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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. A simple method to synthesize single-crystalline lanthanide orthovanadate nanorods

    NASA Astrophysics Data System (ADS)

    Fan, Weiliu; Zhao, Wei; You, Liping; Song, Xinyu; Zhang, Weimin; Yu, Haiyun; Sun, Sixiu

    2004-12-01

    Single-crystalline tetragonal LnVO 4 ( Ln=La, Nd, Sm, Eu, Dy) nanorods were prepared via a simple hydrothermal method, in the absence of any surfactant or template using cheap and simple inorganic salts as raw materials. The products were characterized by XRD, TEM, HRTEM, and PL. It has been shown that after the hydrothermal process, LaVO 4 transformed its crystal structure from monoclinic to tetragonal phase, but LnVO 4 ( Ln=Nd, Sm, Eu, Dy) have not exhibited the structural change. This could be associated with the change of lanthanide ion radius. TEM and HRTEM results show that the nanorods are pure, structurally uniform, single crystalline, and most of them are free from dislocations. Further study reveals the nanorods grow along the [001] direction. A possible growth mechanism of lanthanide orthovanadate nanorods was also proposed. The advantages of our method for the nanorods synthesis lie in the high yield and the low temperature and mild reaction conditions, which permit large scale production at low cost.

  3. 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.

  4. 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.

  5. 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.

  6. Electrochromic and transparent conducting oxide nanorods

    NASA Astrophysics Data System (ADS)

    Limmer, Steven J.; Takahashi, Katsunori; Cao, Guozhong

    2003-11-01

    Electrochromic materials are of interest for a wide variety of applications, such as displays and smart windows. Many electrochromic oxide materials are synthesized through sol-gel processing. We have demonstrated a general technique for the synthesis of oxide nanorods using sol electrophoretic deposition with an appropriate template. This technique can be applied for the synthesis of nanorods of electrochromic materials, such as TiO2, V2O5 and Nb2O5, with diameters of ~100 nm and a length of ~10 μm. By attaching these nanorods to a conducting substrate (such as ITO coated glass), it is possible to characterize the electrochromic behavior of these materials via UV-Vis absorbance spectroscopy. A similar technique has been used to make nanorods of the transparent conducting oxide indium tin oxide (ITO), which is often used as a working electrode in electrochromic devices. Such ITO nanorods have diameters of ~75-140 nm and lengths up to 60 μm.

  7. 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

  8. Directed spatial organization of zinc oxide nanorods.

    SciTech Connect

    Simmons, Neil C.; Liu, Jun; Voigt, James A.; Hsu, Julia W. P.; Tian, Zhengrong Ryan; Matzke, Carolyn M.

    2004-09-01

    The ability to precisely place nanomaterials at predetermined locations is necessary for realizing applications using these new materials. Using an organic template, we demonstrate directed growth of zinc oxide (ZnO) nanorods on silver films from aqueous solution. Spatial organization of ZnO nanorods in prescribed arbitrary patterns was achieved, with unprecedented control in selectivity, crystal orientation, and nucleation density. Surprisingly, we found that caboxylate endgroups of {omega}-alkanethiol molecules strongly inhibit ZnO nucleation. The mechanism for this observed selectivity is discussed.

  9. Ruthenium-coated ruthenium oxide nanorods

    SciTech Connect

    Ducati, Caterina; Dawson, Darryl H.; Saffell, John R.; Midgley, Paul A.

    2004-11-29

    The role of ruthenium and its oxides in catalysis, electrochemistry, and electronics is becoming increasingly important because of the high thermal and chemical stability, low resistivity, and unique redox properties of this metallic system. We report an observation of RuO{sub 2} nanorods decorated with nanometer size Ru metal clusters. We identify precise crystallographic relationships between metal and oxide, and provide a simple model for the synthesis of these structures, based on the theory of columnar growth. The high aspect ratio, high surface area, and quantum size crystalline decorations of these nanostructures make them particularly attractive candidates for further fundamental research and for advanced catalytic and electronic applications.

  10. Laser ablation synthesis of lanthanide oxide clusters: Mechanisms and chemistry

    SciTech Connect

    Gibson, J.K.

    1995-07-15

    Excimer laser ablation into vacuum of hydrated lanthanide oxalates has produced new lanthanide (Ln) oxide cluster ions which were identified by time-of-flight mass spectrometry. In addition to binary oxide clusters (Ln{sub {ital m}}O{sup +}{sub {ital n}}), mixed lanthanide oxide clusters [Ln{sub {ital m}1}Ln{sub {ital m}2}{sup {prime}}O{sup +}{sub {ital n}} with ({ital m}1+{ital m}2){le}9] were discerned for the following Ln-Ln{prime}: La-Tb, La-Ho, La-Lu, and Ho-Lu. The observed cluster ion stoichiometries, abundance distributions, and hydration systematics provide insights into cluster formation mechanisms and chemistries. Time-variable ion sampling revealed cluster enhancement in the tail of the ablation plume. The body of experimental results support cluster formation by aggregation of small ablated species. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  11. 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.

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

    PubMed Central

    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

    2013-01-01

    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. PMID:24220641

  13. 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.…

  14. 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.

  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. 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.

  17. Oxalic acid capped iron oxide nanorods as a sensing platform.

    PubMed

    Sharma, Anshu; Baral, Dinesh; Bohidar, H B; Solanki, Pratima R

    2015-08-01

    A label free impedimetric immunosensor has been fabricated using protein bovine serum albumin (BSA) and monoclonal antibodies against Vibrio cholerae (Ab) functionalized oxalic acid (OA) capped iron oxide (Fe3O4) nanorods for V. cholerae detection. The structural and morphological studies of Fe3O4 and OA-Fe3O4, were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and dynamic light scattering (DLS) techniques. The average crystalline size of Fe3O4, OA-Fe3O4 nanorods were obtained as about 29±1 and 39±1nm, respectively. The hydrodynamic radius of nanorods is found as 116nm (OA-Fe3O4) and 77nm (Fe3O4) by DLS measurement. Cytotoxicity of Fe3O4 and OA-Fe3O4 nanorods has been investigated in the presence of human epithelial kidney (HEK) cell line 293 using MTT assay. The cell viability and proliferation studies reveal that the OA-Fe3O4 nanorods facilitate cell growth. The results of electrochemical response studies of the fabricated BSA/Ab/OA-Fe2O3/ITO immunosensor exhibits good linearity in the range of 12.5-500ng mL(-1) with low detection limit of 0.5ng mL(-1), sensitivity 0.1Ωng(-1)ml(-1)cm(-2) and reproducibility more than 11 times. PMID:26048074

  18. 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.

  19. Attachment of Quantum Dots on Zinc Oxide Nanorods

    NASA Astrophysics Data System (ADS)

    Seay, Jared; Liang, Huan; Harikumar, Parameswar

    2011-03-01

    ZnO nanorods grown by hydrothermal technique are of great interest for potential applications in photovoltaic and optoelectronic devices. In this study we investigate the optimization of the optical absorption properties by a low temperature, chemical bath deposition technique. Our group fabricated nanorods on indium tin oxide (ITO) substrate with precursor solution of zinc nitrate hexahydrate and hexamethylenetramine (1:1 molar ratio) at 95C for 9 hours. In order to optimize the light absorption characteristics of ZnO nanorods, CdSe/ZnS core-shell quantum dots (QDs) of various diameters were attached to the surface of ZnO nanostructures grown on ITO and gold-coated silicon substrates. Density of quantum dots was varied by controlling the number drops on the surface of the ZnO nanorods. For a 0.1 M concentration of QDs of 10 nm diameter, the PL intensity at 385 nm increased as the density of the quantum dots on ZnO nanostructures was increased. For quantum dots at 1 M concentration, the PL intensity at 385 nm increased at the beginning and then decreased at higher density. We will discuss the observed changes in PL intensity with QD concentration with ZnO-QD band structure and recombination-diffusion processes taking place at the interface.

  20. 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.

  1. Inkjet printing lanthanide doped nanorods test paper for visual assays of nitroaromatic explosives.

    PubMed

    Hong, Liang; Mei, Qingsong; Yang, Lei; Zhang, Cheng; Liu, Renyong; Han, Mingyong; Zhang, Ruilong; Zhang, Zhongping

    2013-11-13

    The facile and sensitive strategies for detections of nitroaromatic explosives are highly desirable in many challenging environments, especially for homeland security against terrorism. Here, we inkjet printed polyethylenimine (PEI)-coated Ce, Tb co-doped NaGdF4 nanorods (NaGdF4:Ce/Tb NRs) onto common filter paper to construct test paper for visual and instant detections of a typical explosive 2,4,6-trinitrophenol (TNP). Polyethylenimine molecules not only facilitate the formation of uniform NaGdF4 nanorods but also provide specific recognized sites for TNP by the acid-base pairing interaction. The resultant TNP bound at the surface of PEI-coated NaGdF4:Ce/Tb NRs can strongly quench the phosphorescence with a remarkably high quenching constant by the charge transfer mechanism from NaGdF4:Ce/Tb NRs to TNP. By printing of the probe on a piece of filter paper, trace amounts of TNP can be visually detected by the appearance of a dark color against a bright green background under a UV lamp. This test paper can detect TNP as low as 0.45 ng mm(-2) by the naked eye, which provides a potential application in the rapid, on-line detections of explosives. PMID:24176509

  2. 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

  3. Templated electrodeposition and photocatalytic activity of cuprous oxide nanorod arrays.

    PubMed

    Haynes, Keith M; Perry, Collin M; Rivas, Marlene; Golden, Teresa D; Bazan, Antony; Quintana, Maria; Nesterov, Vladimir N; Berhe, Seare A; Rodríguez, Juan; Estrada, Walter; Youngblood, W Justin

    2015-01-14

    Cuprous oxide (Cu2O) nanorod arrays have been prepared via a novel templated electrodeposition process and were characterized for their photocatalytic behavior in nonaqueous photoelectrochemical cells. Zinc oxide (ZnO) nanorod films serve as sacrificial templates for the in situ formation of polymer nanopore membranes on transparent conductive oxide substrates. Nitrocellulose and poly(lactic acid) are effective membrane-forming polymers that exhibit different modes of template formation, with nitrocellulose forming conformal coatings on the ZnO surface while poly(lactic acid) acts as an amorphous pore-filling material. Robust template formation is sensitive to the seeding method used to prepare the precursor ZnO nanorod films. Photoelectrochemical cells prepared from electrodeposited Cu2O films using methyl viologen as a redox shuttle in acetonitrile electrolyte exhibit significant charge recombination that can be partially suppressed by a combination of surface passivation methods. Surface-passivated nanostructured Cu2O films show enhanced photocurrent relative to planar electrodeposited Cu2O films of similar thickness. We have obtained the highest photocurrent ever reported for electrodeposited Cu2O in a nonaqueous photoelectrochemical cell. PMID:25455203

  4. 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)

  5. 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

  6. 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

  7. Microwave plasma synthesis of lanthanide zirconates from microwave transparent oxides.

    PubMed

    Chou, Yi-Hsin; Hondow, Nicole; Thomas, Chris I; Mitchell, Robert; Brydson, Rik; Douthwaite, Richard E

    2012-02-28

    Lanthanide zirconate phases Ln(2)Zr(2)O(7) and Ln(4)Zr(3)O(12) (Ln = Y, La, Gd, Dy, Ho, Yb) have been prepared using a microwave induced plasma methodology, which allows rapid synthesis using materials which do not couple directly with microwaves at room temperature. We describe the measurement of heating profiles of the precursor binary metal oxides which can be used to identify conditions conducive to the synthesis of more complex oxides. Uncontrolled heating which can be a feature of microwave synthesis of ceramics is not observed, allowing reproducible synthesis. Conventionally these phases are prepared at >1400 °C over hours or days and are being investigated for applications including the immobilisation of nuclear waste where rapid processing is important. Using the microwave plasma method, phase-pure materials have been prepared in minutes. Furthermore, it is clear that Ln(2)Zr(2)O(7) and Ln(4)Zr(3)O(12) also exhibit significant plasma-promoted dielectric heating (e.g. >2200 °C for Dy(4)Zr(3)O(12)) which is typically greater than either of the respective precursors, thus providing a driving force to rapidly complete the reaction. PMID:22215067

