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1

Synthesis and characterization of radiation sensitive TiO 2 \\/monazite photocatalyst  

Microsoft Academic Search

A TiO2\\/monazite photocatalyst was prepared by embedding TiO2 nanoparticles into a monazite substrate surface. TiCl4 hydrolysis\\/citric acid chelating procedure under acidic conditions were used to synthesize the nanophase TiO2 particles. The anatase TiO2\\/monazite photocatalyst surface area, morphology, crystalline and elemental concentrations were characterized using Brunauer-Emmett-Teller\\u000a (BET) method, scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma-atomic emission\\u000a spectrometry

C. T. Yu; C. F. Wang; T. Y. Chen; Y. T. Chang

2008-01-01

2

Synthesis and characterization of N-doped TiO2 photocatalysts with tunable response to solar radiation  

NASA Astrophysics Data System (ADS)

Modification of the electronic structure of wide band gap semiconductors by anion doping is an effective strategy for the development of photocatalytic materials operating under solar light irradiation. In the present work, nitrogen-doped TiO2 photocatalysts of variable dopant content were synthesized by annealing a sol-gel derived TiO2 powder under flowing ammonia at temperatures in the range of 450-800 °C, and their physicochemical and optical properties were compared to those of undoped TiO2 samples calcined in air. Results show that materials synthesized at T = 450-600 °C contain relatively small amounts of dopant atoms and their colour varies from pale yellow to dark green due to the creation of localized states above the valence band of TiO2 and the formation of oxygen vacancies. Treatment with NH3 at T > 600 °C results in phase transformation of anatase to rutile, in a significant decrease of the specific surface area and in formation of TiN at the surface of the TiO2 particles. The resulting dark grey (T = 700 °C) and black (T = 800 °C) materials display strong absorption in both the visible and NIR regions, originating from partial reduction of TiO2 and formation of Ti3+ defect states. The present synthesis method enables tailoring of the electronic structure of the semiconductor and could be used for the development of solar light-responsive photocatalysts for photo(electro)chemical applications.

Petala, Athanasia; Tsikritzis, Dimitris; Kollia, Mary; Ladas, Spyridon; Kennou, Stella; Kondarides, Dimitris I.

2014-06-01

3

SURFACTANT TEMPLATED SOL-GEL SYNTHESIS OF MESOPOROUS TIO2 PHOTOCATALYSTS AND THEIR APPLICATION IN THE DESTRUCTION OF CYANOBACTERIAL TOXINS  

EPA Science Inventory

In the symposium, we will present the synthesis and properties of the mesoporous TIO2 films and membranes and fundamental and systematic study on the decomposition pathway of such biological toxins....

4

Synthesis and characterization of the N-doped TiO2 photocatalyst for the photodegradation of methylene blue and phenol.  

PubMed

To extend the light absorption of TiO2-based photocatalysts towards the visible-light range and to eliminate the rapid recombination of excited electrons/holes during photoreaction, a new type of photocatalyst (N-doped TiO2) powder was prepared through a simple sol-gel process. The crystal phase composition, structure, and light absorption of the new photocatalyst were comprehensively examined via X-ray diffraction, ultraviolet-visible (UV-Vis) absorption spectroscopy, and atomic-absorption spectroscopy. The photo-oxidation efficiency of the photocatalyst was also evaluated in the photodegradation of methylene blue (MB) and of phenol in aqueous solutions under visible-light irradiation from a neon lamp (lambda > 400 nm). The results of the analyses that were performed in this study indicated that the N-doped TiO2 could eliminate the electron/holes recombination and could increase the light absorption in the visible range. The results of the analysis of the UV-Vis diffuse reflection and optical-absorption spectra indicated that a new energy level below 3.2 eV generated in the N-doped TiO2 promoted the optical absorption in the visible-light region and made visible-light excitation possible (E < 3.2 eV). The experiment demonstrated that the photo-oxidation efficiency of MB when N-doped TiO2 powder was used was significantly higher than that when the conventional TiO2 powders were used. The development of such photocatalyst may be considered a breakthrough in the large-scale utilization of solar energy to address the current and future environmental needs. PMID:22121743

Khang, Nguyen Cao; Van Minh, Nguyen; Yang, In-Sang

2011-07-01

5

Synthesis of C, Ag co-modified TiO2 photocatalyst and its application in waste water purification  

NASA Astrophysics Data System (ADS)

Monodispersed C, Ag co-modified TiO2 microspheres were successfully synthesized through a two-step method. Firstly, monodisperse spherical TiO2 particles were obtained via controlled hydrolysis of TBOT (tetrabutyltitanate) in ethanol. Secondly, the C, Ag co-modified TiO2 microspheres were prepared through a simple calcination process, in which the AgNO3 and citric acid was used as Ag and C source, respectively. The physical and chemical properties of C, Ag co-modified TiO2 microspheres were carefully studied by using XRD, SEM, TEM, Raman, PL spectra and UV-vis diffuse reflectance spectra (DRS), while the chemical states of C and Ag were discussed via EDS (energy dispersive spectrometer) and XPS. The photocatalytic activity of the as-prepared products was evaluated by photocatalytic decolorization of Rhodamine B (Rh B) aqueous solution at ambient temperature under UV and visible-light irradiation. The photocatalytic activity research shows that, with the cooperation of two modified materials, C, Ag co-modified TiO2 microspheres exhibit enhanced photocatalytic activity both in ultraviolet and visible-light region compared with that of pure TiO2 and single Ag modified TiO2 microspheres.

Liu, Hui; Dong, Xiaonan; Li, Guangjun; Su, Xing; Zhu, Zhenfeng

2013-04-01

6

Synthesis of N-doped nano TiO2 using guanidine nitrate: an excellent visible light photocatalyst.  

PubMed

An excellent visible light active nitrogen-rich TiO2 nanocatalyst has been synthesized by using guanidine nitrate as the nitrogen source. The catalytic efficiency of the catalyst has been demonstrated by the decomposition of the dye, methyl orange (MO), and the pollutant, 2,4 dichlorophenol (DCP), under common household lightbulbs as well as sunlight. The reactions proceed faster on exposure to solar light (less than 1 h for MO and 4 h for DCP) compared with the commercial light bulbs (3 h for MO and 6 h for DCP). The catalyst could be used up to five times without loss of activity and regenerated for further use just by washing and drying at 200 degrees C. PMID:21449345

Baruwati, Babita; Varma, Rajender S

2011-03-01

7

Zn²+La³+ Co-Doped TiO2 Photocatalyst for the Purification of Air  

Microsoft Academic Search

The Zn2+-La3+Co-doped TiO2 photocatalysts prepared by doping lanthanum ion and zinc ion into TiO2 structure in a sol-gel process were shown to be efficient photocatalyst for the purification of Indoor air.The catalyst samples were then characterized by XRD and UV-vis analyses. The analytical results demonstrated that the lanthanum- zinc co-doping could inhibit the phase transformation of TiO2 and enhance the

Liu Baojiang; Cheng Xubang; He Jinxin

2009-01-01

8

Preparation of N-doped TiO 2 photocatalyst by atmospheric pressure plasma process for VOCs decomposition under UV and visible light sources  

Microsoft Academic Search

The nitrogen doped (N-doped) titanium dioxide (TiO2) photocatalyst was prepared by the atmospheric-pressure plasma-enhanced nanoparticles synthesis (APPENS) process operated\\u000a under normal temperature, i.e. the dielectric barrier discharge plasma process. The N2 carrier gas is dissociated in the AC powered nonthermal plasma environment and subsequently doped into the TiO2 photocatalyst that was capable of being induced by visible light sources. The

Chienchih Chen; Hsunling Bai; Sue-min Chang; Chungliang Chang; Walter Den

2007-01-01

9

Enhanced photocatalytic activity from Gd, La codoped TiO2 nanotube array photocatalysts under visible-light irradiation  

NASA Astrophysics Data System (ADS)

Well-aligned TiO2 nanotube arrays were successfully synthesized from electrochemically anodic oxidation, which were further codoped by Gd and La via hydrothermal and sol-gel methods. The visible-light photocatalytic activities of the Gd, La codoped TiO2 nanotube arrays evaluated by photodegrading methyl orange (MO) have been significantly enhanced compared to that of undoped TiO2. Hereinto, the photocatalytic performance of Gd, La codoped TiO2 nanotube array synthesized by a hydrothermal approach was better than that by a sol-gel method. A lower band gap energy was attributed to the enhanced response to visible light. The new concept was helpful to guide the synthesis of robust visible-light photocatalysts, and the interesting results suggested that the Gd, La codoped TiO2 nanotube arrays were very promising for elevated the solar utilization in environment management.

Cai, Hongyuan; Chen, Xiaoxu; Li, Qinghua; He, Benlin; Tang, Qunwei

2013-11-01

10

XAFS Study on TiO2 Photocatalyst Loaded on Zeolite Synthesized from Steel Slag  

NASA Astrophysics Data System (ADS)

The convenient route for the synthesis of Y-zeolites by utilizing steel slag as a material source was developed. Through hydrothermal treatment, well-crystallized Y-zeolite was obtained. We also synthesized TiO2-loaded Y-zeolites by an impregnation method. The structure of titanium oxide species highly dispersed on the zeolite, which couldn't be detected by XRD patterns, was investigated by XAFS analysis. Photocatalytic activity for decomposition of 2-propanol in liquid phase was found to be enhanced by the hydrophobic surface property of zeolite. It has been demonstrated that the zeolite synthesized from steel slag would be applicable as a promising support of TiO2 photocatalyst.

Kuwahara, Yasutaka; Ohmichi, Tetsutaro; Mori, Kosuke; Katayama, Iwao; Yamashita, Hiromi

2007-02-01

11

Preparation and performances of mesoporous TiO 2 film photocatalyst supported on stainless steel  

Microsoft Academic Search

Mesoporous TiO2 film photocatalysts supported on stainless steel substrates were prepared using the sol–gel method with Ti(OC4H9)4 as a precursor and poly ethylene glycol (PEG) as a structure-directing agent. Mesoporous TiO2 film with a pore diameter of about 15nm was obtained with the addition of PEG (molecular weight =400). The pore diameter of TiO2film was varied with molecular weight of

Li Zhang; Yongfa Zhu; Yu He; Wei Li; Hongbin Sun

2003-01-01

12

Study of gamma irradiation effect on commercial TiO2 photocatalyst.  

PubMed

The aim of this work is to understand the effect of gamma irradiation on commercial TiO2 photocatalyst for water treatment applications. Previous studies concluded that gamma-irradiation is able to modify the electronic properties of TiO2 based photocatalysts and consequently their photocatalytic performance. However, there are some discrepancies in the literature where on one hand a significant enhancement of the material properties is reported and on the other hand only a weak effect is observed. In this study a surface effect on TiO2 is confirmed by using low and medium gamma irradiation doses. PMID:24576993

Bello Lamo, M P; Williams, P; Reece, P; Lumpkin, G R; Sheppard, L R

2014-07-01

13

The preparation of nitrogen-doped photocatalyst TiO2 - xNx by ball milling  

Microsoft Academic Search

The nitrogen-doped photocatalyst TiO2 - xNx is prepared by ball milling of TiO2 in a NH3 [middle dot] H2O solution, and the photocatalyst is characterized by the UV-vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM). Based on the results of the characterization, the mechanisms of the photocatalyst TiO2 - xNx formation

Chen Shifu; Chen Lei; Gao Shen; Cao Gengyu

2005-01-01

14

Synthesis of mesoporous TiO2/SiO2 hybrid films as an efficient photocatalyst by polymeric micelle assembly.  

PubMed

Thermally stable mesoporous TiO2/SiO2 hybrid films with pore size of 50?nm have been synthesized by adopting the polymeric micelle-assembly method. A triblock copolymer, poly(styrene-b-2-vinyl pyridine-b-ethylene oxide), which serves as a template for the mesopores, was utilized to form polymeric micelles. The effective interaction of titanium tetraisopropoxide (TTIP) and tetraethyl orthosilicate (TEOS) with the polymeric micelles enabled us to fabricate stable mesoporous films. By changing the molar ratio of TEOS and TTIP, several mesoporous TiO2/SiO2 hybrid films with different compositions can be synthesized. The presence of amorphous SiO2 phase effectively retards the growth of anatase TiO2 crystal in the pore walls and retains the original mesoporous structure, even at higher temperature (650?°C). These TiO2/SiO2 hybrid films are of very high quality, without any cracks or voids. The addition of SiO2 phase to mesoporous TiO2 films not only adsorbs more organic dyes, but also significantly enhances the photocatalytic activity compared to mesoporous pure TiO2 film without SiO2 phase. PMID:24710980

Li, Yunqi; Bastakoti, Bishnu Prasad; Imura, Masataka; Hwang, Soo Min; Sun, Ziqi; Kim, Jung Ho; Dou, Shi Xue; Yamauchi, Yusuke

2014-05-12

15

TiO2 Nanotubes/MWCNTs Nanocomposite Photocatalysts: Synthesis, Characterization and Photocatalytic Hydrogen Evolution Under UV-Vis Light Illumination  

SciTech Connect

Nanocomposite of TiO2 nanotubes (TiO2NTs) and multiwalled carbon nanotubes (MWCNTs) has been synthesized by a hydrothermal method and firstly used in photocatalytic hydrogen production. The obtained TiO2 NTs/MWCNTs composites were characterized by X-ray diffraction, transmission electron microscopy, Raman spectrum and ultraviolet-visible diffuse reflectance spectroscopy. The experimental results revealed that the MWCNTs were decorated with well dispersed anatase TiO2 nanotubes with a diameter of 8-15 nm. A slight blue shift and weak symmetry was observed for the strongest Raman peak which resulted from strain gradients originating from interface integration between TiO2 nanotubes and MWCNTs. The photocatalytic activity of the as-prepared samples was evaluated by hydrogen evolution from water splitting using Na2S and Na2SO3 as sacrificial reagents under UV-vis light irradiation. Enhanced photocatalytic activity compared with P25 has been observed for the resulted samples. The nanocomposite with optimized MWCNTs content of 1% displayed a hydrogen production rate of 161 u mol/h/g. Good photocatalytic stability of the as-synthesized samples was observed as well.

Li, Hao-Peng; Zhang, Xiao-Yan; Cui, Xiao-Li; Lin, Yuehe

2012-03-01

16

Development of TiO 2 photocatalyst reaction for water purification  

Microsoft Academic Search

A new type of tubular photocatalytic reactor was developed to realize practical application of TiO2 photocatalyst for water purification. The principal part of the reactor consists of the ceramic cylindrical tube whose inner surface is coated with Pt-loaded TiO2 film and the 30 W ultraviolet light lamp which is set longitudinally in the center of the tube. The water to

Lianfeng Zhang; Tatsuo Kanki; Noriaki Sano; Atsushi Toyoda

2003-01-01

17

DC corona ozone generation enhanced by TiO2 photocatalyst  

NASA Astrophysics Data System (ADS)

Non-thermal electrical discharges, such as corona discharge are apart of the source of ozone, charged, and excited species and acoustic noise also the source of electromagnetic radiation of different wavelengths. The important component of this radiation from the standpoint of photocatalyst activation is the ultraviolet radiation. We studied the role of UV radiation on corona discharge ozone production by placing the titanium dioxide photocatalyst into the discharge region. We used hollow needle to mesh DC corona discharge at atmospheric pressure with TiO2 globules on the mesh. The discharge was enhanced by the flow of air through the needle. We found that for the needle biased negatively addition of TiO2 photocatalyst on the mesh electrode drastically increases discharge ozone production as well as the ozone production yield. These quantities are also influenced by the mass of the used photocatalyst and its distribution in the discharge chamber.

Pekã¡Rek, S.

2008-12-01

18

Favorable recycling photocatalyst TiO 2/CFA: Effects of loading percent of TiO 2 on the structural property and photocatalytic activity  

NASA Astrophysics Data System (ADS)

A series of photocatalysts TiO 2/CFA were prepared using coal fly ash (CFA), waste discharged from coal-fired power plant, as substrate, and then these photocatalysts were characterized by scanning electron microscope, X-ray diffraction analysis, nitrogen adsorption test and ultraviolet-visible absorption analysis. The effects of loading percent of TiO 2 on the photocatalytic activity and re-use property of TiO 2/CFA were evaluated by the photocatalytic decoloration and mineralization of methyl orange solution. The results show that the pore volume and the specific surface area of the TiO 2/CFA both increased with the increase in the loading percent of TiO 2, which improved the photocatalytic activity of TiO 2/CFA. However, when the loading percent of TiO 2 was too high (up to 54.51%), superfluous TiO 2 was easy to break away from CFA in the course of water treatment, which was disadvantaged to the recycling property of TiO 2/CFA. In this study, the optimal loading percent of TiO 2 was 49.97%, and the efficiencies of photocatalytic decoloration and mineralization could be maintained above 99% and 90%, respectively, when the photocatalyst was used repeatedly, without any decline, even at the sixth cycle.

Shi, Jian-wen; Chen, Shao-hua; Ye, Zhi-long; Wang, Shu-mei; Wu, Peng

2010-11-01

19

Dramatic activity of mixed-phase TiO2 photocatalyst synthesized by hydrothermal method  

NASA Astrophysics Data System (ADS)

The mixed-phase TiO2 photocatalysts with different anatase/rutile/brookite ratios and high specific surface area (157-218 m2/g) were prepared by hydrothermal method at 100 °C and the effect of rutile content in TiO2 on the BET surface area, light absorption and separation efficiency of photogenerated charge carriers was studied and correlated to the photocatalytic activity of TiO2. Rutile content increased from 0% to 100% by increasing the amount of TiCl4 in aqueous phase and the initial pH value of reaction solution played an important role in the phase composition of TiO2. The photocatalytic mechanism of mixed-phase TiO2 was discussed.

Li, Huiquan; Xu, Bolian; Fan, Yining

2013-02-01

20

Phenol degradation by TiO2 photocatalysts combined with different pulsed discharge systems.  

