hobbs, D. T.; Shehee, T. C.; Clearfield, A.

    2013-09-17

    This project seeks to determine if inorganic or hybrid inorganic ion-exchange materials can be exploited to provide effective americium and curium separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of the tested ion-exchange materials for actinide and lanthanide ions. During FY13, experimental work focused in the following areas: (1) investigating methods to oxidize americium in dilute nitric acid with subsequent ion-exchange performance measurements of ion exchangers with the oxidized americium and (2) synthesis, characterization and testing of ion-exchange materials. Ion-exchange materials tested included alkali titanates, alkali titanosilicates, carbon nanotubes and group(IV) metal phosphonates. Americium oxidation testing sought to determine the influence that other redox active components may have on the oxidation of Am(III). Experimental findings indicated that Pu(IV) is oxidized to Pu(VI) by peroxydisulfate, but there are no indications that the presence of plutonium affects the rate or extent of americium oxidation at the concentrations of peroxydisulfate being used. Tests also explored the influence of nitrite on the oxidation of Am(III). Given the formation of Am(V) and Am(VI) in the presence of nitrite, it appears that nitrite is not a strong deterrent to the oxidation of Am(III), but may be limiting Am(VI) by quickly reducing Am(VI) to Am(V). Interestingly, additional absorbance peaks were observed in the UV-Vis spectra at 524 and 544 nm in both nitric acid and perchloric acid solutions when the peroxydisulfate was added as a solution. These peaks have not been previously observed and do not correspond to the expected peak locations for oxidized americium in solution. Additional studies are in progress to identify these unknown peaks. Three titanosilicate ion exchangers were synthesized using a microwave-accelerated reaction system (MARS) and determined to have high affinities

  10. Lanthanide doped strontium-barium cesium halide scintillators

    SciTech Connect

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

  11. De Novo Designed Imaging Agents Based on Lanthanide Peptides Complexes.

    PubMed

    Peacock, A F A

    2016-01-01

    Herein are discussed a selection of lanthanide peptide/protein complexes in view of their potential applications as imaging agents, both in terms of luminescence detection and magnetic resonance imaging. Though this chapter covers a range of different peptides and protein, if focuses specifically on the opportunities afforded by the de novo design of coiled coils, miniature protein scaffolds, and the development on lanthanide-binding sites into these architectures. The requirements for lanthanide coordination and the challenges that need to be addressed when preparing lanthanide peptides with a view to their potential adoption as clinical imaging applications, will be highlighted. PMID:27586349

  12. Synthesis and luminescence properties of hybrid organic-inorganic transparent titania thin film activated by in-situ formed lanthanide complexes

    SciTech Connect

    Wang Yige; Wang Li; Li Huanrong Liu Peng; Qin Dashan; Liu Binyuan; Zhang Wenjun; Deng Ruiping; Zhang Hongjie

    2008-03-15

    Stable transparent titania thin films were fabricated at room temperature by combining thenoyltrifluoroacetone (TTFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO, P123) copolymers. The obtained transparent titania thin films were systematically investigated by IR spectroscopy, PL emission and excitation spectroscopy and transmission electron microscopy. IR spectroscopy indicates that TTFA coordinates the titanium center during the process of hydrolysis and condensation. Luminescence spectroscopy confirms the in-situ formation of lanthanide complexes in the transparent titania thin film. TEM image shows that the in-situ formed lanthanide complexes were homogeneously distributed throughout the whole thin film. The quantum yield and the number of water coordinated to lanthanide metal center have been theoretically determined based on the luminescence data. - Graphical abstract: Novel stable luminescent organic-inorganic hybrid titania thin film with high transparency activated by in-situ formed lanthanide complexes have been obtained at room temperature via a simple one-pot synthesis approach by using TTFA-modified titanium precursor with amphiphilic triblock copolymer P123. The obtained hybrid thin film displays bright red (or green), near-monochromatic luminescence due to the in-situ formed lanthanide complex.

  13. Determination of critical diameters for intrinsic carrier diffusion-length of GaN nanorods with cryo-scanning near-field optical microscopy

    PubMed Central

    Chen, Y. T.; Karlsson, K. F.; Birch, J.; Holtz, P. O.

    2016-01-01

    Direct measurements of carrier diffusion in GaN nanorods with a designed InGaN/GaN layer-in-a-wire structure by scanning near-field optical microscopy (SNOM) were performed at liquid-helium temperatures of 10 K. Without an applied voltage, intrinsic diffusion lengths of photo-excited carriers were measured as the diameters of the nanorods differ from 50 to 800 nm. The critical diameter of nanorods for carrier diffusion is concluded as 170 nm with a statistical approach. Photoluminescence spectra were acquired for different positions of the SNOM tip on the nanorod, corresponding to the origins of the well-defined luminescence peaks, each being related to recombination-centers. The phenomenon originated from surface oxide by direct comparison of two nanorods with similar diameters in a single map has been observed and investigated. PMID:26876009

  14. The Silver Nanorod Array SERS Substrates

    NASA Astrophysics Data System (ADS)

    Zhao, Yiping; Liu, Yongjun

    2010-08-01

    The fabrication of large area, uniform and high enhancement substrates for surface enhanced Raman scattering (SERS) based sensing is a bottle-neck for practical applications of SERS. Recently using oblique angle deposition (OAD) method, we have fabricated silver nanorod arrays with SERS enhancement factor >108, and SERS intensity variation <14%. The SERS spectra from those substrates have been demonstrated to be able to distinguish different viruses and virus strains, bacteria, microRNAs, or other chemical and biological molecules. We have performed a detailed characterization on those Ag nanorod substrates. The SERS enhancement factor depends strongly on the nanorod length and the fabrication conditions. For different deposition angle, there is an optimal nanorod length that gives the maximum enhancement. The SERS enhancement seems to directly depend on the reflectivity of the Ag nanorod substrates at the excitation wavelength regardless of the deposition angles and rod length. The SERS performance also depends strongly on the configurations of the excitation laser beam: the incident angle, the polarization, and the reflectance of the underlayer substrates. A simple modified Greenler's model is proposed to qualitatively explain those effects. The possible origin for the high enhancement of the Ag nanorod substrates has been studied by placing the Raman probe molecules on different locations of the substrates, and we have found that the side surfaces of the nanorod arrays contributes more to the SERS enhancement compared to the ends. We propose that this is due to the anisotropic absorbance nature of the Ag nanorod substrates.

  15. Photoelectrochemical Properties of Vertically Aligned CuInS2 Nanorod Arrays Prepared via Template-Assisted Growth and Transfer.

    PubMed

    Yang, Wooseok; Oh, Yunjung; Kim, Jimin; Kim, Hyunchul; Shin, Hyunjung; Moon, Jooho

    2016-01-13

    Although copper-based chalcopyrite materials such as CuInS2 have been considered promising photocathodes for solar water splitting, the fabrication route for a nanostructure with vertical orientation has not yet been developed. Here, a fabrication route for vertically aligned CuInS2 nanorod arrays from an aqueous solution using anodic aluminum oxide template-assisted growth and transfer is presented. The nanorods exhibit a phase-pure CuInS2 chalcopyrite structure and cathodic photocurrent response without co-catalyst loading. Small particles of CdS and ZnS were conformally decorated onto CuInS2 nanorods using a successive ion layer adsorption and reaction method. With surface modification of CdS/ZnS, the photoelectrochemical properties of CuInS2 nanorod arrays are enhanced via flat-band potential shift, as determined by analyses of onset potential and Mott-Schottky plots. PMID:26645722

  16. The Actinide-Lanthanide Separation Process

    SciTech Connect

    Lumetta, Gregg J.; Gelis, Artem V.; Carter, Jennifer C.; Niver, Cynthia M.; Smoot, Margaret R.

    2014-02-21

    The Actinide-Lanthanide SEParation (ALSEP) process is described. The process uses an extractant phase consisting of either N,N,N',N'-tetraoctyldiglycolamide (TODGA) or N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) combined with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]). The neutral TODGA or T2EHDGA serves to co-extract the trivalent actinide and lanthanide ions from nitric acid media. Switching the aqueous phase chemistry to a citrate buffered diethylenetriaminepentaacetic acid (DTPA) solution at pH 2.5 to 4 results in selective transfer of the actinides to the aqueous phase, thus resulting in separation of these two groups of elements.

  17. Giant exchange interaction in mixed lanthanides

    PubMed Central

    Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

    2016-01-01

    Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction. PMID:27087470

  18. Lanthanide-halide based humidity indicators

    DOEpatents

    Beitz, James V.; Williams, Clayton W.

    2008-01-01

    The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.

  19. Giant exchange interaction in mixed lanthanides

    NASA Astrophysics Data System (ADS)

    Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

    2016-04-01

    Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction.

  20. Nanometrization of Lanthanide-Based Coordination Polymers.

    PubMed

    Neaime, Chrystelle; Daiguebonne, Carole; Calvez, Guillaume; Freslon, Stéphane; Bernot, Kevin; Grasset, Fabien; Cordier, Stéphane; Guillou, Olivier

    2015-11-23

    Heteronuclear lanthanide-based coordination polymers are microcrystalline powders, the luminescence properties of which can be precisely tuned by judicious choice of the rare-earth ions. In this study, we demonstrate that such materials can also be obtained as stable solutions of nanoparticles in non-toxic polyols. Bulk powders of the formula [Ln2-2x Ln'2x (bdc)3 ⋅4 H2 O]∞ (where H2 bdc denotes 1,4-benzene-dicarboxylic acid, 0≤x≤1, and Ln and Ln' denote lanthanide ions of the series La to Tm plus Y) afford nanoparticles that have been characterized by dynamic light-scattering (DLS) and transmission electron microscopy (TEM) measurements. Their luminescence properties are similar to those of the bulk materials. Stabilities versus time and versus dilution with another solvent have been studied. This study has revealed that it is possible to tune the size of the nanoparticles. This process offers a reliable means of synthesizing suspensions of nanoparticles with tunable luminescence properties and tunable size distributions in a green solvent (glycerol). The process is also extendable to other coordination polymers and other solvents (ethylene glycol, for example). It constitutes a new route for the facile solubilization of lanthanide-based coordination polymers. PMID:26471940

  1. Switchable sensitizers stepwise lighting up lanthanide emissions

    PubMed Central

    Zhang, Yan; Jiao, Peng-Chong; Xu, Hai-Bing; Tang, Ming-Jing; Yang, Xiao-Ping; Huang, Shaoming; Deng, Jian-Guo

    2015-01-01

    Analagous to a long-ranged rocket equipped with multi-stage engines, a luminescent compound with consistent emission signals across a large range of concentrations from two stages of sensitizers can be designed. In this approach, ACQ, aggregation-caused quenching effect of sensitizers, would stimulate lanthanide emission below 10−4 M, and then at concentrations higher than 10−3 M, the “aggregation-induced emission” (AIE) effect of luminophores would be activated with the next set of sensitizers for lanthanide emission. Simultaneously, the concentration of the molecules could be monitored digitally by the maximal excitation wavelengths, due to the good linear relationship between the maximal excitation wavelengths and the concentrations {lg(M)}. This model, wherein molecules are assembled with two stages (both AIE and ACQ effect) of sensitizers, may provide a practicable strategy for design and construction of smart lanthanide bioprobes, which are suitable in complicated bioassay systems in which concentration is variable. PMID:25791467

  2. Actinide and lanthanide separation process (ALSEP)

    SciTech Connect

    Guelis, Artem V.

    2013-01-15

    The process of the invention is the separation of minor actinides from lanthanides in a fluid mixture comprising, fission products, lanthanides, minor actinides, rare earth elements, nitric acid and water by addition of an organic chelating aid to the fluid; extracting the fluid with a solvent comprising a first extractant, a second extractant and an organic diluent to form an organic extractant stream and an aqueous raffinate. Scrubbing the organic stream with a dicarboxylic acid and a chelating agent to form a scrubber discharge. The scrubber discharge is stripped with a simple buffering agent and a second chelating agent in the pH range of 2.5 to 6.1 to produce actinide and lanthanide streams and spent organic diluents. The first extractant is selected from bis(2-ethylhexyl)hydrogen phosphate (HDEHP) and mono(2-ethylhexyl)2-ethylhexyl phosphonate (HEH(EHP)) and the second extractant is selected from N,N,N,N-tetra-2-ethylhexyl diglycol amide (TEHDGA) and N,N,N',N'-tetraoctyl-3-oxapentanediamide (TODGA).

  3. Nanometrization of Lanthanide-Based Coordination Polymers.

    PubMed

    Neaime, Chrystelle; Daiguebonne, Carole; Calvez, Guillaume; Freslon, Stéphane; Bernot, Kevin; Grasset, Fabien; Cordier, Stéphane; Guillou, Olivier

    2015-11-23

    Heteronuclear lanthanide-based coordination polymers are microcrystalline powders, the luminescence properties of which can be precisely tuned by judicious choice of the rare-earth ions. In this study, we demonstrate that such materials can also be obtained as stable solutions of nanoparticles in non-toxic polyols. Bulk powders of the formula [Ln2-2x Ln'2x (bdc)3 ⋅4 H2 O]∞ (where H2 bdc denotes 1,4-benzene-dicarboxylic acid, 0≤x≤1, and Ln and Ln' denote lanthanide ions of the series La to Tm plus Y) afford nanoparticles that have been characterized by dynamic light-scattering (DLS) and transmission electron microscopy (TEM) measurements. Their luminescence properties are similar to those of the bulk materials. Stabilities versus time and versus dilution with another solvent have been studied. This study has revealed that it is possible to tune the size of the nanoparticles. This process offers a reliable means of synthesizing suspensions of nanoparticles with tunable luminescence properties and tunable size distributions in a green solvent (glycerol). The process is also extendable to other coordination polymers and other solvents (ethylene glycol, for example). It constitutes a new route for the facile solubilization of lanthanide-based coordination polymers.

  4. Fabrication of tunable hydrophobic surface of ZnO nanorods with Cu doping

    SciTech Connect

    Chakraborty, Mohua; Thangavel, R.

    2015-08-28

    In this work, tunable wettability of the Zinc Oxide (ZnO) nanorod surface with Cu doping prepared by a hydrothermal method. These grown samples were characterized by XRD, FESEM, AFM and water contact angle measurements. The wettability of the ZnO nanorods surface area was controlled and tuned by different concentration of copper doping. It was found that the hydrophobic surface of doped ZnO Nanorods shows a maximum and minimum contact angle of about 156.60° and 136.36° was achieved with doping concentration of 10 and 20 M % respectively. Further, the surface properties such as surface energy and work of adhesion were calculated for undoped and Cu doped ZnO nanostructure surfaces. These nanosructures can be potentially applicable to enlarge time honoured application of ZnO based electronic devices.

  5. Compact hematite buffer layer as a promoter of nanorod photoanode performances

    PubMed Central

    Milan, R.; Cattarin, S.; Comisso, N.; Baratto, C.; Kaunisto, K.; Tkachenko, N. V.; Concina, I.

    2016-01-01

    The effect of a thin α-Fe2O3 compact buffer layer (BL) on the photoelectrochemical performances of a bare α-Fe2O3 nanorods photoanode is investigated. The BL is prepared through a simple spray deposition onto a fluorine-doped tin oxide (FTO) conducting glass substrate before the growth of a α-Fe2O3 nanorods via a hydrothermal process. Insertion of the hematite BL between the FTO and the nanorods markedly enhances the generated photocurrent, by limiting undesired losses of photogenerated charges at the FTO||electrolyte interface. The proposed approach warrants a marked improvement of material performances, with no additional thermal treatment and no use/dispersion of rare or toxic species, in agreement with the principles of green chemistry. PMID:27733756

  6. Fabrication of tunable hydrophobic surface of ZnO nanorods with Cu doping

    NASA Astrophysics Data System (ADS)

    Chakraborty, Mohua; Thangavel, R.