  8. Surface modification of luminescent lanthanide phosphate nanorods with cationic "Quat-primer" polymers.

    PubMed

    Komban, Rajesh; Beckmann, Ralph; Rode, Sebastian; Ichilmann, Sachar; Kühnle, Angelika; Beginn, Uwe; Haase, Markus

    2011-08-16

    "Quat-primer" polymers bearing cationic groups were investigated as a surface modifier for Tb-doped cerium phosphate green-emitting fluorescent nanorods (NRs). The NRs were synthesized by a microwave process without using any complex agents or ligands and were characterized with different analytical tools such as X-ray diffraction, transmission electron microscopy, and fluorescence spectroscopy. Poly(ethyleneimine) partially quarternized with glycidyltrimethylammonium chloride was synthesized separately and characterized in detail. (1)H and (13)C NMR spectroscopic studies revealed that the quaternary ammonium group was covalently attached to the polymer. UV-vis spectroscopy was used to examine the stability of the colloidal dispersions of the bare NRs as well as the modified NRs. ζ potential, thermogravimetric analysis, and atomic force microscopy studies were carried out to confirm that the positively charged Quat-primer polymer is adsorbed on the negatively charged surface of the NRs, which results in high dispersion stability. Emission spectra of the modified NRs indicated that there was no interference of the Quat-primer polymer with the fluorescence behavior. PMID:21721577

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Synthesis and enhanced light absorption of alumina matrix nanocomposites containing multilayer oxide nanorods and silver nanoparticles

    SciTech Connect

    Gan, Yong X.; Zeng, Xianwu; Su, Lusheng; Yang, Lu; Gan, Bo J.; Zhang, Lihua

    2011-11-15

    Highlights: {yields} Multilayer oxide nanorods (nanocables) were obtained via chemical processing. {yields} Ag nanoparticles were deposited between the core and shell layers of the nanorods. {yields} The structure and composition of the nanorods were analyzed by SEM and TEM. {yields} CoO nanorods and Ag nanoparticles enhance light absorption of the nanocomposites. -- Abstract: In this paper, multilayer oxide nanorods were deposited in the nanopores of anodic aluminum oxide (AAO) via solution infiltration followed by heat treatment. The nanorods have a core-shell structure. First, the shell (nanotube) with the thickness of about 40 nm was made of TiO{sub 2} through the hydrolysis of (NH{sub 4}){sub 2}TiF{sub 6}. Second, silver nanoparticles with the diameter of about 3 nm were added into the TiO{sub 2} layer through thermal decomposition of AgNO{sub 3} at elevated temperatures. Then, cylindrical cores (nanorods) of CoO and ZnO with 200 nm diameter were prepared, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and composition of the nanorods. UV-vis light absorption measurements in the wavelength range from 350 to 1000 nm were performed to study the effect of nanorod and nanoparticle addition on the light absorption property of the alumina nanocomposites. It is found that CoO nanorods increase the light absorption of the alumina matrix composite in the wavelength range from 500 nm to 800 nm, but the TiO{sub 2} shell does not increase the light absorption much. The ZnO nanorods do not change the light absorption either. However, the addition of silver nanoparticles significantly enhances light absorption of both AAO/TiO{sub 2}/Ag/CoO and AAO/TiO{sub 2}/Ag/ZnO nanocomposites. This increase in the visible light absorption reveals that there exists surface plasmon around the fine silver nanoparticles in the nanorods.

  14. Zinc Oxide Nanorod Based Ultraviolet Detectors with Wheatstone Bridge Design

    NASA Astrophysics Data System (ADS)

    Vasudevan, Arun

    This research work, for the first time, investigated metal semiconductor-metal (MSM) zine oxide (ZnO) nanorod based ultra-violet (UV) detectors having a Wheatstone bridge design with a high responsivity at room temperature and above, as well as a responsivity that was largely independent of the change in ambient conditions. The ZnO nanorods which acted as the sensing element of the detector were grown by a chemical growth technique. Studies were conducted to determine the effects on ZnO nanorod properties by varying the concentration of the chemicals used for the rod growth. These studies showed how the rod diameter and the deposition of ZnO nanorods from the solution was controlled by varying the concentration of the chemicals used for the rod growth. Conventional MSM UV detectors were fabricated with ZnO nanorods grown under optimized conditions to determine the dependence of UV response on electrode dimension and rod dimension. These studies gave insights into the dependence of UV response on the width of the electrode, spacing between the electrodes, density of the rod growth, and length and diameter of the rods. The UV responsivity was affected by varying the number of times the seed layer was spin coated, by varying the spin speed of seed layer coating and by varying the annealing temperature of the seed and rod. Based on these studies, optimum conditions for the fabrication of Wheatstone bridge UV ZnO nanorod detectors were determined. The Wheatstone bridge ZnO nanorod UV detectors were fabricated in three different configurations, namely, symmetric, asymmetric, and quasi-symmetric. The transient responses of the symmetric, asymmetric and quasi-symmetric configurations at room temperature and above showed how the response stability differed. At high temperature the responsivity of quasi-symmetric Wheatstone bridge detector configuration did not drop after saturation and the responsivity drifted by 17% to 25% from the room temperature response

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln2(phen)2(SO4)3(H2O)2]n (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]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, SO4 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.

  16. 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.

  17. Solid-liquid separation of oxidized americium from fission product lanthanides

    NASA Astrophysics Data System (ADS)

    Shehee, T. C.; Martin, L. R.; Nash, K. L.

    2010-03-01

    The separation of americium from the lanthanides and curium is a requirement if transmutation of americium is to be performed in advanced nuclear fuel cycles. Oxidation of Am3+ to AmO2+ or AmO22+ may allow separation of Am from Ln and Cm in one step, since the lanthanides and curium do not have higher oxidation states as accessible. Two possible solid-liquid separation methods have been developed to address this difficult separation. Under acidic conditions using oxone or persulfate, the oxidation and retention of tracer Am in the aqueous phase has been observed with a separation factor of 11 ± 1. Most of these studies have been conducted using 237NpO2(NO3), 233UO2(NO3)2, 238Pu(NO3)4 and 241Am(NO3)3 at radiotracer concentrations. Lanthanides precipitate as the sodium or potassium europium double sulfate salt. Under basic conditions, ozone oxidation of Am(CO3)OH(s) solubilizes Am from a lanthanide carbonate hydroxide solid phase to the aqueous phase as the AmO2(CO3)34-or AmO2(CO3)35- species. For the ozone oxidation of the americium tracer a separation factor of 1.6 ± 0.8 and 47 ± 2 for the oxidation/separation in Na2CO3 and NaHCO3 respectively.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Photochemical Oxidative Growth of Iridium Oxide Nanoparticles on CdSe@CdS Nanorods.

    PubMed

    Kalisman, Philip; Nakibli, Yifat; Amirav, Lilac

    2016-01-01

    We demonstrate a procedure for the photochemical oxidative growth of iridium oxide catalysts on the surface of seeded cadmium selenide-cadmium sulfide (CdSe@CdS) nanorod photocatalysts. Seeded rods are grown using a colloidal hot-injection method and then moved to an aqueous medium by ligand exchange. CdSe@CdS nanorods, an iridium precursor and other salts are mixed and illuminated. The deposition process is initiated by absorption of photons by the semiconductor particle, which results with formation of charge carriers that are used to promote redox reactions. To insure photochemical oxidative growth we used an electron scavenger. The photogenerated holes oxidize the iridium precursor, apparently in a mediated oxidative pathway. This results in the growth of high quality crystalline iridium oxide particles, ranging from 0.5 nm to about 3 nm, along the surface of the rod. Iridium oxide grown on CdSe@CdS heterostructures was studied by a variety of characterization methods, in order to evaluate its characteristics and quality. We explored means for control over particle size, crystallinity, deposition location on the CdS rod, and composition. Illumination time and excitation wavelength were found to be key parameters for such control. The influence of different growth conditions and the characterization of these heterostructures are described alongside a detailed description of their synthesis. Of significance is the fact that the addition of iridium oxide afforded the rods astounding photochemical stability under prolonged illumination in pure water (alleviating the requirement for hole scavengers). PMID:26891234

  3. 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.

  4. 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.

  5. '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

  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. 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.

  8. Lanthanide, thorium, and uranium oxide clusters formed by DLV/FTICR

    SciTech Connect

    Pires de Matos, A.; Marcalo, J.; Leal, J.P.

    1995-12-31

    In this work the formation of clusters of all the lanthanides (except promethium), thorium and uranium by direct laser vaporization (DLV) of surface oxidized metallic targets in a vacuum of about 2 x 10{sup -8} Torr. The cluster ions were obtained using a Nd:YAG laser pulse (ca. 30 mJ at the fundamental 1064 nm wavelength) and the ions were stored in the trap of an Extrel (Waters) FTMS 2001-DT Fourier transform ion cyclotron resonance (FTICR) spectrometer.

  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. Morphological and electrochemical properties of crystalline praseodymium oxide nanorods.

    PubMed

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

    2010-01-01

    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. PMID:20672103

  11. Synthesis and Structural Characterization of Orthorhombic Vanadium Oxide Nanorods

    NASA Astrophysics Data System (ADS)

    Garcia, L. M.; Chavira, E.; Santiago-Jacinto, P.; Rendon, L.; Marinero, E. E.; Tejada, A.; Fregoso-Israel, E.; Flores, C.

    2012-02-01

    Nanorod structures for Li storage are of interest for rechargeable battery applications. Vanadium pentoxide is a promising battery cathode material and in this work we report on the synthesis of V2O5 orthorhombic single crystal and polycrystalline nanorods by the sol-gel polymerizing acryl amide method via ethylenediamine tetra acetic acid EDTA assisted hydrothermal process. In order to determine the thermodynamic stability of nanostructured polymorphs vanadates, heat treatments were performed from 450 C to 500 ^oC with annealing times ranging from 48 to 72 h. The morphologies and structures of the nanorods were characterized by XRD, SEM and HRTEM. Thermo Gravimetric Analysis (TGA) was employed to monitor reaction mass losses during the course of the synthesis. Nanorod diameters ranging from 50 to 150 nm were observed. The lengths and diameter of the rods depended on the conditions of the preparation, such as concentration, and reaction time.

  12. 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.

  13. Synthesis and Enhanced Light Absorption of Alumina Matrix Nanocomposites Containing Multilayer Oxide Nanorods and Silver Nanoparticles

    SciTech Connect

    Gan, Y.X.; Zhang, L.; Zeng, X.; Su, L.; Yang, L.; Gan, B.J.

    2011-11-01

    In this paper, multilayer oxide nanorods were deposited in the nanopores of anodic aluminum oxide (AAO) via solution infiltration followed by heat treatment. The nanorods have a core-shell structure. First, the shell (nanotube) with the thickness of about 40 nm was made of TiO{sub 2} through the hydrolysis of (NH{sub 4}){sub 2}TiF{sub 6}. Second, silver nanoparticles with the diameter of about 3 nm were added into the TiO{sub 2} layer through thermal decomposition of AgNO{sub 3} at elevated temperatures. Then, cylindrical cores (nanorods) of CoO and ZnO with 200 nm diameter were prepared, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the structure and composition of the nanorods. UV-vis light absorption measurements in the wavelength range from 350 to 1000 nm were performed to study the effect of nanorod and nanoparticle addition on the light absorption property of the alumina nanocomposites. It is found that CoO nanorods increase the light absorption of the alumina matrix composite in the wavelength range from 500 nm to 800 nm, but the TiO{sub 2} shell does not increase the light absorption much. The ZnO nanorods do not change the light absorption either. However, the addition of silver nanoparticles significantly enhances light absorption of both AAO/TiO{sub 2}/Ag/CoO and AAO/TiO{sub 2}/Ag/ZnO nanocomposites. This increase in the visible light absorption reveals that there exists surface plasmon around the fine silver nanoparticles in the nanorods.

  14. 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

  15. 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.