PubMed

Films of TiO2 nanotubes distributed over the inner surface of a discharge reactor cylinder (CTD) or adhered to a stainless steel electrode surface (PTD) in a discharge reactor were compared with a single-discharge (SD) system to investigate their efficiencies in phenol degradation. Morphology studies indicated that the TiO2 film was destroyed in the PTD system, but that there was no change in the CTD system after discharge. X-ray diffraction results revealed that the anatase phase of the original sample was preserved in the CTD system, but that an anatase-to-rutile phase transformation occurred in the PTD system after discharge. The highest efficiencies of phenol degradation and total organic carbon (TOC) mineralization were observed in the CTD system, and there was no decrease in phenol degradation efficiency upon reuse of a TiO2 film, indicating high catalysis activity and stability of the TiO2 photocatalysts in the combined treatment. TiO2 photocatalysts favored the formation of hydrogen peroxide and disfavored the formation of ozone. A greater degree of oxidation of intermediates and higher energy efficiency in phenol oxidation were observed with the TiO2-plasma systems, especially in the CTD system, compared to those with the SD system. PMID:23981678

Zhang, Yi; Lu, Jiani; Wang, Xiaoping; Xin, Qing; Cong, Yanqing; Wang, Qi; Li, Chunjuan

2013-11-01

21

Cold Spraying of TiO2 Photocatalyst Coating With Nitrogen Process Gas  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) is a promising material for photocatalyst coatings. However, it is difficult to fabricate a TiO2 coating with anatase phase by conventional thermal spray processes due to a thermal transformation to rutile phase. In this paper, anatase TiO2 coatings were fabricated by the cold spray process. To understand the influence of process gas conditions on the fabrication of the coatings, the gas nature (helium or nitrogen) and the gas temperature are investigated. It was possible to fabricate TiO2 coatings with an anatase phase in all spraying conditions. The process gas used is not an important factor to fabricate TiO2 coatings. The thickness of the coatings increased with the process gas temperature increasing. It indicates that the deposition efficiency of the sprayed particles can be enhanced by controlling the spray conditions. The photocatalytic activity of the coatings is similar or better than the feedstock powder due to the formation of a large reaction area. Concludingly, cold spraying is an ideal process for the fabrication of a TiO2 photocatalyst coating.

Yamada, Motohiro; Isago, Hiroaki; Nakano, Hiromi; Fukumoto, Masahiro

2010-12-01

22

The Synthesis of Titanium Dioxide (TiO2) Powder for Cold Spray Process  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) has attracted numerous attentions due to its high photocatalytic property. TiO2 as photocatalyst is best to be coated over large area substrate (walls, windows, etc.). In this case, cold spray process is the most suitable technique, not only because its simplicity and efficiency for large area deposition, but also because it is a low temperature process that would retain the high photocatalytic anatase phase of TiO2 in the coating. However, cold spraying of hard ceramic materials, such as TiO2, is widely known to be difficult. In this study, we are reporting a novel synthesis method of TiO2 powder for cold spray via the hydrolysis of titanyl sulphate (TiOSO4) with addition of ammonium sulphate ((NH4)2SO4). It is a relatively simple synthesis method that can obtain pure anatase structure even without high temperature treatment, although post treatments, such as hydrothermal and calcination further increase the crystallinity and change the morphology of synthesised TiO2. It is believed that the synergetic effect of post treatments and adsorption of NH4+ and SO42- ions on the surface of TiO2 causes the alteration in morphology of TiO2 powder. Finally, the cold spray spot test shows that the TiO2 powders can be cold sprayed. This is a remarkable finding as the difficulty of cold spraying TiO2 is widely known.

Tjitra Salim, N.; Yamada, M.; Nakano, H.; Fukumoto, M.

2011-10-01

23

Nanostructured TiO2 photocatalysts for the determination of organic pollutants.  

PubMed

Owing to the inherent advantages of nanostructured TiO(2) photocatalysts, including high photocatalytic activity, strong oxidation power, low cost, environmental benignity and excellent stability, TiO(2) photocatalyts have recently attracted extensive attention from scientific researchers, technology developers and investors for use in sensing applications. The TiO(2) sensors can be used for lab-based analyses, on-line and on-site determination of organic pollutants in wastewater. This work reviews the application of TiO(2) nanomaterials in photocatalytic and photoelectrocatalytic monitoring of aggregative organic parameters such as total organic carbon (TOC) and chemical oxygen demand (COD), as well as individual organic compounds in aqueous solution. PMID:22133353

Qiu, Jingxia; Zhang, Shanqing; Zhao, Huijun

2012-04-15

24

The preparation of nitrogen-doped photocatalyst TiO 2 ? x N x by ball milling  

Microsoft Academic Search

The nitrogen-doped photocatalyst TiO2?xNx is prepared by ball milling of TiO2 in a NH3·H2O solution, and the photocatalyst is characterized by the UV–vis diffuse reflection spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Transmission electron microscopy (TEM). Based on the results of the characterization, the mechanisms of the photocatalyst TiO2?xNx formation and the increase in the photocatalytic activity

Chen Shifu; Chen Lei; Gao Shen; Cao Gengyu

2005-01-01

25

Design of TiO 2SiC photocatalyst using TiCSiC nano-particles for degradation of 2-propanol diluted in water  

Microsoft Academic Search

TiO2 photocatalyst deposited on SiC (TiO2-SiC) was prepared by a calcination of nano-particles of TiC-SiC precursor obtained by a carbothermic reduction of SiO2-TiO2. The formation of the mixture of well-crystallized anatase and rutile phases of TiO2 was observed on the calcined TiO2-SiC photocatalyst, while amorphous TiO2 species was main component on the TiO2-SiO2 photocatalyst prepared by a conventional sol–gel method.

Hiromi Yamashita; Yoshikatsu Nishida; Shuai Yuan; Kohsuke Mori; Masaaki Narisawa; Yasuyuki Matsumura; Tetsutaro Ohmichi; Iwao Katayama

2007-01-01

26

Structural properties of TiO2 nanocrystallites condensed in vapor-phase for photocatalyst applications  

NASA Astrophysics Data System (ADS)

We have synthesized titanium dioxide (TiO2) nanocrystallites by pulsed laser ablation (PLA) in oxygen (O2) background gas for photocatalyst applications. Varying O2 background gas pressure ( {P_{{{O}_{ 2} }} } ) or substrate target distance (D TS), it was possible to change weight fraction of anatase phase in the anatase/rutile mixture from 0.2 to 1.0. Porosity of the deposited TiO2 films increased with increasing ( {P_{{{O}_{ 2} }} } ) and D TS. Relation between the process parameters and the formed crystal phases was explained from the point of cooling process in vapor-phase. Furthermore, rapid thermal annealing (RTA) was performed as post-annealing, suppressing sintering of the nanocrystallites. Photocatalytic activities of the TiO2 nanocrystallites depended on the RTA temperature and following crystallinity restoring as well as the crystal phase: anatase or rutile.

Yoshida, Takehito; Yagi, Nobuyasu; Nakagou, Riki; Sugimura, Akira; Umezu, Ikurou

2014-03-01

27

A novel approach towards high-performance composite photocatalyst of TiO 2 deposited on activated carbon  

NASA Astrophysics Data System (ADS)

TiO 2 photocatalysts deposited on activated carbon (TiO 2/AC) were prepared by dip-hydrothermal method at 180 °C using peroxotitanate as a precursor, then calcinated at 300-800 °C. The samples were characterized by X-ray diffraction, scanning electron microscopy, Raman spectroscopy and the nitrogen absorption. Their photocatalytic activity was evaluated by degradation of methyl orange (MO). The results showed that TiO 2 particles of anatase type were well deposited on the activated carbon surface. TiO 2/AC calcinated at 600 °C exhibited the best photocatalytic performance. For the comparison, the same photocatalysis experiment was carried out for two mixtures of commercial TiO 2 (Degussa P25) with AC and synthetic TiO 2 with AC. It was found that the composite catalyst TiO 2/AC was better than the two mixtures. Besides, different from fine powdered TiO 2, the granular TiO 2/AC photocatalysts could be easily separated from the bulk solution and reused; indeed, its photocatalytic ability was hardly decreased after a five-cycle for MO degradation. The kinetics of the MO degradation fitted well the Langmuir-Hinshelwood model.

Wang, Xiaojing; Hu, Zhonghua; Chen, Yujuan; Zhao, Guohua; Liu, Yafei; Wen, Zubiao

2009-01-01

28

Fabrication of visible-light-driven N-doped ordered mesoporous TiO2 photocatalysts and their photocatalytic applications.  

PubMed

Herein we report a facile method for the synthesis of N-doped crystalline mesoporous titanium dioxide (NMT) with ordered structure. Structural characterization and HR-TEM studies revealed that NMT exhibits pure anatase phase with highly crystalline ordered mesoporous structure in NMT. The N2 isotherms are of type IV with an H1 hysteresis loop and a pronounced capillary condensation step at high relative pressure for NMT, suggesting the presence of well-ordered mesoporous structure. The reflectance spectrum of NMT shows stronger absorption in the visible region above 400 nm, owing to the substitution of the lattice oxygen by nitrogen. XPS results proved the doping of nitrogen in to oxygen in TiO2 lattice, which confirmed by the presence of peak at 401 eV for N1s. The efficiency of photocatalyst was evaluated by the degradation of Rhodamine-B and antibacterial activity against E. coli under visible-light irradiation. N-doped mesoporous TiO2 shows superior photocatalytic and anti-bacterial activity compared to pure TiO2 under visible-light irradiation. The enhanced photocatalytic activity of NMT is attributed to synergistic effect of NMT that is N-doping and well ordered crystalline mesoporous structure with high surface area of NMT. These findings suggest that N-doped mesoporous TiO2 has potential application in many areas such as degradation of hazardous pollutants, anti-bacterial agents, fuel cells, battery electrode, sensors, opto electronic devices, photo active self-cleaning surfaces. PMID:24734752

Anandan, S; Rao, T N; Gopalan, R; Ikuma, Y

2014-04-01

29

The preparation of nitrogen-doped TiO 2? x N x photocatalyst coated on hollow glass microbeads  

Microsoft Academic Search

In this paper, the effective method for nitrogen-doped TiO2?xNx photocatalyst coated on hollow glass microbeads is described, which uses titanium tetraisopropoxide [Ti(iso-OC3H7)4] as the raw materials and gaseous ammonia as a heat treatment atmosphere. The effects of heat treatment temperature and time on the photocatalytic activity of TiO2?xNx\\/beads are studied. The photocatalyst is characterized by the UV–vis diffuse reflection spectroscopy,

Chen Shifu; Liu Xuqiang; Liu Yunzhang; Cao Gengyu

2007-01-01

30

Preparation and Performances of RuO2/TiO2 Films Photocatalyst Supported on Float Pearls  

NASA Astrophysics Data System (ADS)

RuO2/TiO2 films were deposited on float pearls (FP) by the sol-gel-dipping method. The substrates were coated with RuO2/TiO2 precursor sol, air-dried at 120°C and further heated at 500°C to obtain the coupled photocatalyst of RuO2/TiO2 films supported on FP (RuO2/TiO2/FP). The structure of coupled photocatalyst was characterized by SEM, XRD, and FT-IR technique, respectively. The results showed TiO2 has anatase structure and doped RuO2 was highly dispersed on the surface of TiO2 particles as amorphous. The average thickness of RuO2/TiO2 films (3 layers) on FP was determined to be about 1 ?m. This study was carried out under the following conditions: volume 60 mL, initial concentration of beta-cypermethrin (BEC) 45 mg/L, pH 6.5, amount of RuO2/TiO2/PF 5 g/L, air flow rate 200 mL/min, reaction time 60 min. The degradation rates of BEC are 88.1% (125 W Hg lamp), 82.8% (8 W UV lamp), and 75.1% (8 W solar lamp), respectively. The photocatalytic degradation of BEC was experimentally demonstrated to follow the Langmuir-Hinshelwood kinetic model, and the reaction rate constant (17.5 mg/(L min)) and the adsorption constant (3.486 L/g) were determined, respectively. It was also found that the RuO2/TiO2/FP photocatalyst has significantly the visible light photoactivity for degradation of BEC.

Yao, Bing-hua; Wang, Li-ming; Wang, Cheng; Wang, Yi-xun; Zhao, Gao-yang

2007-12-01

31

Comparative investigation on photocatalytic hydrogen evolution over Cu, Pd, and Au-loaded mesoporous TiO 2 photocatalysts  

Microsoft Academic Search

Photocatalytic activity for hydrogen evolution from water using methanol as hole scavenger was comparatively investigated over mesoporous TiO2 photocatalysts with various contents of Cu, Pd, and Au cocatalyst loadings prepared by single-step sol–gel (SSSG) process with surfactant template. The photocatalysts were analytically characterized by X-ray diffraction (XRD), N2 adsorption–desorption, Brunauer–Emmett–Teller (BET) surface area, Barrett–Joyner–Halenda (BJH) pore size distribution, scanning electron

Thammanoon Sreethawong; Susumu Yoshikawa

2005-01-01

32

Ordered Mesoporous Black TiO2 as Highly Efficient Hydrogen Evolution Photocatalyst.  

PubMed

Mesoporous TiO2 has gained increasing interest because of its outstanding properties and promising applications in a wide range of fields. Herein, we report the facile synthesis of ordered mesoporous black TiO2 (OMBT) materials, which exhibit excellent photocatalytic hydrogen evolution performances. In this case, the employment of a thermally stable and high-surface-area mesoporous TiO2 as the hydrogenation precursor is the key for fabricating the OMBT materials, which not only facilitate H2 gas diffusion into TiO2 and interaction with their structures but also maintain the ordered mesoporous structures as well as inhibit the phase transformation (from anatase to rutile) and crystal growth during hydrogenation at 500 °C. The resultant OMBT materials possess a relatively high surface area of ?124 m(2) g(-1) and a large pore size and pore volume of ?9.6 nm and 0.24 cm(3) g(-1), respectively. More importantly, the OMBT materials can extend the photoresponse from ultraviolet to visible and infrared light regions and exhibit a high solar-driven hydrogen production rate (136.2 ?mol h(-1)), which is almost two times as high as that of pristine mesoporous TiO2 (76.6 ?mol h(-1)). PMID:24937035

Zhou, Wei; Li, Wei; Wang, Jian-Qiang; Qu, Yang; Yang, Ying; Xie, Ying; Zhang, Kaifu; Wang, Lei; Fu, Honggang; Zhao, Dongyuan

2014-07-01

33

Highly Active TiO2-Based Visible-Light Photocatalyst with Nonmetal Doping and Plasmonic Metal Decoration  

SciTech Connect

A sandwich-structured photocatalyst shows an excellent performance in degradation reactions of a number of organic compounds under UV, visible light, and direct sunlight (see picture). The catalyst was synthesized by a combination of nonmetal doping and plasmonic metal decoration of TiO2 nanocrystals, which improves visible-light activity and enhances light harvesting and charge separation, respectively.

Zhang, Qiao [University of California, Riverside; Lima, Diana Q. [University of California, Riverside; Chi, Miaofang [ORNL; Yin, Yadong [University of California, Riverside

2011-01-01

34

TiO2-V2O5 nanocomposites as alternative energy storage substances for photocatalysts.  

PubMed

TiO2-V2O5 was prepared and evaluated as an energy storage material for photocatalysts with high capacity and initial charging rate. The compound was successfully obtained by sol-gel technique and effects of compound composition and calcination temperature on the energy storage ability were investigated. The synthesized compounds were characterized by means of X-ray powder diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray analysis (SEM-EDX) and transmission electron microscopy (TEM). The results reveals that the compound of Ti:V molar ratio equal to 1:0.11 calcined at 550 degrees C exhibited superior energy storage ability than parent substances and 1.7-times higher capacity and 2.3-times higher initial charging rate compared to WO3, indicating that the compound is a remarkable alternative to conventional energy storage substances. PMID:22524065

Ngaotrakanwiwat, Pailin; Meeyoo, Vissanu

2012-01-01

35

A TiO2/AC composite photocatalyst with high activity and easy separation prepared by a hydrothermal method.  

PubMed

In the present work, a TiO2/activated carbon (AC) photocatalyst with high activity and easy separation was prepared using a hydrothermal method. Phenol, methyl orange (MO) and Cr(VI) were used as target pollutants to test the activity and decantability. SEM, XRD, FTIR, diffuse reflectance spectra (UV/DRS) and N2 adsorption isotherms were used to characterize the crystalline and electronic structure. Results show that the AC composite has a significant effect on the TiO2 activity. With suitable AC content, the TiO2/xAC catalysts prepared were much more active. The TiO2/5AC catalyst exhibited easy separation and less deactivation after several runs, and was less sensitive to pH changes. UV/DRS revealed that no electronic bandgap changes in TiO2 occurred on addition of the AC. SEM and XRD results suggest that better TiO2 distribution can be achieved when an optimal AC content is used. A Ti-O-C bond was formed and a slight conjugation effect appeared between the AC bulk and TiO2. The advantages of the obtained TiO2/5AC catalyst revealed its great practical potential in wastewater treatment. PMID:17049160

Liu, S X; Chen, X Y; Chen, X

2007-05-01

36

Synthesis, characterization and photocatalytic performance of self-assembled mesoporous TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

A facile synthesis route is reported for preparation of mesoporous TiO2 nanoparticles (MT-x) through evaporation induced self-assembly by using Pluronic F127, titanium isopropoxide, and various amounts of ethanol as templating agents, titanium sources and solvents, respectively. A variety of different spectroscopic and analytical techniques, such as small- and large-angle powder X-ray diffraction (XRD), N2 adsorption-desorption isotherms, transmission electron microscopy (TEM), Raman and Fourier transform infrared (FTIR) spectroscopies were used to characterize the physicochemical properties of various MT-x catalysts. Among the catalysts, MT-20 was found to have better mesostructures formed by the arrangement of anatase TiO2 nanoparticles of ca. 17.3 nm with broad interparticle pore size distribution. Hydrogen generation from water splitting on MT-20 using visible light was enhanced by at least 8.7 times if compared with the conventional TiO2 photocatalyst. The superior photocatalytic performances observed for the synthesized MT-20 may be attributed to the presence of unique nanostructures in the TiO2 photocatalysts.