    2015-08-01

    In this work, tunable wettability of the Zinc Oxide (ZnO) nanorod surface with Cu doping prepared by a hydrothermal method. These grown samples were characterized by XRD, FESEM, AFM and water contact angle measurements. The wettability of the ZnO nanorods surface area was controlled and tuned by different concentration of copper doping. It was found that the hydrophobic surface of doped ZnO Nanorods shows a maximum and minimum contact angle of about 156.60° and 136.36° was achieved with doping concentration of 10 and 20 M % respectively. Further, the surface properties such as surface energy and work of adhesion were calculated for undoped and Cu doped ZnO nanostructure surfaces. These nanosructures can be potentially applicable to enlarge time honoured application of ZnO based electronic devices.

  7. Facile synthesized nanorod structured vanadium pentoxide for high-rate lithium batteries

    SciTech Connect

    Pan, Anqiang; Zhang, Jiguang; Nie, Zimin; Cao, Guozhong H.; Arey, Bruce W.; Li, Guosheng; Liang, Shu-quan; Liu, Jun

    2010-04-23

    Nano-structured vanadium oxide (V2O5) is fabricated via facile thermal-decomposition of a vanadium precursor and vanadyl oxalate produced by reacting micro-sized V2O5 with oxalic acid. The V2O5 nanorods produced by this method exhibit much better electrochemical performance than commercial micro-sized V2O5. The optimized-nanorod electrodes with a high density of (001) planar defects give the best specific discharge capacities of 270 mAh g-1 at C/2 (147 mA g-1) coupled with good cycle stability with only 0.32% fading per cycle. Even at a high rate of 4C (1176 mA g-1), the nanorod electrode still delivers 198 mAh g-1. These results suggest that the nanostructured V2O5 is a good cathode for high-rate, lithium-ion battery applications.

  8. Compact hematite buffer layer as a promoter of nanorod photoanode performances

    NASA Astrophysics Data System (ADS)

    Milan, R.; Cattarin, S.; Comisso, N.; Baratto, C.; Kaunisto, K.; Tkachenko, N. V.; Concina, I.

    2016-10-01

    The effect of a thin α-Fe2O3 compact buffer layer (BL) on the photoelectrochemical performances of a bare α-Fe2O3 nanorods photoanode is investigated. The BL is prepared through a simple spray deposition onto a fluorine-doped tin oxide (FTO) conducting glass substrate before the growth of a α-Fe2O3 nanorods via a hydrothermal process. Insertion of the hematite BL between the FTO and the nanorods markedly enhances the generated photocurrent, by limiting undesired losses of photogenerated charges at the FTO||electrolyte interface. The proposed approach warrants a marked improvement of material performances, with no additional thermal treatment and no use/dispersion of rare or toxic species, in agreement with the principles of green chemistry.

  9. NH3 sensing properties polyaniline: TiO2 nanorods heterostructure

    NASA Astrophysics Data System (ADS)

    Patil, U. V.; Ramgir, Niranjan S.; Debnath, A. K.; Karmakar, N.; Aswal, D. K.; Kothari, D. C.; Gupta, S. K.

    2016-05-01

    NH3 sensing properties of polyaniline: TiO2 nanorods heterostructures have been investigated. TiO2 nanorods were synthesized using hydrothermal method. Thin layer of polyanilene was deposited by in-situ oxidative polymerization of aniline over TiO2 nanorods film. The heterostructure film exhibited an enhanced sensor response towards NH3 at room temperature. For example, heterostructure films exhibited a sensor response of 610% towards 100 ppm of NH3 with a response and recovery times of 40 and 60 s, respectively. This response and response kinetics is better than pure PANI films that exhibited a response of 210% with a response and recovery time of 21 and 160 s, respectively.

  10. High-performance nanothermite composites based on aloe-vera-directed CuO nanorods.

    PubMed

    Patel, Vinay Kumar; Bhattacharya, Shantanu

    2013-12-26

    In this work, we demonstrate the development of high-performance nanothermite composites derived from super-reactive CuO nanorods oxidizers fabricated by simple biogenic routes using Aloe vera plant extracts. Nanorods of various length scales have been realized via simple sonoemulsion and solid-state biosynthesis routes using Aloe vera gel as a green surfactant promoting the directional growth of CuO nanorods in both solid and emulsion phase. The biosynthesized CuO nanorods (oxidizers)/fuel (nanoaluminum) composites ignited vigorously with abundant gas generation, developing high heat of reaction of 1.66 kJ g(-1) and very high pressurization rate of around 1.09 MPa μs(-1) and peak pressure of 65.4 MPa when blasted inside a constant volume pressure cell with a charge density of 0.2 g cm(-3). The pressurization rates so obtained are four times higher with twice the peak pressure in comparison to such nanothermites formulated via other available state of the art wet-chemical techniques, which reflects the catalytic role of Aloe vera surface functional groups (A. vera-sfg) enhancing the reactivity of CuO oxidizers with excess gas release rate during exothermic reaction with nanoaluminum. Through this work, Aloe vera gel has for the first time been identified as a novel biotemplate for green synthesis of nanorod structures of metal oxides, and we have also studied the utility of A. vera-sfg in the creation of super-reactive CuO oxidizers producing excellent heat of reaction and dynamic pressure characteristics as demanded in propellants, explosives, and pyrotechnics.

  11. Hydrothermally Processed Photosensitive Field-Effect Transistor Based on ZnO Nanorod Networks

    NASA Astrophysics Data System (ADS)

    Kumar, Ashish; Bhargava, Kshitij; Dixit, Tejendra; Palani, I. A.; Singh, Vipul

    2016-11-01

    Formation of a stable, reproducible zinc oxide (ZnO) nanorod-network-based photosensitive field-effect transistor using a hydrothermal process at low temperature has been demonstrated. K2Cr2O7 additive was used to improve adhesion and facilitate growth of the ZnO nanorod network over the SiO2/Si substrate. Transistor characteristics obtained in the dark resemble those of the n-channel-mode field-effect transistor (FET). The devices showed I on/ I off ratio above 8 × 102 under dark condition, field-effect mobility of 4.49 cm2 V-1 s-1, and threshold voltage of -12 V. Further, under ultraviolet (UV) illumination, the FET exhibited sensitivity of 2.7 × 102 in off-state (-10 V) versus 1.4 in on-state (+9.7 V) of operation. FETs based on such nanorod networks showed good photoresponse, which is attributed to the large surface area of the nanorod network. The growth temperature for ZnO nanorod networks was kept at 110°C, enabling a low-temperature, cost-effective, simple approach for high-performance ZnO-based FETs for large-scale production. The role of network interfaces in the FET performance is also discussed.

  12. Gold nanorod-templated synthesis of polymetallic hollow nanostructures with enhanced electrocatalytic performance.

    PubMed

    Guo, Xia; Ye, Wei; Zhu, Rui; Wang, Wenxin; Xie, Fang; Sun, Hongyan; Zhao, Qing; Ding, Yi; Yang, Jian

    2014-10-21

    Anisotropic polymetallic hollow nanostructures are highly desired for many applications because of their unique morphology, large specific surface areas and attractive electronic effects. Here, a simple method using gold nanorods as a self-sacrificed template has been developed for the fabrication of hollow dumbbell-like nanorods of Au@PtAg. The formation of the hollow structures involves the growth of another metallic shell first, and then the etching of gold nanorods, which is induced by oxygen and ascorbic acid. The lattice mismatch and cohesive energy of the shell, along with its surface passivation, greatly affect the subsequent etching and the resulting products, as has been demonstrated by a positive control in the case of Rh and a negative control in the case of Pd. Hollow dumbbell-like nanorods of Au@PtAg show great enhancement for the dehydrogenation pathway in the oxidation of formic acid, as compared to solid Au@PtAg nanorods, PtAu nanotubes and commercial Pt/C. PMID:25155233

  13. One-dimensional copper hydroxide nitrate nanorods and nanobelts for radiochemical applications.

    PubMed

    Liu, Bin

    2012-11-21

    I report a facile wet-chemical method for the synthesis of one-dimensional copper hydroxide nitrate nanostructures in 2-propanol under solvothermal conditions. Single-crystalline nearly monodispersed copper hydroxide nitrate nanorods and nanobelts with selected breadths in the range of 100 nm to 1 μm have been successfully prepared by a solvothermal method through controlling the experimental parameters, including initial concentrations of reagents, reaction temperature, solvent and reaction time. The resultant nanorods and nanobelts were characterized using FESEM, TEM, XRD, FTIR and TGA techniques. Upon thermal calcination, the copper hydroxide nitrate nanorods and nanobelts self-assemble into one-dimensional arrays (rods, belts or tubes) of copper oxide nanoparticles. The as-prepared copper hydroxide nitrate nanorods and nanobelts were tested as ion exchangers for removal of long-lived radioactive anions such as (129)I(-) and (99)TcO(4)(-). The copper hydroxide nitrate nanorods or nanobelts were over two times more active in the removal of anion species than copper hydroxide nitrate nanoplatelets. PMID:23070067

  14. Hydrothermally Processed Photosensitive Field-Effect Transistor Based on ZnO Nanorod Networks

    NASA Astrophysics Data System (ADS)

    Kumar, Ashish; Bhargava, Kshitij; Dixit, Tejendra; Palani, I. A.; Singh, Vipul

    2016-07-01

    Formation of a stable, reproducible zinc oxide (ZnO) nanorod-network-based photosensitive field-effect transistor using a hydrothermal process at low temperature has been demonstrated. K2Cr2O7 additive was used to improve adhesion and facilitate growth of the ZnO nanorod network over the SiO2/Si substrate. Transistor characteristics obtained in the dark resemble those of the n-channel-mode field-effect transistor (FET). The devices showed I on/I off ratio above 8 × 102 under dark condition, field-effect mobility of 4.49 cm2 V-1 s-1, and threshold voltage of -12 V. Further, under ultraviolet (UV) illumination, the FET exhibited sensitivity of 2.7 × 102 in off-state (-10 V) versus 1.4 in on-state (+9.7 V) of operation. FETs based on such nanorod networks showed good photoresponse, which is attributed to the large surface area of the nanorod network. The growth temperature for ZnO nanorod networks was kept at 110°C, enabling a low-temperature, cost-effective, simple approach for high-performance ZnO-based FETs for large-scale production. The role of network interfaces in the FET performance is also discussed.

  15. Heterostructured TiO2 Nanorod@Nanobowl Arrays for Efficient Photoelectrochemical Water Splitting.

    PubMed

    Wang, Wenhui; Dong, Jingya; Ye, Xiaozhou; Li, Yang; Ma, Yurong; Qi, Limin

    2016-03-01

    Heterostructured TiO2 nanorod@nanobowl (NR@NB) arrays consisting of rutile TiO2 nanorods grown on the inner surface of arrayed anatase TiO2 nanobowls are designed and fabricated as a new type of photoanodes for photoelectrochemical (PEC) water splitting. The unique heterostructures with a hierarchical architecture are readily fabricated by interfacial nanosphere lithography followed by hydrothermal growth. Owing to the two-dimensionally arrayed structure of anatase nanobowls and the nearly radial alignment of rutile nanorods, the TiO2 NR@NB arrays provide multiple scattering centers and hence exhibit an enhanced light harvesting ability. Meanwhile, the large surface area of the NR@NB arrays enhances the contact with the electrolyte while the nanorods offer direct pathways for fast electron transfer. Moreover, the rutile/anatase phase junction in the NR@NB heterostructure improves charge separation because of the facilitated electron transfer. Accordingly, the PEC measurements of the TiO2 NR@NB arrays on the fluoride-doped tin oxide (FTO) substrate show significantly enhanced photocatalytic properties for water splitting. Under AM1.5G solar light irradiation, the unmodified TiO2 NR@NB array photoelectrode yields a photocurrent density of 1.24 mA cm(-2) at 1.23 V with respect to the reversible hydrogen electrode, which is almost two times higher than that of the TiO2 nanorods grown directly on the FTO substrate. PMID:26779803

  16. Heterostructured TiO2 Nanorod@Nanobowl Arrays for Efficient Photoelectrochemical Water Splitting.

    PubMed

    Wang, Wenhui; Dong, Jingya; Ye, Xiaozhou; Li, Yang; Ma, Yurong; Qi, Limin

    2016-03-01

    Heterostructured TiO2 nanorod@nanobowl (NR@NB) arrays consisting of rutile TiO2 nanorods grown on the inner surface of arrayed anatase TiO2 nanobowls are designed and fabricated as a new type of photoanodes for photoelectrochemical (PEC) water splitting. The unique heterostructures with a hierarchical architecture are readily fabricated by interfacial nanosphere lithography followed by hydrothermal growth. Owing to the two-dimensionally arrayed structure of anatase nanobowls and the nearly radial alignment of rutile nanorods, the TiO2 NR@NB arrays provide multiple scattering centers and hence exhibit an enhanced light harvesting ability. Meanwhile, the large surface area of the NR@NB arrays enhances the contact with the electrolyte while the nanorods offer direct pathways for fast electron transfer. Moreover, the rutile/anatase phase junction in the NR@NB heterostructure improves charge separation because of the facilitated electron transfer. Accordingly, the PEC measurements of the TiO2 NR@NB arrays on the fluoride-doped tin oxide (FTO) substrate show significantly enhanced photocatalytic properties for water splitting. Under AM1.5G solar light irradiation, the unmodified TiO2 NR@NB array photoelectrode yields a photocurrent density of 1.24 mA cm(-2) at 1.23 V with respect to the reversible hydrogen electrode, which is almost two times higher than that of the TiO2 nanorods grown directly on the FTO substrate.