  16. Anti-Proliferative Effect of Copper Oxide Nanorods Against Human Cervical Carcinoma Cells.

    PubMed

    Pandurangan, Muthuraman; Nagajyothi, P C; Shim, Jaesool; Kim, Doo Hwan

    2016-09-01

    Metal oxide nanoparticles have been widely investigated for its use in the pharmacological field. The present study was aimed to investigate the cytotoxicity of copper oxide nanorods in human cervical carcinoma cells. The effect of copper oxide nanorods on cell viability was determined by sulforhodamine-B (SRB) assay. The fluorescence and confocal microscopy analyzes showed the cell rounding and nuclear fragmentation following exposure of copper oxide nanorods. Reactive oxygen species (ROS) was increased and could initiate membrane lipid peroxidation, which in turn regulate cytokinetic movements of cells. The messenger RNA (mRNA) expression of p53 and caspase 3 was increased, which further confirms the occurrence of apoptosis at the transcriptional level. Furthermore, caspase-3 enzyme activity was increased, which also confirms the occurrence of apoptosis in tumor cells at the translational level. Taking all our experimental results together, it may suggest that the copper oxide nanorods could be a potential anti-tumor agent to inhibit cancer cell proliferation. PMID:26811107

  17. 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.

  18. 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…

  19. Structural and optical properties of Nd3+ doped gadolinium oxide 1D nanorods

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    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:Gd2O3] 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.

  20. 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.

  1. 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

  2. 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. PMID:26883005

  3. Synthesis and characterization of hydrothermally grown zinc oxide (ZnO) nanorods for optical waveguide application

    NASA Astrophysics Data System (ADS)

    Pandey, Chandan A.; Rahim, Rafis; Manjunath, S.; Hornyak, Gabor L.; Mohammed, Waleed S.

    2015-07-01

    We report a simple method to synthesize Zinc oxide nanorods, grown without using catalysis with less complicity. This was done by hydrothermal treatment of zinc nitrate and hexamine at 90°C and various times (5- 20h) and also we find that the nanorod size and shape depends on heating rate, temperature and heating time. ZnO nanorods have been investigated for their light guiding ability and their effective index of refraction for use in near air index optical systems by developing a ridge waveguide structure. ZnO nanorod waveguides (100 μm w x 2.5 μm h x 1mm l) were grown on a seeded glass substrate template using hydrothermal process at 90°C. Modification of the substrate surface in order to obtain dense perpendicularly-oriented ordered nanorods induced selective growth. These structures were characterized by SEM, EDX, and XRD. The guiding property, i.e. locally excited photoluminescence propagation along the length of the waveguide, was analyzed with imageprocessing program in MATLAB. Following application of a fiber optic white light source on the ZnO nanostructure, we found that light propagation occurred within the glass substrate. No such propagation occurred if light was applied on uncoated areas of the glass. Modeling of waveguide behavior to determine the number propagating modes was exercised using waveguide mode solver in COMSOL.

  4. 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.

  5. Influence of growth ambient on the surface and structural properties of vanadium oxide nanorods

    NASA Astrophysics Data System (ADS)

    Tien, Li-Chia; Chen, Yu-Jyun

    2013-06-01

    The influence of growth ambient on the surface and structural properties of vanadium oxide nanorods have been studied by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy (RS). The vanadium oxide nanorods, which were synthesized through an ambient controlled vapor transport process, exhibit different surface electronic properties depending upon the growth ambient. The Raman data indicates that the as-grown samples are orthorhombic V2O5 phase with a small variation of stoichiometry. Under highly oxidative conditions, nearly stoichiometry sample can be grown. If the samples were grown under less oxidizing conditions, an increase of structural disorder was observed. The observed V 2p core level spectra of both samples showed a single peak with chemical shifts corresponding to the V5+ and V4+. XPS results suggested that the highly oxidized vanadium ions (V5+) are gradually reduced to lower oxidation state (V4+) with the decreases of ambient oxygen levels during growth. The results clearly show that surface non-stoichiometry may be correlated with structural disorder of V2O5 nanorods. The growth ambient and post-annealing may influence the vanadium oxidation state and subsequent surface reactivity significantly.

  6. 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.

  7. 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.

  8. Thermolysis of lanthanide dithiocarbamate complexes

    SciTech Connect

    Boncher, William L.; Regulacio, Michelle D.; Stoll, Sarah L.

    2010-01-15

    Polycrystalline lanthanide sulfide materials were formed at low temperatures using a single-source precursor based on the lanthanide dithiocarbamate complex. The synthesis temperatures are generally lower than standard solid state preparations, avoid toxic sulfurizing gases and provide a convenient route to prepare lanthanide chalcogenide nanoparticles. Depending on the reaction conditions and oxophilicity of the lanthanide, the sulfide material was formed with oxidized products including oxysulfides, oxysulfates and the oxide. - Graphical abstract: Polycrystalline lanthanide sulfide materials were formed at low temperatures using a single-source precursor based on the lanthanide dithiocarbamate complex.

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

    PubMed

    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; Le Si Dang, D

    2009-08-19

    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

  10. Low-temperature oxidation of CO catalysed by Co(3)O(4) nanorods.

    PubMed

    Xie, Xiaowei; Li, Yong; Liu, Zhi-Quan; Haruta, Masatake; Shen, Wenjie

    2009-04-01

    Low-temperature oxidation of CO, perhaps the most extensively studied reaction in the history of heterogeneous catalysis, is becoming increasingly important in the context of cleaning air and lowering automotive emissions. Hopcalite catalysts (mixtures of manganese and copper oxides) were originally developed for purifying air in submarines, but they are not especially active at ambient temperatures and are also deactivated by the presence of moisture. Noble metal catalysts, on the other hand, are water tolerant but usually require temperatures above 100 degrees C for efficient operation. Gold exhibits high activity at low temperatures and superior stability under moisture, but only when deposited in nanoparticulate form on base transition-metal oxides. The development of active and stable catalysts without noble metals for low-temperature CO oxidation under an ambient atmosphere remains a significant challenge. Here we report that tricobalt tetraoxide nanorods not only catalyse CO oxidation at temperatures as low as -77 degrees C but also remain stable in a moist stream of normal feed gas. High-resolution transmission electron microscopy demonstrates that the Co(3)O(4) nanorods predominantly expose their {110} planes, favouring the presence of active Co(3+) species at the surface. Kinetic analyses reveal that the turnover frequency associated with individual Co(3+) sites on the nanorods is similar to that of the conventional nanoparticles of this material, indicating that the significantly higher reaction rate that we have obtained with a nanorod morphology is probably due to the surface richness of active Co(3+) sites. These results show the importance of morphology control in the preparation of base transition-metal oxides as highly efficient oxidation catalysts. PMID:19360084

  11. 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

  12. Tailoring copper oxide semiconductor nanorod arrays for photoelectrochemical reduction of carbon dioxide to methanol.

    PubMed

    Rajeshwar, Krishnan; de Tacconi, Norma R; Ghadimkhani, Ghazaleh; Chanmanee, Wilaiwan; Janáky, Csaba

    2013-07-22

    Solar photoelectrochemical reduction of carbon dioxide to methanol in aqueous media was driven on hybrid CuO/Cu2O semiconductor nanorod arrays for the first time. A two-step synthesis was designed and demonstrated for the preparation of these hybrid copper oxide one-dimensional nanostructures on copper substrates. The first step consisted in the growth of CuO nanorods by thermal oxidation of a copper foil at 400 °C. In the second step, controlled electrodeposition of p-type Cu2O crystallites on the CuO walls was performed. The resulting nanorod morphology with controllable wall thickness by adjusting the Cu2O electrodeposition time as well as their surface/bulk chemical composition were probed by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. Photoelectrosynthesis of methanol from carbon dioxide was demonstrated at -0.2 V vs SHE under simulated AM1.5 solar irradiation on optimized hybrid CuO/Cu2O nanorod electrodes and without assistance of any homogeneous catalyst (such as pyridine or imidazole) in the electrolyte. The hybrid composition, ensuring double pathway for photoelectron injection to CO2, along with high surface area were found to be crucial for efficient performance in methanol generation under solar illumination. Methanol formation, tracked by gas chromatography/mass spectrometry, indicated Faradaic efficiencies of ~95%. PMID:23712877

  13. 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.

  14. 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.

  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. Strong metal-support interactions between gold nanoparticles and ZnO nanorods in CO oxidation.

    PubMed

    Liu, Xiaoyan; Liu, Ming-Han; Luo, Yi-Chia; Mou, Chung-Yuan; Lin, Shawn D; Cheng, Hongkui; Chen, Jin-Ming; Lee, Jyh-Fu; Lin, Tien-Sung

    2012-06-20

    The catalytic performances of supported gold nanoparticles depend critically on the nature of support. Here, we report the first evidence of strong metal-support interactions (SMSI) between gold nanoparticles and ZnO nanorods based on results of structural and spectroscopic characterization. The catalyst shows encapsulation of gold nanoparticles by ZnO and the electron transfer between gold and the support. Detailed characterizations of the interaction between Au nanoparticles and ZnO were done with transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR), and FTIR study of adsorbed CO. The significance of the SMSI effect is further investigated by probing the efficiency of CO oxidation over the Au/ZnO-nanorod. In contrast to the classical reductive SMSI in the TiO(2) supported group VIII metals which appears after high temperature reduction in H(2) with electron transfer from the support to metals, the oxidative SMSI in Au/ZnO-nanorod system gives oxygen-induced burial and electron transfer from gold to support. In CO oxidation, we found that the oxidative SMSI state is associated with positively charged gold nanoparticles with strong effect on its catalytic activity before and after encapsulation. The oxidative SMSI can be reversed by hydrogen treatment to induce AuZn alloy formation, de-encapsulation, and electron transfer from support to Au. Our discovery of the SMSI effects in Au/ZnO nanorods gives new understandings of the interaction between gold and support and provides new way to control the interaction between gold and the support as well as catalytic activity. PMID:22612449

  17. Development of Resistance-Based pH Sensor Using Zinc Oxide Nanorods.

    PubMed

    Copal, Vernalyn C; Tuico, Anthony R; Mendoza, Jamie P; Ferrolino, John Paul R; Vergara, Christopher Jude T; Salvador, Arnel A; Estacio, Elmer S; Somintac, Armando S

    2016-06-01

    The resistance-based pH sensing capability of ZnO nanorods was presented in this study. Interdigitated finger structures of nickel/gold (Ni/Au) electrodes were fabricated on the substrates prior to the sensing material. The effect of varying electrode widths was also considered. Zinc oxide (ZnO) film, as seed layer, was deposited via spray pyrolysis, and zinc oxide nanorods (ZnO-NRs) were grown via low temperature chemical bath deposition. Resistance measurements have shown plausible difference in varying pH of a test solution. The sensor was found reasonably more appreciable in sensing acidic solutions. The electrode widths were also found to relay substantial consequence in the resistance-based sensor. The least electrode-width design has shown a significant increase in the sensitivity of the sensor, with higher initial resistance and greater range of response. PMID:27427677

  18. Methanol and methane formation over palladium dispersed on the lanthanide rare earth oxides

    SciTech Connect

    Vannice, M.A.; Sudhakar, C.; Freeman, M.

    1987-11-01

    To complete their study of the effect of the rare earth oxide (REO) support on the CO hydrogenation reaction over Pd, this metal was dispersed on the oxides of the late lanthanide elements - Tb through Lu. The Pd surface area was measured before and after kinetic runs at 0.1 MPa (1 atm) and 1.5 MPa with these Pd/REO catalysts. Methanation activation energies were 30.4 +/- 1.1 kcal/mole. The turnover frequency (TOF) at 548 K for methane ranged from 1.2 x 10/sup -3/ to 4.8 x 10/sup -3/ s/sup -1/, which is up to 40 times that on Pd powder. The average activation energy for methanol synthesis was 19.6 +/- 0.8 kcal/mole, and TOFs varied from 1.6 x 10/sup -3/ to 6.1 x 10/sup -3/ s/sup -1/. When these results are combined, the patterns for methanation at 0.1 MPa and CH/sub 3/OH synthesis at 1.5 MPa are established as a function of the position of the REO in the periodic table. There is a clear influence of the support on catalytic properties. No trend occurs between methanation activity and the acidity of the support, but a correlation exists between the CH/sub 4/ TOF and the activation energy for electrical conductivity. The TOF for CH/sub 3/OH synthesis shows a strong correlation with the basicity of the REO, which varies with the lanthanide contraction. This behavior also indicated that the support participates directly in the reaction sequence, and this trend strongly supports a mechanism involving formate species on the REO surface, which are formed most readily on the most basic oxides, such as La/sub 2/O/sub 3/. The possibility of a heterogeneous analog of the Cannizzaro reaction is pointed out, and this route may also influence methanol formation.