Lin, Yuan-Chung; Liu, Shou-Heng; Syu, Han-Ren; Ho, Tsung-Han

37

Graphene strongly wrapped TiO2 for high-reactive photocatalyst: A new sight for significant application of graphene.  

PubMed

A new idea was employed to simultaneously reduce graphene oxide (GO) and wrap it on the surface of high-reactive anatase TiO2 for fabricating novel TiO2-graphene (GP) hybrid materials. The process was based on the surface negatively charged property of GO. With the introduction of strong chemical interaction between TiO2 and GP, the GP wrapped TiO2 gives a strong red-shift of the light absorption edge and a further narrowed bandgap compared to that of GP randomly supported TiO2. This structure can also significantly enhance the separation efficiency of photogenerated electrons and holes. Furthermore, in contrast to the normal anatase TiO2, as-prepared TiO2 is dominated with the high-reactive {001} facet. The superiority of the formed "core-shell" structure is confirmed by photocatalytic degradation of methylene blue (MB) under the xenon lamp and visible light irradiation. New photocatalytic mechanisms are also proposed based on the obtained results. This work may open a new doorway for new significant application of GP to prepare more GP-based high-reactive photocatalysts for environmental protection. PMID:24910049

Ni, Yaru; Wang, Wei; Huang, Wenjuan; Lu, Chunhua; Xu, Zhongzi

2014-08-15

38

A visible-light-driven composite photocatalyst of TiO2 nanotube arrays and graphene quantum dots  

PubMed Central

Summary TiO2 nanotube arrays are well-known efficient UV-driven photocatalysts. The incorporation of graphene quantum dots could extend the photo-response of the nanotubes to the visible-light range. Graphene quantum dot-sensitized TiO2 nanotube arrays were synthesized by covalently coupling these two materials. The product was characterized by Fourier-transform infrared spectrometry (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and UV–vis absorption spectroscopy. The product exhibited high photocatalytic performance in the photodegradation of methylene blue and enhanced photocurrent under visible light irradiation.

Chan, Donald K L; Cheung, Po Ling

2014-01-01

39

Promotion effect of Al 2O 3–SiO 2 interlayer and Pt loading on TiO 2\\/nickel-foam photocatalyst for degrading gaseous acetaldehyde  

Microsoft Academic Search

TiO2 photocatalysts coated on foam nickel were prepared by sol–gel method. Al2O3–SiO2 films introducing as transition interlayer between TiO2 and nickel metal foam were used to promote the photocatalytic activity of TiO2. The results show that TiO2\\/Al2O3–SiO2 composite films have much higher photocatalytic activity and stability for degradation of gaseous acetaldehyde than TiO2 films. The significant enhancement effect arises from

Jian Yuan; Hai Hu; Mingxia Chen; Jianwei Shi; Wenfeng Shangguan

2008-01-01

40

Preparation and Characterization of TiO2-Based Photocatalysts by Chemical Vapour Deposition  

NASA Astrophysics Data System (ADS)

In the present work, a novel technique for the preparation of TiO2-based photocatalysts modified with SiO2 is presented, using a pulsed ArF laser to induce a chemical vapor deposition process. The irradiated gas mixture was composed of TiCl4/SiCl4 precursors in excess of oxygen. Laser irradiation at 193 nm with a repetition frequency of 10 Hz induced the deposition of thin nano-sized mixed oxide films. In order to improve the photocatalytic activity of the catalysts and to expand the activity from the UV to the visible part of the spectrum, doping of the catalysts with chromium oxides was performed. For that aim, the same technique of catalyst preparation was used, irradiating the same gas mixture with the addition of chromyl chloride as Cr precursor. The thin films prepared were annealed up to 500°C in order to remove crystal defects, which could be responsible for poor photocatalytic activity. The dependence of structure and properties on reaction process and irradiation conditions (laser energy and fluence, precursors pressure) were examined. The main aim was to find the best conditions for the production of highly photoactive catalysts and to decrease deactivation processes during the photo-oxidation. The composition, structure and morphology of the oxide catalysts prepared were studied by various spectroscopies, electron microscopy and diffraction techniques.

Nacevski, Goran; Marinkovski, Mirko; Tomovska, Radmila; Fajgar, Radek

41

Microfibrous TiO 2 supported photocatalysts prepared by metal-organic chemical vapor infiltration for indoor air and waste water purification  

Microsoft Academic Search

The photocatalytic degradation of gaseous (toluene) and aqueous (imazapyr, malic acid, orange G) pollutants over TiO2 supported photocatalysts is investigated using a batch reactor. A strong influence of the microstructural characteristics of TiO2 on the decomposition kinetics of the pollutants is found. Well crystallized, porous TiO2-anatase films grown under low pressure at 400–500°C by MOCVD on glass plates and by

Christos Sarantopoulos; Eric Puzenat; Chantal Guillard; Jean-Marie Herrmann; Alain N. Gleizes; Francis Maury

2009-01-01

42

Use of titanium dioxide (TiO2) photocatalysts as alternative means for Listeria monocytogenes biofilm disinfection in food processing.  

PubMed

The aim of this work was to study the photocatalytic activity of titanium dioxide (TiO(2)) against Listeria monocytogenes bacterial biofilm. Different TiO(2) nanostructured thin films were deposited on surfaces such as stainless steel and glass using the doctor-blade technique. All the surfaces were placed in test tubes containing Brain Heart (BH) broth and inoculated with L. monocytogenes. Test tubes were then incubated for 10 days at 16°C in order to allow biofilm development. After biofilm formation, the surfaces were illuminated by ultraviolet A light (UVA; wavelength of 315-400 nm). The quantification of biofilms was performed using the bead vortexing method, followed by agar plating and/or by conductance measurements (via the metabolic activity of biofilm cells). The presence of the TiO(2) nanoparticles resulted in a fastest log-reduction of bacterial biofilm compared to the control test. The biofilm of L. monocytogenes for the glass nanoparticle 1 (glass surface modified by 16% w/v TiO(2)) was found to have decreased by 3 log CFU/cm(2) after 90 min irradiation by UVA. The use of TiO(2) nanostructured photocatalysts as alternative means of disinfecting contaminated surfaces presents an intriguing case, which by further development may provide potent disinfecting solutions. Surface modification using nanostructured titania and UV irradiation is an innovative combination to enhance food safety and economizing time and money. PMID:21056789

Chorianopoulos, N G; Tsoukleris, D S; Panagou, E Z; Falaras, P; Nychas, G-J E

2011-02-01

43

Photodegradation of phenanthrene by N-doped TiO2 photocatalyst  

Microsoft Academic Search

The photodegradation of phenanthrene has been catalyzed by nanostructures of TiO2 doped with nitrogen, N-doped TiO2. The N-doped TiO2 was prepared from the sol-gel reaction of Titanium(IV) bis(ethyl acetoacetato)diisopropoxide with 25% ammonia solution. The N-doped TiO2 was calcined at various temperatures from 300 to 700°C. X-ray diffraction (XRD) results showed that N-doped TiO2 remained amorphous at 300°C but anatase-to-rutile transformation

Weekit Sirisaksoontorn; Surachai Thachepan; Apisit Songsasen

2009-01-01

44

Synthetic trends for BiVO4 photocatalysts: Molybdenum substitution vs. TiO2 and SnO2 heterojunctions  

NASA Astrophysics Data System (ADS)

The influence of hydrothermal synthesis, thermal post-treatment at 500 °C and Mo content on a series of Bi1-x/3V1-xMoxO4 (0.02photocatalysts was investigated for methylene blue (MB) degradation and O2 evolution. Mo incorporation stabilizes the tetragonal scheelite phase of BiVO4, thereby inducing a small blue shift of the band gap. This adverse effect can be partially compensated by incorporation of lower Mo amounts (up to ca. 4%), which stabilizes the particle morphology upon calcination. Both BiVO4@TiO2 and BiVO4:Mo@TiO2 heterojunction composites with TiO2 particle coatings in the 10 nm range were newly synthesized and displayed promising photocatalytic performance in MB degradation. Comparative studies with SnO2 heterojunctions revealed a superior influence of TiO2 deposition over SnO2 coating on both BiVO4 and Bi1-x/3V1-xMoxO4 oxide substrates. Different synthetic guidelines for BiVO4-based solid solutions and heterojunctions in photocatalytic wastewater treatment and water oxidation are discussed.

Kontic, Roman; Patzke, Greta R.

2012-05-01

45

Boosting fuel cell performance with a semiconductor photocatalyst: TiO2/Pt-Ru hybrid catalyst for methanol oxidation.  

PubMed

A hybrid carbon fiber electrode (CFE) consisting of TiO2 semiconductor photocatalyst and Pt-Ru catalyst has been developed to boost the performance of direct methanol fuel cells (DMFC). These two catalyst nanoparticles are deposited on opposite sides of the carbon fiber paper such that methanol oxidation is carried out catalytically on Pt-Ru and photocatalytically on TiO2 under UV-light irradiation. Since both catalysts carry out methanol oxidation independently, we observe an additive effect in the current generation. The carbon support fibers provide a large network to collect the electrons from both of these catalytic processes and thus assist in efficient current generation. In addition, TiO2 improves the performance of the Pt-Ru catalyst in dark, indicating possible surface area improvement or diminished poisoning effects. The concept of incorporating a photocatalyst provides new ways to minimize precious metal content and enhance the performance of DMFCs. At low catalyst loadings (0.15 mg/cm2) at 295 K, a 25% enhancement in the peak power density is observed upon illumination with light. PMID:16852456

Drew, Kristine; Girishkumar, G; Vinodgopal, K; Kamat, Prashant V

2005-06-23

46

Preparation and characterization of N-S-codoped TiO(2) photocatalyst and its photocatalytic activity.  

PubMed

N-S-codoped anatase nanosized TiO(2) photocatalyst (NSTO) was successfully prepared by one-step hydrothermal method from a mixed aqueous solution of Ti(SO(4))(2) and thiourea. The samples were characterized by XRD, UV-vis, XPS, FT-IR and EA. From results of UV-vis, a red shift of the absorption edge was brought out owing to N and S codoping, and the extension for photoabsorption range of NSTO occurred. XRD, XPS, EA and FT-IR studies revealed that N and S were in situ codoped in the lattice of TiO(2) and N concentration decreased from the surface to the center of NSTO. Especially, the photocatalytic tests indicated that NSTO exhibited a high activity for decompositions of methyl orange both under UV-light and vis-light irradiation comparing to S-doped TiO(2) (STO) and undoped TiO(2) (TO). The high activity of NSTO can be related to the results of the synergetic effects of strong absorption in the UV-vis region, red shift in adsorption edge, oxygen vacancies and the enhancement of surface acidity induced by N and S codoping. PMID:18206303

Wei, Fengyu; Ni, Liangsuo; Cui, Peng

2008-08-15

47

Surface Acidity and Photocatalytic Activity of Nb 2O 5\\/TiO 2 Photocatalysts  

Microsoft Academic Search

Samples of Nb2O5\\/TiO2 mixed oxide powders were prepared by the incipient wetness method. The photocatalytic activities of TiO2 based catalysts were evaluated by the degradation of 1,4-dichlorobenzene (DCB). The addition of Nb2O5 to TiO2 greatly increased its photocatalytic activity and also increased the catalyst's surface acidity, as determined by the n-butylamine titration method. A correlation between the maximum photocatalytic activity

H. Cui; K. Dwight; S. Soled; A. Wold

1995-01-01

48

Feasibility of Silver Doped TiO2/Glass Fiber Photocatalyst under Visible Irradiation as an Indoor Air Germicide  

PubMed Central

This study investigated the feasibility of using Ag-TiO2 photocatalyst supported on glass fiber (Ag-TiO2/GF) prepared by a sol-gel method as an indoor air germicide. An experimental model was designed to investigate the bacterial disinfection efficiency of Staphylococcus (Staph), the most popular bacterium in hospitals in Korea, by the Ag-TiO2/GF photocatalyst. The silver content in Ag/TiO2 was altered from 1 to 10% to investigate the optimal ratio of Ag doped on TiO2/glass fiber (TiO2/GF) for photocatalytic disinfection of Staph. This study confirmed that Ag in Ag-TiO2/GF could work as an electron sink or donor to increase photocatalytic activity and promote the charge separation of electron-hole pairs generated from TiO2 after photon absorption. Ag also acts as an intermediate agent for the transfer of photo-generated electrons from the valence band of TiO2 to an acceptor (O2 gas) to promote photo-oxidation processes. The photocatalytic disinfection activity of Ag-TiO2/GF under visible light increased with the increase in silver content up to 7.5% and then slightly decreased with further increasing silver content. The highest disinfection efficiency and disinfection capacity of Staph using 7.5% Ag-TiO2/GF were 75.23% and 20 (CFU?s?1?cm?2) respectively. The medium level of humidity of 60% ± 5% showed better photocatalytic disinfection than the lower (40% ± 5%) or higher (80% ± 5%) levels.

Pham, Thanh-Dong; Lee, Byeong-Kyu

2014-01-01

49

Visible-light-derived photocatalyst based on TiO(2-?)N? with a tubular structure.  

PubMed

We succeeded in achieving visible-light responsiveness on a tubular TiO(2) sample through the treatment of a tubular TiO(2) that has a large surface area with an aqueous solution of ammonia or triethylamine at room temperature and subsequent calcination at 623 K, which produced a nitrided tubular TiO(2) sample. It was found that the ease of nitridation is dependent on the surface states; washing the tubular TiO(2) sample with an aqueous acidic solution is very effective and indispensable. This treatment causes the appearance of acidic sites on the tubular TiO(2), which was proved by the following experiments: NH(3) temperature-programmed desorption and two types of organic reactions exploiting the acid properties. The prepared samples, TiO(2-?)N(?), efficiently absorb light in the visible region, and they exhibit a prominent feature for the decomposition of methylene blue in an aqueous solution at 300 K under irradiation with visible light, indicating the achievement of visible-light responsiveness on the tubular TiO(2) sample. This type of tubular TiO(2-?)N(?) sample has merit in the sense that it has a large surface area and a characteristic high transparency for enabling photocatalytic reactions because it has a tubular structure and is composed of thin walls. PMID:21910440

Hirose, Yoshikazu; Mori, Toshinori; Morishita, Yuka; Itadani, Atsushi; Kudoh, Takayuki; Ohkubo, Takahiro; Matsuda, Tomoko; Kittaka, Shigeharu; Kuroda, Yasushige

2011-10-17

50

Photocatalytic synthesis of TiO(2) and reduced graphene oxide nanocomposite for lithium ion battery.  

PubMed

In this work, we synthesized graphene oxide (GO) using the improved Hummers' oxidation method. TiO2 nanoparticles can be anchored on the GO sheets via the abundant oxygen-containing functional groups such as epoxy, hydroxyl, carbonyl, and carboxyl groups on the GO sheets. Using the TiO2 photocatalyst, the GO was photocatalytically reduced under UV illumination, leading to the production of TiO2-reduced graphene oxide (TiO2-RGO) nanocomposite. The as-prepared TiO2, TiO2-GO, and TiO2-RGO nanocomposite were used to fabricate lithium ion batteries (LIBs) as the active anode materials and their corresponding lithium ion insertion/extraction performance was evaluated. The resultant LIBs of the TiO2-RGO nanocomposite possesses more stable cyclic performance, larger reversible capacity, and better rate capability, compared with that of the pure TiO2 and TiO2-GO samples. The electrochemical and materials characterization suggest that the graphene network provides efficient pathways for electron transfer, and the TiO2 nanoparticles prevent the restacking of the graphene nanosheets, resulting in the improvement in both electric conductivity and specific capacity, respectively. This work suggests that the TiO2 based photocatalytic method could be a simple, low-cost, and efficient approach for large-scale production of anode materials for lithium ion batteries. PMID:22738305

Qiu, Jingxia; Zhang, Peng; Ling, Min; Li, Sheng; Liu, Porun; Zhao, Huijun; Zhang, Shanqing

2012-07-25

51

Surface Acidity and Photocatalytic Activity of Nb 2O 5/TiO 2 Photocatalysts  

NASA Astrophysics Data System (ADS)

Samples of Nb 2O 5/TiO 2 mixed oxide powders were prepared by the incipient wetness method. The photocatalytic activities of TiO 2 based catalysts were evaluated by the degradation of 1,4-dichlorobenzene (DCB). The addition of Nb 2O 5 to TiO 2 greatly increased its photocatalytic activity and also increased the catalyst's surface acidity, as determined by the n-butylamine titration method. A correlation between the maximum photocatalytic activity and the number and strength of acid sites were observed. Consequently, the same structural feature that enhances the adsorption of n-butylamine appears to promote the catalytic activity.

Cui, H.; Dwight, K.; Soled, S.; Wold, A.

1995-02-01

52

One-step preparation of silver and indium oxide co-doped TiO 2 photocatalyst for the degradation of rhodamine B  

Microsoft Academic Search

A novel co-doped TiO2 photocatalyst, Ag\\/In2O3–TiO2, was developed through a one-step sol–gel process followed by a solvent thermal treatment in the presence of triblock copolymer surfactant. The product showed very small particle size (12±2nm) with metallic Ag clusters well-distributed on the surface of the product, at the same time, the product was mainly in the anatase phase with high crystallinity.