  17. Genotoxicity and Cytotoxicity of Cadmium Sulfide Nanomaterials to Mice: Comparison Between Nanorods and Nanodots

    PubMed Central

    Liu, Lu; Sun, Meiqing; Li, Qingzhao; Zhang, Hongmei; Alvarez, Pedro J.J.; Liu, Huajie; Chen, Wei

    2014-01-01

    Abstract Cadmium sulfide (CdS) nanomaterials (such as CdS nanodots or nanorods) are widely used in optical, electronic, and biological applications. Large-scale production and use of these materials will likely result in accidental and incidental releases, which raise concerns about their potential environmental and human-health impacts. Most studies on toxicity of Cd-containing nanomaterials have focused on nanodots, and the relative toxicity of Cd-containing nanorods is not well understood. Here, we compared genotoxicity and cytotoxicity of CdS nanorods (30–50 nm diameter, 500–1100 nm length) and cubic CdS nanodots (3–5 nm) in mice by examining total cadmium accumulation in organs, acute toxicity, DNA damage, spermatozoon viability and abnormality, kidney and liver damage, and oxidative stress. Compared with (smaller) nanodots, nanorods resulted in relatively low bioaccumulation, acute toxicity, and damage to spermatozoa and the tested organs. Differences in toxicity between CdS nanodots and nanorods could not be fully explained by differences in their metal ion (Cd2+) release patterns, based on control tests with mice gavaged with dissolved CdCl2 at equivalent concentrations. This underscores that toxicity of metallic nanomaterials could not be solely predicted based either on their elemental composition or on the amount of ions released before receptor intake. Particle morphology (including size) may also need to be considered. PMID:25053877

  18. Acidic 1,3-propanediaminetetraacetato lanthanides with luminescent and catalytic ester hydrolysis properties

    SciTech Connect

    Chen, Mao-Long; Shi, Yan-Ru; Yang, Yu-Chen; Zhou, Zhao-Hui

    2014-11-15

    In acidic solution, a serials of water-soluble coordination polymers (CPs) were isolated as zonal 1D-CPs 1,3-propanediaminetetraacetato lanthanides [Ln(1,3-H{sub 3}pdta)(H{sub 2}O){sub 5}]{sub n}·2Cl{sub n}·3nH{sub 2}O [Ln=La, 1; Ce, 2; Pr, 3; Nd, 4; Sm, 5] (1,3-H{sub 4}pdta=1,3-propanediaminetetraacetic acid, C{sub 11}H{sub 18}N{sub 2}O{sub 8}) in high yields. When 1 eq. mol potassium hydroxide was added to the solutions of 1D-CPs, respectively, two 1D-CPs [Ln(1,3-H{sub 2}pdta)(H{sub 2}O){sub 3}]{sub n}·Cl{sub n}·2nH{sub 2}O [Ln=Sm, 6; Gd, 7] were isolated at room temperature and seven 2D-CPs [Ln(1,3-H{sub 2}pdta)(H{sub 2}O){sub 2}]{sub n}·Cl{sub n}·2nH{sub 2}O [Ln=La, 8; Ce, 9; Pr, 10; Nd, 11; Sm, 12; Eu, 13; Gd, 14] were isolated at 70 °C. When the crystals of 1–4 were hydrothermally heated at 180 °C with 1–2 eq. mol potassium hydroxide, four 3D-CPs [Ln(1,3-Hpdta)]{sub n}·nH{sub 2}O [Ln=La, 15; Ce, 16; Pr, 17; Nd, 18] were obtained. The two 2D-CPs [Ln(1,3-Hpdta)(H{sub 2}O)]{sub n}·4nH{sub 2}O (Sm, 19; Eu, 20) were isolated in similar reaction conditions. With the increments of pH value in the solution and reaction temperature, the structure becomes more complicated. 1–5 are soluble in water and 1 was traced by solution {sup 13}C({sup 1}H) NMR technique, the water-soluble lanthanides 1 and 5 show catalytic activity to ester hydrolysis reaction respectively, which indicate their important roles in the hydrolytic reaction. The europium complexes 13 and 20 show visible fluorescence at an excitation of 394 nm. The structure diversity is mainly caused by the variation of coordinated ligand in different pH values and lanthanide contraction effect. Acidic conditions are favorable for the isolations of lanthanide complexes in different structures and this may helpful to separate different lanthanides. The thermal stability investigations reveal that acidic condition is favorable to obtain the oxides at a lower temperature. - Graphical abstract: A series

  19. Salicylamide-lanthanide complexes for use as luminescent markers

    SciTech Connect

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2008-07-29

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one salicylamidyl moiety. Also provided are probes incorporating the salicylamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  20. Salicylamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2002-01-01

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one salicylamidyl moiety. Also provided are probes incorporating the salicylamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  1. Phthalamide lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth M.; Xu, Jide

    2003-01-01

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  2. Salicylamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2006-03-28

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one salicylamidyl moiety. Also provided are probes incorporating the salicylamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  3. Phthalamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth M.; Xu, Jide

    2005-03-08

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  4. Phthalamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2008-10-28

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  5. Nitride tuning of lanthanide chromites.

    PubMed

    Black, Ashley P; Johnston, Hannah E; Oró-Solé, Judith; Bozzo, Bernat; Ritter, Clemens; Frontera, Carlos; Attfield, J Paul; Fuertes, Amparo

    2016-03-21

    LnCrO(3-x)N(x) perovskites with Ln = La, Pr and Nd and nitrogen contents up to x = 0.59 have been synthesised through ammonolysis of LnCrO4 precursors. These new materials represent one of the few examples of chromium oxynitrides. Hole-doping through O(2-)/N(3-) anion substitution suppresses the magnetic transition far less drastically than Ln(3+)/M(2+) (M = Ca, Sr) cation substitutions because of the greater covalency of metal-nitride bonds. Hence, nitride-doping is a more benign method for doping metal oxides without suppressing electronic transitions. PMID:26916315

  6. Biocompatible and high-performance amino acids-capped MnWO4 nanocasting as a novel non-lanthanide contrast agent for X-ray computed tomography and T1-weighted magnetic resonance imaging

    NASA Astrophysics Data System (ADS)

    Dong, Kai; Liu, Zhen; Liu, Jianhua; Huang, Sa; Li, Zhenhua; Yuan, Qinghai; Ren, Jinsong; Qu, Xiaogang

    2014-01-01

    -weighted MR imaging capabilities. As an alternative to T2-weighted MRI and CT dual-modality contrast agents, the nanoprobes can provide a positive contrast signal, which prevents confusion with the dark signals from hemorrhage and blood clots. To the best of our knowledge, this is the first report that a non-lanthanide imaging nanoprobe is applied for CT and T1-weighted MRI simultaneously. Moreover, comparing with gadolinium-based T1-weighted MRI and CT dual-modality contrast agents that were associated with nephrogenic systemic fibrosis (NSF), our contrast agents have superior biocompatibility, which is proved by a detailed study of the pharmacokinetics, biodistribution, and in vivo toxicology. Together with excellent dispersibility, high biocompatibility and superior contrast efficacy, these nanoprobes provide detailed and complementary information from dual-modality imaging over traditional single-mode imaging and bring more opportunities to the new generation of non-lanthanide nanoparticulate-based contrast agents. Electronic supplementary information (ESI) available: TEM images of MnWO4 nanoparticles synthesized at pH = 7, 180 °C pH = 9, 180 °C pH = 6, 200 °C with various amino acid molecules as capped agents, survey XPS spectra, FTIR spectrum of glycine capped MnWO4 nanorods, photos of glycine capped MnWO4 nanorods in various solutions including PBS, DMEM cell medium, and FBS, in vivo coronal view CT images of a rat before and after intravenous injection of iobitridol at different timed intervals, in vivo CT imaging of the rat one month after intravenous injection of MnWO4 nanorods, CT values of the heart, liver, spleen and kidney of a rat before and after intravenous administration of MnWO4 nanorods and iobitridol at different time intervals, hematology analysis and blood biochemical assay. See DOI: 10.1039/c3nr05455a

  7. Solvent systems combining neutral and acidic extractants for separating trivalent lanthanides from the transuranic elements.

    SciTech Connect

    Lumetta, G. J.; Gelis, A. V.; Vandegrift, G. F.; Chemical Sciences and Engineering Division; PNL

    2010-01-01

    This paper is a review of recent publications that have focused on combined extractant systems for separating trivalent actinides from the lanthanides. These mixed solvent systems combine an acidic extractant with a neutral extractant to achieve the actinide/lanthanide separation. Depending on the neutral extractant used, three categorizations of systems can be considered, including combinations of acidic extractants with 1 diamides, 2 carbamoylmethylphosphine oxides, and 3 polydentate nitrogen-donor ligands. This review of relevant publications indicates that, although there is significant potential for practical exploitation of mixed neutral/acidic extractant systems to achieve a single-step separation of trivalent actinides from acidic high-level waste solutions, the fundamental chemistry underlying these combined systems is not yet well understood. For example, although there is strong evidence suggesting that adducts form between the neutral and acidic extractants, the nature of these adducts generally is not known. Likewise, the structures of the mixed complexes formed between the metal ions and the two different extractants are not fully understood. Research into these basic phenomena likely will provide clues about how to design practical mixed-extractant systems that can be used to efficiently separate the transuranic elements from the lanthanides and other components of irradiated fuel.

  8. Biosorption of Lanthanides from Aqueous Solutions Using Pretreated Buccinum tenuissimum Shell Biomass

    PubMed Central

    Koto, Yusuke; Kano, Naoki; Wang, Yudan; Sakamoto, Nobuo; Imaizumi, Hiroshi

    2010-01-01

    Biosorption experiment from aqueous solutions containing known amount of rare earth elements (REEs) using pre-treated Buccinum tenuissimum shell was explored to evaluate the efficiency of shell biomass as sorbent for REEs. In this work, four kinds of sieved shell samples: (a) “Ground original sample”, (b) “Heat-treatment (480°C, 6 hours) sample”, (c) “Heat-treatment (950°C, 6 hours) sample” and (d) “Heat-treatment (950°C, 6 hours) and water added sample” were used. Furthermore, to confirm the characteristics of the shell biomass, the crystal structure, the surface morphology, and the specific surface area of these shell samples were determined. Consequently, the following matters have been mainly clarified. (1) The crystal structure of the shell biomass was transformed from aragonite (CaCO3) into calcite (CaCO3) phase by heat-treatment (480°C, 6 hours); then mainly transformed into calcium oxide (CaO) by heat-treatment (950°C, 6 hours), and calcium hydroxide (Ca(OH)2) by heat-treatment (950°C, 6 hours) and adding water. (2) The shell biomass showed excellent sorption capacity for lanthanides. (3) Adsorption isotherms using the shell biomass can be described by Langmuir and Freundlich isotherms satisfactorily for lanthanides except “heat-treatment (950°C, 6 hours) sample”. (4) Shell biomass (usually treated as waste material) can be an efficient sorbent for lanthanides in future. PMID:20981250

  9. Biosorption of Lanthanides from Aqueous Solutions Using Pretreated Buccinum tenuissimum Shell Biomass.

    PubMed

    Koto, Yusuke; Kano, Naoki; Wang, Yudan; Sakamoto, Nobuo; Imaizumi, Hiroshi

    2010-01-01

    Biosorption experiment from aqueous solutions containing known amount of rare earth elements (REEs) using pre-treated Buccinum tenuissimum shell was explored to evaluate the efficiency of shell biomass as sorbent for REEs. In this work, four kinds of sieved shell samples: (a) "Ground original sample", (b) "Heat-treatment (480°C, 6 hours) sample", (c) "Heat-treatment (950°C, 6 hours) sample" and (d) "Heat-treatment (950°C, 6 hours) and water added sample" were used. Furthermore, to confirm the characteristics of the shell biomass, the crystal structure, the surface morphology, and the specific surface area of these shell samples were determined. Consequently, the following matters have been mainly clarified. (1) The crystal structure of the shell biomass was transformed from aragonite (CaCO(3)) into calcite (CaCO(3)) phase by heat-treatment (480°C, 6 hours); then mainly transformed into calcium oxide (CaO) by heat-treatment (950°C, 6 hours), and calcium hydroxide (Ca(OH)(2)) by heat-treatment (950°C, 6 hours) and adding water. (2) The shell biomass showed excellent sorption capacity for lanthanides. (3) Adsorption isotherms using the shell biomass can be described by Langmuir and Freundlich isotherms satisfactorily for lanthanides except "heat-treatment (950°C, 6 hours) sample". (4) Shell biomass (usually treated as waste material) can be an efficient sorbent for lanthanides in future.

  10. Surface Modification of ZnO Nanorods with Hamilton Receptors

    PubMed Central

    Zeininger, Lukas; Klaumünzer, Martin; Peukert, Wolfgang; Hirsch, Andreas

    2015-01-01

    A new prototype of a Hamilton receptor suitable for the functionalization of inorganic nanoparticles was synthesized and characterized. The hydrogen bonding receptor was coupled to a catechol moiety, which served as anchor group for the functionalization of metal oxides, in particular zinc oxide. Synthesized zinc oxide nanorods [ZnO] were used for surface functionalization. The wet-chemical functionalization procedure towards monolayer-grafted particles [ZnO-HR] is described and a detailed characterization study is presented. In addition, the detection of specific cyanurate molecules is demonstrated. The hybrid structures [ZnO-HR-CA] were stable towards agglomeration and exhibited enhanced dispersability in apolar solvents. This observation, in combination with several spectroscopic experiments gave evidence of the highly directional supramolecular recognition at the surface of nanoparticles. PMID:25872141

  11. Plasmonics of Gold Nanorods. Considerations for Biosensing

    NASA Astrophysics Data System (ADS)

    Liz-Marzán, Luis M.; Pérez-Juste, Jorge; Pastoriza-Santos, Isabel

    In this chapter, we explore the sensitivity of gold nanorods toward changes in the dielectric constant of the surrounding medium. Experimental data for pure and silica-coated nanorods with varying shell thickness are compared to calculations based on the boundary element method (BEM). They indicate that anisotropy and sharp tips make nanoparticles more environmentally sensitive. We also find that sensitivity decreases as silica shell thickness increases, as expected from a dielectric screening effect. Even when coated with thin shells, gold nanorods are found to be excellent candidates for biosensing applications.

  12. Ag nanoparticles-decorated ZnO nanorod array on a mechanical flexible substrate with enhanced optical and antimicrobial properties

    NASA Astrophysics Data System (ADS)

    Chen, Yi; Tse, Wai Hei; Chen, Longyan; Zhang, Jin

    2015-03-01

    Heteronanostructured zinc oxide nanorod (ZnO NR) array are vertically grown on polydimethylsiloxane (PDMS) through a hydrothermal method followed by an in situ deposition of silver nanoparticles (Ag NPs) through a photoreduction process. The Ag-ZnO heterostructured nanorods on PDMS are measured with an average diameter of 160 nm and an average length of 2 μm. ZnO NRs measured by high-resolution transmission electron microscope (HRTEM) shows highly crystalline with a lattice fringe of 0.255 nm, which corresponds to the (0002) planes in ZnO crystal lattice. The average diameter of the Ag NPs in situ deposited on the ZnO NRs is estimated at 22 ± 2 nm. As compared to the bare ZnO NRs, the heterostructured Ag-ZnO nanorod array shows enhanced ultraviolet (UV) absorption at 440 nm, and significant emission in the visible region (λem = 542 nm). In addition, the antimicrobial efficiency of Ag-ZnO heterostructured nanorod array shows obvious improvement as compared to bare ZnO nanorod array. The cytotoxicity of ZnO nanorod array with and without Ag NPs was studied by using 3 T3 mouse fibroblast cell line. No significant toxic effect is imposed on the cells.