  19. 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.

  20. Contributions of surface topography and cytotoxicity to the macrophage response to zinc oxide nanorods.

    PubMed

    Zaveri, Toral D; Dolgova, Natalia V; Chu, Byung Hwan; Lee, Jiyeon; Wong, Joey; Lele, Tanmay P; Ren, Fan; Keselowsky, Benjamin G

    2010-04-01

    Macrophages associated with implanted biomaterials are primary mediators of chronic inflammation and foreign body reaction to the implant. Hence, various approaches have been investigated to modulate macrophage interactions with biomaterial surfaces to mitigate inflammatory responses. Nanostructured materials possess unique surface properties, and nanotopography has been reported to modulate cell adhesion and viability in a cell type-dependent manner. Zinc oxide (ZnO) has been investigated in a number of biomedical applications and surfaces presenting well-controlled nanorod structures of ZnO have recently been developed. In order to investigate the influence of nanotopography on macrophage adhesive response, we evaluated macrophage adhesion and viability on ZnO nanorods, compared to a relatively flat sputtered ZnO controls and using glass substrates for reference. We found that although macrophages are capable of initially adhering to and spreading on ZnO nanorod substrates, the number of adherent macrophages on ZnO nanorods was reduced compared to ZnO flat substrate and glass. Additionally adherent macrophage number on ZnO flat substrate was reduced as compared to glass. While these data suggest nanotopography may modulate macrophage adhesion, reduced cell viability on both sputtered and nanorod ZnO substrate indicates appreciable toxicity associated with ZnO. Cell death was apparently not apoptotic, given the lack of activated caspase-3 immunostaining. A decrease in viable macrophage numbers when ZnO substrates were present in the same media verified the role of ZnO substrate dissolution, and dissolved levels of Zn in culture media were quantified. In order to determine long-term physiological responses, ZnO nanorod-coated and sputtered ZnO-coated polyethylene terephthalate (PET) discs were implanted subcutaneously in mice for 14 d. Upon implantation, both ZnO-coated discs resulted in a discontinuous cellular fibrous capsule indicative of unresolved inflammation

  1. 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

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

    PubMed

    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

  3. 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

  4. 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.

  5. Cold-bonding in sub-10 nm indium tin oxide nanorods

    NASA Astrophysics Data System (ADS)

    Neng, Wan; Tao, Lin; Jun, Xu

    2016-04-01

    Cold-bonding in a typical metal oxide material nanostructure, indium tin oxide nanorods (ITONs), was observed and studied by combining precise in situ nano-manipulation, transmission electron microscopy (TEM) observation and on-line electrical properties measurements. Our studies revealed an oriented attachment process caused by enhanced atom mobility or diffusion and rearrangement at the contact, which worked efficiently in reconnecting the ITONs. Electrical measurements exhibited low contact resistance between the re-connectable ITON segments. Our observations indicate that small-sized nanostructures could be cold-bonded easily following a similar mechanism with their electrical properties retained.

  6. Cold-bonding in sub-10 nm indium tin oxide nanorods.

    PubMed

    Neng, Wan; Tao, Lin; Jun, Xu

    2016-04-22

    Cold-bonding in a typical metal oxide material nanostructure, indium tin oxide nanorods (ITONs), was observed and studied by combining precise in situ nano-manipulation, transmission electron microscopy (TEM) observation and on-line electrical properties measurements. Our studies revealed an oriented attachment process caused by enhanced atom mobility or diffusion and rearrangement at the contact, which worked efficiently in reconnecting the ITONs. Electrical measurements exhibited low contact resistance between the re-connectable ITON segments. Our observations indicate that small-sized nanostructures could be cold-bonded easily following a similar mechanism with their electrical properties retained. PMID:26939723

  7. 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

  8. 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.

  9. 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.

  10. Characterization of Gold-Sputtered Zinc Oxide Nanorods-a Potential Hybrid Material.

    PubMed

    Perumal, Veeradasan; Hashim, Uda; Gopinath, Subash C B; Rajintra Prasad, Haarindraprasad; Wei-Wen, Liu; Balakrishnan, S R; Vijayakumar, Thivina; Rahim, Ruslinda Abdul

    2016-12-01

    Generation of hybrid nanostructures has been attested as a promising approach to develop high-performance sensing substrates. Herein, hybrid zinc oxide (ZnO) nanorod dopants with different gold (Au) thicknesses were grown on silicon wafer and studied for their impact on physical, optical and electrical characteristics. Structural patterns displayed that ZnO crystal lattice is in preferred c-axis orientation and proved the higher purities. Observations under field emission scanning electron microscopy revealed the coverage of ZnO nanorods by Au-spots having diameters in the average ranges of 5-10 nm, as determined under transmission electron microscopy. Impedance spectroscopic analysis of Au-sputtered ZnO nanorods was carried out in the frequency range of 1 to 100 MHz with applied AC amplitude of 1 V RMS. The obtained results showed significant changes in the electrical properties (conductance and dielectric constant) with nanostructures. A clear demonstration with 30-nm thickness of Au-sputtering was apparent to be ideal for downstream applications, due to the lowest variation in resistance value of grain boundary, which has dynamic and superior characteristics. PMID:26787050

  11. One pot synthesis of opposing 'rose petal' and 'lotus leaf' superhydrophobic materials with zinc oxide nanorods.

    PubMed

    Myint, Myo Tay Zar; Hornyak, Gabor L; Dutta, Joydeep

    2014-02-01

    The synthesis in one pot(1) of opposing 'rose petal' and 'lotus leaf' superhydrophobic materials from commercially available superhydrophilic cloth substrates of varying texture is described for the first time. Surfaces of 'rough' textured cloth and 'smooth' textured cloth were simultaneously rendered superhydrophobic by growing zinc oxide (ZnO) nanorods by a hydrothermal process in the same chemical bath. Contact angle hysteresis and water pendant drop tests revealed strong water adhesion to ZnO microrod-treated rough cloth. The combination of water contact angle >150° and strong adhesion is indicative of the 'rose petal effect' with potential for water pinning. Smooth cloth with ZnO nanorods exhibited no adhesion to water droplets with facilitative roll-off. The combination of water contact angle >150° and weak to no adhesion with water is indicative of the 'lotus leaf effect' with potential for self-cleaning. Pendant water drop tests indicated cohesive failure of water on rough cloth coated with ZnO nanorods. Natural rose petals demonstrated adhesive failure between the petal surface and water droplet. A parsimonious explanation is presented. We also describe the development of superhydrophobic clothes without the need for special conditions or further chemical modification. PMID:24267327

  12. 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.

  13. 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

  14. Gas-phase generation of noble metal-tipped NiO nanorods by rapid thermal oxidation

    NASA Astrophysics Data System (ADS)

    Koga, Kenji; Hirasawa, Makoto

    2014-12-01

    The thermal oxidation of alloy nanoparticles (NPs) composed of nickel and a noble metal was investigated by high-resolution electron microscopic observations of the NPs oxidized in a gas phase under different oxidation conditions. When Ni0.8Au0.2 NPs were heated with oxygen from room temperature, oxidation progressed to form Au-NiO core-shell structures, however, the Au core spilled out by breaking the NiO shell at high temperatures. In contrast, when the alloy NPs were subjected to rapid thermal oxidation, which was enabled by heating the NPs at high temperatures (≥500 °C) and then abruptly exposed to oxygen, oxidation advanced anisotropically such that a NiO island protruded and built up to form a NiO nanorod. This resulted in the formation of Au-tipped NiO nanorods in which a hemispherical Au tip bonded to a NiO nanorod via a Au {111}/NiO{100} interface. We found that the relative sizes of Au and NiO in Au-tipped NiO nanorods were easily and widely controlled by changing the Au mole fraction (0.05-0.8) of the alloy NPs. Similarly, rapid thermal oxidation of Ni-Pt NPs generated Pt-tipped NiO nanorods in which a spherical Pt tip was half-embedded in a NiO nanorod. The present gas-phase approach has great potential for fabricating functional asymmetric hybrid nanostructures in clean conditions.

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. Hydroxyl-containing antimony oxide bromide nanorods combined with chitosan for biosensors.

    PubMed

    Lu, Xianbo; Wen, Zhenhai; Li, Jinghong

    2006-11-01

    A hydroxyl-containing antimony oxide bromide (AOB) nanorods was synthesized by a hydrothermal method. TEM and SEM images showed that the as-prepared AOB nanorods were very copious with diameters of about 50 nm. The AOB nanorods could be easily combined with biopolymer chitosan (Chi) to form an organic-inorganic hybrid material, and a biocompatible, crack-free and porous Chi-AOB composite film could be readily obtained. Horseradish peroxidase (HRP) was chosen as a model protein to construct a reagentless mediator-free third-generation HRP biosensor. UV-visible and FTIR spectroscopy revealed that HRP entrapped in the composite film could retain its native secondary structure. A pair of stable and well-defined redox peaks of HRP with a formal potential of about -0.24 V (vs. Ag/AgCl) in a pH 7.0 phosphate-buffered solution (PBS) were obtained at the HRP-Chi-AOB composite film modified glassy carbon (GC) electrode. With advantages of organic-inorganic hybrid materials, dramatically facilitated direct electron transfer of HRP and excellent bioelectrocatalytic activity towards H(2)O(2) were demonstrated. The apparent Michaelis-Menten constant K(M)(app) was calculated to be 7.5mum, indicating that HRP entrapped in the composite film possessed high affinity to H(2)O(2) and exhibited high enzymatic activity. The prepared biosensor displayed good sensitivity and reproducibility, wide linear range, low detection limit, fast response and excellent long-term stability. The Chi-AOB composite film could be used efficiently for the entrapment of other redox-active proteins and may find wide potential applications in biosensors, biocatalysis, biomedical devices and bioelectronics. PMID:16901539

  4. Segmented Pt/Ru, Pt/Ni, and Pt/RuNi nanorods as model bifunctional catalysts for methanol oxidation.

    PubMed

    Liu, Fang; Lee, Jim Yang; Zhou, Wei Jiang

    2006-01-01

    Five-segment (Pt-Ru-Pt-Ru-Pt, Pt-Ni-Pt-Ni-Pt, and Pt-RuNi-Pt-RuNi-Pt) nanorods with the same overall rod length and the same total Pt segment length were prepared by sequential electrodeposition of the metals into the pores of commercially available anodic aluminum oxide (AAO) membranes. Field-emission scanning electron microscopy (FESEM) showed that the nanorods were about 210 nm in diameter and about 1.5 microm in length. The alternating Pt and oxophilic metal(s) segments could be easily differentiated in backscattered-electron images. X-ray diffraction (XRD) analysis of the nanorods indicated that Pt and Ni were polycrystalline with fcc structures, Ru was hcp, and the co-deposited RuNi adopted the nickel fcc structure with some negative shifts in the Bragg angles. The chemical states of Pt, Ru, and Ni on the nanorod surface were assayed by X-ray photoelectron spectroscopy (XPS), and the presence of Pt(0), Pt(II), Pt(IV), Ru(0), Ru(VI), Ni(0), and Ni(II) was observed. The nanorods were catalytically active for the room-temperature electrooxidation of methanol in acidic solutions. The relative rates of reaction showed the Pt-RuNi pair sites as having the lowest overpotential to dissociate water, the highest catalytic activity in methanol oxidation, and the strongest CO-tolerance in the potential window employed. The use of segmented nanorods with identifiable Pt-oxophilic metal(s) interfaces removes many of the ambiguities in the interpretation of experimental data from conventional alloy catalysts, thereby enabling a direct comparison of the activities of various types of pair sites in methanol oxidation. PMID:17193567

  5. 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.

  6. Study of transport properties of copper/zinc-oxide-nanorods-based Schottky diode fabricated on textile fabric

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    In this work, a copper/zinc-oxide (ZnO)-nanorods-based Schottky diode was fabricated on the textile fabric substrate. ZnO nanorods were grown on a silver-coated textile fabric substrate by using the hydrothermal route. Scanning electron microscopy and x-ray diffraction techniques were used for the structural study. The electrical characterization of copper/ZnO-nanorods-based Schottky diodes was investigated by using a semiconductor parameter analyzer and an impedance spectrometer. The current density-voltage (J-V) and capacitance-voltage (C-V) measurements were used to estimate the electrical parameters. The threshold voltage (Vth), ideality factor (η), barrier height (ϕb), reverse saturation current density (Js), carrier concentration (ND) and built-in potential (Vbi) were determined by using experimental data and (simulated) curve fitting. This study describes the possible fabrication of electronic and optoelectronic devices on textile fabric substrate with an acceptable performance.