Xia Yang; Leilei Xu; Xiaodan Yu; Yihang Guo

2008-01-01

53

Preparation of TiO 2-pillared montmorillonite as photocatalyst Part I. Microwave calcination, characterisation, and adsorption of a textile azo dye  

Microsoft Academic Search

Two photocatalysts based on TiO2-pillared intercalated montmorillonite have been prepared by microwave for 10 min at 700 W or by furnace heating at 673 K. Montmorillonite pillaring with TiO2 increased the basal spacing to 14.7 Å (conventional heating) and 17.6 Å (microwave heating). XRD patterns of both materials showed the presence of 100% anatase with a slightly higher rate of crystallinity obtained through microwave calcination

Boualem Damardji; Hussein Khalaf; Laurent Duclaux; Bernard David

2009-01-01

54

TiO 2 -based photocatalysts impregnated with metallo-porphyrins employed for degradation of 4-nitrophenol in aqueous solutions: role of metal and macrocycle  

Microsoft Academic Search

Photodegradation of organic compounds in water solutions by means of economically advantageous and environment-friendly processes\\u000a is a topic of growing interest. In recent years a great attention has been devoted to TiO2-based photocatalysts for the oxidative degradation of various organic pollutants. In this context, we have prepared new photo-catalytic\\u000a polycrystalline TiO2 systems impregnated with sensitizers, i.e., copper, iron or manganese

Giuseppe Mele; Roberta del Sole; Giuseppe Vasapollo; Elisa García-López; Leonardo Palmisano; Li Jun; Rudolf S?ota; Gabriela Dyrda

2007-01-01

55

[Visible-light responding BiVO4/TiO2 nanocomposite photocatalyst].  

PubMed

The two kinds of new nanocomposites BiVO4/TiO2 nanowires were synthesized by hydrothermal process. Their crystal structure, morphology and photocatalytic activities for degradation of methylene blue solution were characterized using various measurement techniques. The XRD results indicate that they are made up of monoclinic BiVO4 and anatase TiO2 phases. The SEM, TEM and HRTEM images show that the two samples include BiVO4 nanoparticles supported onto TiO2 nanowires. The UV-Vis absorption spectra reveal that the absorption edges of the samples exhibit red-shift in comparison with that of the pure TiO2 nanowires. The measurement results for the visible-light photodegradation of methylene blue show that the nanocomposite sample prepared from the layered titanate nanowires with Bi3+ has the highest photocatalytic activity. PMID:20828005

Ji, Tian-hao; Yang, Fang; Zhou, Jiao-yan; Du, Hai-yan; Sun, Jia-yue

2010-07-01

56

[A study on preparation and characteristic of RuO2/TiO2 coupled photocatalyst].  

PubMed

RuO2/TiQ2 coupled photocatalyst was prepared by sol-gel-dipping method. Being a model reaction, the photocatalytic degradation of direct fast black G was investigated in RuO2/TiO2 powder suspension irradiated by UV-lamp. The results showed that the addition of RuO2 to TiO2 greatly enhanced its photocatalytic activity, and the optimum dipped content of RuO2 was 0.16%, the optimum value of the calcinations temperature and the addition of RuO2/TiO2 powder were 500 degrees C and 5.00 g x L(-1), respectively. The photocatalytic degradation of direct fast black G was experimentally demonstrated to follow the Langmuir-Hinshelwood kinetic model, and the adsorption constant (14.22 L x mmol(-1)) and the reaction rate constant [4.94 x 10(-3) mmol(L x min)(-1)] were determined, respectively. PMID:16201376

Yao, Bing-hua; Wang, Li-ming; Yu, Xiao-jiao; Yang, Guo-nong; Zhao, Gao-yang; Zheng, Huai-li

2005-06-01

57

Highly efficient and recyclable triple-shelled Ag@Fe3O4@SiO2@TiO2 photocatalysts for degradation of organic pollutants and reduction of hexavalent chromium ions  

NASA Astrophysics Data System (ADS)

Herein, we demonstrate the design and fabrication of the well-defined triple-shelled Ag@Fe3O4@SiO2@TiO2 nanospheres with burr-shaped hierarchical structures, in which the multiple distinct functional components are integrated wonderfully into a single nanostructure. In comparison with commercial TiO2 (P25), pure TiO2 microspheres, Fe3O4@SiO2@TiO2 and annealed Ag@Fe3O4@SiO2@TiO2 nanocomposites, the as-obtained amorphous triple-shelled Ag@Fe3O4@SiO2@TiO2 hierarchical nanospheres exhibit a markedly enhanced visible light or sunlight photocatalytic activity towards the photodegradation of methylene blue and photoreduction of hexavalent chromium ions in wastewater. The outstanding photocatalytic activities of the plasmonic photocatalyst are mainly due to the enhanced light harvesting, reduced transport paths for both mass and charge transport, reduced recombination probability of photogenerated electrons/holes, near field electromagnetic enhancement and efficient scattering from the plasmonic nanostructure, increased surface-to-volume ratio and active sites in three dimensional (3D) hierarchical porous nanostructures, and improved photo/chemical stability. More importantly, the hierarchical nanostructured Ag@Fe3O4@SiO2@TiO2 photocatalysts could be easily collected and separated by applying an external magnetic field and reused at least five times without any appreciable reduction in photocatalytic efficiency. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, make these multifunctional nanostructures promising candidates to remediate aquatic contaminants and meet the demands of future environmental issues.Herein, we demonstrate the design and fabrication of the well-defined triple-shelled Ag@Fe3O4@SiO2@TiO2 nanospheres with burr-shaped hierarchical structures, in which the multiple distinct functional components are integrated wonderfully into a single nanostructure. In comparison with commercial TiO2 (P25), pure TiO2 microspheres, Fe3O4@SiO2@TiO2 and annealed Ag@Fe3O4@SiO2@TiO2 nanocomposites, the as-obtained amorphous triple-shelled Ag@Fe3O4@SiO2@TiO2 hierarchical nanospheres exhibit a markedly enhanced visible light or sunlight photocatalytic activity towards the photodegradation of methylene blue and photoreduction of hexavalent chromium ions in wastewater. The outstanding photocatalytic activities of the plasmonic photocatalyst are mainly due to the enhanced light harvesting, reduced transport paths for both mass and charge transport, reduced recombination probability of photogenerated electrons/holes, near field electromagnetic enhancement and efficient scattering from the plasmonic nanostructure, increased surface-to-volume ratio and active sites in three dimensional (3D) hierarchical porous nanostructures, and improved photo/chemical stability. More importantly, the hierarchical nanostructured Ag@Fe3O4@SiO2@TiO2 photocatalysts could be easily collected and separated by applying an external magnetic field and reused at least five times without any appreciable reduction in photocatalytic efficiency. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, make these multifunctional nanostructures promising candidates to remediate aquatic contaminants and meet the demands of future environmental issues. Electronic supplementary information (ESI) available: Synthesis of TiO2 microspheres; synthesis of Fe3O4@SiO2@TiO2 nanospheres; synthesis of Ag@Fe3O4@TiO2 nanospheres; SEM images of the as-prepared products: (a) Ag@Fe3O4, (b) Ag@Fe3O4@SiO2 and (c) Ag@Fe3O4@SiO2@TiO2 (Fig. S1); TEM images of the Ag@Fe3O4@SiO2 synthesized with adding different amount of TEOS (Fig. S2); SEM, TEM and EDS spectrum of Fe3O4@SiO2@TiO2 NPs (Fig. S3); SEM and TEM images of as-prepared TiO2 microspheres (Fig. S4); nitrogen adsorption-desorption isotherm and pore size distribution plot for as-prepared Fe3O4@SiO2@TiO2 and TiO2 microspheres (Fig. S5); adsorption rate curve of MB in dark for Ag@Fe3O4@SiO2@TiO2 samples (Fig.

Su, Jianwei; Zhang, Yunxia; Xu, Sichao; Wang, Shuan; Ding, Hualin; Pan, Shusheng; Wang, Guozhong; Li, Guanghai; Zhao, Huijun

2014-04-01

58

Plasmon-enhanced water splitting on TiO2-passivated GaP photocatalysts.  

PubMed

Integrating plasmon resonant nanostructures with photocatalytic semiconductors shows great promise for high efficiency photocatalytic water splitting. However, the electrochemical instability of most III-V semiconductors severely limits their applicability in photocatalysis. In this work, we passivate p-type GaP with a thin layer of n-type TiO2 using atomic layer deposition. The TiO2 passivation layer prevents corrosion of the GaP, as evidenced by atomic force microscopy and photoelectrochemical measurements. In addition, the TiO2 passivation layer provides an enhancement in photoconversion efficiency through the formation of a charge separating pn-region. Plasmonic Au nanoparticles deposited on top of the TiO2-passivated GaP further increases the photoconversion efficiency through local field enhancement. These two enhancement mechanisms are separated by systematically varying the thickness of the TiO2 layer. Because of the tradeoff between the quickly decaying plasmonic fields and the formation of the pn-charge separation region, an optimum performance is achieved for a TiO2 thickness of 0.5 nm. Finite difference time domain (FDTD) simulations of the electric field profiles in this photocatalytic heterostructure corroborate these results. The effects of plasmonic enhancement are distinguished from the natural catalytic properties of Au by evaluating similar photocatalytic TiO2/GaP structures with catalytic, non-plasmonic metals (i.e., Pt) instead of Au. This general approach of passivating narrower band gap semiconductors enables a wider range of materials to be considered for plasmon-enhanced photocatalysis for high efficiency water splitting. PMID:24401904

Qiu, Jing; Zeng, Guangtong; Pavaskar, Prathamesh; Li, Zhen; Cronin, Stephen B

2014-02-21

59

Selective oxidation of alcohols in aqueous suspensions of rhodium ion-modified TiO2 photocatalysts under irradiation of visible light.  

PubMed

Photocatalytic oxidation of benzyl alcohols in aqueous suspensions of rhodium ion-modified titanium(iv) oxide (Rh(3+)/TiO2) in the presence of O2 under irradiation of visible light was examined. In the photocatalytic oxidation of benzyl alcohol, benzaldehyde was obtained in a high yield (97%) with >99% conversion of benzyl alcohol. Rh(3+)/TiO2 photocatalysts having various physical properties were prepared using commercially available TiO2 powders as supporting materials for Rh(3+) to investigate the effect(s) of physical properties of TiO2 on photocatalytic activities of Rh(3+)/TiO2 for selective oxidation. Adsorption properties of benzyl alcohol, benzaldehyde and benzoic acid on TiO2 were also investigated to understand the high benzaldehyde selectivity over the Rh(3+)/TiO2 photocatalyst. The reaction mechanism was discussed on the basis of the results of photocatalytic oxidation of various p-substituted benzyl alcohol derivatives. PMID:24832087

Kitano, Sho; Tanaka, Atsuhiro; Hashimoto, Keiji; Kominami, Hiroshi

2014-06-28

60

Characterization and activity of visible-light driven TiO2 photocatalyst doped with tungsten.  

PubMed

This research aimed to expand the activity of TiO(2) down to the visible light region by modifying the sol-gel conditions and doping with tungsten. The optimum conditions for calcination temperature, acid type, and heating rate were 200°C, HNO(3), and 1°C/min, respectively. The undoped TiO(2) synthesized under these conditions could significantly absorb the visible light whereas the commercial Degussa P-25 could not. The absorptivity decreased sequentially as the wavelength increased from 400 to 700 nm. Within 6 h of 2-W blue-light illumination, 23% of 0.1 mM 2-chlorophenol was removed. The XRD result showed that the crystalline was anatase phase. The visible-light absorption property of the TiO(2) became even better when doped with tungsten. At the optimum W to TiO(2) ratio of 0.5%, the degradation of 0.1 mM 2-chlorophenol increased to 53% indicating a higher photocatalytic activity. Both crystalline and amorphous TiO(2) could exhibit the photocatalytic activity under the visible light region. PMID:21045341

Putta, T; Lu, M C; Anotai, J

2010-01-01

61

Fabricating TiO2 Photocatalysts by rf Reactive Magnetron Sputtering at Varied Oxygen Partial Pressures  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) thin films were fabricated onto non-alkali glass substrates by rf reactive magnetron sputtering at room temperature using Ti-metal target at varied oxygen partial pressure [O2/(Ar + O2)]. The sputtering deposition was performed under an rf power of 200 W. The target to substrate distance was kept at 80 mm, and the total gas pressure was 10 mTorr after 2 h of deposition. It was found that the crystalline structure, surface morphology, and photocatalytic activities of the TiO2 thin films were affected by the oxygen partial pressure during deposition. The XRD patterns exhibited a broad-hump shape indicating the amorphous structure of TiO2 thin films. The thin films deposited at a relatively high value of oxygen partial pressure (70%) had a good photo-induced decomposition of methylene blue (MB), photo-induced hydrophilicity, and had a small grain size.

Lin, W. S.; Kao, L. M.; Li, W. P.; Hsu, C. Y.; Hou, K. H.

2011-08-01

62

Anatase TiO 2 nanolayer coating on cobalt ferrite nanoparticles for magnetic photocatalyst  

Microsoft Academic Search

TiO2\\/CoFe2O4 composite nanoparticles with a core–shell structure have been obtained. The core CoFe2O4 nanoparticles were synthesized via co-precipitation method, and the shell TiO2 nanocrystals were derived via sol–gel technology followed by heat-treatment at 450 °C. The morphology and the crystalline structure of composite nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray diffraction, respectively. The as-prepared composite particles can

Wuyou Fu; Haibin Yang; Minghua Li; Minghui Li; Nan Yang; Guangtian Zou

2005-01-01

63

Thin film TiO 2 photocatalyst deposited by reactive magnetron sputtering  

Microsoft Academic Search

TiO2 films were deposited by r.f. reactive magnetron sputtering on non-alkali glass at 200 °C under total gas pressure of 0.3, 1.0 and 3.0 Pa with oxygen flow ratio [O2\\/(O2+Ar)] of 30%. All films showed polycrystalline anatase structure, in which a small portion of rutile phase was observed only for the films deposited at 0.3 Pa. The films deposited at

Makiko Yamagishi; Shna Kuriki; P. K. Song; Yuzo Shigesato

2003-01-01

64

Visible-light-induced photocatalytic reduction of Cr(VI) with coupled Bi2O3/TiO2 photocatalyst and the synergistic bisphenol A oxidation.  

PubMed

Coupled Bi2O3/TiO2 photocatalysts were fabricated by sol-gel and hydrothermal methods and characterized using various spectroscopy techniques. Photocatalytic reduction of Cr(VI) in aqueous solution, together with the synergistic effect of photodegradation of bisphenol A (BPA), was investigated using these coupled Bi2O3/TiO2 under visible-light irradiation. Coupling of Bi2O3 inhibited the phase transformation from anatase to rutile and extended absorption region to visible light. Bi ions did not enter TiO2 lattice and were more likely to bond with oxygen atoms to form Bi2O3 on the surface of TiO2. Photovoltage signals in visible range revealed the effective interfacial charge transfer between Bi2O3 and TiO2. Two percent Bi2O3/TiO2 exhibited the highest photocatalytic activity of visible-light-induced reduction of Cr(VI). The addition of BPA effectively increased the photocatalytic reduction of Cr(VI). Simultaneously, the presence of Cr(VI) promoted the degradation of BPA, which was demonstrated by the investigation of TOC removal yield and generated intermediates. A possible mechanism of photocatalytic reduction of Cr(VI) and degradation of BPA in Bi2O3/TiO2 system was proposed. The synergistic effect, observed between reduction of Cr(VI) and degradation of BPA, provides beneficial method for environmental remediation and purification of the complex wastewater. PMID:22935862

Yang, Juan; Dai, Jun; Li, Jiantong

2013-04-01

65

Mesoporous core-shell TiO2 walnuts for photocatalysts and photodetectors with improved performances.  

PubMed

Mesoporous core-shell TiO2 walnuts (CSTWs) were successfully prepared by a facile one-step hydrothermal method. This superior micro-nanostructure endowed the sample with hierarchical mesopores and a high surface area of 90.97 m(2) g(-1). Their particle size, diameter and morphology could be readily controlled by varying the growth parameters. The influence of the glucose amount, the urea amount and the calcination temperature on the formation of microspheres was investigated. The formation mechanism of the mesoporous CSTWs was studied. The photocatalytic activity of CSTWs had been carried out by degradation of gaseous benzene. The results indicated that, compared with commercial TiO2 (Degussa P25), CSTWs exhibited significant photocatalytic activity. Moreover, the mesoporous CSTWs were also configured as high-performance photodetectors. When illuminated by UV light with a wavelength of 365 nm, the current was found to be significantly enhanced, and an IUV/Idark of about 500, a good rise time and decay time were obtained. PMID:24695865

He, Fei; Zhang, Chao; Zhou, Di; Cheng, Ling; Li, Tao; Li, Guangxing

2014-04-23

66

A study of parameter setting and characterization of visible-light driven nitrogen-modified commercial TiO 2 photocatalysts  

Microsoft Academic Search

An optimal condition applied to the Taguchi method with an L9 orthogonal array for preparing a visible-light driven nitrogen-modified TiO2 (N-TiO2) photocatalyst by a simple hydrolysis method has been examined for material characteristics and a photodecolorization test of methyl blue (MB) under various visible light source (fluorescent and blue LED lamps) irradiations. Results of the material characterization showed that the

Yu-Lin Kuo; Te-Li Su; Fu-Chen Kung; Tsai-Jung Wu

2011-01-01

67

Nano TiO 2 photo-catalyst and sodium hypophosphite for cross-linking cotton with poly carboxylic acids under UV and high temperature  

Microsoft Academic Search

The present research attempts to accomplish a cross-linking finish on the bleached cotton fabric by using a nano titanium dioxide photo-catalyst which can effectively operate under UV irradiation. In this study, the bleached cotton fabrics were treated with two cross-linking agents including 1,2,3,4-butane tetracarboxylic acid (BTCA) and citric acid (CA) in the presence of sodium hypophosphite (SHP) and nano TiO2

A. Nazari; M. Montazer; A. Rashidi; M. Yazdanshenas; M. Anary-Abbasinejad

2009-01-01

68

Preparation, characterization and performance of a novel visible light responsive spherical activated carbon-supported and Er3+:YFeO3-doped TiO2 photocatalyst.  