  13. Optical forces in nanorod metamaterial

    PubMed Central

    Bogdanov, Andrey A.; Shalin, Alexander S.; Ginzburg, Pavel

    2015-01-01

    Optomechanical manipulation of micro and nano-scale objects with laser beams finds use in a large span of multidisciplinary applications. Auxiliary nanostructuring could substantially improve performances of classical optical tweezers by means of spatial localization of objects and intensity required for trapping. Here we investigate a three-dimensional nanorod metamaterial platform, serving as an auxiliary tool for the optical manipulation, able to support and control near-field interactions and generate both steep and flat optical potential profiles. It was shown that the ‘topological transition’ from the elliptic to hyperbolic dispersion regime of the metamaterial, usually having a significant impact on various light-matter interaction processes, does not strongly affect the distribution of optical forces in the metamaterial. This effect is explained by the predominant near-fields contributions of the nanostructure to optomechanical interactions. Semi-analytical model, approximating the finite size nanoparticle by a point dipole and neglecting the mutual re-scattering between the particle and nanorod array, was found to be in a good agreement with full-wave numerical simulation. In-plane (perpendicular to the rods) trapping regime, saddle equilibrium points and optical puling forces (directed along the rods towards the light source), acting on a particle situated inside or at the nearby the metamaterial, were found. PMID:26514667

  14. Structural and Morphology of ZnO Nanorods Synthesized Using ZnO Seeded Growth Hydrothermal Method and Its Properties as UV Sensing

    PubMed Central

    Ridhuan, Nur Syafinaz; Abdul Razak, Khairunisak; Lockman, Zainovia; Abdul Aziz, Azlan

    2012-01-01

    In this study, zinc oxide (ZnO) nanorod arrays were synthesized using a simple hydrothermal reaction on ZnO seeds/n-silicon substrate. Several parameters were studied, including the heat-treatment temperature to produce ZnO seeds, zinc nitrate concentration, pH of hydrothermal reaction solution, and hydrothermal reaction time. The optimum heat-treatment temperature to produce uniform nanosized ZnO seeds was 400°C. The nanorod dimensions depended on the hydrothermal reaction parameters. The optimum hydrothermal reaction parameters to produce blunt tip-like nanorods (770 nm long and 80 nm in top diameter) were 0.1 M zinc nitrate, pH 7, and 4 h of growth duration. Phase analysis studies showed that all ZnO nanorods exhibited a strong (002) peak. Thus, the ZnO nanorods grew in a c-axis preferred orientation. A strong ultraviolet (UV) emission peak was observed for ZnO nanorods grown under optimized parameters with a low, deep-level emission peak, which indicated high optical property and crystallinity of the nanorods. The produced ZnO nanorods were also tested for their UV-sensing properties. All samples responded to UV light but with different sensing characteristics. Such different responses could be attributed to the high surface-to-volume ratio of the nanorods that correlated with the final ZnO nanorods morphology formed at different synthesis parameters. The sample grown using optimum synthesis parameters showed the highest responsivity of 0.024 A/W for UV light at 375 nm under a 3 V bias. PMID:23189199

  15. Understanding stability trends along the lanthanide series.

    PubMed

    Regueiro-Figueroa, Martín; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Platas-Iglesias, Carlos

    2014-04-01

    The stability trends across the lanthanide series of complexes with the polyaminocarboxylate ligands TETA(4-) (H4TETA=2,2',2'',2'''-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetraacetic acid), BCAED(4-) (H4BCAED=2,2',2'',2'''-{[(1,4-diazepane-1,4-diyl)bis(ethane-2,1-diyl)]bis(azanetriyl)}tetraacetic acid), and BP18C6(2-) (H2BP18C6=6,6'-[(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)bis(methylene)]dipicolinic acid) were investigated using DFT calculations. Geometry optimizations performed at the TPSSh/6-31G(d,p) level, and using a 46+4f(n) ECP for lanthanides, provide bond lengths of the metal coordination environments in good agreement with the experimental values observed in the X-ray structures. The contractions of the Ln(3+) coordination spheres follow quadratic trends, as observed previously for different isostructural series of complexes. We show here that the parameters obtained from the quantitative analysis of these data can be used to rationalize the observed stability trends across the 4f period. The stability trends along the lanthanide series were also evaluated by calculating the free energy for the reaction [La(L)](n+/-)(sol)+Ln(3+)(sol)→[Ln(L)](n+/-)(sol)+La(3+)(sol). A parameterization of the Ln(3+) radii was performed by minimizing the differences between experimental and calculated standard hydration free energies. The calculated stability trends are in good agreement with the experimental stability constants, which increase markedly across the series for BCAED(4-) complexes, increase smoothly for the TETA(4-) analogues, and decrease in the case of BP18C6(2-) complexes. The resulting stability trend is the result of a subtle balance between the increased binding energies of the ligand across the lanthanide series, which contribute to an increasing complex stability, and the increase in the absolute values of hydration energies along the 4f period.

  16. Multicoordinate ligands for actinide/lanthanide separations.

    PubMed

    Dam, Henk H; Reinhoudt, David N; Verboom, Willem

    2007-02-01

    In nuclear waste treatment processes there is a need for improved ligands for the separation of actinides (An(III)) and lanthanides (Ln(III)). Several research groups are involved in the design and synthesis of new An(III) ligands and in the confinement of these and existing An(III) ligands onto molecular platforms giving multicoordinate ligands. The preorganization of ligands considerably improves the An(III) extraction properties, which are largely dependent on the solubility and rigidity of the platform. This tutorial review summarizes the most important An(III) ligands with emphasis on the preorganization strategy using (macrocyclic) platforms.

  17. Complexes of Lapachol and Lawsone with Lanthanides.

    PubMed

    Genovese, Salvatore; Taddeo, Vito Alessandro; Epifano, Francesco; Fiorito, Serena

    2015-11-01

    Naturally occurring 2-hydroxy-1,4-naphthoquinones are well known to form readily stable complexes with transition metals. In this short communication we describe for the first time the synthesis and preliminary data about structural characterization of complexes between two naturally widespread 2-hydroxy-1,4-naphthoquinones, namely lapachol (1) and lawsone (2), with selected lanthanides like lanthanum, gadolinium, and ytterbium. When tested as cytotoxic compounds, such complexes exhibited an activity that was either higher or equal to that of the parent naphthoquinone. PMID:26749803

  18. Gold nanorod-templated synthesis of polymetallic hollow nanostructures with enhanced electrocatalytic performance

    NASA Astrophysics Data System (ADS)

    Guo, Xia; Ye, Wei; Zhu, Rui; Wang, Wenxin; Xie, Fang; Sun, Hongyan; Zhao, Qing; Ding, Yi; Yang, Jian

    2014-09-01

    Anisotropic polymetallic hollow nanostructures are highly desired for many applications because of their unique morphology, large specific surface areas and attractive electronic effects. Here, a simple method using gold nanorods as a self-sacrificed template has been developed for the fabrication of hollow dumbbell-like nanorods of Au@PtAg. The formation of the hollow structures involves the growth of another metallic shell first, and then the etching of gold nanorods, which is induced by oxygen and ascorbic acid. The lattice mismatch and cohesive energy of the shell, along with its surface passivation, greatly affect the subsequent etching and the resulting products, as has been demonstrated by a positive control in the case of Rh and a negative control in the case of Pd. Hollow dumbbell-like nanorods of Au@PtAg show great enhancement for the dehydrogenation pathway in the oxidation of formic acid, as compared to solid Au@PtAg nanorods, PtAu nanotubes and commercial Pt/C.Anisotropic polymetallic hollow nanostructures are highly desired for many applications because of their unique morphology, large specific surface areas and attractive electronic effects. Here, a simple method using gold nanorods as a self-sacrificed template has been developed for the fabrication of hollow dumbbell-like nanorods of Au@PtAg. The formation of the hollow structures involves the growth of another metallic shell first, and then the etching of gold nanorods, which is induced by oxygen and ascorbic acid. The lattice mismatch and cohesive energy of the shell, along with its surface passivation, greatly affect the subsequent etching and the resulting products, as has been demonstrated by a positive control in the case of Rh and a negative control in the case of Pd. Hollow dumbbell-like nanorods of Au@PtAg show great enhancement for the dehydrogenation pathway in the oxidation of formic acid, as compared to solid Au@PtAg nanorods, PtAu nanotubes and commercial Pt/C. Electronic

  19. Gold coated ZnO nanorod biosensor for glucose detection

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Anuradha; Jain, Chhavi; Rao, V. Padmanapan; Banerjee, S.

    2012-06-01

    Gold coated ZnO nanorod based biosensor has been fabricated for its glucose detecting abilities and compared with that of ZnO nanorod based biosensor. SEM images of electrochemically grown ZnO nanorods show hexagonally grown ZnO nanorods on an ITO substrate. Electrochemical analysis show that gold coated ZnO based biosensors have higher sensitivity, lower limit of detection and a wider linear range for glucose detection. The results demonstrate that gold coated ZnO nanorod based biosensors are a promising material for biosensor applications over single component ZnO nanorod based biosensor.

  20. Investigation of the phototoxic effect of ZnO nanorods on fibroblasts and melanoma human cells

    NASA Astrophysics Data System (ADS)

    Kishwar, S.; Siddique, M.; Israr-Qadir, M.; Nur, O.; Willander, M.; Öllinger, K.

    2014-11-01

    Photocytotoxic effects of as-grown and zinc oxide (ZnO) nanorods coated with 5-aminolevulinic acid (ALA) have been studied on human cells, i.e. melanoma and foreskin fibroblast, under dark and ultraviolet light exposures. Zinc oxide nanorods have been grown on the very sharp tip (diameter = 700 nm) of borosilicate glass pipettes and then were coated by the photosensitizer for targeted investigations inside human cells. The coated glass pipette’s tip with photosensitizer has been inserted inside the cells with the help of a micro-manipulator and irradiated through ultraviolet light (UVA), which reduces the membrane potential of the mitochondria leading to cell death. Cell viability loss has been detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay when exposed to the dissolved ZnO nanorods and the production of the reactive oxygen species (ROS) has been detected along with the enhanced cytotoxic effect under UVA irradiation. Additionally, the influence of the lipid soluble antioxidant vitamin E and water-soluble N-acetyl-cysteine toward the enhancement or reduction of the toxicity has been investigated. A comparative analysis of the toxic nature of ZnO nanorods has been drawn between normal human fibroblast and melanoma cells, which can be favorable for understanding the clinical setting for killing tumor cells.

  1. Tailoring terahertz plasmons with silver nanorod arrays

    PubMed Central

    Cao, Wei; Song, Chunyuan; Lanier, Thomas E.; Singh, Ranjan; O'Hara, John F.; Dennis, William M.; Zhao, Yiping; Zhang, Weili

    2013-01-01

    Plasmonic materials that strongly interact with light are ideal candidates for designing subwavelength photonic devices. We report on direct coupling of terahertz waves in metallic nanorods by observing the resonant transmission of surface plasmon polariton waves through lithographically patterned films of silver nanorod (100 nm in diameter) micro-hole arrays. The best enhancement in surface plasmon resonant transmission is obtained when the nanorods are perfectly aligned with the electric field direction of the linearly polarized terahertz wave. This unique polarization-dependent propagation of surface plasmons in structures fabricated from nanorod films offers promising device applications. We conclude that the anisotropy of nanoscale metallic rod arrays imparts a material anisotropy relevant at the microscale that may be utilized for the fabrication of plasmonic and metamaterial based devices for operation at terahertz frequencies.

  2. Optical trapping of the anisotropic crystal nanorod.

    PubMed

    Bareil, Paul B; Sheng, Yunlong

    2015-05-18

    We observed in the optical tweezers experiment that some anisotropic nanorod was stably trapped in an orientation tiled to the beam axis. We explain this trapping with the T-matrix calculation. As the vector spherical wave functions do not individually satisfy the anisotropic vector wave equation, we expand the incident and scattered fields in the isotropic buffer in terms of E→, and the internal field in the anisotropic nanoparticle in terms of D→, and use the boundary condition for the normal components of D→ to compute the T-matrix. We found that when the optical axes of an anisotropic nanorod are not aligned to the nanorod axis, the nanorod may be trapped stably at a tilted angle, under which the lateral torque equals to zero and the derivative of the torque is negative. PMID:26074566

  3. Lanthanide Complexes as a Test for Evidence of Life

    NASA Technical Reports Server (NTRS)

    Benavides, Jeannette

    1998-01-01

    The objective of this research is to advance the understanding of the interaction of lanthanide metals with biological organic molecules and to develop a technique to detect these compounds in the solid state and in situ in Mars and other planetary bodies. The detection of these complexes should provide evidence of life past or present. In addition, detection of the metals alone will provide important information about the geological history of a planetary body. Lanthanides were chosen as our focus of interest because they form very stable complexes with organic molecules in solution and they produce intense luminescence in the ultraviolet and visible spectra. The rare earth complexes available are mostly synthetic for diverse applications in medicine. There is not much work done on the complexes that form in nature. Lanthanides have many applications and they are mined aR over the world, however, since the interest has been only in the elements, the analytical techniques employed destroy any organic ligands that may be present. In order to determine if and which lanthanide complexes form in nature and their concentration, soil samples have been collected from areas rich in soluble lanthanide compounds like phosphates and also rich in vegetation. The soil samples will be analyzed and the lanthanide complexes if present will be isolated and characterized. A spectrometer to detect the lanthanide complexes in situ and in the solid state will be designed. In this workshop, the research approach and its implications will be discussed.

  4. Coupling of the 4f Electrons in Lanthanide Molecules

    SciTech Connect

    Kazhdan, Daniel

    2008-09-01

    (C5Me5)2LnOTf where Ln = La, Ce, Sm, Gd, and Yb have been synthesized and these derivatives are good starting materials for the synthesis of (C5Me5)2LnX derivatives. (C5Me5)2Ln(2,2'-bipyridine), where Ln = La, Ce, Sm, and Gd, along with several methylated bipyridine analogues have been synthesized and their magnetic moments have been measured as a function of temperature. In lanthanum, cerium, and gadolinium complexes the bipyridine ligand ligand is unequivocally the radical anion, and the observed magnetic moment is the result of intramolecular coupling of the unpaired electron on the lanthanide fragment with the unpaired electron on the bipyridine along with the intermolecular coupling between radicals. Comparison with the magnetic moments of the known compounds (C5Me5)2Sm(2,2'-bipyridine) and (C5Me5)2Yb(2,2'-bipyridine) leads to an understanding of the role of the SmII/SmIII and YbII/YbIII couple in the magnetic properties of (C5Me5)2Sm(2,2'-bipyridine) and (C5Me5)2Yb(2,2'-bipyridine). In addition, crystal structures of (C5Me5)2Ln(2,2'-bipyridine) and [(C5Me5)2Ln(2,2'-bipyridine)][BPh4](Ln= Ce and Gd), where the lanthanide is unequivocally in the +3 oxidation state, give the crystallographic characteristics of bipyridine as an anion and as a neutral ligand in the same coordination environment, respectively. Substituted bipyridine ligands coordinated to (C5Me5)2Yb are studied to further understand how the magnetic coupling in (C5Me5)2Yb(2,2'-bipyridine) changes with substitutions. In the cases of (C5Me5)2Yb(5,5'-dimethyl-2,2'-bipyridine) and (C5Me5

  5. Functionalized CdS nanospheres and nanorods

    NASA Astrophysics Data System (ADS)

    Lee, Hyeokjin; Yang, Heesun; Holloway, Paul H.

    2009-12-01

    Functionalized nanoparticles are discussed. Surfaces of CdS:Mn/ZnS core/shell nanospheres (Qdots) were converted from hydrophobic to hydrophilic by growth of a SiO 2 shell. The colloidal dispersion was stabilize by adding a surfactant with a negative surface charge, and a cell-penetrating-peptide, TAT, was attached through a primary amine group. The TAT functionalized Qdots were shown to pass the blood-brain-barrier and luminescence in the infused half of the brain. In addition, nanorods of S 2- rich CdS were synthesized by reaction of excess S with Cd precursors in the presence of ethylene diamine. The photoluminescence (PL) peak from the S 2- rich CdS nanorods was broad with a maximum at ∼710 nm, which was 40 nm longer in wavelength than the PL peak from Cd 2+ rich CdS (∼670 nm) nanorods. The influence of surface electron or hole trap states on the luminescent pathway of CdS nanorods were used to explain these shifts in wavelength. Nanocrystals of Au with ∼2 nm diameters were grown on S 2- rich surfaces of CdS nanorods. Significant quenching of photoluminescence was observed from Au nanocrystals on CdS nanorods due to interfacial charge separation. Charge separation by Au nanocrystals on CdS resulted in enhanced UV photocatalytic degradation of Procion red mix-5B (PRB) dye in aqueous solution.