  7. Characterization of single transition metal oxide nanorods by combining atomic force microscopy and polarized micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Najjar, Samar; Talaga, David; Coffinier, Yannick; Szunerits, Sabine; Boukherroub, Rabah; Servant, Laurent; Couzi, Michel; Bonhommeau, Sébastien

    2011-09-01

    Accurate chemical and structural characterization of free-standing zinc oxide (ZnO) and hematite (α-Fe2O3) nanorods has been carried out using an AFM/Raman correlative technique under polarized light. ZnO nanorods are found to be wurtzite-type single crystalline objects homogeneous in composition and grown along their principal axis of symmetry. Hematite specimens are rhombohedral corundum-type single crystals grown along a direction orthogonal to their principal axis of symmetry and exhibiting structural disorder. Certain hematite nanorods turn out to be very sensitive to laser heating. These studies reveal the high potential of the coupled AFM/Raman technique to examine the properties of these promising nanomaterials.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Optical and structural properties of zinc oxide nanorod synthesized by sol-gel method

    NASA Astrophysics Data System (ADS)

    Iskandar, Mochamad Riza; Saepuloh, Enang; Safriani, Lusi; Bahtiar, Ayi

    2013-09-01

    Zinc Oxide (ZnO) nanocrystal has been intensively studied not only for its fundamental scientific interest, but also for its potential in many optoelectronic applications, such as electroluminescence devices, chemical sensors, electrochromic windows and solar cells. Recently, ZnO nanocrystal has been used as electron acceptor materials for high power conversion efficiency hybrid solar cells due to good combination of its wide bandgap (3.37 eV), large exciton binding energy (60 meV), high charge carrier mobility, mechanical and thermal stability. The synthesis of monodisperse ZnO is an important key for achieving high performance of hybrid solar cells, because the properties of its nanocrystals strongly depend on its size and shape. We have successfully synthesized ZnO nanorod with 5 nm diameter and 11-13 nm in length by using sol-gel method as confirmed by TEM measurement. The ZnO nanorod has optical bandgap 3.38 eV and wurzite crystal structure.

  13. 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.

  14. 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. PMID:26100433

  15. 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

  16. 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.

  17. 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.

  18. 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

  19. Thermochromic VO{sub 2} nanorods and other vanadium oxides nanostructures

    SciTech Connect

    Kam, Kinson C.; Cheetham, Anthony K. . E-mail: cheetham@mrl.ucsb.edu

    2006-05-25

    Thermochromic VO{sub 2} nanorods were prepared via thermal conversion of the metastable VO{sub 2}-B phase synthesized by hydrothermal methods. We observe an increased thermochromic transition temperature to {approx}75-80 deg. C by variable-temperature infrared spectroscopy. Nano- and sub-micron structures of other vanadium oxides (V{sub 3}O{sub 7} (NH{sub 4}){sub 0.5}V{sub 2}O{sub 5}, and V{sub 2}O{sub 5}) were obtained simply by varying the starting materials in the hydrothermal synthesis. We also obtained nanostructures of the high temperature tetragonal rutile phase of VO{sub 2} by thermolysis of single-source vanadium (IV) precursors.

  20. 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

  1. 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.

  2. Cobalt oxide acicular nanorods with high sensitivity for the non-enzymatic detection of glucose.

    PubMed

    Kung, Chung-Wei; Lin, Chia-Yu; Lai, Yi-Hsuan; Vittal, R; Ho, Kuo-Chuan

    2011-09-15

    Acicular cobalt oxide nanorods (CoONRs) were prepared for the non-enzymatic detection of glucose, first by directly growing layered cobalt carbonate hydroxide (LCCH) on a conducting fluorine-doped tin oxide (FTO) substrate using a simple chemical bath deposition (CBD) technique and then by transforming the LCCH into CoONRs through pyrolysis. The composition and grain size of the films of LCCH and CoONRs were verified by X-ray diffraction (XRD); their morphologies were examined by scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images. CoONRs showed high electrocatalytic activity for the electro-oxidation of glucose in alkaline media, and the activity was strongly influenced by NaOH concentration, annealing temperature of CoONRs, and thickness of CoONRs film. The pertinent sensor could be successfully used for the quantification of glucose by amperometric method. The sensing parameters include wide linear range up to 3.5 mM, a high sensitivity of 571.8 μA/(cm(2) mM), and a remarkable low detection limit of 0.058 μM. The CoONRs modified electrode exhibited a high selectivity for glucose in human serum, against ascorbic acid, uric acid, and acetaminophen. PMID:21767942

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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.

  9. Electropolymerization of Uniform Polyaniline Nanorod Arrays on Conducting Oxides as Counter Electrodes in Dye-Sensitized Solar Cells.

    PubMed

    He, Ziming; Liu, Jing; Khoo, Si Yun; Tan, Timothy Thatt Yang

    2016-01-01

    Conventional techniques for the synthesis of oriented polyaniline (PANI) nanostructures are often complex or time consuming. Through an innovative reduced graphene oxide (rGO) modified FTO and a low-potential electropolymerization strategy, the rapid and template-free growth of a highly ordered PANI nanorod array on the FTO substrate is realized. The highly ordered nanostructure of the PANI array leads to a high electrocatalytic activity and chemical stability. The importance of the polymerization potential and rGO surface modification to achieve this nanostructure is revealed. Compared to platinum, the PANI nanorod array exhibits an enhanced performance and stability as counter electrodes in dye-sensitized solar cells, with a 17.6 % enhancement in power conversion efficiency. PMID:26732134

  10. Confocal laser scanning microscopy measurement of the morphology of vanadium pentoxide nanorods grown by electron beam irradiation or thermal oxidation

    NASA Astrophysics Data System (ADS)

    Kang, Manil; Hong, Donghyuk; Kim, Taesung; Chu, Minwoo; Kim, Sok Won

    2013-01-01

    In order to observe the morphology of nanostructures at the submicroscale, we use a confocal laser scanning (CLS) microscope built in our laboratory. The theoretical resolution of the hand-made CLS microscope is 150 nm and the performance of the microscope is evaluated by observing a USAF target. Vanadium pentoxide nanorods grown by electron beam irradiation and thermal oxidation methods are used as nanostructures and the morphologies of the nanorods observed by confocal laser scanning microscopy (CLSM) are compared with those obtained by scanning electron microscopy. The magnification and resolution of the CLSM were estimated to be approximately 1500 and 800 nm, respectively. From the results, we confirm that the CLSM can be used to measure nanostructures at the sub-micro-scale without a preconditioning process.

  11. 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

  12. Graphene-zinc oxide nanorods nanocomposite based sensor for voltammetric quantification of tizanidine in solubilized system

    NASA Astrophysics Data System (ADS)

    Jain, Rajeev; Dhanjai; Sinha, Ankita

    2016-04-01

    A new graphene/zinc oxide nanorods modified glassy carbon electrode (GR/ZnORs/GCE) based electrochemical sensor has been developed for the sensitive determination tizanidine (TZ) in solubilized system. The fabricated sensor was characterized by various electrochemical methods. Different kinetic parameters affecting the monitored electrocatalytic response were investigated and optimized for tizanidine determination at fabricated GR/ZnORs/GCE sensor and successfully compared with the results obtained at GR/SiO2/GCE, GR/GCE and at bare GCE. Under optimized conditions the square wave current is linear over the concentration range 0.80 ng mL-1 to 10.0 μg mL-1 with detection limit and quantification limit of 0.10 ng mL-1 and 3.45 ng mL-1 respectively. The applicability of proposed method is further extended to in vitro determination of the drug in pharmaceutical formulation with an acceptable recovery from 97.89% to 101.09%.

  13. 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.

  14. 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

  15. 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

  16. 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

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    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).

  18. 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.

  19. 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

  20. Preparation and characterization of bionanocomposite films filled with nanorod-rich zinc oxide.

    PubMed

    Nafchi, Abdorreza Mohammadi; Nassiri, Roghayeh; Sheibani, Samira; Ariffin, Fazilah; Karim, A A

    2013-07-01

    The effects of zinc oxide nanorods (ZnO-nr) incorporation on the physical, mechanical, heat sealability, barrier, thermal and antibacterial properties of sago starch and bovine gelatin bionanocomposites films were investigated. The ZnO was incorporated into the films at different concentrations (1-5%, w/w total solid). All films were plasticized with 40% (w/w of total solid) of a combination of sorbitol/glycerol at 3:1 ratio. Incorporation of 5% of ZnO-nr to starch and gelatin films decreased the permeability to oxygen by 40% and 55%, respectively. Moisture content and water absorption capacity of the films were decreased by increasing the ZnO-nr contents. Mechanical and heat seal properties of the films were increased more than 20%. The films exhibited UV absorption and displayed an excellent antimicrobial activity against the Escherichia coli. These properties suggest that bionanocomposites based on ZnO-nr have the potential as an active packaging material for food and pharmaceutical industries. PMID:23688475

  1. Sol–gel synthesized zinc oxide nanorods and their structural and optical investigation for optoelectronic application

    PubMed Central

    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). PMID:25221458

  2. Mixed-ligand chelate extraction of lanthanides with 1-phenyl-3-methyl-4-(trifluoroacetyl)-5-pyrazolone and some phosphine oxide compounds

    SciTech Connect

    Umetani, S.; Freiser, H.

    1987-09-23

    Mixed-ligand chelate extraction of lanthanides (Ln) such as La, Pr, Eu, Ho, and Yb into chloroform with 1-phenyl-3-methyl-4-(trifluoroacetyl)-5-pyrazolone (HPMTFP) and with one of three phosphine oxide compounds is studied. The phosphine oxide compounds employed in the present work are tri-n-octylphosphine oxide (TOPO), n-octylphenyl(N,N-diisobutylcarbamoylmethyl)phosphine oxide (CMPO), and methylenebis(diphenylphosphine oxide) (MBDPO). Lanthanide ions are found to be extracted from a 0.1 M sodium perchlorate medium as Ln(PMTFP)/sub 3/(TOPO)/sub 2/ and Ln(PMTFP)/sub 3/(CMPO), respectively. In the extraction of lanthanides with the mixture of HPMTFP and MBDPO, the extracted species are found to be Ln(PMTFP)/sub 3/(MBDPO) or Ln(PMTFP)/sub 2/(ClO/sub 4/)(MBDPO)/sub 2/ in the absence or presence of sodium perchlorate, respectively. The extraction constants of these systems do not increase monotonically with atomic number but have a maximum at Eu or Ho. 11 references, 4 tables.

  3. 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

  4. 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.

  5. 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

  6. Thermo and photoluminescence properties of Eu3+ activated hexagonal, monoclinic and cubic gadolinium oxide nanorods

    NASA Astrophysics Data System (ADS)

    Dhananjaya, N.; Nagabhushana, H.; Nagabhushana, B. M.; Rudraswamy, B.; Shivakumara, C.; Ramesh, K. P.; Chakradhar, R. P. S.

    2011-04-01

    Different phases of Eu3+ activated gadolinium oxide (Gd (OH)3, GdOOH and Gd2O3) nanorods have been prepared by the hydrothermal method with and without cityl trimethyl ammonium bromide (CTAB) surfactant. Cubic Gd2O3:Eu (8 mol%) red phosphor has been prepared by the dehydration of corresponding hydroxide Gd(OH)3:Eu after calcinations at 350 and 600 °C for 3 h, respectively. When Eu3+ ions were introduced into Gd(OH)3, lattice sites which replace the original Gd3+ ions, a strong red emission centered at 613 nm has been observed upon UV illumination, due to the intrinsic Eu3+ transition between 5D0 and 7F configurations. Thermoluminescence glow curves of Gd (OH)3: Eu and Gd2O3:Eu phosphors have been recorded by irradiating with gamma source (60CO) in the dose range 10-60 Gy at a heating rate of 6.7 °C sec-1. Well resolved glow peaks in the range 42-45, 67-76, 95-103 and 102-125 °C were observed. When γ-irradiation dose increased to 40 Gy, the glow peaks were reduced and with increase in γ-dose (50 and 60 Gy) results the shift in first two glow peak temperatures at about 20 °C and a new shouldered peak at 86 °C was observed. It is observed that there is a shift in glow peak temperatures and variation in intensity, which is mainly attributed to different phases of gadolinium oxide. The trapping parameters namely activation energy (E), order of kinetics (b) and frequency factor were calculated using peak shape and the results are discussed.