PubMed

A novel spherical activated carbon (SAC) supported and Er(3+):YFeO(3)-doped TiO(2) visible-light responsive photocatalyst (Er(3+):YFeO(3)/TiO(2)-SAC) was synthesized by a modified sol-gel method with ultrasonic dispersion. It was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscope (EDS), powder X-ray diffractometer (XRD) and UV-vis diffuse reflectance spectrophotometer (DRS). The photocatalytic activity of Er(3+):YFeO(3)/TiO(2)-SAC was evaluated for degradation of methyl orange (MO) under visible light irradiation. The effects of calcination temperature and irradiation time on its photocatalytic activity were examined. The experimental results indicated that Er(3+):YFeO(3) could function as an upconversion luminescence agent, enabling photocatalytic degradation of MO by TiO(2) under visible light. The Er(3+):YFeO(3)/TiO(2) calcinated at 700°C showed the highest photocatalytic capability compared to those calcinated at other temperatures. The photocatalytic degradation of MO followed the Langmuir-Hinshelwood kinetic model. Although the photocatalyst showed a good physical stability and could tolerate a shear force up to 25 × 10(-3)N/g, its photocatalytic activity decreased over a four-cycle of reuse in concentrated MO solution, indicating that the decreased activity was ascribed to the fouling of catalyst surface by MO during the degradation process. However, the fouled Er(3+):YFeO(3)/TiO(2)-SAC could be regenerated through water rinsing-calcination or acid rinsing-calcination treatment. PMID:22119303

Hou, Dianxun; Feng, Liang; Zhang, Jianbin; Dong, Shuangshi; Zhou, Dandan; Lim, Teik-Thye

2012-01-15

69

Fabrication of a TiO2-BDD heterojunction and its application as a photocatalyst for the simultaneous oxidation of an azo dye and reduction of Cr(VI).  

PubMed

A TiO2-boron doped diamond (TiO2-BDD) heterojunction was employed as a photocatalyst to simultaneously oxidize an azo dye C.I. reactive yellow 15 (RY15) and reduce hexavalent chromium (Cr(VI)). This heterojunction was fabricated first by depositing a BDD film on a Ti sheet in a hot filament chemical vapor deposition reactor, followed by covering a layer of TiO2 in a metal-organic chemical vapor deposition system. The morphology of this heterojunction was characterized by using a scanning electron microscope (SEM). X-ray diffraction (XRD), Raman spectroscopy, and current-voltage (I-V) measurement were used to characterize its structures. Additionally, the characterization of surface photovoltage showed that the TiO2-BDD heterojunction exhibited a higher photovoltage response and a better ability for charge separation than the photocatalyst of TiO2 directly deposited on a Ti sheet (TiO2-Ti). The photocatalytic experiments revealed that the kinetic constants for the oxidation of RY15 and the reduction of Cr(VI) were, respectively, increased by 85 and 71% when the photocatalyst of TiO2-Ti was replaced by the TiO2-BDD heterojunction. Meanwhile, a significant synergy was confirmed in the simultaneous oxidation of RY15 and reduction of Cr(VI). The enhanced photocatalytic ability of the TiO2-BDD composite could be attributed to the heterojunction. The possible photocatalytic mechanism was also discussed. PMID:18546724

Yu, Hongbin; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

2008-05-15

70

Environment-friendly biomimetic synthesis of TiO2 nanomaterials for photocatalytic application  

NASA Astrophysics Data System (ADS)

We have demonstrated an environment-friendly biomimetic synthesis method for the preparation of TiO2 nanomaterials with different crystal phases and morphologies. This is the first time that it has been found that the crystal phase of TiO2 can be controlled just by using different biotemplates, and cannot be changed by calcination up to 750?°C. In our experiment, anatase TiO2 was obtained by using yeast and albumen templates, while rutile TiO2 was formed by using dandelion pollen as the template.

Bao, Shu-Juan; Lei, Chao; Xu, Mao-Wen; Cai, Chang-Jun; Jia, Dian-Zeng

2012-05-01

71

Nanostructured AgBr loaded TiO2: An efficient sunlight active photocatalyst for degradation of Reactive Red 120.  

PubMed

The AgBr loaded TiO2 catalyst was prepared by a feasible approach with AgBr and tetraisopropyl orthotitanate and characterized by BET surface area measurement, diffuse reflectance spectra (DRS), scanning electron microscope (SEM), energy dispersive spectra (EDS), X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscope (AFM) analysis. The results of characterization reveal that AgBr loaded TiO2 has a nanostructure. Formation of the nanostructure in AgBr loaded TiO2 results in substantial shifting of the absorption edge of TiO2 to red and enhancement of visible light absorption. Electrochemical impedance spectroscopy measurements reveal that AgBr loaded TiO2 has a higher photoconductivity than prepared TiO2 due to higher separation efficiency of electron-hole pairs. Cyclic voltammetric studies reveal enhanced conductivity in AgBr loaded TiO2, which causes an increase in its photocatalytic activity. AgBr loaded TiO2 exhibited a higher photocatalytic activity than TiO2-P25 and prepared TiO2 in the photodegradation of Reactive Red 120 (RR 120). PMID:21801445

Velmurugan, Rengasamy; Sreedhar, Bojja; Swaminathan, Meenakshisundaram

2011-01-01

72

SiH/TiO2 and GeH/TiO2 Heterojunctions: Promising TiO2-based Photocatalysts under Visible Light  

PubMed Central

We use hybrid density functional calculations to find that the monolayer silicane (SiH) and the anatase TiO2(101) composite (i.e. the SiH/TiO2 heterojunction) is a promising TiO2-based photocatalyst under visible light. The band gap of the SiH/TiO2(101) heterojunction is 2.082?eV, which is an ideal material for the visible-light photoexcitation of electron-hole pairs. Furthermore, the SiH/TiO2(101) heterojunction has a favorable type-II band alignment and thus the photoexcited electron can be injected to the conduction band of anatase TiO2 from that of silicane. Finally, the proper interface charge distribution facilitates the carrier separation in the SiH/TiO2(101) interface region. The electron injection and carrier separation can prevent the recombination of electron-hole pairs. Our calculation results suggest that such electronic structure of SiH/TiO2(101) heterojunction has significant advantages over these of doped TiO2 systems for visible-light photocatalysis.

Niu, Mang; Cheng, Daojian; Cao, Dapeng

2014-01-01

73

SiH/TiO2 and GeH/TiO2 Heterojunctions: Promising TiO2-based Photocatalysts under Visible Light  

NASA Astrophysics Data System (ADS)

We use hybrid density functional calculations to find that the monolayer silicane (SiH) and the anatase TiO2(101) composite (i.e. the SiH/TiO2 heterojunction) is a promising TiO2-based photocatalyst under visible light. The band gap of the SiH/TiO2(101) heterojunction is 2.082 eV, which is an ideal material for the visible-light photoexcitation of electron-hole pairs. Furthermore, the SiH/TiO2(101) heterojunction has a favorable type-II band alignment and thus the photoexcited electron can be injected to the conduction band of anatase TiO2 from that of silicane. Finally, the proper interface charge distribution facilitates the carrier separation in the SiH/TiO2(101) interface region. The electron injection and carrier separation can prevent the recombination of electron-hole pairs. Our calculation results suggest that such electronic structure of SiH/TiO2(101) heterojunction has significant advantages over these of doped TiO2 systems for visible-light photocatalysis.

Niu, Mang; Cheng, Daojian; Cao, Dapeng

2014-05-01

74

Low energy ion-beam modification of TiO 2 photocatalyst thin film for visible light absorption  

Microsoft Academic Search

Photocatalytic reaction of activated TiO2 can be directly used for water splitting to produce hydrogen for fuel cell. TiO2 thin films have been deposited using sol–gel method and subsequently heat-treated at 500 °C to form anatase phase. Ar+ or N+ ions with energy of 30 keV were implanted in anatase TiO2 thin films with different ion doses in order to modify the

R. Fernandes; N. Patel; R. Dholam; M. Adami; A. Miotello

2009-01-01

75

Indoor air purification by photocatalyst TiO 2 immobilized on an activated carbon filter installed in an air cleaner  

Microsoft Academic Search

The enhancement effect of using TiO2 immobilized on activated carbon (TiO2\\/AC) filter for removing indoor air pollutant at parts-per-billion (ppb) levels has been previously reported. To further evaluate the TiO2\\/AC filter for practical application, it was installed in an air cleaner available in the commercial market and tested inside an environmental chamber. Nitrogen oxide (NO) and toluene were selected as

C. H. Ao; S. C. Lee

2005-01-01

76

Synthesis and characterization of sulfated TiO2 nanorods and ZrO2/TiO2 nanocomposites for the esterification of biobased organic acid.  

PubMed

TiO(2) nanorods and ZrO(2)-modified TiO(2) nanocomposites have been prepared by hydrothermal synthesis and the deposition-precipitation method. Their sulfated products were tested as solid superacid catalysts for the esterification of levulinic acid which was used as a model bio-oil molecule. SEM and TEM characterization showed that TiO(2) nanorods with diameters ranging from 20 to 200 nm and with lengths of up to 5 ?m were synthesized by a hydrothermal method at 180 °C. ZrO(2) nanoparticles with the diameters ranging from 10 to 20 nm were evenly deposited on TiO(2) nanorods. IR and XPS results suggested that sulfated ZrO(2)/TiO(2) nanocomposite has higher content of sulfate groups on the surface with a S/(Zr+Ti) ratio of 13.6% than sulfated TiO(2) nanorods with a S/Ti ratio of 4.9%. The HPLC results showed that sulfated ZrO(2)/TiO(2) nanocomposite have enhanced catalytic activity for esterification reaction between levulinic acid and ethanol compared to sulfated TiO(2) nanorods. The conversion of levulinic acid to ethyl levulinate can reach to 90.4% at the reaction temperature of 105 °C after 180 min. PMID:22891691

Li, Zhonglai; Wnetrzak, Renata; Kwapinski, Witold; Leahy, James J

2012-09-26

77

TiO 2\\/MgO composite photocatalyst: the role of MgO in photoinduced charge carrier separation  

Microsoft Academic Search

In order to minimize the charge recombination, a new bilayer TiO2\\/MgO nanoporous catalyst was fabricated in which the thin layer of insulating MgO on TiO2 acts as electron trap and barrier for recombination, enhancing the overall photocatalytic activity of TiO2. The photocatalytic activity of MgO coated TiO2 has been studied for the oxidation of 2-chlorophenol, 2,4-dichlorophenol (2,4-DCP) and 4-aminobenzoic acid

J Bandara; C. C Hadapangoda; W. G Jayasekera

2004-01-01

78

Preparation and properties of a nano TiO 2 \\/Fe 3 O 4 composite superparamagnetic photocatalyst  

Microsoft Academic Search

Nano TiO2\\/Fe3O4 composite particles with different molar ratios of TiO2 to Fe3O4 were prepared via sol-gel method. X-ray diffraction, transmission electron microscopy, and vibration sample magnetometry\\u000a were used to characterize the TiO2\\/Fe3O4 particles. The photocatalytic activity of the particles was tested by degrading methyl blue solution under UV illumination\\u000a (254 nm). The results indicate that with the content of TiO2

Yuxiang Li; Mei Zhang; Min Guo; Xidong Wang

2009-01-01

79

Fe doped TiO2-graphene nanostructures: synthesis, DFT modeling and photocatalysis.  

PubMed

In this work, Fe-doped TiO2 nanoparticles ranging from a 0.2 to 1 weight % were grown from the surface of graphene sheet templates containing -COOH functionalities using sol-gel chemistry in a green solvent, a mixture of water/ethanol. The assemblies were characterized by a variety of analytical techniques, with the coordination mechanism examined theoretically using the density functional theory (DFT). Scanning electron microscopy and transmission electron microscopy images showed excellent decoration of the Fe-doped TiO2 nanoparticles on the surface of the graphene sheets >5 nm in diameter. The surface area and optical properties of the Fe-doped photocatalysts were measured by BET, UV and PL spectrometry and compared to non-graphene and pure TiO2 analogs, showing a plateau at 0.6% Fe. Interactions between graphene and Fe-doped anatase TiO2 were also studied theoretically using the Vienna ab initio Simulation Package based on DFT. Our first-principles theoretical investigations validated the experimental findings, showing the strength in the physical and chemical adsorption between the graphene and Fe-doped TiO2. The resulting assemblies were tested for photodegradation under visible light using 17?-estradiol (E2) as a model compound, with all investigated catalysts showing significant enhancements in photocatalytic activity in the degradation of E2. PMID:25002220

Farhangi, Nasrin; Ayissi, Serge; Charpentier, Paul A

2014-08-01

80

Solvothermal synthesis of mesoporous TiO2 microspheres and their excellent photocatalytic performance under simulated sunlight irradiation  

NASA Astrophysics Data System (ADS)

TiO2 nanomaterials have been extensively studied as photocatalysts, in which mesoporous TiO2 microspheres would be good candidates for abatement of organic pollutants in waste water on account of their high photocatalytic activities and easily reclaiming. Here, mesoporous TiO2 microspheres were synthesized by a facile solvothermal method and characterized. The formation mechanism of the TiO2 microspheres was investigated based on series of control experiments. The photocatalytic activities of the as-prepared TiO2 microspheres were evaluated by photodegradations of methyl orange (MO) and phenol aqueous solutions, respectively, under simulated sunlight irradiation, and compared with those of commercial TiO2 (P25). The TiO2 microspheres exhibit excellent photodegradation activities on both MO and phenol, comparing to P25. For the two model pollutants, the photodegradation percentages by the TiO2 microspheres are both more than twice of those by P25 in the same condition. Moreover, it can quickly settle down mostly (>90%) in 20 min from the photocatalytic reaction mixture under gravity after stopping stirring and be reclaimed easily. Thus it could be a promising photocatalyst for waste water treatment.

Zhu, Lianjie; Liu, Kun; Li, Hongbin; Sun, Youguang; Qiu, Mo

2013-06-01

81

Nanocrystal Cu2O-loaded TiO2 nanotube array films as high-performance visible-light bactericidal photocatalyst.  

PubMed

In this work, we report the use of a non-toxic nanocrystal Cu(2)O-loaded TiO(2) nanotube array (Cu(2)O/TNTs) film as high-performance visible-light bactericidal photocatalyst. The samples were characterized by field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible diffusion reflection spectroscopy. This Cu(2)O/TNTs film photocatalyst is capable of complete inactivation of Escherichia coli in 5?×?10(7) colony-forming units/mL within a record short disinfection time of 20 min under visible-light irradiation. The average bactericidal percentage of the Cu(2)O/TNTs for E. coli under visible-light irradiation are 20 times and 6.6 times higher than those of TNTs under the same conditions and Cu(2)O/TNTs without light, respectively. This superior bactericidal performance is mainly attributed to the high ability to produce OH radicals by both photogenerated electron and hole of the prepared photocatalyst under visible light. The Cu(2)O/TNTs film photocatalyst makes it applicable to broad fields including drinking water disinfection. PMID:22740049

Zhang, Shengsen; Liu, Chang; Liu, Xiaolu; Zhang, Haimin; Liu, Porun; Zhang, Shanqing; Peng, Feng; Zhao, Huijun

2012-12-01

82

Application of TiO2-coated alumina beads to dielectric barrier discharge-photocatalyst hybrid process for NO and SO2 removals.  

PubMed

NO and SO2 removal by dielectric barrier discharge-photocatalyst (DBD-P) hybrid process was examined for various conditions of process variables. Alumina beads were coated with TiO2 thin film by a rotating cylindrical PCVD reactor and they were packed inside the cylindrical reactor. The NO and SO2 removal efficiencies can be enhanced by using a combination of dielectric barrier discharge and photodegradation by TiO2. The stronger the applied voltage is, the higher the pulse frequency is, or the longer the gas residence time is, the higher the NO and SO2 removal efficiencies become. By applying additional photocatalytic effect, NO removal efficiency increased more significantly than SO2 removal efficiency, because SO2 removal efficiency was already high by dielectric barrier discharge only. In this study, we found that the alumina beads coated with TiO2 thin film by a rotating cylindrical PCVD reactor could be used effectively to remove NO and SO2 by DBD-P hybrid process. PMID:21456180

Nasonova, Anna; Pham, Hung Cuong; Kim, Dong-Joo; Kim, Woo-Sik; Charinpanitkul, Tawatchai; Kim, Kyo-Seon

2011-02-01

83

A hydrothermal synthesis of Pr3+ doped mesoporous TiO2 for UV light photocatalysis.  