  6. Fabrication and NO2 gas sensing performance of TeO2-core/CuO-shell heterostructure nanorod sensors

    PubMed Central

    2014-01-01

    TeO2-nanostructured sensors are seldom reported compared to other metal oxide semiconductor materials such as ZnO, In2O3, TiO2, Ga2O3, etc. TeO2/CuO core-shell nanorods were fabricated by thermal evaporation of Te powder followed by sputter deposition of CuO. Scanning electron microscopy and X-ray diffraction showed that each nanorod consisted of a single crystal TeO2 core and a polycrystalline CuO shell with a thickness of approximately 7 nm. The TeO2/CuO core-shell one-dimensional (1D) nanostructures exhibited a bamboo leaf-like morphology. The core-shell nanorods were 100 to 300 nm in diameter and up to 30 μm in length. The multiple networked TeO2/CuO core-shell nanorod sensor showed responses of 142% to 425% to 0.5- to 10-ppm NO2 at 150°C. These responses were stronger than or comparable to those of many other metal oxide nanostructures, suggesting that TeO2 is also a promising sensor material. The responses of the core-shell nanorods were 1.2 to 2.1 times higher than those of pristine TeO2 nanorods over the same NO2 concentration range. The underlying mechanism for the enhanced NO2 sensing properties of the core-shell nanorod sensor can be explained by the potential barrier-controlled carrier transport mechanism. PACS 61.46. + w; 07.07.Df; 73.22.-f PMID:25489289

  7. Lanthanide coordination polymers: Synthesis, diverse structure and luminescence properties

    SciTech Connect

    Song, Xue-Qin Lei, Yao-Kun; Wang, Xiao-Run; Zhao, Meng-Meng; Peng, Yun-Qiao; Cheng, Guo-Quan

    2014-10-15

    The new semirigid exo-bidentate ligand incorporating furfurysalicylamide terminal groups, namely, 1,4-bis([(2′-furfurylaminoformyl)phenoxyl]methyl)-2,5-bismethylbenzene (L) was synthesized and used as building blocks for constructing lanthanide coordination polymers with luminescent properties. The series of lanthanide nitrate complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. The semirigid ligand L, as a bridging ligand, reacts with lanthanide nitrates forming three distinct structure types: chiral noninterpenetrated two-dimensional (2D) honeycomblike (6,3) (hcb, Schläfli symbol 6{sup 3}, vertex symbol 6 6 6) topological network as type I, 1D zigzag chain as type II and 1D trapezoid ladder-like chain as type III. The structural diversities indicate that lanthanide contraction effect played significant roles in the structural self-assembled process. The luminescent properties of Eu{sup III}, Tb{sup III} and Dy{sup III} complexes are discussed in detail. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, the lanthanide ions in Eu{sup III}, Tb{sup III} and Dy{sup III} complexes can be efficiently sensitized by the ligand. - Graphical abstract: We present herein six lanthanide coordination polymers of a new semirigid exo-bidentate ligand which not only display diverse structures but also possess strong luminescence properties. - Highlights: • We present lanthanide coordination polymers of a new semirigid exo-bidentate ligand. • The lanthanide coordination polymers exhibit diverse structures. • The luminescent properties of Tb{sup III}, Eu{sup III} and Dy{sup III} complexes are discussed in detail.

  8. Ion exchange in hydroxyapatite with lanthanides.

    PubMed

    Cawthray, Jacqueline F; Creagh, A Louise; Haynes, Charles A; Orvig, Chris

    2015-02-16

    Naturally occurring hydroxyapatite, Ca5(PO4)3(OH) (HAP), is the main inorganic component of bone matrix, with synthetic analogues finding applications in bioceramics and catalysis. An interesting and valuable property of both natural and synthetic HAP is the ability to undergo cationic and anionic substitution. The lanthanides are well-suited for substitution for the Ca(2+) sites within HAP, because of their similarities in ionic radii, donor atom requirements, and coordination geometries. We have used isothermal titration calorimetry (ITC) to investigate the thermodynamics of ion exchange in HAP with a representative series of lanthanide ions, La(3+), Sm(3+), Gd(3+), Ho(3+), Yb(3+) and Lu(3+), reporting the association constant (Ka), ion-exchange thermodynamic parameters (ΔH, ΔS, ΔG), and binding stoichiometry (n). We also probe the nature of the La(3+):HAP interaction by solid-state nuclear magnetic resonance ((31)P NMR), X-ray diffraction (XRD), and inductively coupled plasma-optical emission spectroscopy (ICP-OES), in support of the ITC results. PMID:25594577

  9. Picosecond dynamics from lanthanide chloride melts

    NASA Astrophysics Data System (ADS)

    Kalampounias, Angelos G.

    2012-12-01

    The picosecond dynamics of molten lanthanide chlorides is studied by means of vibrational spectroscopy. Polarized Raman spectra of molten LaCl3, NdCl3, GdCl3, DyCl3, HoCl3 and YCl3 are fitted to a model enabling to obtain the times of vibrational dephasing, tν and vibrational frequency modulation tω. Our aim is to find possible sensitive indicators of short-time dynamics. It has been found that all lanthanide chlorides exhibit qualitative similarities in the vibrational relaxation and frequency modulation times in the molten state. It appears that the vibrational correlation functions of all melts comply with the Rothschild approach assuming that the environmental modulation is described by a stretched exponential decay. The evolution of the dispersion parameter α indicates the deviation of the melts from the model simple liquid and the similar local environment in which the oscillator is placed and with which it is coupled. The "packing" of the anions around central La3+ cation seems to be the key factor for the structure and the dynamics of the melts. The results are discussed in the framework of the current phenomenological status of the field.

  10. Citrate-Stabilized Gold Nanorods

    PubMed Central

    2015-01-01

    Stable aqueous dispersions of citrate-stabilized gold nanorods (cit-GNRs) have been prepared in scalable fashion by surfactant exchange from cetyltrimethylammonium bromide (CTAB)-stabilized GNRs, using polystyrenesulfonate (PSS) as a detergent. The surfactant exchange process was monitored by infrared spectroscopy, surface-enhanced Raman scattering (SERS), and X-ray photoelectron spectroscopy (XPS). The latter established the quantitative displacement of CTAB (by PSS) and of PSS (by citrate). The Cit-GNRs are indefinitely stable at low ionic strength, and are conducive to further ligand exchange without loss of dispersion stability. The reliability of the surface exchange process supports the systematic analysis of ligand structure on the hydrodynamic size of GNRs, as described in a companion paper. PMID:25254292

  11. Methods of making functionalized nanorods

    DOEpatents

    Gur, Ilan; Milliron, Delia; Alivisatos, A. Paul; Liu, Haitao

    2012-01-10

    A process for forming functionalized nanorods. The process includes providing a substrate, modifying the substrate by depositing a self-assembled monolayer of a bi-functional molecule on the substrate, wherein the monolayer is chosen such that one side of the bi-functional molecule binds to the substrate surface and the other side shows an independent affinity for binding to a nanocrystal surface, so as to form a modified substrate. The process further includes contacting the modified substrate with a solution containing nanocrystal colloids, forming a bound monolayer of nanocrystals on the substrate surface, depositing a polymer layer over the monolayer of nanocrystals to partially cover the monolayer of nanocrystals, so as to leave a layer of exposed nanocrystals, functionalizing the exposed nanocrystals, to form functionalized nanocrystals, and then releasing the functionalized nanocrystals from the substrate.

  12. Some aspects of the geochemistry of yttrium and the lanthanides

    USGS Publications Warehouse

    Fleischer, Michael

    1965-01-01

    Recent data on the relative abundances of the lanthanides and yttrium in meteorites, basaltic rocks, granitic rocks and sedimentary rocks are reviewed. It is shown that the data are inadequate to substantiate or to disprove Taylor's derivation from these data of a 1:1 abundance ratio of basaltic to granitic rocks in the continental crust. Graphs are given to illustrate the variation of lanthanides in minerals with paragenesis. Both the paragenesis and the crystal chemistry of minerals affect the composition of the lanthanides.

  13. Lanthanide-doped upconverting phosphors for bioassay and therapy

    NASA Astrophysics Data System (ADS)

    Guo, Huichen; Sun, Shiqi

    2012-10-01

    Lanthanide-doped fluorescent materials have gained increasing attention in recent years due to their unique luminescence properties which have led to their use in wide-ranging fields including those of biological applications. Aside from being used as agents for in vivo imaging, lanthanide-doped fluorescent materials also present many advantages for use in bioassays and therapy. In this review, we summarize the applications of lanthanide-doped up-converting phosphors (UCPs) in protein and gene detection, as well as in photodynamic and gene therapy in recent years, and outline their future potential in biological applications. The current report could serve as a reference for researchers in relevant fields.

  14. Vertically aligned ZnO nanorods via self-assembled spray pyrolyzed nanoparticles for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Dwivedi, Charu; Dutta, V.

    2012-03-01

    Well-aligned zinc oxide (ZnO) nanorods are fabricated on indium-tin-oxide (ITO) coated glass substrates via self-assembly of ZnO nanoparticles created using continuous spray pyrolysis (CoSP) technique. The method involves pre-treatment by dip-coating the substrate with a solution comprising of zinc salt for creating a seed layer, and then spray-pyrolyzed ZnO nanoparticles self-assemble on the pre-treated substrate. The effect of the substrate pre-treatment and the deposition time (tdep) of nanoparticles is investigated. The results show that the substrate pre-treatment influences the growth of ZnO nanorods which are absent without the pre-treatment. Nanoparticle collection and nanorod growth on different substrates are done simultaneously. The thin films of as-grown nanorods are used as photoelectrode materials to fabricate dye-sensitized solar cells (DSSCs) and the effect of nanorods grown for different times has been studied. The best performance with this cell structure is found for the layer with tdep=15 min, which showed a conversion efficiency of 1.77% for the cell area of 0.25 cm2.

  15. Temperature-dependent adsorption of surfactant molecules and associated crystallization kinetics of noncentrosymmetric Fe(IO{sub 3}){sub 3} nanorods in microemulsions

    SciTech Connect

    El-Kass, Moustafa; Ladj, Rachid; Mugnier, Yannick; Le Dantec, Ronan; Hadji, Rachid; Marty, Jean-Christophe; Rouxel, Didier; Durand, Christiane; Fontvieille, Dominique; Rogalska, Ewa; and others

    2013-11-15

    Graphical abstract: - Highlights: • Crystallization of Fe(IO{sub 3}){sub 3} in microemulsions probed by hyper-Rayleigh scattering. • A faster growth and a better shape control of nanorods are obtained at 80 °C. • Different persistent cell deformations are related to the crystallization kinetics. • A temperature-dependent adsorption of surfactants on nanorods is suggested. - Abstract: Aggregation-induced crystallization of iron iodate nanorods within organic–inorganic aggregates of primary amorphous precursors is probed by time-dependent hyper-Rayleigh scattering measurements in Triton X-100 based-microemulsions. In the context of a growing interest of noncentrosymmetric oxide nanomaterials in multi-photon bioimaging, we demonstrate by a combination of X-ray diffraction and electron microscopy that an increase in the synthesis of temperature results in faster crystallization kinetics and in a better shape-control of the final Fe(IO{sub 3}){sub 3} nanorods. For initial microemulsions of fixed composition, room-temperature synthesis leads to bundles of 1–3 μm long nanorods, whereas shorter individual nanorods are obtained when the temperature is increased. Results are interpreted in terms of kinetically unfavorable mesoscale transformations due to the strong binding interactions with Triton molecules. The interplay between the nanorod crystallization kinetics and their corresponding unit cell deformation, evidenced by lattice parameter refinements, is attributed to a temperature-dependent adsorption of surfactants molecules at the organic–inorganic interface.

  16. Tragacanth gum biopolymer as reducing and stabilizing agent in biosonosynthesis of urchin-like ZnO nanorod arrays: A low cytotoxic photocatalyst with antibacterial and antifungal properties.

    PubMed

    Ghayempour, Soraya; Montazer, Majid; Mahmoudi Rad, Mahnaz

    2016-01-20

    Tragacanth, a natural gum, has been used for centuries as emulsifier, thickener, stabilizer and binder in various fields such as food, medical and cosmetic industries. In this study, Tragacanth gum was used as a clean and natural reducing and stabilizing agent for preparation of urchin-like ZnO nanorod arrays at low-temperature using ultrasonic irradiation. The morphology and structure of urchin-like ZnO nanorod arrays was investigated by XRD, FESEM images, EDX, UV-vis and FT-IR spectroscopy. The hexagonal zinc oxide nanorods were synthesized with the average diameter of 55-80 nm and length of 240 nm. The peak appeared in 447 cm(-1) in FTIR spectra and the peak around 362.3 nm in UV-vis spectra of ZnO nanorods confirmed the successful synthesis of ZnO nanorods. The urchin-like ZnO nanorod arrays indicated a good photocatalytic activity through degradation of methylene blue with 92.2% efficiency and rate constant of 0.0027 min(-1) at 120 min. Finally, the synthesized urchin-like ZnO nanorod arrays indicated 100% antibacterial activity against S. aureus and E. coli and 93% antifungal activity against C. albicans with a low cytotoxicity.

  17. Tragacanth gum biopolymer as reducing and stabilizing agent in biosonosynthesis of urchin-like ZnO nanorod arrays: A low cytotoxic photocatalyst with antibacterial and antifungal properties.

    PubMed

    Ghayempour, Soraya; Montazer, Majid; Mahmoudi Rad, Mahnaz

    2016-01-20

    Tragacanth, a natural gum, has been used for centuries as emulsifier, thickener, stabilizer and binder in various fields such as food, medical and cosmetic industries. In this study, Tragacanth gum was used as a clean and natural reducing and stabilizing agent for preparation of urchin-like ZnO nanorod arrays at low-temperature using ultrasonic irradiation. The morphology and structure of urchin-like ZnO nanorod arrays was investigated by XRD, FESEM images, EDX, UV-vis and FT-IR spectroscopy. The hexagonal zinc oxide nanorods were synthesized with the average diameter of 55-80 nm and length of 240 nm. The peak appeared in 447 cm(-1) in FTIR spectra and the peak around 362.3 nm in UV-vis spectra of ZnO nanorods confirmed the successful synthesis of ZnO nanorods. The urchin-like ZnO nanorod arrays indicated a good photocatalytic activity through degradation of methylene blue with 92.2% efficiency and rate constant of 0.0027 min(-1) at 120 min. Finally, the synthesized urchin-like ZnO nanorod arrays indicated 100% antibacterial activity against S. aureus and E. coli and 93% antifungal activity against C. albicans with a low cytotoxicity. PMID:26572351

  18. Synthesis and Lanthanide Coordination Properties of New 2,6-Bis(N-tert-butylacetamide)pyridine and 2,6-Bis(N-tert-butylacetamide)pyridine-N-oxide Ligands

    SciTech Connect

    Binyamin, Iris; Pailloux, Sylvie; Duesler, Eileen N.; Rapko, Brian M.; Paine, Robert T.

    2006-07-24

    One method of treatment under consideration for processing of high-level radioactive fuel materials involves nuclear incineration. The success of the approach, in part, depends on the separation of minor actinides Am and Cm from the dominant actinides U and Pu prior to incineration. Therefore, there is fundamental interest, as well as practical demands, for the development of new selective coordination and separations chemistry for these species in aqueous solutions. Several families of ligands such as carbamoylmethylphophonates (CMP), (RO)2P(O)CH2C(O)NR2, carbamoylmethylphophine oxides (CMPO), R2P(O)CH2C(O)NR2, and alkyl malonamides, [RR'NC(O)2''H], have attracted the greatest attention as selective actinide ion chelators due in part to their stability toward strong radiation fields, as well as their ability to function in contact with the acidic aqueous solutions typically used to handle the actinide ions. In our group, we have been developing another family of ligands that offer promising performance in actinide separations: phosphinomethylpyridine-N-oxides, NOPO and NOPOPO.

  19. Bio-Functional Au/Si Nanorods for Pathogen Detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technical Abstract Nanotechnology applications for food safety and biosecurity, especially development of nanoscale sensors for foodborne pathogen measurement are emerging. A novel bio-functional nanosensor for Salmonella detection was developed using hetero-nanorods. The silica nanorods were fabr...