  7. 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

  8. 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.

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

    SciTech Connect

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

    2009-11-15

    We developed a facile synthetic route of porous cobalt oxide (Co{sub 3}O{sub 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{sub 2}O{sub 4} nanorods without destruction of the original morphology. The as-prepared Co{sub 3}O{sub 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 {mu}m. 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{sub 3}O{sub 4} nanorods was investigated. Moreover, the porous Co{sub 3}O{sub 4} nanorods exhibited high electrochemical performance when applied as cathode materials for lithium-ion batteries, which gives them good potential applications. - Graphical abstract: The porous Co{sub 3}O{sub 4} nanorods synthesized via a microemulsion-based method in combination with subsequent calcination were applied in the negative electrode materials for lithium-ion batteries and exhibited high electrochemical performance.

  10. Functionalized zinc oxide nanorod with ionophore-membrane coating as an intracellular Ca2+ selective sensor

    NASA Astrophysics Data System (ADS)

    Asif, M. H.; Fulati, A.; Nur, O.; Willander, M.; Brännmark, Cecilia; Strâlfors, Peter; Börjesson, Sara I.; Elinder, Fredrik

    2009-07-01

    The tip of a borosilicate glass capillary with functionalized hexagonal ZnO nanorods was used to make a sensitive electrochemical intracellular Ca2+ sensor. To adjust the sensor for Ca2+ measurements with sufficient selectivity and stability, polyvinylchloride membrane containing Ca2+ ionophores were coated on the surface. The membrane covered ZnO nanorods exhibited a Ca2+-dependent electrochemical potential difference versus an Ag/AgCl reference electrode. The potential difference was linear over a large concentration range (100 nM-10 mM). The measurements of Ca2+ concentrations using our ZnO nanorods sensor in human fat cells or in frog egg cells were consistent with values of Ca2+ concentrations reported in the literature. This nanoelectrode device paves the way to measurements of intracellular biochemical species in specific locations within single living cells.

  11. 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.

  12. 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.

  13. 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)

  14. 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)

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. 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. PMID:25958523

  20. 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

  1. 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. PMID:26741150

  2. 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.

  3. Photoelectrochemical characteristics of TiO2 nanorod arrays grown on fluorine doped tin oxide substrates by the facile seeding layer assisted hydrothermal method

    NASA Astrophysics Data System (ADS)

    Sui, Mei-rong; Han, Cui-ping; Gu, Xiu-quan; Wang, Yong; Tang, Lu; Tang, Hui

    2016-05-01

    TiO2 nanorod arrays (NRAs) were prepared on fluorine doped tin oxide (FTO) substrates by a facile two-step hydrothermal method. The nanorods were selectively grown on the FTO regions which were covered with TiO2 seeding layer. It took 5 h to obtain the compact arrays with the nanorod length of ~2 μm and diameter of ~50 nm. The photoelectrochemical (PEC) properties of TiO2 NRAs are also investigated. It is demonstrated that the TiO2 NRAs indicate the good photoelectric conversion ability with an efficiency of 0.22% at a full-wavelength irradiation. A photocurrent density of 0.21 mA/cm2 is observed at 0.7 V versus the saturated calomel electrode (SCE). More evidences suggest that the charge transferring resistance is lowered at an irradiation, while the flat-band potential ( V fb) is shifted towards the positive side.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. In situ tuning of gold nanorod plasmon through oxidative cyanide etching.

    PubMed

    Carattino, Aquiles; Khatua, Saumyakanti; Orrit, Michel

    2016-06-21

    Single gold nanorods exhibit great opportunities for bio-sensing, enhanced spectroscopies and photothermal therapy. A key property of these particles is the surface plasmon resonance, that is strongly dependent on their shape. Methods for tuning this resonance after the synthesis of the particles are of great interest for many applications. In this work we show that, through very well known chemistry between gold atoms and cyanide ions, it is possible to tune the surface plasmon of single 25 × 50 nm rods by more than 100 nm towards longer wavelengths. This is achieved by slowly etching gold atoms from the surface of the particles, preserving their specific optical properties. PMID:27221741

  14. 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

  15. Photochemical Synthesis of Shape-Controlled Nanostructured Gold on Zinc Oxide Nanorods as Photocatalytically Renewable Sensors.

    PubMed

    Xu, Jia-Quan; Duo, Huan-Huan; Zhang, Yu-Ge; Zhang, Xin-Wei; Fang, Wei; Liu, Yan-Ling; Shen, Ai-Guo; Hu, Ji-Ming; Huang, Wei-Hua

    2016-04-01

    Biosensors always suffer from passivation that prevents their reutilization. To address this issue, photocatalytically renewable sensors composed of semiconductor photocatalysts and sensing materials have emerged recently. In this work, we developed a robust and versatile method to construct different kinds of renewable biosensors consisting of ZnO nanorods and nanostructured Au. Via a facile and efficient photochemical reduction, various nanostructured Au was obtained successfully on ZnO nanorods. As-prepared sensors concurrently possess excellent sensing capability and desirable photocatalytic cleaning performance. Experimental results demonstrate that dendritic Au/ZnO composite has the strongest surface-enhanced Raman scattering (SERS) enhancement, and dense Au nanoparticles (NPs)/ZnO composite has the highest electrochemical activity, which was successfully used for electrochemical detection of NO release from cells. Furthermore, both of the SERS and electrochemical sensors can be regenerated efficiently for renewable applications via photodegrading adsorbed probe molecules and biomolecules. Our strategy provides an efficient and versatile method to construct various kinds of highly sensitive renewable sensors and might expand the application of the photocatalytically renewable sensor in the biosensing area. PMID:26928162

  16. 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. PMID:26232677

  17. 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. PMID:26771200

  18. 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.

  19. Luminescent lanthanide complexes of a bis-bipyridine-phosphine-oxide ligand as tools for anion detection.

    PubMed

    Charbonnière, Loïc J; Ziessel, Raymond; Montalti, Marco; Prodi, Luca; Zaccheroni, Nelsi; Boehme, Christian; Wipff, Georges

    2002-07-01

    The Gd(3+), Tb(3+), and Eu(3+) complexes of a bis-bipyridine-phenylphosphine oxide ligand PhP(O)(bipy)(2) 1 (bipy for 6-methylene-6'-methyl-2,2'-bipyridine) have been synthesized. In acetonitrile solutions at room temperature, the Tb(3+) and Eu(3+) complexes show a metal-centered luminescence, indicative of an efficient energy transfer from the two bipy subunits to the Ln center. The photophysical properties drastically depend on the nature of the anions present in solution. In particular, addition of 2 equiv of nitrate anions to a solution containing the [Ln.1](OTf-)(3) leads to an 11-fold increase of the luminescence intensity for the Eu(3+) and a 7-fold increase for the Tb(3+) complexes. Similar effects are provided with Cl-, F-, and CH(3)COO- anions. UV-vis titration experiments were used to determine association constants for binding of, respectively, one, two, and three anions. Stepwise anion addition has also been investigated on the molecular level using quantum mechanical (QM) calculations for the Eu complexes. These calculations reproduce the experimental findings, especially if solvent molecule addition is taken into account. The X-ray crystal structure of the nitrate salt of the Tb complex, as well as QM calculation of a similar Eu complex, demonstrates the coordination of three nitrate anions in a bidentate mode and the step-by-step relegation of the bipy subunits in the second coordination sphere. These features give valuable insights into the mechanism of the overall light amplification process. PMID:12083932

  20. Improved photoelectrochemical water oxidation kinetics using a TiO2 nanorod array photoanode decorated with graphene oxide in a neutral pH solution.

    PubMed

    Chae, Sang Youn; Sudhagar, Pitchaimuthu; Fujishima, Akira; Hwang, Yun Jeong; Joo, Oh-Shim

    2015-03-28

    We prepared TiO2 nanorod (NR) arrays on a fluorine-doped tin oxide substrate and decorated with graphene oxide (GO) to study their photoelectrochemical (PEC) water oxidation activities in two different electrolytes. The PEC performances of GO-decorated TiO2 NR photoanodes were characterized by optical and electrochemical impedance spectroscopy measurements. In 1 M KOH, the photocurrent density of the TiO2 NR film decreased after deposition of GO, while in the neutral pH electrolyte (phosphate buffered 0.5 M Na2SO4), the TiO2 NR photoanode showed enhanced performance after deposition with the 2 wt% GO solution. This was a consequence of the decrease in charge transfer resistance between the electrode surface and the electrolyte. The improvement of photocurrents by GO decoration was obvious near the onset potential of the photocurrents in the neutral pH electrolyte. These opposite contributions of GO on the TiO2 NR photoanodes suggest that GO can promote water oxidation effectively in a neutral electrolyte because depending on the pH of the electrolyte, different chemical species interact with the surface of the photoanode in the water oxidation reaction. PMID:25711207

  1. 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

  2. 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.

  3. Electrochromic properties of large-area and high-density arrays of transparent one-dimensional β-Ta2O5 nanorods on indium-tin-oxide thin-films

    NASA Astrophysics Data System (ADS)

    Devan, Rupesh S.; Gao, Shun-Yu; Ho, Wei-Der; Lin, Jin-Han; Ma, Yuan-Ron; Patil, Pramod S.; Liou, Yung

    2011-03-01

    We report on the synthesis, crystalline structure, and electrochromic properties of transparent one-dimensional (1D) orthorhombic (β) Ta2O5 nanorods grown in a large-area high-density array. The transparent 1D β-Ta2O5 nanorod array was synthesized on a conducting indium-tin-oxide thin-film via hot-filament metal-oxide vapor deposition. The array contained ˜1900 β-Ta2O5 nanorods per square micrometer, which were on average, ˜17 nm wide and ˜300 nm long. The good coloration/bleaching cycles, large ion-diffusion coefficient (˜2.35×10-8 cm2/s), and high reversibility (˜79.8%) demonstrate that the 1D β-Ta2O5 nanorods to be a potential electrochromic material for electrochromic devices or smart windows.

  4. 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.

  5. 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.

  6. Enhanced methanol electro-oxidation over in-situ carbon and graphene supported one dimensional NiMoO4 nanorods

    NASA Astrophysics Data System (ADS)

    Jothi, Palani Raja; Kannan, Shanthi; Velayutham, G.

    2015-03-01

    Non-precious NiMoO4 nanorods with carbon and graphene have been designed for methanol oxidation via one pot hydrothermal method. The physicochemical and electrocatalytic features of these catalysts are characterized. Among the three catalysts, carbon modified NiMoO4 shows an enhanced catalytic activity in terms of current density, onset potential, cyclic stability and high tolerance to intermediate towards methanol electro-oxidation. Moreover, the NiMoO4/C catalyst delivers a current density of 49 mA cm-2 at low onset potential of 0.45 V (vs. Hg/HgO) in 1 M KOH and 2.0 M methanol electrolyte. This greater electrocatalytic activity is attributed to the unique 1D microstructure of NiMoO4 nanorods with well distributed carbonaceous material, which enhances the efficient transport of electron/ion kinetics at the electrode and electrolyte interfaces. From this observation, it is concluded that the carbon modified NiMoO4 nanorods could be a promising alternate non-noble electrocatalysts for direct methanol fuel cell (DMFC) applications.

  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. Optical, structural and electrochromic studies of molybdenum oxide thin films with nanorod structure

    NASA Astrophysics Data System (ADS)

    Dhanasankar, M.; Purushothaman, K. K.; Muralidharan, G.