PubMed

Pr3+ doped mesoporous TiO2 photocatalysts with a different molar ratio of Pr to Ti were prepared by a hydrothermal method using triblock copolymer as the template. The as-prepared samples were systematically characterized by X-ray diffraction, N2 adsorption-desorption, X-ray photoelectron spectra, transmission electron microscopy and UV-visible diffuse reflectance spectroscopy. The characterizations indicated all the samples had mesoporous structure and narrow pore size distribution. Pr3+ doping enlarged the surface area and decreased the crystallite size. The surface area of the samples varied from 136 to 170 m2/g, and the average crystallite size ranged between 5.04 and 7.60 nm. The effect of Pr3+ doping amount on the photocatalytic activity of mesoporous TiO2 was evaluated by the degradation of methyl orange under UV light irradiation. The results showed that the suitable amount of Pr3+ doped samples exhibited the higher photocatalytic activity than mesoporous TiO2. Among the samples, 1 at.% Pr3+ doped mesoporous TiO2 showed the highest photocatalytic activity. PMID:24757971

Wang, Yong; Chen, Guihua; Shen, Qianhong; Yang, Hui; Li, Liquan; Song, Yanjiang

2014-07-01

84

Photocatalyst of TiO 2\\/ZnO nano composite film: Preparation, characterization, and photodegradation activity of methyl orange  

Microsoft Academic Search

The TiO2\\/ZnO nano composite film with atomic ratios of Ti\\/(Ti+Zn) of 100%, 75%, 50%, 25%, and 0% was successfully prepared via sol–gel process from directly mixing TiO2\\/ZnO sol followed by heat treatment at 500°C for 2h in air. The SEM observation and the XRD measurement revealed that the microstructural morphology and the crystallization behavior of the composite film were essentially

Jintao Tian; Lijuan Chen; Yansheng Yin; Xin Wang; Jinhui Dai; Zhibin Zhu; Xiaoyun Liu; Pingwei Wu

2009-01-01

85

An efficient TiO 2 thin-film photocatalyst: photocatalytic properties in gas-phase acetaldehyde degradation  

Microsoft Academic Search

A semitransparent TiO2 film with extraordinarily high photocatalytic activity was prepared on a glass substrate by sintering a TiO2 sol at 450 °C. Crystallographic analysis by X-ray diffraction and Raman spectroscopy showed that the film was purely anatase. The photocatalytic properties of the film were investigated by measuring the photodegradative oxidation of gaseous acetaldehyde at various concentrations under strong and

Iis Sopyan; Mitsuru Watanabe; Sadao Murasawa; Kazuhito Hashimoto; Akira Fujishima

1996-01-01

86

Amine functionalized TiO2-carbon nanotube composite: synthesis, characterization and application to glucose biosensing  

NASA Astrophysics Data System (ADS)

The synthesis of amine functionalized TiO2-coated multiwalled carbon nanotubes (NH2-TiO2-CNTs) using sol-gel method was investigated. The synthesized nanocomposite was characterized with XRD, FTIR spectroscopy, BET test and SEM imaging. The results demonstrated a unique nanostructure with no destruction of the CNTs' shape. In addition, the presence of amine groups on the composite surface was confirmed by FTIR. This nanocomposite was used for one-step immobilization of glucose oxidase (GOx) to sense glucose. The result of cyclic voltammetry showed a pair of well-defined and quasi-reversible peaks for direct electron transfer of GOx in the absence of glucose. Also, the result of electrochemical impedance spectroscopy indicated that GOx was successfully immobilized on the surface of NH2-TiO2-CNTs. Furthermore, good amperometric response showed that immobilized GOx on the NH2-TiO2-CNTs exhibits exceptional bioelectrocatalytic activity toward glucose oxidation.

Tasviri, Mahboubeh; Rafiee-Pour, Hossain-Ali; Ghourchian, Hedayatollah; Gholami, Mohammad Reza

2011-12-01

87

The hybrid photocatalyst of TiO2-SiO2 thin film prepared from rice husk silica  

NASA Astrophysics Data System (ADS)

The TiO2-SiO2 thin film was prepared by self-assembly method by mixing SiO2 precursor with titanium precursor solution and aged to obtain a co-precipitation of silica and titanium crystals. Dip coating method was applied for thin film preparation on glass slide. The X-ray diffraction (XRD) of the self-assembly thin film had no characteristic property of SiO2 and even anatase TiO2 but indicated new crystal structure which was determined from the Fourier Transform Infrared Spectrophotometer (FTIR) as a hybridized Ti-O-Si bonding. The surface area and surface volume of the self-assembly sample were increased when SiO2 was incorporated into the film. The self-assembly TiO2-SiO2 thin film exhibited the enhanced photocatalytic decolorization of methylene blue (MB) dye. The advantages of SiO2 are; (1) to increase the adsorbability of the film and (2) to provide the hydroxyl radical to promote the photocatalytic reaction. The self-assembly thin film with the optimum molar ratio (SiO2:TiO2) as 20:80 gave the best performance for photocatalytic decolorization of MB dye with the overall efficiency of 81%.

Klankaw, P.; Chawengkijwanich, C.; Grisdanurak, N.; Chiarakorn, Siriluk

2012-03-01

88

Influence of argon flow rate on TiO 2 photocatalyst film deposited by dc reactive magnetron sputtering  

Microsoft Academic Search

Titanium oxide films were deposited at different argon flow rates by dc reactive magnetron sputtering. A lower oxygen flow rate threshold could be achieved at a higher argon flow rate. The substrate temperature was approximately 130 °C after 5 h deposition. The deposited TiO2 films were of the anatase phase with a (220) preferred orientation. The crystallite sizes of the

Wenjie Zhang; Ying Li; Shenglong Zhu; Fuhui Wang

2004-01-01

89

Degradation of phenol and benzoic acid in the presence of a TiO 2-based heterogeneous photocatalyst  

Microsoft Academic Search

This paper reports the results of a study on the titanium dioxide Wackherr's “Oxyde de titane standard”, which shows very interesting photocatalytic activity. Produced for cosmetic purposes as a white pigment, its features make it very interesting in the field of heterogeneous photocatalysis. The results obtained with this photocatalyst are compared with the behaviour of the well-studied and widely used

Davide Vione; Claudio Minero; Valter Maurino; M. Eugenia Carlotti; Tatiana Picatonotto; Ezio Pelizzetti

2005-01-01

90

Synthesis of Structured Macroporous TiO2 Thin Films and Investigation on Their Photocatalytic Activities  

NASA Astrophysics Data System (ADS)

Synthesis of structured macroporous TiO2 thin films on quartz substrate (macro-TiO2/Q) was performed by a dip-coating method using poly(methyl methacrylate) (PMMA) microspheres as template. Obtained TiO2 thin films kept high transparency and had anatase crystalline structure. SEM observations revealed that the macropores were uniformly formed on the film surface. The size of macropores was quite similar to the diameter of PMMA microspheres as template. In comparison to the nonporous TiO2 thin films (TiO2/Q), macro-TiO2/Q exhibited twice higher photocatalytic activity for decolorization of methylene blue in water. Decomposition of acetaldehyde in gas phase also proceeded efficiently on macro-TiO2/Q. Moreover, the surface of macro-TiO2/Q was easily hydrophilized after a short period of UV light irradiation and maintained lower water contact angle in the dark for a long period as compared to those of TiO2/Q.

Kamegawa, Takashi; Suzuki, Norihiko; Yamashita, Hiromi

2011-10-01

91

Synthesis of chiral TiO2 nanofibre with electron transition-based optical activity  

PubMed Central

The optical chirality induced at the absorption bands due to electronic exciton coupling of the transition dipole moments between chromophores in close proximity is ubiquitous in helical organic materials. However, inorganic materials with optical activity resulting from electronic transitions have not been explored. Here we report the synthesis of chiral TiO2 fibres via transcription of the helical structure of amino acid-derived amphiphile fibres through coordination bonding interactions between the organics and the TiO2 source. Upon calcination, the as-prepared amorphous TiO2 double-helical fibres with a pitch length of ~100?nm were converted to double-helical crystalline fibres with stacks of anatase nanocrystals in an epitaxial helical relationship. Both the amorphous and anatase crystalline helical TiO2 fibres exhibited optical response to circularly polarized light at the absorption edge around ~350?nm. This was attributed to the semiconductor TiO2-based electronic transitions from the valence band to the conduction band under an asymmetric electric field.

Liu, Shaohua; Han, Lu; Duan, Yingying; Asahina, Shunsuke; Terasaki, Osamu; Cao, Yuanyuan; Liu, Ben; Ma, Liguo; Zhang, Jialiang; Che, Shunai

2012-01-01

92

Visible light-active nano-sized Fe-doped TiO2 photocatalysts and their characterization  

Microsoft Academic Search

Nano-sized Fe-doped TiO2 samples with different amounts of iron dopant (1.0-10.0 at.%) were synthesized from titanium tetraisopropoxide (TTIP) in absolute ethanol by the modified sol-gel method. The precursor of the iron nitrate (Fe(NO3)3middot9H2O) to be doped was added to an alcoholic solution containing TTIP. This solution was loaded into a pouch type cellophane membrane and placed in a clear solution

N. Wetchakun; P. Pirakitikulr; K. Chiang; S. Phanichphant

2008-01-01

93

Photocatalytic water splitting using Pt-loaded visible light-responsive TiO 2 thin film photocatalysts  

Microsoft Academic Search

Visible light-responsive TiO2 (Vis-TiO2) thin films which exhibit a unique declined O\\/Ti composition from the surface to the deep inside bulk have been successfully developed under a substrate temperature of 873K by applying a radio-frequency magnetron sputtering deposition (RF-MS) method. By controlling the Ar gas pressure during the deposition procedure, it was possible to control the optical properties of the

Masaaki Kitano; Masato Takeuchi; Masaya Matsuoka; John M. Thomas; Masakazu Anpo

2007-01-01

94

Surface properties of iron-titania photocatalysts employed for 4-nitrophenol photodegradation in aqueous TiO 2 dispersion  

Microsoft Academic Search

Iron(III) doped specimens (0.01–5% atomic Fe : Ti) have been prepared by impregnating polycrystalline “home prepared” TiO2 (mainly anatase) and have been studied for photocatalytic degradation of 4-nitrophenol in aqueous dispersions. Some structural and surface properties have been studied by X-ray diffraction, specific surface area and porosity measurements and FTIR monitoring of pyridine, ammonia and methanoic acid adsorption for surface

L. Palmisano; M. Schiavello; A. Sclafani; C. Martin; I. Martin; V. Rives

1994-01-01

95

Fabrication characterization and activity of a solar light driven photocatalyst: cerium doped TiO2 magnetic nanofibers.  

PubMed

A novel magnetic separable composite photocatalytic nanofiber consisting of TiO2 as the major phase, CeO(2-y) and CoFe2O4 as the dopant phase was prepared by sol-gel method and electrospinning technique, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectrum (UV-vis DRS) and vibrating sample magnetometer (VSM). The photocatalytic activity of the resultant CoFe2O4-TiO2 and CeO(2-y)/CoFe2O4-TiO2 nanofibers was evaluated by photodegradation of methylene blue (MB) in an aqueous solution under xenon lamp (the irradiation spectrum energy distribution is similar to sunlight) irradiation in a photochemical reactor. The results showed that the dopant of Ce could affect the absorbance ability and photo-response range. The sample containing 1.0 wt% CeO(2-y) exhibited the highest degradation with 35% for MB under simulate solar light irradiation. Furthermore, the as-synthesized composite photocatalytic nanofibers could be separated easily by an external magnetic field, thus it might hold potential for application in wastewater treatment. PMID:22755084

Li, Cong-Ju; Wang, Bin; Wang, Jiao-Na

2012-03-01

96

Synthesis Of Silver Sulfide Stratified Photocatalyst  

SciTech Connect

In this report, silver sulfide (Ag{sub 2}S) was selected as a new H{sub 2}S splitting photocatalyst material, and considered the synthesis method of Ag{sub 2}S photocatalyst particles with stratified structure. Previous stratified particles were synthesized by using metal oxide (hydroxide) as the precursor. Ag{sub 2}O particles as the precursor of Ag{sub 2}S were synthesized by mixing AgNO{sub 3} solution and NaOH, and their particle sizes could be controlled by the solutions' concentration. Then, Ag{sub 2}S particles were obtained by adding Na{sub 2}S solution into suspending solution of Ag{sub 2}O particles with optimum sizes. Particle sizes of Ag{sub 2}S were changed by Na{sub 2}S concentration control, and remaining Ag{sub 2}O precursor could be dissolved by adding NH{sub 3} solution. The photocatalytic H{sub 2}S splitting could be realized by UV-light irradiation on the Ag{sub 2}S particles without co-catalyst like Pt.

Baba, Y.; Yokoyama, S.; Takahashi, H.; Tohji, K. [Graduate School of Environmental Studies Tohoku University, 6-6-20 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi-ken 980-8579 (Japan)

2008-02-25

97

Synthesis and photocatalytic activity of co-doped mesoporous TiO2 on Brij98\\/CTAB composite surfactant template  

Microsoft Academic Search

Using composite surfactant templates, polyoxyethylene (20) oleyl ether (Brij98) and cetyl trimethyl ammonium bromide (CTAB), as structure-directing agents, N and La co-doped mesoporous TiO2 complex photocatalysts were synthesized successfully. The micromorphology of co-doped mesoporous TiO2 samples was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FT-IR), energy-dispersive X-ray spectrometer (EDS) and N2 adsorption-desorption measurements. The

Xiaotong Zhang; Guowei Zhou; Jing Xu; Guangwei Bai; Lei Wang

2010-01-01

98

Synthesis and photocatalytic activity of co-doped mesoporous TiO 2 on Brij98\\/CTAB composite surfactant template  

Microsoft Academic Search

Using composite surfactant templates, polyoxyethylene (20) oleyl ether (Brij98) and cetyl trimethyl ammonium bromide (CTAB), as structure-directing agents, N and La co-doped mesoporous TiO2 complex photocatalysts were synthesized successfully. The micromorphology of co-doped mesoporous TiO2 samples was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FT-IR), energy-dispersive X-ray spectrometer (EDS) and N2 adsorption–desorption measurements. The

Xiaotong Zhang; Guowei Zhou; Jing Xu; Guangwei Bai; Lei Wang

2010-01-01

99

Recent advances in visible-light-responsive photocatalysts for hydrogen production and solar energy conversion--from semiconducting TiO2 to MOF/PCP photocatalysts.  

PubMed

The present perspective describes recent advances in visible-light-responsive photocatalysts intended to develop novel and efficient solar energy conversion technologies, including water splitting and photofuel cells. Water splitting is recognized as one of the most promising techniques to convert solar energy as a clean and abundant energy resource into chemical energy in the form of hydrogen. In recent years, increasing concern is directed to not only the development of new photocatalytic materials but also the importance of technologies to produce hydrogen and oxygen separately. Photofuel cells can convert solar energy into electrical energy by decomposing bio-related compounds and livestock waste as fuels. The advances of photocatalysts enabling these solar energy conversion technologies have been going on since the discovery of semiconducting titanium dioxide materials and have extended to organic-inorganic hybrid materials, such as metal-organic frameworks and porous coordination polymers (MOF/PCP). PMID:23760469

Horiuchi, Yu; Toyao, Takashi; Takeuchi, Masato; Matsuoka, Masaya; Anpo, Masakazu

2013-08-28

100

Computer simulation of the energy gap in ZnO- and TiO2-based semiconductor photocatalysts  

NASA Astrophysics Data System (ADS)

Ab initio calculations of the electronic structures of binary ZnO- and TiO2-based oxides are performed to search for optimum dopants for efficient absorption of the visible part of solar radiation. Light elements B, C, and N are chosen for anion substitution. Cation substitution is simulated by 3 d elements (Cr, Mn, Fe, Co) and heavy metals (Sn, Sb, Pb, Bi). The electronic structures are calculated by the full-potential linearized augmented plane wave method using the modified Becke-Johnson exchange-correlation potential. Doping is simulated by calculating supercells Zn15D1O16, Zn16O15D1, Ti15D1O32, and Ti8O15D1, where one-sixteenth of the metal (Ti, Zn) or oxygen atoms is replaced by dopant atoms. Carbon and antimony are found to be most effective dopants for ZnO: they form an energy gap ? E = 1.78 and 1.67 eV, respectively. For TiO2, nitrogen is the most effective dopant (? E = 1.76 eV).

Skorikov, N. A.; Korotin, M. A.; Kurmaev, E. Z.; Cholakh, S. O.

2012-12-01

101

Highly efficient and recyclable triple-shelled Ag@Fe3O4@SiO2@TiO2 photocatalysts for degradation of organic pollutants and reduction of hexavalent chromium ions.  

PubMed

Herein, we demonstrate the design and fabrication of the well-defined triple-shelled Ag@Fe3O4@SiO2@TiO2 nanospheres with burr-shaped hierarchical structures, in which the multiple distinct functional components are integrated wonderfully into a single nanostructure. In comparison with commercial TiO2 (P25), pure TiO2 microspheres, Fe3O4@SiO2@TiO2 and annealed Ag@Fe3O4@SiO2@TiO2 nanocomposites, the as-obtained amorphous triple-shelled Ag@Fe3O4@SiO2@TiO2 hierarchical nanospheres exhibit a markedly enhanced visible light or sunlight photocatalytic activity towards the photodegradation of methylene blue and photoreduction of hexavalent chromium ions in wastewater. The outstanding photocatalytic activities of the plasmonic photocatalyst are mainly due to the enhanced light harvesting, reduced transport paths for both mass and charge transport, reduced recombination probability of photogenerated electrons/holes, near field electromagnetic enhancement and efficient scattering from the plasmonic nanostructure, increased surface-to-volume ratio and active sites in three dimensional (3D) hierarchical porous nanostructures, and improved photo/chemical stability. More importantly, the hierarchical nanostructured Ag@Fe3O4@SiO2@TiO2 photocatalysts could be easily collected and separated by applying an external magnetic field and reused at least five times without any appreciable reduction in photocatalytic efficiency. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, make these multifunctional nanostructures promising candidates to remediate aquatic contaminants and meet the demands of future environmental issues. PMID:24710730

Su, Jianwei; Zhang, Yunxia; Xu, Sichao; Wang, Shuan; Ding, Hualin; Pan, Shusheng; Wang, Guozhong; Li, Guanghai; Zhao, Huijun

2014-05-21

102

Electronic properties of F/Zr co-doped anatase TiO 2 photocatalysts from GGA + U calculations  

NASA Astrophysics Data System (ADS)

The energetic and electronic properties of F and/or Zr-doped anatase TiO 2 are investigated by first-principles calculations. For F-doping, reduced Ti 3+ ions are formed and Ti orbitals lie slightly below the conduction band, leading to band gap narrowing. For Zr-doping, Zr 4d orbitals reside well into the conduction band, with essentially no band gap change. For F/Zr-codoping, the electronic structure is similar to that for F-monodoping, where Ti 3+ gap states are induced by both the oxygen vacancy and F dopant. The influence of oxygen vacancies indicates that interplay between dopants and oxygen vacancies is key for improvement of photocatalytic activity. The theoretical findings present a reasonable explanation of recent experimental results.