  20. Periodic Trends in Lanthanide Compounds through the Eyes of Multireference ab Initio Theory.

    PubMed

    Aravena, Daniel; Atanasov, Mihail; Neese, Frank

    2016-05-01

    Regularities among electronic configurations for common oxidation states in lanthanide complexes and the low involvement of f orbitals in bonding result in the appearance of several periodic trends along the lanthanide series. These trends can be observed on relatively different properties, such as bonding distances or ionization potentials. Well-known concepts like the lanthanide contraction, the double-double (tetrad) effect, and the similar chemistry along the lanthanide series stem from these regularities. Periodic trends on structural and spectroscopic properties are examined through complete active space self-consistent field (CASSCF) followed by second-order N-electron valence perturbation theory (NEVPT2) including both scalar relativistic and spin-orbit coupling effects. Energies and wave functions from electronic structure calculations are further analyzed in terms of ab initio ligand field theory (AILFT), which allows one to rigorously extract angular overlap model ligand field, Racah, and spin-orbit coupling parameters directly from high-level ab initio calculations. We investigated the elpasolite Cs2NaLn(III)Cl6 (Ln(III) = Ce-Nd, Sm-Eu, Tb-Yb) crystals because these compounds have been synthesized for most Ln(III) ions. Cs2NaLn(III)Cl6 elpasolites have been also thoroughly characterized with respect to their spectroscopic properties, providing an exceptionally vast and systematic experimental database allowing one to analyze the periodic trends across the lanthanide series. Particular attention was devoted to the apparent discrepancy in metal-ligand covalency trends between theory and spectroscopy described in the literature. Consistent with earlier studies, natural population analysis indicates an increase in covalency along the series, while a decrease in both the nephelauxetic (Racah) and relativistic nephelauxetic (spin-orbit coupling) reduction with increasing atomic number is calculated. These apparently conflicting results are discussed on the

  1. Lanthanide complexes of azidophenacyl-DO3A as new synthons for click chemistry and the synthesis of heterometallic lanthanide arrays.

    PubMed

    Tropiano, Manuel; Kenwright, Alan M; Faulkner, Stephen

    2015-04-01

    Lanthanide complexes of azidophenacyl DO3A are effective substrates for click reactions with ethyne derivatives, giving rise to aryl triazole appended lanthanide complexes, in which the aryl triazole acts as an effective sensitising chromophore for lanthanide luminescence. They also undergo click chemistry with propargylDO3A derivatives, giving rise to heterometallic complexes.

  2. Ultrasmall lanthanide-doped nanoparticles as multimodal platforms

    NASA Astrophysics Data System (ADS)

    Yust, Brian G.; Pedraza, Francisco J.; Sardar, Dhiraj K.

    2014-03-01

    Recently, there has been a great amount of interest in nanoparticles which are able to provide a platform with high contrast for multiple imaging modalities in order to advance the tools available to biomedical researchers and physicians. However, many nanoparticles do not have ideal properties to provide high contrast in different imaging modes. In order to address this, ultrasmall lanthanide doped oxide and fluoride nanoparticles with strong NIR to NIR upconversion fluorescence and a strong magnetic response for magnetic resonance imaging (MRI) have been developed. Specifically, these nanoparticles incorporate gadolinium, dysprosium, or a combination of both into the nano-crystalline host to achieve the magnetic properties. Thulium, erbium, and neodymium codopants provide the strong NIR absorption and emission lines that allow for deeper tissue imaging since near infrared light is not strongly absorbed or scattered by most tissues within this region. This also leads to better image quality and lower necessary excitation intensities. As a part of the one pot synthesis, these nanoparticles are coated with peg, pmao, or d-glucuronic acid to make them water soluble, biocompatible, and bioconjugable due to the available carboxyl or amine groups. Here, the synthesis, morphological characterization, magnetic response, NIR emission, and the quantum yield will be discussed. Cytotoxicity tested through cell viability at varying concentrations of nanoparticles in growth media will also be discussed.

  3. Single and multi-layered core-shell structures based on ZnO nanorods obtained by aerosol assisted chemical vapor deposition

    SciTech Connect

    Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M.

    2015-07-15

    Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition

  4. Separation of Minor Actinides from Lanthanides by Dithiophosphinic Acid Extractants

    SciTech Connect

    D. R. Peterman; M. R. Greenhalgh; R. D. Tillotson; J. R. Klaehn; M. K. Harrup; T. A. Luther; J. D. Law; L. M. Daniels

    2008-09-01

    The selective extraction of the minor actinides (Am(III) and Cm(III)) from the lanthanides is an important part of advanced reprocessing of spent nuclear fuel. This separation would allow the Am/Cm to be fabricated into targets and recycled to a reactor and the lanthanides to be dispositioned. This separation is difficult to accomplish due to the similarities in the chemical properties of the trivalent actinides and lanthanides. Research efforts at the Idaho National Laboratory have identified an innovative synthetic pathway yielding new regiospecific dithiophosphinic acid (DPAH) extractants. The synthesis provides DPAH derivatives that can address the issues concerning minor actinide separation and extractant stability. For this work, two new symmetric DPAH extractants have been prepared. The use of these extractants for the separation of minor actinides from lanthanides will be discussed.

  5. Lanthanides migration and immobilization in U-Zr nuclear fuels

    NASA Astrophysics Data System (ADS)

    Bozzolo, G.; Hofman, G. L.; Yacout, A. M.; Mosca, H. O.

    2012-06-01

    Redistribution of lanthanides fission products during irradiation and migration to the surface of U-Zr based metallic fuels is a concern due to their interaction with the cladding. The existing remedy for preventing this effect is the introduction of diffusion barriers on the cladding inner surface or by adding thermodynamically stable compound-forming elements to the fuel. Exploring this second option, in this work atomistic modeling with the Bozzolo-Ferrante-Smith (BFS) method for alloys is used to study the formation of lanthanide-rich precipitates in U-Zr fuel and the segregation patterns of all constituents to the surface. Surface energies for all elements were computed and, together with the underlying concepts of the computational methodology and large scale simulations, the migration of lanthanides to the surface region in U-Zr fuels is explained. The role of additions to the fuel such as In, Ga, and Tl for immobilization of lanthanides is discussed.

  6. Separation of actinides from lanthanides utilizing molten salt electrorefining

    SciTech Connect

    Grimmett, D.L.; Fusselman, S.P.; Roy, J.J.; Gay, R.L.; Krueger, C.L.; Storvick, T.S.; Inoue, T.; Hijikata, T.; Takahashi, N.

    1996-10-01

    TRUMP-S (TRansUranic Management through Pyropartitioning Separation) is a pyrochemical process being developed to separate actinides form fission products in nuclear waste. A key process step involving molten salt electrorefining to separate actinides from lanthanides has been studied on a laboratory scale. Electrorefining of U, Np, Pu, Am, and lanthanide mixtures from molten cadmium at 450 C to a solid cathode utilizing a molten chloride electrolyte resulted in > 99% removal of actinides from the molten cadmium and salt phases. Removal of the last few percent of actinides is accompanied by lowered cathodic current efficiency and some lanthanide codeposition. Actinide/lanthanide separation ratios on the cathode are ordered U > Np > Pu > Am and are consistent with predictions based on equilibrium potentials.

  7. Lanthanide ions as required cofactors for DNA catalysts.

    PubMed

    Dokukin, Victor; Silverman, Scott K

    2012-01-01

    We report that micromolar concentrations of lanthanide ions can be required cofactors for DNA-hydrolyzing deoxyribozymes. Previous work identified deoxyribozymes that simultaneously require both Zn(2+) and Mn(2+) to achieve DNA-catalyzed DNA hydrolysis (10(12) rate enhancement); a mutant of one such DNA catalyst requires only Zn(2+). Here we show that in vitro selection in the presence of 10 µM lanthanide ion (Ce(3+), Eu(3+), or Yb(3+)) along with 1 mM Zn(2+) leads to numerous DNA-hydrolyzing deoxyribozymes that strictly require the lanthanide ion as well as Zn(2+) for catalytic activity. These DNA catalysts have a range of lanthanide dependences, including some deoxyribozymes that strongly favor one particular lanthanide ion (e.g., Ce(3+) > Eu(3+) > Yb(3+)) and others that function well with more than one lanthanide ion. Intriguingly, two of the Yb(3+)-dependent deoxyribozymes function well with Yb(3+) alone (K(d,app) ~10 µM, in the absence of Zn(2+)) and have little or no activity with Eu(3+) or Ce(3+). In contrast to these selection outcomes when lanthanide ions were present, new selections with Zn(2+) or Mn(2+) alone, or Zn(2+) with Mg(2+)/Ca(2+), led primarily to deoxyribozymes that cleave DNA by deglycosylation and β-elimination rather than by hydrolysis, including several instances of depyrimidination. We conclude that lanthanide ions warrant closer attention as cofactors when identifying new nucleic acid catalysts, especially for applications in which high concentrations of polyvalent metal ion cofactors are undesirable.

  8. Lighting up cells with lanthanide self-assembled helicates

    PubMed Central

    Bünzli, Jean-Claude G.

    2013-01-01

    Lanthanide bioprobes and bioconjugates are ideal luminescent stains in view of their low propensity to photobleaching, sharp emission lines and long excited state lifetimes permitting time-resolved detection for enhanced sensitivity. We show here how the interplay between physical, chemical and biochemical properties allied to microfluidics engineering leads to self-assembled dinuclear lanthanide luminescent probes illuminating live cells and selectively detecting biomarkers expressed by cancerous human breast cells. PMID:24511387

  9. Preparation and Photoluminescence of ZnO Comb-Like Structure and Nanorod Arrays

    NASA Astrophysics Data System (ADS)

    Yin, Song; Chen, Yi-qing; Su, Yong; Zhou, Qing-tao

    2007-06-01

    A large quantity of Zinc oxide (ZnO) comb-like structure and high-density well-aligned ZnO nanorod arrays were prepared on silicon substrate via thermal evaporation process without any catalyst. The morphology, growth mechanism, and optical properties of the both structures were investigated using XRD, SEM, TEM and PL. The resulting comb-teeth, with a diameter about 20 nm, growing along the [0001] direction have a well-defined epitaxial relationship with the comb ribbon. The ZnO nanorod arrays have a diameter about 200 nm and length up to several micrometers growing approximately vertical to the Si substrate. A ZnO film was obtained before the nanorods growth. A growth model is proposed for interpreting the growth mechanism of comb-like zigzag-notch nanostructure. Room temperature photoluminescence measurements under excitation wavelength of 325 nm showed that the ZnO comb-like nanostructure has a weak UV emission at around 384 nm and a strong green emission around 491 nm, which correspond to a near band-edge transition and the singly ionized oxygen vacancy, respectively. In contrast, a strong and sharp UV peak and a weak green peak was obtained from the ZnO nanorod arrays.

  10. Lithium storage capability of CuGeO{sub 3} nanorods

    SciTech Connect

    Feng, JinKui; Lai, Man On; Lu, Li

    2012-07-15

    Highlights: ► We synthesized nanosized CuGeO{sub 3} by a facial hydrothermal method for Li battery. ► A high capacity of 690 mAh g{sup −1} at 50 cycles is achieved. ► The capacity is remarkably higher than that of the GeO{sub 2} electrode. ► The nanosized CuGeO{sub 3} also shows good cyclability. -- Abstract: Copper metagermanate (CuGeO{sub 3}) nanorods were synthesized through a low temperature hydrothermal method at 180 °C. The as-synthesized CuGeO{sub 3} nanorods show a well crystallined nanostructure with diameters in the range from 40 to 70 nm, and a length from 250 to 350 nm. Electrochemical measurements demonstrate that the CuGeO{sub 3} nanorods exhibit a first charge capacity of 924 mAh g{sup −1} and 690 mAh g{sup −1} after 50 cycles, which is remarkably improved than the pure nanosize GeO{sub 2} electrode. This investigation indicates that CuGeO{sub 3} nanorods could be utilized as a high capacity anode material in lithium-ion batteries by reducing particle size and metal oxide addition. The lithium storage mechanisms for the improved capacity retention were also studied.

  11. Multifunctional Particles: Magnetic Nanocrystals and Gold Nanorods Coated with Fluorescent Dye-Doped Silica Shells

    PubMed Central

    Heitsch, Andrew T.; Smith, Danielle K.; Patel, Reken E.; Ress, David; Korgel, Brian A.

    2008-01-01

    Multifunctional colloidal core-shell nanoparticles of magnetic nanocrystals (of iron oxide or FePt) or gold nanorods encapsulated in silica shells doped with the fluorescent dye, Tris(2,2′-bipyridyl)dichlororuthenium(II) hexahydrate (Rubpy) were synthesized. The as-prepared magnetic nanocrystals are initially hydrophobic and were coated with silica using a microemulsion approach, while the as-prepared gold nanorods are hydrophilic and were coated with silica using a Stöber-type of process. Each approach yielded monodisperse nanoparticles with uniform fluorescent dye-doped silica shells. These colloidal heterostructures have the potential to be used as dual-purpose tags—exhibiting a fluorescent signal that could be combined with either dark-field optical contrast (in the case of the gold nanorods), or enhanced contrast in magnetic resonance images (in the case of magnetic nanocrystal cores). The optical and magnetic properties of the fluorescent silica-coated gold nanorods and magnetic nanocrystals are reported. PMID:19578476

  12. Hydrogen peroxide generation and photocatalytic degradation of estrone by microstructural controlled ZnO nanorod arrays

    NASA Astrophysics Data System (ADS)

    Liu, Yangsi; Han, Jie; Qiu, Wei; Gao, Wei

    2012-12-01

    The strong oxidant, hydrogen peroxide (H2O2), generated by ZnO nanorod arrays under UV light irradiation was monitored by fluorescence analysis. The ZnO nanorod arrays were synthesized via a low temperature hydrothermal method and their dimensions, i.e., diameter and height, can be controlled by adjusting the concentration of zinc nitrate (Zn(NO3)2·6H2O) and hexamethylenetetramine (HMT). The morphology, nanostructure, surface roughness and optical property were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM) and transmittance spectra, respectively. The ZnO nanorod arrays were applied in the degradation of estrone, which is an emerging steroid estrogen contaminant. The results revealed that the ZnO nanorod array produced from 25 mM Zn2+ and HMT had the highest aspect ratio, the largest surface roughness and the lowest band gap energy, which was beneficial to the efficiency of UV light utilization, photocatalytic degradation of estrone and H2O2 generation.

  13. Facile synthesis of ZnO/CuInS2 nanorod arrays for photocatalytic pollutants degradation.

    PubMed

    Yang, Yawei; Que, Wenxiu; Zhang, Xinyu; Xing, Yonglei; Yin, Xingtian; Du, Yaping

    2016-11-01

    Vertically-aligned ZnO nanorod arrays on a fluorine-doped tin oxide glass substrate were homogeneously coated with visible light active CuInS2 quantum dots by using a controllable electrophoretic deposition strategy. Compared with the pure ZnO nanorod arrays, the formation of high-quality ZnO/CuInS2 heterojunction with well-matched band energy alignment expanded the light absorption from ultraviolet to visible region and facilitated efficient charge separation and transportation, thus yielding remarkable enhanced photoelectrochemical performance and photocatalytic activities for methyl orange and 4-chlorophenol degradation. The ZnO/CuInS2 film with the deposition duration of 80min showed the highest degradation rate and photocurrent density (0.95mA/cm(2)), which was almost 6.33 times higher than that of the pure ZnO nanorod arrays film. The CuInS2 QDs sensitized ZnO nanorod arrays film was proved to be a superior structure for photoelectrochemical and photocatalytic applications due to the optimized CuInS2 loading and well-maintained one-dimensional nanostructure. PMID:27322900

  14. Electrochemically grown ZnO nanorods for hybrid solar cell applications

    SciTech Connect

    Hames, Yakup; Alpaslan, Zuehal; Koesemen, Arif; San, Sait Eren; Yerli, Yusuf

    2010-03-15

    A hybrid solar cell is designed and proposed as a feasible and reasonable alternative, according to acquired efficiency with the employment of zinc oxide (ZnO) nanorods and ZnO thin films at the same time. Both of these ZnO structures were grown electrochemically and poly(3-hexylthiophene):phenyl-C61-butyric acid methyl ester; (P3HT:PCBM) was used as an active polymer blend, which was found to be compatible to prepared indium-tin-oxide (ITO) substrate base. This ITO base was introduced with mentioned ZnO structure in such a way that, the most efficient configuration was optimized to be ITO/ZnO film/ZnO nanorod/P3HT: PCBM/Ag. Efficiency of this optimized device is found to be 2.44%. All ZnO works were carried out electrochemically, that is indeed for the first time and at relatively lower temperatures. (author)

  15. Electrical characteristics of ZnO nanorods reinforced polymer nanocomposite thin films

    SciTech Connect

    Bhattacharjee, Snigdha; Roy, Asim

    2015-05-15

    ZnO nanorods have been prepared by simple chemical method, which is used to fabricate organic bistable devices (OBDs). OBDs are fabricated by incorporating different weight percent (wt %) of chemically synthesized Zinc Oxide (ZnO) nanorods into polymethylmethacrylate (PMMA). Current-voltage (I-V) measurements of the spin coated ZnO+PMMA nanocomopsite thin film on indium tin oxide (ITO) coated glass substrate showed current hysteresis behaviour, which is an indication of memory effect. The samples exhibit two distinct resistance states, ON and OFF states, characterised by relatively low and high resistance of the OBDs, respectively. It is also observed that with change in ZnO dopant concentration the value of ON/OFF current changes. Higher ON/OFF current ratio is desired for practical applications. Current conduction mechanism of the devices has been explained invoking various existing models, and it has been found that the trapped-charge-limited conduction mechanism was dominant in our samples.