    2010-02-01

    The MoO 3 thin films were prepared via sol-gel dip coating method on glass and FTO glass substrate. The optical and other properties of multilayered MoO 3 films with 2-10 layers were investigated. The MoO 3 films were studied using UV-Visible transmission, XRD, SEM, FTIR and Cyclic Voltammetry (CV) measurements. The band gap value for MoO 3 films was evaluated and in the range of 3.2 eV-3.72 eV. The XRD spectrum reveals that the crystallinity increases along the (020) and (040) planes with the increase in thickness. The SEM images showed the formation of nanorods upto six layers. The FTIR spectrum confirms the formation of MoO 3. The 6 layered films show the maximum anodic (spike)/cathodic (peak) diffusion coefficient of 18.84/1.701 × 10 -11 cm 2/s. The same film exhibits the change in optical transmission of 49% with the bleached/coloured state transmission of 62/13%.

  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. 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.

  11. Cytotoxicity, oxidative stress, and inflammation in human Hep G2 liver epithelial cells following exposure to gold nanorods.

    PubMed

    Lingabathula, Harikiran; Yellu, Narsimhareddy

    2016-06-01

    The gold nanorods (GNRs) are great potentials in imaging, therapy, biosensing, and many other commercial applications. However, GNRs interactions with human cells and potential health risks remain not well known. The present investigation aimed to evaluate the in vitro toxicity of 10 and 25 nm GNRs (10-50 μg/mL) following exposure for 48 h in human Hep G2 liver epithelial cells using 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), lactate dehydrogenase (LDH) leakage, glutathione (GSH) estimation, lipid peroxidation (TBARS), caspase-3 levels, and interleukin-8 (IL-8) release assays. Exposure of GNRs to cells results in decrease in cell viability and causes cell membrane damage through LDH leakage results in cytotoxicity. The IC50 (concentration required to inhibit 50% of cells) values of 10 nm GNRs, 25 nm GNRs, and quartz (toxic control)-treated cells were found to be 19.9, 26.8, and 36.35 μg/mL, suggesting the higher cytotoxicity of GNRs. The GNRs exposure to liver cells found in depleted GSH levels, increased lipid peroxidation, and increased caspase-3 levels leads to induction of oxidative stress. In addition, enhanced levels of IL-8 were found, a sign of inflammation. The 10 nm GNRs have shown significant toxicity against all biochemical assays when compare to 25 nm GNRs and quartz-treated cells. Finally, the data indicate that the concentration size-dependent in vitro toxicity of GNRs toward liver Hep G2 cells. The toxicity of GNRs may be due to cell membrane damage, induction of oxidative stress, and inflammatory mediator release. Further investigations are necessitated to elucidate the in vivo toxicity of GNRs. PMID:27098122

  12. 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

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

    PubMed

    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

  14. 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

  15. Lanthanide-containing polyimides

    NASA Technical Reports Server (NTRS)

    Stoakley, D. M.; St. Clair, Anne K.

    1987-01-01

    The preparation of a variety of lanthanide-containing polyimide films is described, and results of their characterization are presented. The properties investigated include the glass transition temperature, thermooxidative stability, magnetic susceptibility, and electrical conductivity of the polymer. Films containing lanthanide chlorides, fluorides, and sulfides are flexible, but those containing lanthanide nitrates are extremely brittle. The addition of lanthanide acetates and acetylacetonates caused immediate gelation of two of the synthesis-mixture ingredients. It was found that, in general, the addition of lanthanide to the polyimide increases the density and glass transition temperature of the polymer but slightly decreases the thermooxidative stability.

  16. 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

  17. 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

  18. 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

  19. Label-free colorimetric sensor for ultrasensitive detection of heparin based on color quenching of gold nanorods by graphene oxide.

    PubMed

    Fu, Xiuli; Chen, Lingxin; Li, Jinhua; Lin, Meng; You, Huiyan; Wang, Wenhai

    2012-04-15

    A novel label-free colorimetric strategy was developed for ultrasensitive detection of heparin by using the super color quenching capacity of graphene oxide (GO). Hexadecyltrimethylammonium bromide (CTAB)-stabilized gold nanorods (AuNRs) could easily self-assembly onto the surface of GO through electrostatic interaction, resulting in decrease of the surface plasmon resonance (SPR) absorption and consequent color quenching change of the AuNRs from deep to light. Polycationic protamine was used as a medium for disturbing the electrostatic interaction between AuNRs and GO. The AuNRs were prevented from being adsorbed onto the surface of GO because of the stronger interaction between protamine and GO, showing a native color of the AuNRs. On the contrary, in the presence of heparin, which was more easily to combine with protamine, the AuNRs could self-assembly onto the surface of GO, resulting in the native color disappearing of AuNRs. As the concentration of heparin increased, the color of AuNRs would gradually fade until almost colorless. The amounts of self-assembly AuNRs were proportional to the concentration of heparin, and thereby the changes in the SPR absorption and color had been used to monitor heparin levels. Under optimized conditions, good linearity was obtained in a range of 0.02-0.28 μg/mL (R=0.9957), and a limit of detection was 5 ng/mL. The simultaneous possession of high sensitivity and selectivity, simplicity, rapidity, and visualization enabled this sensor to be potentially applicable for ultrasensitive and rapid on-site detection toward trace heparin. PMID:22387039

  20. Hydrothermal synthesis and humidity sensing properties of size-controlled Zirconium Oxide (ZrO2) nanorods.

    PubMed

    Wang, Zhuyi; Lu, Yi; Yuan, Shuai; Shi, Liyi; Zhao, Yin; Zhang, Meihong; Deng, Wei

    2013-04-15

    Size-controlled ZrO2 nanorods were prepared via a facile hydrothermal treatment approach in the presence of NH4F as mineralizer. The effects of the type and concentration of mineralizers on the particle size and dispersibility of ZrO2 nanorods were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption-desorption measurements (BET), and X-ray photoelectron spectroscopy (XPS), confirming the essential role of F(-) in tuning the particle size. Humidity sensors based on ZrO2 nanorods with different sizes exhibit different sensitivity depending on their proportion of surface adsorbed oxygen. High sensitivity, linear response, small hysteresis, and rapid response-recovery behavior (5s for adsorption and 38s for desorption) make ZrO2 prepared by our method a good candidate for application in humidity sensor. The complex impedance spectra were used to elucidate its humidity sensing mechanism in detail. PMID:23411357

  1. 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.

  2. In situ growth of ruthenium oxide-nickel oxide nanorod arrays on nickel foam as a binder-free integrated cathode for hydrogen evolution

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Xiong, Kun; Chen, Siguo; Li, Li; Deng, Zihua; Wei, Zidong

    2015-01-01

    In this paper we describe a novel catalyst based on RuO2-NiO nanorod arrays constructed in situ on a Ni foam substrate by a hydrothermal process for catalyzing the hydrogen evolution reaction (HER). Field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), linear scanning voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) are used to systematically investigate the microstructure, composition, and electrochemical performance of the catalyst. The prepared electrode exhibits excellent HER performance and long-term stability. This impressive electrochemical performance is largely attributed to the material's unique nanostructure. Noticeable the presence of nickel oxide/hydroxide on the surface of the catalyst promotes the dissociation of water and the formation of hydrogen intermediates that can then adsorb onto the nearby ruthenium species and recombine into molecular hydrogen at a very rapid rate. The hydrothermal method for directly growing electroactive nanostructured arrays on a conductive substrate offers a promising route for developing a new class of Ni-based high performance electrodes for the HER in practical applications.

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

    NASA Astrophysics Data System (ADS)

    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).

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

    PubMed

    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

  5. 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

  6. 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).

  7. 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).

  8. Separation of actinides from lanthanides

    DOEpatents

    Smith, B.F.; Jarvinen, G.D.; Ryan, R.R.

    1988-03-31

    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 is described. 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).

  9. 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.

  10. Effective Atomic Numbers of Lanthanides with Gamma Radiation for Photon Energy Absorption

    NASA Astrophysics Data System (ADS)

    Shantappa, Anil; Hanagodimath, S. M.

    Effective atomic numbers for photon energy absorption, ZPEA,eff have been calculated for photon from 1 keV to 20 MeV for selected oxides of lanthanides, such as Lanthanum oxide, Cerium oxide, Samarium oxide, Europium oxide, Dysprosium oxide, Thulium oxide, Ytterbium oxide. The ZPEA,eff values then compared with ZPI,eff for photon interaction. The ZPEA,eff values have been found to change with energy and composition of selected lanthanides. Oxides of lanthanides are considered as better shielding materials to the exposure of gamma radiation. The values of effective atomic number for photon energy absorption help in the calculation of absorbed dose.

  11. 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

  12. 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

  13. 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…

  14. 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.

  15. 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. PMID:24940607

  16. 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.

  17. 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

  18. Manganese Oxide Nanorod-Decorated Mesoporous ZSM-5 Composite as a Precious-Metal-Free Electrode Catalyst for Oxygen Reduction.

    PubMed

    Cui, Xiangzhi; Hua, Zile; Chen, Lisong; Zhang, Xiaohua; Chen, Hangrong; Shi, Jianlin

    2016-05-10

    A precious-metal-free cathode catalyst, MnO2 nanorod-decorated mesoporous ZSM-5 zeolite nanocomposite (MnO2 / m-ZSM-5), has been successfully synthesized by a hydrothermal and electrostatic interaction approach for efficient electrochemical catalysis of the oxygen reduction reaction (ORR). The active MnOOH species, that is, Mn(4+) /Mn(3+) redox couple and Brønsted acid sites on the mesoporous ZSM-5 matrix facilitate an approximately 4 e(-) process for the catalysis of the ORR comparable to commercial 20 wt % Pt/C. Stable electrocatalytic activity with 90 % current retention after 5000 cycles, and more importantly, excellent methanol tolerance is observed. Synergetic catalytic effects between the MnO2 nanorods and the mesoporous ZSM-5 matrix are proposed to account for the high electrochemical catalytic performance. PMID:27038172

  19. 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

  20. Trade-off between Zr Passivation and Sn Doping on Hematite Nanorod Photoanodes for Efficient Solar Water Oxidation: Effects of a ZrO2 Underlayer and FTO Deformation.

    PubMed

    Subramanian, Arunprabaharan; Annamalai, Alagappan; Lee, Hyun Hwi; Choi, Sun Hee; Ryu, Jungho; Park, Jung Hee; Jang, Jum Suk

    2016-08-01

    Herein we report the influence of a ZrO2 underlayer on the PEC (photoelectrochemical) behavior of hematite nanorod photoanodes for efficient solar water splitting. Particular attention was given to the cathodic shift in onset potential and photocurrent enhancement. Akaganite (β-FeOOH) nanorods were grown on ZrO2-coated FTO (fluorine-doped tin oxide) substrates. Sintering at 800 °C transformed akaganite to the hematite (α-Fe2O3) phase and induced Sn diffusion into the crystal structure of hematite nanorods from the FTO substrates and surface migration, shallow doping of Zr atoms from the ZrO2 underlayer. The ZrO2 underlayer-treated photoanode showed better water oxidation performance compared to the pristine (α-Fe2O3) photoanode. A cathodic shift in the onset potential and photocurrent enhancement was achieved by surface passivation and shallow doping of Zr from the ZrO2 underlayer, along with Sn doping from the FTO substrate to the crystal lattice of hematite nanorods. The Zr based hematite nanorod photoanode achieved 1 mA/cm(2) at 1.23 VRHE with a low turn-on voltage of 0.80 VRHE. Sn doping and Zr passivation, as well as shallow doping, were confirmed by XPS, Iph, and M-S plot analyses. Electrochemical impedance spectroscopy revealed that the presence of a ZrO2 underlayer decreased the deformation of FTO substrate, improved electron transfer at the hematite/FTO interface and increased charge-transfer resistance at the electrolyte/hematite interface. This is the first systematic investigation of the effects of Zr passivation, shallow doping, and Sn doping on hematite nanorod photoanodes through application of a ZrO2 underlayer on the FTO substrate. PMID:27420603

  1. Crystal structures and magnetic properties of fluorite-related oxides Ln{sub 3}NbO{sub 7} (Ln=lanthanides)

    SciTech Connect

    Doi, Yoshihiro; Harada, Yuka; Hinatsu, Yukio

    2009-04-15

    Crystal structures and magnetic properties of the ternary oxides Ln{sub 3}NbO{sub 7} (Ln=La, Pr, Nd, Sm-Lu) are reported. Their powder X-ray diffraction measurements and Rietveld analyzes show that they have the fluorite-related structures with space group Pnma (Ln=La, Pr, Nd), C222{sub 1} (Ln=Sm-Tb), or Fm-3m (Ln=Dy-Lu). Magnetic susceptibility measurements were carried out from 1.8 to 400 K. The Ln{sub 3}NbO{sub 7} compounds for Ln=Pr, Gd, Dy-Yb show Curie-Weiss paramagnetic behavior, and Sm{sub 3}NbO{sub 7} and Eu{sub 3}NbO{sub 7} show van Vleck paramagnetism. On the other hand, two magnetic anomalies were observed for both Nd{sub 3}NbO{sub 7} (0.6 and 2.7 K) and Tb{sub 3}NbO{sub 7} (2.0 and 3.2 K). From the results of specific heat measurements, it was found that these anomalies are due to the antiferromagnetic ordering of Ln ions in two different crystallographic sites (the 8-coordinated and 7-coordinated sites). - Ternary oxides Ln{sub 3}NbO{sub 7} (Ln=lanthanides) have the fluorite-related structures with space group Pnma (Ln=La, Pr, Nd), C222{sub 1} (Ln=Sm-Tb), or Fm-3m (Ln=Dy-Lu). In them, Nd{sub 3}NbO{sub 7} and Tb{sub 3}NbO{sub 7} show 'two-step' antiferromagnetic transitions due to the long-range antiferromagnetic ordering of Ln ions in different crystallographic sites.