Long, Run; English, Niall J.

2010-10-01

103

Pt(II) porphyrin modified TiO2 composites as photocatalysts for efficient 4-NP degradation  

NASA Astrophysics Data System (ADS)

Three Pt(II) porphyrins 5,10,15,20-tetra-[2 or 3 or 4-(3-phenoxy)propoxy]phenyl porphyrin]platinum(II) (1-3) were synthesized and characterized spectroscopically. The corresponding Pt(II) porphyrins-TiO2 composites were then prepared and characterized by means of FT-IR and diffused reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of Pt(II) porphyrins-TiO2 catalyst was investigated by testing the photodegradation of 4-nitrophenol (4-NP) in aqueous solution under irradiation with Xenon lamp. The results indicated that Pt(II) porphyrins greatly enhanced the photocatalytic efficiency of bare TiO2 in photodegrading the 4-NP, and the distinct space tropisms of peripheral substituents in meso-sites of porphyrin ring led to different results.

Duan, Ming-yue; Li, Jun; Li, Min; Zhang, Zeng-qi; Wang, Chen

2012-05-01

104

Direct synthesis of mesoporous TiO 2 and its catalytic performance in DBT oxidative desulfurization  

Microsoft Academic Search

This paper presents a synthesis process of mesoporous titanium dioxide materials (TiO2) with tetrabutyl titanate as the precursor at ambient conditions. Phosphotungstic acid (PWA) was used as the catalyst, and quaternary ammonium bromide including octadecyltrimethylammonium bromide (STAB), cethyltrimethylammonium bromide (CTAB), (1-tetradecyl)trimethylammonium bromide (TTAB), and dodecyltrimethylammonium bromide (DTAB) as the structure-directing agent. STAB was found to be the best structure-directing agent.

D. Huang; Y. J. Wang; Y. C. Cui; G. S. Luo

2008-01-01

105

Ultrasonically Activated Hydrothermal Synthesis of Fine TiO 2 and ZrO 2 Powders  

Microsoft Academic Search

Fine TiO2 and ZrO2 powders were prepared by hydrothermal synthesis at 150 and 250°C (10 min, 1 h, 3 h) from aqueous titanyl and zirconyl salts and amorphous titanyl and zirconyl hydroxide gels with and without ultrasonic activation. The synthesized materials were characterized by x-ray diffraction, scanning and transmission electron-microscopic techniques, and nitrogen capillary adsorption measurements. The results demonstrate that

P. E. Meskin; A. E. Baranchikov; V. K. Ivanov; D. R. Afanas'ev; A. I. Gavrilov; B. R. Churagulov; N. N. Oleinikov

2004-01-01

106

TiO2 nanotubes: recent advances in synthesis and gas sensing properties.  

PubMed

Synthesis--particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances. Doping largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes. PMID:24184919

Galstyan, Vardan; Comini, Elisabetta; Faglia, Guido; Sberveglieri, Giorgio

2013-01-01

107

TiO 2 photocatalytic oxidation: I. Photocatalysts for liquid-phase and gas-phase processes and the photocatalytic degradation of chemical warfare agent simulants in a liquid phase  

Microsoft Academic Search

The results of studies on the effect of the preparation procedure on the properties of TiO2-based photocatalysts and the kinetics and mechanism of the photocatalytic oxidation of organic water pollutants are surveyed. The effects of calcination temperature, surface modification with platinum, and acid-base treatment of the surface of titanium dioxide on its activity in model gas-phase and liquid-phase reactions are

A. V. Vorontsov; D. V. Kozlov; P. G. Smirniotis; V. N. Parmon

2005-01-01

108

Highly reactive {001} facets of TiO2-based composites: synthesis, formation mechanism and characterization  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) is one of the most widely investigated metal oxides due to its extraordinary surface, electronic and catalytic properties. However, the large band gap of TiO2 and massive recombination of photogenerated electron-hole pairs limit its photocatalytic and photovoltaic efficiency. Therefore, increasing research attention is now being directed towards engineering the surface structure of TiO2 at the most fundamental and atomic level namely morphological control of {001} facets in the range of microscale and nanoscale to fine-tune its physicochemical properties, which could ultimately lead to the optimization of its selectivity and reactivity. The synthesis of {001}-faceted TiO2 is currently one of the most active interdisciplinary research areas and demonstrations of catalytic enhancement are abundant. Modifications such as metal and non-metal doping have also been extensively studied to extend its band gap to the visible light region. This steady progress has demonstrated that TiO2-based composites with {001} facets are playing and will continue to play an indispensable role in the environmental remediation and in the search for clean and renewable energy technologies. This review encompasses the state-of-the-art research activities and latest advancements in the design of highly reactive {001} facet-dominated TiO2via various strategies, including hydrothermal/solvothermal, high temperature gas phase reactions and non-hydrolytic alcoholysis methods. The stabilization of {001} facets using fluorine-containing species and fluorine-free capping agents is also critically discussed in this review. To overcome the large band gap of TiO2 and rapid recombination of photogenerated charge carriers, modifications are carried out to manipulate its electronic band structure, including transition metal doping, noble metal doping, non-metal doping and incorporating graphene as a two-dimensional (2D) catalyst support. The advancements made in these aspects are thoroughly examined, with additional insights related to the charge transfer events for each strategy of the modified-TiO2 composites. Finally, we offer a summary and some invigorating perspectives on the major challenges and new research directions for future exploitation in this emerging frontier, which we hope will advance us to rationally harness the outstanding structural and electronic properties of {001} facets for various environmental and energy-related applications.

Ong, Wee-Jun; Tan, Lling-Lling; Chai, Siang-Piao; Yong, Siek-Ting; Mohamed, Abdul Rahman

2014-01-01

109

TiO 2/carbon nanotube hybrid nanostructures: Solvothermal synthesis and their visible light photocatalytic activity  

NASA Astrophysics Data System (ADS)

MWCNT/TiO 2 hybrid nanostructures were prepared via solvothermal synthesis and sol-gel method with benzyl alcohol as a surfactant. As-prepared hybrid materials were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly decorated with anatase nanocrystals in solvothermal condition, but MWCNTs were embedded in a majority of TiO 2 nanoparticles by sol-gel method. When the weight ratio of MWCNTs to TiO 2 was 20%, MWCNT/TiO 2 hybrid nanostructures prepared by solvothermal synthesis exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. Post-annealing of MWCNT/TiO 2 nanostructures at 400 °C resulted in the formation of the carbonaceous Ti-C bonds on the interface between TiO 2 and MWCNTs, which enhanced the photoabsorbance of the hybrid materials in the visible light region and improved the visible-light degradation efficiency of methylene blue.

Tian, Lihong; Ye, Liqun; Deng, Kejian; Zan, Ling

2011-06-01

110

Disinfection of drinking water contaminated with Cryptosporidium parvum oocysts under natural sunlight and using the photocatalyst TiO2.  

PubMed

The results of a batch-process solar disinfection (SODIS) and solar photocatalytic disinfection (SPCDIS) on drinking water contaminated with Cryptosporidium are reported. Cryptosporidium parvum oocyst suspensions were exposed to natural sunlight in Southern Spain and the oocyst viability was evaluated using two vital dyes [4',6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI)]. SODIS exposures (strong sunlight) of 8 and 12h reduced oocyst viability from 98% (+/-1.3%) to 11.7% (+/-0.9%) and 0.3% (+/-0.33%), respectively. SODIS reactors fitted with flexible plastic inserts coated with TiO2 powder (SPCDIS) were found to be more effective than those which were not. After 8 and 16 h of overcast and cloudy solar irradiance conditions, SPCDIS reduced oocyst viability from 98.3% (+/-0.3%) to 37.7% (+/-2.6%) and 11.7% (+/-0.7%), respectively, versus to that achieved using SODIS of 81.3% (+/-1.6%) and 36.0% (+/-1.0%), respectively. These results confirm that solar disinfection of drinking water can be an effective household intervention against Cryptosporidium contamination. PMID:17624798

Méndez-Hermida, Fernando; Ares-Mazás, Elvira; McGuigan, Kevin G; Boyle, Maria; Sichel, Cosima; Fernández-Ibáñez, Pilar

2007-09-25

111

Enhanced photocatalytic activity of nitrogen doped TiO2 photocatalysts sensitized by metallo Co, Ni-porphyrins  

NASA Astrophysics Data System (ADS)

Nitrogen doped anatase TiO2 powders (N-TiO2) were sensitized by four kinds of metalloporphyrins (CoTHPP, CoTPP, NiTHPP, and NiTPP). The resulting materials were characterized by XRD, TEM, XPS, DRS and N2 adsorption. The results showed that the crystal structure and morphology of N-TiO2 were not affected by the existence of porphyrin on its surface, but the surface area increased after the N-TiO2 sensitized by metalloporphyrins. The photocatalytic degradation of methyl blue (MB) experiments showed that the metalporphyrins sensitized N-TiO2 composite catalysts, especially the CoTHPP/N-TiO2 and CoTPP/N-TiO2, exhibited higher degradation efficiency than the unsentisized N-TiO2 powders. In addition, the photocatalytic degradations of MB using the composite catalysts were all demonstrated to follow first-order kinetic model. The composite catalysts can be recycled four times without significant loss of photocatalytic activity.

Niu, Jinfen; Yao, Binghua; Chen, Yuanqing; Peng, Chao; Yu, Xiaojiao; Zhang, Jian; Bai, Guanghai

2013-04-01

112

A novel synthesis method for TiO2 particles with magnetic Fe3O4 cores.  

PubMed

TiO2@(AC/Fe3O4) (AC is activated carbon) was prepared by using AC and Fe3O4 as joint support. The morphological features, crystal structure, and magnetism of the final product were characterized. The results indicate that TiO2 particles formed on the surface of AC and Fe3O4; the sizes of TiO2 and Fe3O4 were 0.5 and 0.7 ?m respectively, and that of AC fell within a wide range. The highly crystalline cubic structures of the TiO2 particles was in accord with the standard X-ray diffractometry spectrum of magnetite and anatase. The maximum saturation magnetization of TiO2@(AC/Fe3O4) was 75 emu g(-1), which was enough to support magnetic recovery. The rate of methylene blue (MB) removal photocatalyzed by TiO2@(AC/Fe3O4) was higher by 50% than that achieved with AC/Fe3O4 photocatalysis, and similar to that achieved with TiO2@AC. The removal rate (kobs) decreased drastically from 1.77 × 10(-2) to 9.36 × 10(-3)min(-1) when the initial concentration of MB solution increased from 2.0 to 5.0 mg L(-1). The kobs value increased from 9.41 × 10(-3) to 1.34 × 10(-2)min(-1) with increasing photocatalyst dosage from 0.2 to 1.0 g, then slightly decreased to 1.33 × 10(-2)min(-1) at 2.0 g dosage. PMID:24845326

Dong, Qi; Zhang, Keqiang; An, Yi

2014-01-01

113

CTAB-assisted synthesis of mesoporous F–N-codoped TiO 2 powders with high visible-light-driven catalytic activity and adsorption capacity  

Microsoft Academic Search

This article describes the preparation of mesoporous rod-like F–N-codoped TiO2 powder photocatalysts with anatase phase via a sol–gel route at the temperature of 373K, using cetyltrimethyl ammonium bromide (CTAB) as surfactant. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–visible diffuse reflectance spectra (UV–vis DRS). The

Yi Xie; Xiujian Zhao; Yuanzhi Li; Qingnan Zhao; Xuedong Zhou; Qihua Yuan

2008-01-01

114

Novel polypyrrole-sensitized hollow TiO2/fly ash cenospheres: Synthesis, characterization, and photocatalytic ability under visible light  

NASA Astrophysics Data System (ADS)

The polypyrrole-sensitized TiO2 layer on fly ash cenosphere (PPy-TiO2/FAC) was successfully prepared as a promising photocatalyst with visible light response. Photocatalytic activity and kinetics of PPy-TiO2/FAC under visible light were detected in details from aspects of different dopant concentration of HCl and different pyrrole (Py)/Ti molar ratio by detecting photodegradation of methylene blue (MB) and phenol, respectively. It was found that the decomposition rate increased with the increasing Py/Ti molar ratio up to an optimal value, beyond which the photocatalytic activity showed a decreasing tendency. The concentration of HCl in the preparation of PPy-TiO2/FAC also largely influenced the photodecomposition rate of target contamination. The results demonstrate that when the molar ratio of Py/Ti is 1% and the concentration of HCl is 1 mol L-1, the synthesized photocatalyst showed the best photocatalytic activity under visible light.

Wang, Bing; Li, Chuang; Pang, Jianfeng; Qing, Xutang; Zhai, Jianping; Li, Qin

2012-10-01

115

Patterning Effect of a Sol-Gel TiO2 Overlayer on the Photocatalytic Activity of a TiO2\\/SnO2 Bilayer-Type Photocatalyst  

Microsoft Academic Search

TiO2 films with a thickness of 75 ± 5 nm (anatase) were formed on SnO2-film (580 ± 80 nm) coated soda-lime glass substrates (SnO2\\/SL-glass) by a sol-gel method. Although the photocatalytic activity for CH3CHO oxidation (?ex > 300 nm) significantly exceeded that of a standard TiO2\\/quartz sample, it decayed with illumination time (t) at t > 0.75 h. Stripes of

Akihiko Hattori; Yoshifumi Tokihisa; Hiroaki Tada; Noboru Tohge; Seishiro Ito; Kazutaka Hongo; Ryuichi Shiratsuchi; Gyoichi Nogami

2001-01-01

116

Synthesis of highly stable sub-8 nm TiO2 nanoparticles and their multilayer electrodes of TiO2/MWNT for electrochemical applications.  

PubMed

Next-generation electrochemical energy storage for integrated microsystems and consumer electronic devices requires novel electrode materials with engineered architectures to meet the requirements of high performance, low cost, and robustness. However, conventional electrode fabrication processes such as doctor blading afford limited control over the electrode thickness and structure at the nanoscale and require the incorporation of insulating binder and other additives, which can promote agglomeration and reduce active surface area, limiting the inherent advantages attainable from nanoscale materials. We have engineered a route for the synthesis of highly stable, sub-8 nm TiO2 nanoparticles and their subsequent incorporation with acid-functionalized multiwalled carbon nanotubes (MWNTs) into nanostructured electrodes using aqueous-based layer-by-layer electrostatic self-assembly. Using this approach, binder-free thin film electrodes with highly controllable thicknesses up to the micrometer scale were developed with well-dispersed, nonagglomerated TiO2 nanoparticles on MWNTs. Upon testing in an Li electrochemical half-cell, these electrodes demonstrate high capacity (>150 mAh/gel(ectrode) at 0.1 A/gel(ectrode)), good rate capability (>100 mAh/gel(ectrode) up to 1 A/g(electrode)) and nearly no capacity loss up to 200 cycles for electrodes with thicknesses up to 1480 nm, indicating their promise as thin-film negative electrodes for future Li storage applications. PMID:24003950

Hyder, Md Nasim; Gallant, Betar M; Shah, Nisarg J; Shao-Horn, Yang; Hammond, Paula T

2013-10-01

117

Synthesis and performance of novel magnetically separable nanospheres of titanium dioxide photocatalyst with egg-like structure  

Microsoft Academic Search

A magnetically separable photocatalyst TiO2\\/SiO2\\/NiFe2O4 (TSN) nanosphere with egg-like structure was prepared by a unique process that combined a liquid catalytic phase transformation method, reverse micelle technique and chemical precipitation means. The prepared photocatalyst shows high photocatalytic activity for the degradation of methyl orange in water. The magnetic property measurements indicate that the photocatalyst possesses a superparamagnetic nature. It can

Shihong Xu; Wenfeng Shangguan; Jian Yuan; Mingxia Chen; Jianwei Shi; Zhi Jiang

2008-01-01

118

The design, fabrication, and photocatalytic utility of nanostructured semiconductors: focus on TiO2-based nanostructures  

PubMed Central

Recent advances in basic fabrication techniques of TiO2-based nanomaterials such as nanoparticles, nanowires, nanoplatelets, and both physical- and solution-based techniques have been adopted by various research groups around the world. Our research focus has been mainly on various deposition parameters used for fabricating nanostructured materials, including TiO2-organic/inorganic nanocomposite materials. Technically, TiO2 shows relatively high reactivity under ultraviolet light, the energy of which exceeds the band gap of TiO2. The development of photocatalysts exhibiting high reactivity under visible light allows the main part of the solar spectrum to be used. Visible light-activated TiO2 could be prepared by doping or sensitizing. As far as doping of TiO2 is concerned, in obtaining tailored material with improved properties, metal and nonmetal doping has been performed in the context of improved photoactivity. Nonmetal doping seems to be more promising than metal doping. TiO2 represents an effective photocatalyst for water and air purification and for self-cleaning surfaces. Additionally, it can be used as an antibacterial agent because of its strong oxidation activity and superhydrophilicity. Therefore, applications of TiO2 in terms of photocatalytic activities are discussed here. The basic mechanisms of the photoactivities of TiO2 and nanostructures are considered alongside band structure engineering and surface modification in nanostructured TiO2 in the context of doping. The article reviews the basic structural, optical, and electrical properties of TiO2, followed by detailed fabrication techniques of 0-, 1-, and quasi-2-dimensional TiO2 nanomaterials. Applications and future directions of nanostructured TiO2 are considered in the context of various photoinduced phenomena such as hydrogen production, electricity generation via dye-sensitized solar cells, photokilling and self-cleaning effect, photo-oxidation of organic pollutant, wastewater management, and organic synthesis.