  16. Calibration beads containing luminescent lanthanide ion complexes

    NASA Astrophysics Data System (ADS)

    Leif, Robert C.; Jin, Dayong; Piper, James; Vallarino, Lidia M.; Williams, John W.; Yang, Sean; Zucker, Robert M.

    2008-02-01

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including microscopes. Methods: 0.5, 3, and 5 micron (µm) beads containing a luminescent europium-complex were manufactured and the luminescence distribution of the 5 µm beads was measured with a time-delayed luminescence flow cytometer and a timedelayed digital microscope. The distribution of the luminescence intensity from the europium-complex in individual beads was determined on optical sections by confocal microscopy. The emission spectra of the beads under UV excitation were determined with a PARISS® spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation were measured under LED excitation with a fluorescence microscope. Results: The kinetics of UV bleaching were very similar for the 0.5, 3, and 5 µm beads. Emission peaks were found at 592, 616, and 685 nanometers (nm). The width of the principal peak at half-maximum (616 nm) was 9.9 nm. The luminescence lifetimes in water and in air were 340 and 460 microseconds (µs), respectively. The distribution of the europium- complex in the beads was homogeneous. Conclusions: The 5 µm beads can be used for spectral calibration of microscopes equipped with a spectrograph, as test particles for time-delayed luminescence flow cytometers, and possibly as labels for macromolecules and cells.

  17. Interactions of Plutonium and Lanthanides with Ordered Mesoporous Materials

    NASA Astrophysics Data System (ADS)

    Parsons-Moss, Tashi

    Ordered mesoporous materials are porous solids with a regular, patterned structure composed of pores between 2 and 50 nm wide. Such materials have attracted much attention in the past twenty years because the chemistry of their synthesis allows control of their unique physicochemical properties, which can be tuned for a variety of applications. Generally, ordered mesoporous materials have very high specific surface areas and pore volumes, and offer unique structures that are neither crystalline nor amorphous. The large tunable interface provided by ordered mesoporous solids may be advantageous in applications involving sequestration, separation, or detection of actinides and lanthanides in solution. However, the fundamental chemical interactions of actinides and lanthanides must be understood before applications can be implemented. This dissertation focuses primarily on the fundamental interactions of plutonium with organically modified mesoporous silica, as well as several different porous carbon materials, both untreated and chemically oxidized. A method for functionalizing mesoporous silica by self assembly and molecular grafting of functional organosilane ligands was optimized for the 2D-hexagonal ordered mesoporous silica known as SBA-15 (Santa Barbara amorphous silica). Four different organically-modified silica materials were synthesized and characterized with several techniques. To confirm that covalent bonds were formed between the silane anchor of the ligand and the silica substrate, functionalized silica samples were analyzed with 29Si nuclear magnetic resonance spectroscopy. Infrared spectroscopy was used in combination with 13C and 31P nuclear magnetic resonance spectroscopy to verify the molecular structures of the ligands after they were synthesized and grafted to the silica. The densities of the functional silane ligands on the silica surface were estimated using thermogravimetric analysis. Batch sorption experiments were conducted with solutions of

  18. Hydrothermal synthesis, characterizations and photoluminescence study of single crystalline hexagonal ZnO nanorods with three dimensional flowerlike microstructures

    NASA Astrophysics Data System (ADS)

    Kale, Rohidas B.; Hsu, Yung-Jung; Lin, Yi-Feng; Lu, Shih-Yuan

    2014-05-01

    A simple, low-cost, and environmentally benign hydrothermal approach has been successfully developed to synthesize uniform, large-scale well-crystallized ZnO nanorods with different aspect ratios that were united together to form three dimensional (3D) flowerlike structures. The method involved direct growth of ZnO 3D microstructures using aqueous solution of Zn(CH3COO)2 as the precursor and NaOH to adjust the pH of resultant solution. Surfactants or templates were not used during the entire synthetic process. Moreover, the morphology evolution of the ZnO nanorods with reaction time suggests a recrystallization-dissolution-growth mechanism that continuously takes place for prolonged interval of time. The XRD pattern of the as-grown ZnO nanorods and relevant analyses confirm the well crystallized hexagonal structure of the ZnO microstructures and no evidence of any other impurity phases. SEM observations reveal that the ZnO product grew in the form of nanorods that were united together to form 3D flowerlike morphology. The high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) shows that the ZnO nanorods were single crystalline and grew along the c-axis of the crystal plane. PL measurements of the as-synthesized nanorods exhibit excellent excitation features and strong band-edge UV luminescence even at room temperature. The uniform single crystalline, defect free, and high aspect ratio nanorods may find promising applications in optoelectronics and photo-catalysts. The growth habit of ZnO crystal is also illustrated. This method is suitable for large-scale production of ZnO microstructures and could be extended for syntheses of other metal oxides.

  19. Hydroquinone Based Synthesis of Gold Nanorods.

    PubMed

    Picciolini, Silvia; Mehn, Dora; Ojea-Jiménez, Isaac; Gramatica, Furio; Morasso, Carlo

    2016-08-10

    Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag(+)) present in the "growth solution". By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM.

  20. Growth process for gallium nitride porous nanorods

    SciTech Connect

    Wildeson, Isaac Harshman; Sands, Timothy David

    2015-03-24

    A GaN nanorod and formation method. Formation includes providing a substrate having a GaN film, depositing SiN.sub.x on the GaN film, etching a growth opening through the SiN.sub.x and into the GaN film, growing a GaN nanorod through the growth opening, the nanorod having a nanopore running substantially through its centerline. Focused ion beam etching can be used. The growing can be done using organometallic vapor phase epitaxy. The nanopore diameter can be controlled using the growth opening diameter or the growing step duration. The GaN nanorods can be removed from the substrate. The SiN.sub.x layer can be removed after the growing step. A SiO.sub.x template can be formed on the GaN film and the GaN can be grown to cover the SiO.sub.x template before depositing SiN.sub.x on the GaN film. The SiO.sub.x template can be removed after growing the nanorods.

  1. Hydroquinone Based Synthesis of Gold Nanorods.

    PubMed

    Picciolini, Silvia; Mehn, Dora; Ojea-Jiménez, Isaac; Gramatica, Furio; Morasso, Carlo

    2016-01-01

    Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag(+)) present in the "growth solution". By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM. PMID:27585238

  2. GaN nanorod light emitting diodes with suspended graphene transparent electrodes grown by rapid chemical vapor deposition

    SciTech Connect

    Xu, Kun; Xu, Chen Deng, Jun; Zhu, Yanxu; Guo, Weiling; Mao, Mingming; Xun, Meng; Chen, Maoxing; Zheng, Lei; Xie, Yiyang; Sun, Jie

    2013-11-25

    Ordered and dense GaN light emitting nanorods are studied with polycrystalline graphene grown by rapid chemical vapor deposition as suspended transparent electrodes. As the substitute of indium tin oxide, the graphene avoids complex processing to fill up the gaps between nanorods and subsequent surface flattening and offers high conductivity to improve the carrier injection. The as-fabricated devices have 32% improvement in light output power compared to conventional planar GaN-graphene diodes. The suspended graphene remains electrically stable up to 300 °C in air. The graphene can be obtained at low cost and high efficiency, indicating its high potential in future applications.

  3. Electronic Structure Engineering of Cu2O Film/ZnO Nanorods Array All-Oxide p-n Heterostructure for Enhanced Photoelectrochemical Property and Self-powered Biosensing Application

    PubMed Central

    Kang, Zhuo; Yan, Xiaoqin; Wang, Yunfei; Bai, Zhiming; Liu, Yichong; Zhang, Zheng; Lin, Pei; Zhang, Xiaohui; Yuan, Haoge; Zhang, Xueji; Zhang, Yue

    2015-01-01

    We have engineered the electronic structure at the interface between Cu2O and ZnO nanorods (NRs) array, through adjusting the carrier concentration of Cu2O. The electrodeposition of Cu2O at pH 11 acquired the highest carrier concentration, resulting in the largest interfacial electric field between Cu2O and ZnO, which finally led to the highest separation efficiency of photogenerated charge carriers. The optimized Cu2O/ZnO NRs array p-n heterostructures exhibited enhanced PEC performance, such as elevated photocurrent and photoconversion efficiency, as well as excellent sensing performance for the sensitive detection of glutathione (GSH) in PBS buffer even at applied bias of 0 V which made the device self-powered. Besides, the favorable selectivity, high reproducibility and extremely wide detection range, make such heterostructure a promising candidate for PEC biosensing applications, probably for the extended field of PEC water splitting or other solar photovoltaic beacons. PMID:25600940

  4. A DNA-Assembled Fe3O4@Ag Nanorod in Silica Matrix for Cholesterol Biosensing

    NASA Astrophysics Data System (ADS)

    Satvekar, R. K.; Tiwari, A. P.; Rohiwal, S. S.; Tiwale, B. M.; Pawar, S. H.

    2015-12-01

    A novel nanocomposite having DNA-assembled Fe3O4@Ag nanorods in silica matrix has been proposed for fabrication of bienzymatic cholesterol nanobiosensor. Cholesterol oxidase and horseradish peroxidase have been co-encapsulated in Silica/Fe3O4@Ag-DNA nanocomposite deposited on the indium tin oxide electrode. Cyclic voltammetry was employed for the electrochemical behavior of proposed biosensor and used to estimate cholesterol with a linear range of 5-195 mg/dL.

  5. Energy transfer between a biological labelling dye and gold nanorods

    NASA Astrophysics Data System (ADS)

    Racknor, Chris; Singh, Mahi R.; Zhang, Yinan; Birch, David J. S.; Chen, Yu

    2014-03-01

    We have demonstrated energy transfer between a biological labelling dye (Alexa Fluor 405) and gold nanorods experimentally and theoretically. The fluorescence lifetime imaging microscopy and density matrix method are used to study a hybrid system of dye and nanorods under one- and two-photon excitations. Energy transfer between dye and nanorods via the dipole-dipole interaction is found to cause a decrease in the fluorescence lifetime change. Enhanced energy transfer from dye to nanorods is measured in the presence of an increased density of nanorods. This study has potential applications in fluorescence lifetime-based intra-cellular sensing of bio-analytes as well as nuclear targeting cancer therapy.

  6. Development and Testing of an Americium/Lanthanide Separation Flowsheet Using Sodium Bismuthate

    SciTech Connect

    Jack Law; Bruce Mincher; Troy Garn; Mitchell Greenhalgh; Nicholas Schmitt; Veronica Rutledge

    2014-04-01

    The separation of Am from the lanthanides and curium is a key step in proposed advanced fuel cycle scenarios. The partitioning and transmutation of Am is desirable to minimize the long-term heat load of material interred in a future high-level waste repository. A separation process amenable to process scale-up remains elusive. Given only subtle chemistry differences within and between the ions of the trivalent actinide and lanthanide series this separation is challenging ; however, higher oxidation states of americium can be prepared using sodium bismuthate and separated via solvent extraction using diamylamylphosphonate (DAAP) extraction. Among the other trivalent metals only Ce is also oxidized and extracted. Due to the long-term instability of Am(VI) , the loaded organic phase is readily selectively stripped to partition the actinide to a new acidic aqueous phase. Batch extraction distribution ratio measurements were used to design a flowsheet to accomplish this separation. Additionally, crossflow filtration was investigated as a method to filter the bismuthate solids from the feed solution prior to extraction. Results of the filtration studies, flowsheet development work and flowsheet performance testing using a centrifugal contactor are detailed.

  7. Morphological and structural evolution of alpha-MnO{sub 2} nanorods synthesized via an aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction

    SciTech Connect

    Fu Xiaobo; Feng Jiyun; Wang Huan; Ng, Ka Ming

    2010-04-15

    An aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction under mild conditions was used to synthesize alpha-MnO{sub 2} nanorods. The morphological and structural evolution of alpha-MnO{sub 2} nanorods during their growth were tracked by Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and BET analysis. The crystallization of alpha-MnO{sub 2} nanorods was found to proceed through three steps: (1) Amorphous or poorly ordered nuclei formed first. (2) Then hollow nanoshperes consisting of gamma-MnO{sub 2} nanorods formed via the Ostwald ripening process. (3) The hollow nanospheres broke down and the gamma-MnO{sub 2} nanorods finally transformed into the alpha-MnO{sub 2} nanorods with increasing temperature or reaction time. The phase transformation from gamma-MnO{sub 2} to alpha-MnO{sub 2} nanorods was accomplished by a short-range rearrangement of MnO{sub 6} octahedra. In addition, the performance of the MnO{sub 2} materials as a catalyst was evaluated in the aerobic oxidation of benzyl alcohol, showing that their catalytic activities were mainly dependent on their BET surface areas. - Graphical abstract: alpha-MnO{sub 2} nanorods were synthesized via an aqueous route through MnO{sub 4}{sup -}/Mn{sup 2+} reaction under mild conditions.

  8. Nanoparticle Optics of Complex Nanorod Architectures

    SciTech Connect

    Shuford, Kevin L; Park, Sungho

    2009-01-01

    Computational studies on the optical properties of nanorods with unique compositions and exotic surface structure are presented. The distinctive architectures investigated-and compared to smooth Au rods-include Ni/Au multiblock rods and nanoporous Au rods. The surface plasmon resonances are extremely dependent upon the morphology and makeup of the nanorods. For a rod with a given aspect ratio, the resonance structure is sensitive to attributes such as the size of Ni sections of multiblock rods and pore structure of nanoporous rods. These studies indicate that control of the optical properties of nanorods is possible via characteristics other than the aspect ratio and suggest that a broader range of tunability is attainable.

  9. Photocatalytic reduction of CO2 by CuxO nanocluster loaded SrTiO3 nanorod thin film

    NASA Astrophysics Data System (ADS)

    Shoji, Shusaku; Yin, Ge; Nishikawa, Masami; Atarashi, Daiki; Sakai, Etsuo; Miyauchi, Masahiro

    2016-08-01

    Photocatalytic carbon dioxide (CO2) conversion into carbon monoxide (CO) using H2O as an electron donor was achieved by the strontium titanate (SrTiO3: STO) nanorod thin films loaded with amorphous copper oxide (CuxO) nanoclusters. The loading of the CuxO-cocatalysts onto STO nanorods clearly improved the photocatalytic activity compared to bare STO nanorods. The CuxO-cocatalysts are composed of abundant and non-toxic elements, and can be loaded by using a simple and economical method. Our findings demonstrate that CuxO nanoclusters function as a general cocatalyst and can be used in combination with various semiconductors to construct low-cost and efficient photocatalytic CO2 reduction systems.