  2. 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. PMID:26758594

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. In Vivo Toxicity Studies of Europium Hydroxide Nanorods in Mice

    PubMed Central

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

    2009-01-01

    Lanthanide nanoparticles and nanorods have been widely used for diagnostic and therapeutic applications in biomedical nanotechnology due to their fluorescence properties and pro-angiogenic to endothelial cells, respectively. Recently, we have demonstrated that europium (III) hydroxide [EuIII(OH)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 mgKg−1day−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 sacrificed on day 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. PMID:19616569

  8. Structure of Glass-Forming Melts - Lanthanide in Borosilicates

    SciTech Connect

    Li, Hong; Li, Liyu; Qian, Morris; Strachan, Denis M.; Wang, Zheming

    2004-05-17

    Over the past few years, we studied several complex Na2O-Al2O3-B2O3-SiO2 glass systems to answer key questions: effects of melt chemistry on solubility of lanthanide oxides; lanthanide solution behavior, and intermediate-range ordering in the melts. This paper summarizes our currently understanding on rare earth elements in borosilicate glasses, covering solution behavior, solubility limits, crystalization and phase separation.

  9. 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.

  10. Production of stable aqueous dispersion of poly(3,4-ethylenedioxythiophene) nanorods using graphene oxide as a stabilizing agent and their application for nitrite detection.

    PubMed

    Liu, Sen; Tian, Jingqi; Wang, Lei; Luo, Yonglan; Sun, Xuping

    2011-12-01

    A stable aqueous dispersion of poly(3,4-ethylenedioxythiophene) (PEDOT) nanorods stabilized by graphene oxide (GO) has been successfully prepared via interface polymerization of EDOT in the presence of GO for the first time. The non-covalent functionalization of PEDOT by GO leads to a PEDOT-GO dispersion that can be stable for several days without the observation of any floating or precipitated particles. Several analytical techniques including Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) have been used to characterize the resultant PEDOT-GO nanocomposites. It is found that such PEDOT-GO nanocomposites exhibit good catalytic activity toward the oxidation of nitrite, leading to a sensor for detection of nitrite. The linear detection range and detection limit are estimated to be 4 μM to 2.48 mM (r = 0.999), and 1.2 μM at a signal-to-noise ratio of 3, respectively. PMID:21975458

  11. 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)

  12. 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. PMID:26580293

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. Multiplexed enzyme-free electrochemical immunosensor based on ZnO nanorods modified reduced graphene oxide-paper electrode and silver deposition-induced signal amplification strategy.

    PubMed

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

    2015-09-15

    Herein, an origami multiplexed enzyme-free electrochemical (EC) immunodevice is developed for the first time. Typically, ZnO nanorods (ZNRs) modified reduced graphene oxide (rGO)-paper electrode is used as a sensor platform, in which rGO improves the electronic transmission rate and ZNRs provide abundant sites for capture probes binding. Furthermore, by combining the large surface area of rGO and high catalytic activity of bovine serum protein (BSA)-stabilized silver nanoparticles (Ag@BSA) toward H2O2 reduction, rGO/Ag@BSA composites can be used as an excellent signal labels. The current signal is generated from the reduction of H2O2 and further amplified by a subsequent signal labels-promoted deposition of silver. Under optimal conditions, the proposed immunoassays exhibit excellent precision, high sensitivity and a wide linear range of 0.002-120 mIU mL(-1) for human chorionic gonadotropin, 0.001-110 ng mL(-1) for prostate-specific antigen, and 0.001-100 ng mL(-1) for carcinoembryonic antigen. The results for real sample analysis demonstrate that the newly constructed immunosensor arrays provide a simple and cost-effective method for clinical applications. PMID:25884731

  19. 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

  20. Luminescent lanthanide coordination polymers

    SciTech Connect

    Ma, L.; Evans, O.R.; Foxman, B.M.; Lin, W.

    1999-12-13

    One-dimensional lanthanide coordination polymers with the formula Ln(isonicotinate){sub 3}(H{sub 2}O){sub 2} (Ln = Ce, Pr, Nd, Sm, Eu, Tb; 1a-f) were synthesized by treating nitrate or perchlorate salts of Ln(III) with 4-pyridinecarboxaldehyde under hydro(solvo)thermal conditions. Single-crystal and powder X-ray diffraction studies indicate that these lanthanide coordination polymers adopt two different structures. While Ce(III), Pr(III), and Nd(III) complexes adopt a chain structure with alternating Ln-(carboxylate){sub 2}-Ln and Ln-(carboxylate){sub 4}-Ln linkages, Sm(III), Eu(III), and Tb(III) complexes have a doubly carboxylate-bridged infinite-chain structure with one chelating carboxylate group on each metal center. In both structures, the lanthanide centers also bind to two water molecules to yield an eight-coordinate, square antiprismatic geometry. The pyridine nitrogen atoms of the isonicotinate groups do not coordinate to the metal centers in these lanthanide(III) complexes; instead, they direct the formation of Ln(III) coordination polymers via hydrogen bonding with coordinated water molecules. Photoluminescence measurements show that Tb(isonicotinate){sub 3}(H{sub 2}O){sub 2} is highly emissive at room temperature with a quantum yield of {approximately}90%. These results indicate that highly luminescent lanthanide coordination polymers can be assembled using a combination of coordination and hydrogen bonds. Crystal data for 1a: monoclinic space group P2{sub 1}/c, a = 9.712(2) {angstrom}, b = 19.833(4) {angstrom}, c = 11.616(2) {angstrom}, {beta} = 111.89(3){degree}, Z = 4. Crystal data for 1f: monoclinic space group C2/c, a = 20.253(4) {angstrom}, b = 11.584(2) {angstrom}, c = 9.839(2) {angstrom}, {beta} = 115.64(3){degree}, Z = 8.

  1. Dispersion and Alignment of CdSe Nanorods in Polymer Nanocomposites

    NASA Astrophysics Data System (ADS)

    Rasin, Boris; Frischknecht, Amalie; Diroll, Benjamin; Tsai, Lindsay; Murray, Christopher; Composto, Russell

    2014-03-01

    The thermodynamic factors that affect the dispersion of polymer-brush grafted nanorods (NR) added to homopolymer matrix films have been studied by both experiments and theory. Whereas prior studies have focused on gold nanorods with fixed diameter (12nm-16nm) and varying length (37nm to 98 nm), these studies investigate the smaller diameter (4 nm) CdSe nanorods with length 27 nm to determine if nanorod curvature increases wetting between brush and matrix chains. Here we investigate two chemically similar brush / matrix systems polystyrene (PS)-NR / PS and poly(ethylene oxide) (PEO)-NR/PEO as a function of matrix to brush degree of polymerization, P/N. For the PS-NR / PS system for P/N =.5 the nanorods observed in the polymer matrix are primarily either individual nanorods or individual chains of end to end positioned nanorods. For P/N =13 aggregates consisting of side to side positioned nanorods and side to side positioned nanorod chains are observed. Individual nanorods and individual nanorod chains are also observed. The transition from wet to dry brush is explored and compared with the gold NR studies as well as density functional theory calculations. The effect of electrical field alignment on nanorod orientation is also presented.

  2. Directing the deposition of ferromagnetic cobalt onto Pt-tipped CdSe@CdS nanorods: synthetic and mechanistic insights.

    PubMed

    Hill, Lawrence J; Bull, Mathew M; Sung, Younghun; Simmonds, Adam G; Dirlam, Philip T; Richey, Nathaniel E; DeRosa, Sean E; Shim, In-Bo; Guin, Debanjan; Costanzo, Philip J; Pinna, Nicola; Willinger, Marc-Georg; Vogel, Walter; Char, Kookheon; Pyun, Jeffrey

    2012-10-23

    A methodology providing access to dumbbell-tipped, metal-semiconductor and metal oxide-semiconductor heterostructured nanorods has been developed. The synthesis and characterization of CdSe@CdS nanorods incorporating ferromagnetic cobalt nanoinclusions at both nanorod termini (i.e., dumbbell morphology) are presented. The key step in the synthesis of these heterostructured nanorods was the decoration of CdSe@CdS nanorods with platinum nanoparticle tips, which promoted the deposition of metallic CoNPs onto Pt-tipped CdSe@CdS nanorods. Cobalt nanoparticle tips were then selectively oxidized to afford CdSe@CdS nanorods with cobalt oxide domains at both termini. In the case of longer cobalt-tipped nanorods, heterostructured nanorods were observed to self-organize into complex dipolar assemblies, which formed as a consequence of magnetic associations of terminal CoNP tips. Colloidal polymerization of these cobalt-tipped nanorods afforded fused nanorod assemblies from the oxidation of cobalt nanoparticle tips at the ends of nanorods via the nanoscale Kirkendall effect. Wurtzite CdS nanorods survived both the deposition of metallic CoNP tips and conversion into cobalt oxide phases, as confirmed by both XRD and HRTEM analysis. A series of CdSe@CdS nanorods of four different lengths ranging from 40 to 174 nm and comparable diameters (6-7 nm) were prepared and modified with both cobalt and cobalt oxide tips. The total synthesis of these heterostructured nanorods required five steps from commercially available reagents. Key synthetic considerations are discussed, with particular emphasis on reporting isolated yields of all intermediates and products from scale up of intermediate precursors. PMID:22900605

  3. 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. PMID:26397420

  4. 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.

  5. Electrochemical Synthesis of ZnO Nanorods/Nanotubes/Nanopencils on Transparent Aluminium-Doped Zinc Oxide Thin Films for Photocatalytic Applications.

    PubMed

    Le, Thi Ngoc Tu; Pham, Tan Thi; Ngo, Quang Minh; Vu, Thi Hanh Thu

    2015-09-01

    We report an electrochemical synthesis of homogeneous and well-aligned ZnO nanorods (NRs) on transparent conducting aluminium-doped zinc oxide (AZO) thin films as electrodes. The selected ZnO NRs was then chemically corroded in HCl and KCl aqueous solutions to form nanopencils (NPs), and nanotubes (NTs), respectively. A DC magnetron sputtering was employed to fabricate AZO thin films at various thicknesses. The obtained AZO thin films have a c-direction orientation, transmittance above 80% in visible region, and sheet resistance approximately 40 Ω/sq. They are considered to be relevant as electrodes and seeding layers for electrochemical. The ZnO NRs are directly grown on the AZOs without a need of catalysts or additional seeding layers at temperature as low as 85 degrees C. Their shapes are strongly associated with the AZO thickness that provides a valuable way to control the diameter of ZnO NRs grown atop. With the addition of HCI and KCl aqueous solutions, ZnO NRs were modified their shape to NPs and NTs with the reaction time, respectively. All the ZnO NRs, NPs, and NTs are preferred to grow along c-direction that indicates a lattice matching between AZO thin films and ZnO nanostructrures. Photoluminescence spectra and XRD patterns show that they have good crystallinities. A great photocatalytic activity of ZnO nanostructures promises potential application in environmental treatment and protection. The ZnO NTs exhibits a higher photocatalysis than others possibly due to the oxygen vacancies on the surface and the polarizability of Zn2+ and O2-. PMID:26716213

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.