  10. Property enchancement of polyimide films by way of the incorporation of lanthanide metal ions

    NASA Technical Reports Server (NTRS)

    Thompson, David W.

    1993-01-01

    Lanthanide metal ions were incorporated into the polyimide derived from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 1,3-bis(aminophenoxy) benzene (APB) in an attempt to produce molecular level metal-polymer composites. The lanthanide series of metal ions (including aluminum, scandium, and yttrium) provide discrete and stable metal ions in the 3+ oxidation state. Throughout the series there is a uniform variation in ionic size ranging from 50 pm for aluminum to a maximum of 103.4 pm for cerium and gradually decreasing again to 84.8 pm for lutetium. The high charge-to-size ratio for these ions as well as the ability to obtain large coordination numbers makes them excellent candidates for interacting with the polymer substructure. The distinct lack of solubility of simple lanthanide salts such as the acetates and halides has made it difficult to obtain metal ions distributed in the polymer framework as discrete ions or metal complexes rather than microcomposites of metal clusters. (Lanthanum nitrates are quite soluble, but the presence of the strongly oxidizing nitrate ion leads to serious degradation of the polymer upon thermal curing. This work was successful at extending the range of soluble metals salts by using chelating agents derived from the beta-diketones dipivaloylmethane, dibenzoylmethane, trifluoroacetylacetone, and hexafluoroacetylacetone. Metal acetates which are insoluble in dimethylacetamide dissolve readily in the presence of the diketones. Addition of the polyimide yields a homogeneous resin which is then cast into a clear film. Upon curing clear films were obtained with the dibenzoylmethane and trifluoroacetylacetone ligands. The dipavaloylmethane precipitates the metal during the film casting process, and hexafluoroacetylacetone gives cured films which are deformed and brittle. These clear films are being evaluated for the effect of the metal ions on the coefficient of thermal expansion, resistance to atomic oxygen, and on

  11. Collective alignment of nanorods in thin Newtonian films

    NASA Astrophysics Data System (ADS)

    Gu, Yu; Burtovyy, Ruslan; Townsend, James; Owens, Jeffery; Luzinov, Igor; Kornev, Konstantin

    2013-11-01

    We provide a complete analytical description of the alignment kinetics of magnetic nanorods in magnetic field. Nickel nanorods were formed by template electrochemical deposition in alumina membranes from a dispersion in a water-glycerol mixture. To ensure uniformity of the dispersion, the surface of the nickel nanorods was covered with polyvinylpyrrolidone (PVP). A 40-70 nm coating prevented aggregation of nanoroda. These modifications allowed us to control alignment of the nanorods in a magnetic field and test the proposed theory. An orientational distribution function of nanorods was introduced. We demonstrated that the 0.04% volume fraction of nanorods in the glycerol-water mixture behaves as a system of non-interacting particles. However, the kinetics of alignment of a nanorod assembly does not follow the predictions of the single-nanorod theory. The distribution function theory explains the kinetics of alignment of a nanorod assembly and shows the significance of the initial distribution of nanorods in the film. It can be used to develop an experimental protocol for controlled ordering of magnetic nanorods in thin films. This work was supported by the Air Force Office of Scientific Research, Grant numbers FA9550-12-1-0459 and FA8650-09-D-507 5900.

  12. One-step in situ synthesis of graphene–TiO{sub 2} nanorod hybrid composites with enhanced photocatalytic activity

    SciTech Connect

    Sun, Mingxuan Li, Weibin; Sun, Shanfu; He, Jia; Zhang, Qiang; Shi, Yuying

    2015-01-15

    Chemically bonded graphene/TiO{sub 2} nanorod hybrid composites with superior dispersity were synthesized by a one-step in situ hydrothermal method using graphene oxide (GO) and TiO{sub 2} (P25) as the starting materials. The as-prepared samples were characterized by XRD, XPS, TEM, FE-SEM, EDX, Raman, N{sub 2} adsorption, and UV–vis DRS techniques. Enhanced light absorption and a red shift of absorption edge were observed for the composites in the ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS). Their effective photocatalytic activity was evaluated by the photodegradation of methylene blue under visible light irradiation. An enhancement of photocatalytic performance was observed over graphene/TiO{sub 2} nanorod hybrid composite photocatalysts, as 3.7 times larger than that of pristine TiO{sub 2} nanorods. This work demonstrated that the synthesis of TiO{sub 2} nanorods and simultaneous conversion of GO to graphene “without using reducing agents” had shown to be a rapid, direct and clean approach to fabricate chemically bonded graphene/TiO{sub 2} nanorod hybrid composites with enhanced photocatalytic performance.

  13. Hydroxyaptite nanorods patterned ZrO2 bilayer coating on zirconium for the application of percutaneous implants.

    PubMed

    Zhang, Lan; Han, Yong; Tan, Guoxin

    2015-03-01

    Percutaneous implant requires a tight bond between the underlying dermis of skin and implant surface to prevent epithelial down-growth and infection, while fibroblasts play a key role in the skin-implant integration. In this work, nanorod-shaped hydroxyaptite (HA) with a mean diameter of 70 nm and length of 400 nm was hydrothermally grown on micro-arc oxidized (MAOed) Ca- and P-doped ZrO2 to form a bilayer coating. The hydrothermal formation mechanism of HA nanorods was explored, and the adsorption of total protein on the coating from α-MEM medium containing 10% fetal bovine serum was examined. Employing L-929 cells, the behaviors of fibroblasts on the bilayer coating, including adhesion and proliferation were evaluated together the polished Zr and as-MAOed ZrO2. The obtained results show that the HA nanorods nucleated on ZrO2 and grew at the expense of the doped Ca and P ions during the hydrothermal treatment (HT). The HA nanorods patterned coating enhanced protein absorption, and significantly improved the adhesion and proliferation of fibroblasts compared to the as-MAOed ZrO2 and polished Zr. It suggests that the HA nanorods/ZrO2 coated zirconium has a potential application for percutaneous implants to enhance the attachment of skin. PMID:25635615

  14. Multishell Au/Ag/SiO2 nanorods with tunable optical properties as single particle orientation and rotational tracking probes

    DOE PAGESBeta

    Chen, Kuangcai; Lin, Chia -Cheng; Vela, Javier; Fang, Ning

    2015-04-07

    In this study, three-layer core–shell plasmonic nanorods (Au/Ag/SiO2–NRs), consisting of a gold nanorod core, a thin silver shell, and a thin silica layer, were synthesized and used as optical imaging probes under a differential interference contrast microscope for single particle orientation and rotational tracking. The localized surface plasmon resonance modes were enhanced upon the addition of the silver shell, and the anisotropic optical properties of gold nanorods were maintained. The silica coating enables surface functionalization with silane coupling agents and provides enhanced stability and biocompatibility. Taking advantage of the longitudinal LSPR enhancement, the orientation and rotational information of the hybridmore » nanorods on synthetic lipid bilayers and on live cell membranes were obtained with millisecond temporal resolution using a scientific complementary metal-oxide-semiconductor camera. The results demonstrate that the as-synthesized hybrid nanorods are promising imaging probes with improved sensitivity and good biocompatibility for single plasmonic particle tracking experiments in biological systems.« less

  15. Hydroxyaptite nanorods patterned ZrO2 bilayer coating on zirconium for the application of percutaneous implants.

    PubMed

    Zhang, Lan; Han, Yong; Tan, Guoxin

    2015-03-01

    Percutaneous implant requires a tight bond between the underlying dermis of skin and implant surface to prevent epithelial down-growth and infection, while fibroblasts play a key role in the skin-implant integration. In this work, nanorod-shaped hydroxyaptite (HA) with a mean diameter of 70 nm and length of 400 nm was hydrothermally grown on micro-arc oxidized (MAOed) Ca- and P-doped ZrO2 to form a bilayer coating. The hydrothermal formation mechanism of HA nanorods was explored, and the adsorption of total protein on the coating from α-MEM medium containing 10% fetal bovine serum was examined. Employing L-929 cells, the behaviors of fibroblasts on the bilayer coating, including adhesion and proliferation were evaluated together the polished Zr and as-MAOed ZrO2. The obtained results show that the HA nanorods nucleated on ZrO2 and grew at the expense of the doped Ca and P ions during the hydrothermal treatment (HT). The HA nanorods patterned coating enhanced protein absorption, and significantly improved the adhesion and proliferation of fibroblasts compared to the as-MAOed ZrO2 and polished Zr. It suggests that the HA nanorods/ZrO2 coated zirconium has a potential application for percutaneous implants to enhance the attachment of skin.

  16. Hyperthermic effects of gold nanorods on tumor cells

    PubMed Central

    Huff, Terry B.; Tong, Ling; Zhao, Yan; Hansen, Matthew N.; Cheng, Ji-Xin; Wei, Alexander

    2008-01-01

    Summary Plasmon-resonant gold nanorods, which have large absorption cross sections at near-infrared (NIR) frequencies, are excellent candidates as multifunctional agents for image-guided therapies based on localized hyperthermia. The controlled modification of the nanorods' surface chemistry is of critical importance, as issues of cell-specific targeting and nonspecific uptake must be addressed prior to clinical evaluation. Nanorods coated with CTAB (a cationic surfactant used in nanorod synthesis) are internalized within hours into KB cells by a nonspecific uptake pathway, whereas the careful removal of CTAB from nanorods functionalized with folate results in their accumulation on the cell surface over the same time interval. In either case, the nanorods render the tumor cells highly susceptible to photothermal damage when irradiated at the nanorods' longitudinal plasmon resonance, generating extensive blebbing of the cell membrane at laser fluences as low as 44 W/cm2. PMID:17716198

  17. Bio-functional Au/Si nanorods for pathogen detection

    NASA Astrophysics Data System (ADS)

    Park, Bosoon; Fu, Junxue; Zhao, Yiping; Siragusa, Gregory R.; Cho, Yong-Jin; Lawrence, Kurt C.; Windham, William R.

    2007-09-01

    Nanotechnology applications for food safety and biosecurity, especially development of nanoscale sensors for foodborne pathogen measurement are emerging. A novel bio-functional nanosensor for Salmonella detection was developed using hetero-nanorods. The silica nanorods were fabricated by glancing angle deposition method and the gold was sputtered onto the silica nanorods. Alexa488-succinimide dye was immobilized onto the annealed Si nanorods via the attachment between dye ester and primary amine group supplied by the 3-Aminopropyltriethoxysilane. The anti-Salmonella was conjugated to gold via Dithiobis[succinimidylpropionate] self-assembly monolayer. Due to the high aspect ratio nature of the Si nanorods, hundreds or thousands of dye molecules attached to the Si nanorods produced enhanced fluorescence signal. These biologically functionalized nanorods can be used to detect Salmonella with fluorescent microscopic imaging. This new nanoscale biosensor will be able to detect other foodborne pathogenic bacteria for food safety and security applications.

  18. Nanorods and nanotubes: Synthesis, manipulation and properties

    NASA Astrophysics Data System (ADS)

    Wong, Eric Warren

    Nanorods and nanotubes represent idealized structures for investigating phenomena associated with reduced dimensionality and are potential building blocks for nanostructured materials. Understanding their synthesis as well as physical properties is crucial if they are to form the basis for future devices. The synthesis of carbide nanotubes and nanorods is described. Also presented is a general method that combines micropatterning techniques with scanning force microscopy (SFM) to probe individual quasi-one-dimensional materials. Polycrystalline TiC and NbC nanorods, with 20-30 nm diameters and lengths exceeding 1 mum, were synthesized by reacting gaseous Ti-I or Nb-I at 550-1100sp°C with carbon nanotubes which served as structural templates. Template growth from nanotubes appears general since polycrystalline BCsb{x} and amorphous Fesb3C nanorods were produced from Bsb2Osb2 and FeClsb3, respectively. However, reaction of Si-I precursors with nanotubes or graphite above 1050sp°C resulted in single crystal SiC nanorods, with 1-20 nm diameters and 1-20 mum lengths, that grew catalytically from MoSisb2 nanoparticles by a vapor-solid mechanism. Above 1200sp°C, single crystal TiC nanorods grew from nanotubes and Ti-I or TiO by an undetermined mechanism. To probe electrical transport in carbon nanotubes, a method was devised where a static gold contact was lithographically formed with one end of a nanotube while a second dynamic contact was made by a conducting SFM probe. The conducting SFM tip can simultaneously map the topography and conductance of the nanotube. The transport properties of a series of structurally distinct nanotubes were studied and shown to sensitively depend on their structure, the presence of defects causing dramatic increases in resistivity. The mechanics of SiC nanorods and carbon nanotubes were studied using an analogous technique. An SFM tip was used to measure the forces required to bend nanobeams. The SiC nanorods had elastic moduli in close

  19. Two-stage epitaxial growth of vertically-aligned SnO2 nano-rods on(001) ceria

    SciTech Connect

    Solovyov, Vyacheslav F.; Wu, Li-jun; Rupich, Martin W.; Sathyamurthy, Srivatsan; Li, Xiaoping; Li, Qiang

    2014-09-20

    Growth of high-aspect ratio oriented tin oxide, SnO2, nano-rods is complicated by a limited choice of matching substrates. We show that a (001) cerium oxide, CeO2, surface uniquely enables epitaxial growth of tin-oxide nano-rods via a two-stage process. First, (100) oriented nano-wires coat the ceria surface by lateral growth, forming a uniaxially-textured SnO2 deposit. Second, vertical SnO2nano-rods nucleate on the deposit by homoepitaxy. We demonstrate growth of vertically oriented 1-2 μm long nano-rods with an average diameter of ≈20 nm.

  20. Lanthanide accumulation in the periplasmic space of Escherichia coli B.

    PubMed

    Bayer, M E; Bayer, M H

    1991-01-01

    Treatment of growing Escherichia coli B with lanthanide ions [lanthanum(III), terbium(III), and europium(III)] and subsequent aldehyde-OsO4 fixation caused areas of high contrast to appear within the periplasm (the space between inner and outer membrane of the cell envelope). X-ray microanalysis of ultrathin sections of Epon-embedded or acrylic resin-embedded cells revealed the presence of the lanthanide and of phosphorus in the areas, whose contrast greatly exceeded that of other stained structures. Comparatively small amounts of the lanthanide were also present in the outer membrane and in the cytoplasm. The distribution of the periplasmic areas of high contrast was found to be random and not clustered at areas of current or future septum formation. Irregular cell shapes were observed after lanthanide treatment before onset of fixation. In contrast to glutaraldehyde-OsO4 fixation, glutaraldehyde used as the sole fixer caused a scattered distribution of the lanthanide. Cryofixation (slam-freezing) and freeze substitution revealed a lanthanum stain at both the periplasm and the outer part of the outer membrane. Deenergization of the cell membrane by either phage T4 or carbonyl cyanide m-chlorophenylhydrazone abolished the metal accumulation. Furthermore, addition of excess calcium, administered together with the lanthanide solution, diminished the quantity and size of areas of high contrast. Cells grown in media of high NaCl concentration revealed strongly stained areas of periplasmic precipitates, whereas cells grown under low-salt conditions showed very few high-contrast patches in the periplasm. Terbium treatment (during fixation) enhanced the visibility of the sites of inner-outer membrane contact (the membrane adhesion sites) in plasmolized cells, possibly as the result of an accumulation of the metal at the adhesion domains. The data suggest a rapid interaction of the lanthanides with components of the cell envelope, the periplasm, and the energized inner