Banerjee, Arghya Narayan

2011-01-01

119

Coexistence of an anatase/TiO2(B) heterojunction and an exposed (001) facet in TiO2 nanoribbon photocatalysts synthesized via a fluorine-free route and topotactic transformation  

NASA Astrophysics Data System (ADS)

In this work, we report a novel approach to fabricate hierarchical TiO2 microspheres (HTMS) assembled by ultrathin nanoribbons where an anatase/TiO2(B) heterojunction and high energy facet coexist. The as-adopted approach involves (1) nonaqueous solvothermal treatment of a mixture of tetrabutyl titanate and acetic acid and (2) topotactical transformation into HTMS via thermal annealing. By this approach, the TiO2(B) phase usually synthesized from an alkaline treatment route could be initially formed. Subsequently, phase transition from TiO2(B) to anatase TiO2 occurs upon thermal treatment. It is demonstrated that such phase transition is accompanied by crystallographic orientation along the c-axis of anatase and TiO2(B) crystals, resulting in not only a coherent interface between two phases but also oriented attachment of anatase mesocrystals along the [001] direction, and finally high-energy (001) facet exposure. Interestingly, this work provides an alternative fluorine-free route for the synthesis of TiO2 crystals with high-energy (001) facet exposure. The structural analysis reveals that lattice-match induced topotactic transformation from TiO2(B) to anatase is the sole reason for the (001) facet exposure of anatase TiO2. The photocatalytic test for acetaldehyde decomposition shows that HTMS with anatase/TiO2(B) heterojunction and high-energy (001) facet exhibits superior photocatalytic efficiency compared with the relevant commercial product P25, which can be ascribed to the synergistic effect of large surface area, anatase/TiO2(B) heterojunction as well as high-energy facet exposure.

Wang, Changhua; Zhang, Xintong; Liu, Yichun

2014-04-01

120

Coexistence of an anatase/TiO2(B) heterojunction and an exposed (001) facet in TiO2 nanoribbon photocatalysts synthesized via a fluorine-free route and topotactic transformation.  

PubMed

In this work, we report a novel approach to fabricate hierarchical TiO2 microspheres (HTMS) assembled by ultrathin nanoribbons where an anatase/TiO2(B) heterojunction and high energy facet coexist. The as-adopted approach involves (1) nonaqueous solvothermal treatment of a mixture of tetrabutyl titanate and acetic acid and (2) topotactical transformation into HTMS via thermal annealing. By this approach, the TiO2(B) phase usually synthesized from an alkaline treatment route could be initially formed. Subsequently, phase transition from TiO2(B) to anatase TiO2 occurs upon thermal treatment. It is demonstrated that such phase transition is accompanied by crystallographic orientation along the c-axis of anatase and TiO2(B) crystals, resulting in not only a coherent interface between two phases but also oriented attachment of anatase mesocrystals along the [001] direction, and finally high-energy (001) facet exposure. Interestingly, this work provides an alternative fluorine-free route for the synthesis of TiO2 crystals with high-energy (001) facet exposure. The structural analysis reveals that lattice-match induced topotactic transformation from TiO2(B) to anatase is the sole reason for the (001) facet exposure of anatase TiO2. The photocatalytic test for acetaldehyde decomposition shows that HTMS with anatase/TiO2(B) heterojunction and high-energy (001) facet exhibits superior photocatalytic efficiency compared with the relevant commercial product P25, which can be ascribed to the synergistic effect of large surface area, anatase/TiO2(B) heterojunction as well as high-energy facet exposure. PMID:24699768

Wang, Changhua; Zhang, Xintong; Liu, Yichun

2014-05-21

121

Facile synthesis of TiO2/microcrystalline cellulose nanocomposites: photocatalytically active material under visible light irradiation  

EPA Science Inventory

Doped TiO2 nanocomposites were prepared in situ by a facile and simple synthesis utilizing benign and renewable precursors such as microcrystalline cellulose (MC) and TiCl4 through hydrolysis in alkaline medium without the addition of organic solvents. The as-prepared nanocompos...

122

TiO2 Nanoparticles Are Phototoxic to Marine Phytoplankton  

Microsoft Academic Search

Nanoparticulate titanium dioxide (TiO2) is highly photoactive, and its function as a photocatalyst drives much of the application demand for TiO2. Because TiO2 generates reactive oxygen species (ROS) when exposed to ultraviolet radiation (UVR), nanoparticulate TiO2 has been used in antibacterial coatings and wastewater disinfection, and has been investigated as an anti-cancer agent. Oxidative stress mediated by photoactive TiO2 is

Robert J. Miller; Samuel Bennett; Arturo A. Keller; Scott Pease; Hunter S. Lenihan

2012-01-01

123

Hydrothermal Synthesis of Mo-Doped VO2/TiO2 Composite Nanocrystals with Enhanced Thermochromic Performance.  

PubMed

This paper reports a one-step TiO2 seed-assistant hydrothermal synthesis of Mo-doped VO2(M)/TiO2 composite nanocrystals. It was found that excess Mo doping can promote formation of the VO2(M) phase, and rutile TiO2 seed is beneficial to morphology control, size reduction, and infrared modulation of Mo-doped VO2(M) nanocrystals. The Mo-doped VO2 nanocrystals epitaxially grow on TiO2 seeds and have a quasi-spherical shape with size down to 20 nm and a nearly 35% infrared modulation near room temperature. The findings of this work demonstrate important progress in the near-room-temperature thermochromic performance of VO2(M) nanomaterials, which will find potential application in constructing VO2(M) nanocrystal-based smart window coatings. PMID:24734771

Li, Dengbing; Li, Ming; Pan, Jing; Luo, Yuanyuan; Wu, Hao; Zhang, Yunxia; Li, Guanghai

2014-05-14

124

Green synthesis of TiO2 nanocrystals with improved photocatalytic activity by ionic-liquid assisted hydrothermal method.  

PubMed

Owing to potential industrial applications and fundamental significance, tailored synthesis of well-defined anatase TiO2 nanocrystals with exposed highly reactive {001} facets has stimulated great research interest. In this work, surface-fluorinated anatase TiO2 nanocrystals have been successfully prepared by using an ionic liquid (IL) assisted hydrothermal synthetic route. TiCl4 is used as precursor, and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim](+)[BF4](-)) as morphology-controlling agent. The anion of the IL plays a key role in controlling the crystallization process via a dissolution-recrystallization process. Compared with the benchmark material Degussa P25, the fluorinated anatase TiO2 nanocrystals exhibit superior photocatalytic activity. PMID:23670586

Wang, Bin; Guo, Lingju; He, Meng; He, Tao

2013-06-28

125

Stereospecific growth of densely populated rutile mesoporous TiO2 nanoplate films: a facile low temperature chemical synthesis approach.  

PubMed

We report for the first time, using a simple and environmentally benign chemical method, the low temperature synthesis of densely populated upright-standing rutile TiO(2) nanoplate films onto a glass substrate from a mixture of titanium trichloride, hydrogen peroxide and thiourea in triply distilled water. The rutile TiO(2) nanoplate films (the phase is confirmed from x-ray diffraction analysis, selected area electron diffraction, energy-dispersive x-ray analysis, and Raman shift) are 20-35 nm wide and 100-120 nm long. The chemical reaction kinetics for the growth of these upright-standing TiO(2) nanoplate films is also interpreted. Films of TiO(2) nanoplates are optically transparent in the visible region with a sharp absorption edge close to 350 nm, confirming an indirect band gap energy of 3.12 eV. The Brunauer-Emmet-Teller surface area, Barret-Joyner-Halenda pore volume and pore diameter, obtained from N(2) physisorption studies, are 82 m(2) g(-1), 0.0964 cm(3) g(-1) and 3.5 nm, respectively, confirming the mesoporosity of scratched rutile TiO(2) nanoplate powder that would be ideal for the direct fabrication of nanoscaled devices including upcoming dye-sensitized solar cells and gas sensors. PMID:20160342

Lee, Go-Woon; Ambade, Swapnil B; Cho, Young-Jin; Mane, Rajaram S; Shashikala, V; Yadav, Jyotiprakash; Gaikwad, Rajendra S; Lee, Soo-Hyoung; Jung, Kwang-Deog; Han, Sung-Hwan; Joo, Oh-Shim

2010-03-12

126

Solvent-controlled synthesis and electrochemical lithium storage of one-dimensional TiO2 nanostructures.  

PubMed

In this paper, one-dimensional (1-D) nanostructured TiO2 of different morphologies and structures have been selectively synthesized via a convenient, low-temperature solvothermal route and following calcination. Transmission electron microscopy, selected area electron diffraction, X-ray diffraction, and Brunauer-Emmett-Teller methods were used to characterize the morphology, crystalline structure, and specific surface area of these nanostructured TiO2. The formation of different morphologies, including nanowires and nanotubes, was achieved through a deliberate control of the cosolvent. In addition to the solvent-controlled procedures, another important feature of the synthesis in the present study was that either single-crystalline nanowires (TiO2-B) or polycrystalline nanotubes (anatase and TiO2-B) were achieved by heat treatment at 350 degrees C. The electrochemical performances of the nanowires and nanotubes were further explored in terms of their potential application as anode materials for lithium-ion batteries. The lithium-insertion reactions involved in the two materials were elucidated by means of a galvanostatic method, cyclic voltammetry, and electrochemical impedance spectroscopy. The results suggest that both the crystalline structure and the unique 1-D morphology might be responsible for their favorable electrochemical properties. This work will be valuable for the understanding of the formation of nanostructured TiO2 by the wet-chemistry process and further applications. PMID:16903753

Wang, Qiang; Wen, Zhenhai; Li, Jinghong

2006-08-21

127

Synthesis and characterization of TiO2 and Ag/TiO2 nanostructure  

NASA Astrophysics Data System (ADS)

Single phase anatase TiO2 nanoparticles were prepared using Titanium tertachloride (TiCl4) as precursor through an inexpensive method. Well dispersed nanocomposites of silver at TiO2 were synthesized successfully by photochemical route. Both TiO2 and Ag/TiO2 were characterized using X-Ray Diffraction (XRD) and transmission electron microscopy (TEM). The particle size of TiO2 is found to be ~ 11 nm and ~ 22 nm for Ag/TiO2, by XRD and confirmed by TEM. TEM micrographs also show the single phase crystal of TiO2 and confirm the deposition of silver among TiO2.

Gahlot, Swati; Thakur, Amit Kumar; Kulshrestha, Vaibhav; Shahi, V. K.

2013-02-01

128

Role of oxygen vacancy in the plasma-treated TiO 2 photocatalyst with visible light activity for NO removal  

Microsoft Academic Search

The photocatalytic activity for NO removal under an oxidative atmosphere has been studied over commercial TiO2 and plasma-treated TiO2 powders. By the plasma treatment, the photocatalytic activity for NO removal appeared in the visible light region up to 600nm without a decrease in the ultraviolet light activity. It was found that the NO was removed as nitrate (NO3?) by photocatalytic

Isao Nakamura; Nobuaki Negishi; Shuzo Kutsuna; Tatsuhiko Ihara; Shinichi Sugihara; Koji Takeuchi

2000-01-01

129

Hydrothermal synthesis and characterization of TiO 2 nanorod arrays on glass substrates  

Microsoft Academic Search

Large-scale, well-aligned single crystalline TiO2 nanorod arrays were prepared on the pre-treated glass substrate by a hydrothermal approach. The as-prepared TiO2 nanorod arrays were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. X-ray diffraction results show that the main phase of TiO2 is rutile. Scanning electron microscopy and transmission electron microscopy results demonstrate that the large-scale TiO2

Yuxiang Li; Min Guo; Mei Zhang; Xidong Wang

2009-01-01

130

Double-doped TiO2 nanoparticles as an efficient visible-light-active photocatalyst and antibacterial agent under solar simulated light  

NASA Astrophysics Data System (ADS)

Silver and nitrogen doped TiO2 nanoparticles (NPs) were synthesized via sol–gel method. The physicochemical properties of the achieved NPs were characterized by various methods including X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultra violet–visible absorption spectroscopy (UV–vis). Both visible-light photocatalytic activity and antimicrobial properties were successfully demonstrated for the degradation of Rhodamine B (Rh. B.), as a model dye, and inactivation of Escherichia coli (E. coli), as a representative of microorganisms. The concentration of the employed dopant was optimized and the results revealed that the silver and nitrogen doped TiO2 NPs extended the light absorption spectrum toward the visible region and significantly enhanced the photodegradation of model dye and inactivation of bacteria under visible-light irradiation while double-doped TiO2 NPs exhibited highest photocatalytic and antibacterial activity compared with single doping. The significant enhancement in the photocatalytic activity and antibacterial properties of the double doped TiO2 NPs, under visible-light irradiation, can be attributed to the generation of two different electronic states acting as electron traps in TiO2 and responsible for narrowing the band gap of TiO2 and shifting its optical response from UV to the visible-light region.

Ashkarran, Ali Akbar; Hamidinezhad, Habib; Haddadi, Hedayat; Mahmoudi, Morteza

2014-05-01

131

Synthesis and optimizable electrochemical performance of reduced graphene oxide wrapped mesoporous TiO2 microspheres  

NASA Astrophysics Data System (ADS)

A facile microwave solvothermal process is developed to prepare an anatase TiO2 anode material that maintains multiple properties including high surface area, high crystallinity, uniform mesoporous, perfect microspheres and uniform particle size. Using this fine anatase TiO2 product, a TiO2/RGO (RGO: reduced graphene oxide) hybrid material is prepared under UV-light irradiation. Incorporation of RGO improves the electrochemical kinetics of the TiO2 microspheres, which results in superior electrochemical performance in terms of specific capacity, rate capability and cycle stability. The material shows a discharge capacity of 155.8 mA h g-1 at the 5 C rate. Even at the 60 C rate, a high discharge capacity of 83.6 mA h g-1 is still obtained which is two times higher than that of pristine mesoporous TiO2.A facile microwave solvothermal process is developed to prepare an anatase TiO2 anode material that maintains multiple properties including high surface area, high crystallinity, uniform mesoporous, perfect microspheres and uniform particle size. Using this fine anatase TiO2 product, a TiO2/RGO (RGO: reduced graphene oxide) hybrid material is prepared under UV-light irradiation. Incorporation of RGO improves the electrochemical kinetics of the TiO2 microspheres, which results in superior electrochemical performance in terms of specific capacity, rate capability and cycle stability. The material shows a discharge capacity of 155.8 mA h g-1 at the 5 C rate. Even at the 60 C rate, a high discharge capacity of 83.6 mA h g-1 is still obtained which is two times higher than that of pristine mesoporous TiO2. Electronic supplementary information (ESI) available: TGA of TiO2/RGO sample, XPS and AFM of the graphene oxide, SEM of TiO2 nanoparticles, SEM of the TiO2 and TiO2/RGO after cycles, rate performance of RGO, rate performance of TiO2/RGO with different contents of RGO. See DOI: 10.1039/c3nr06393c

Yan, Xiao; Li, Yanjuan; Du, Fei; Zhu, Kai; Zhang, Yongquan; Su, Anyu; Chen, Gang; Wei, Yingjin

2014-03-01

132

The synthesis of aqueous-dispersible anatase TiO2 nanoplatelets  

NASA Astrophysics Data System (ADS)

Aqueous well-dispersed and phase-pure anatase TiO2 truncated octahedron nanoplatelets (NPLs) were prepared via controlled hydrolysis of titanium tetrachloride (TiCl4) in ethylene glycol at 240 °C. Two shapes, square and hexagon, were observed by microscopy, exactly corresponding to the truncated octahedron NPLs. Ethylene glycol was found to produce water in situ that reacts with TiCl4 to produce TiO2 and HCl—the latter promoting TiO2 colloid peptization. TiO2 truncated octahedron NPLs are formed under the stabilizing action of ethylene glycol thermolysis derivatives, such as aldehydes. Crystal growth of the TiO2 NPLs was affected by the reaction temperature that determines the water production rate and HCl-assisted peptization. TGA and FT-IR results showed ~1.2% ethylene glycol thermolysis derivatives are attached to the surface of the TiO2 NPLs, which prevents their agglomeration, hence making them easily dispersible in aqueous media. HR-TEM and SAED results showed that the TiO2 NPLs are well crystallized and that the SAED patterns of the single TiO2 NPL changes with its size and shape. XRD patterns showed that the TiO2 NPLs are phase-pure anatase and the percentage of the {101} plane in the TiO2 NPLs to be only 18%—a structural feature that renders the TiO2 NPLs with enhanced UV absorption and reactivity properties.

Shan, Guo-Bin; Demopoulos, George P.

2010-01-01

133

Synthesis of reduced graphene oxide-anatase TiO2 nanocomposite and its improved photo-induced charge transfer properties  

NASA Astrophysics Data System (ADS)

The construction of reduced graphene oxide or graphene oxide with semiconductor has gained more and more attention due to its unexpected optoelectronic and electronic properties. The synthesis of reduced graphene oxide (RGO) or graphene oxide-semiconductor nanocomposite with well-dispersed decorated particles is still a challenge now. Herein, we demonstrate a facile method for the synthesis of graphene oxide-amorphous TiO2 and reduced graphene oxide-anatase TiO2 nanocomposites with well-dispersed particles. The as-synthesized samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis absorption spectroscopy, Fourier transform infrared spectrometry, and thermogravimetric analysis. The photovoltaic properties of RGO-anatase TiO2 were also compared with that of similar sized anatase TiO2 by transient photovoltage technique, and it was interesting to find that the combination of reduced graphene oxide with anatase TiO2 will significantly increase the photovoltaic response and retard the recombination of electron-hole pairs in the excited anatase TiO2.The construction of reduced graphene oxide or graphene oxide with semiconductor has gained more and more attention due to its unexpected optoelectronic and electronic properties. The synthesis of reduced graphene oxide (RGO) or graphene oxide-semiconductor nanocomposite with well-dispersed decorated particles is still a challenge now. Herein, we demonstrate a facile method for the synthesis of graphene oxide-amorphous TiO2 and reduced graphene oxide-anatase TiO2 nanocomposites with well-dispersed particles. The as-synthesized samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis absorption spectroscopy, Fourier transform infrared spectrometry, and thermogravimetric analysis. The photovoltaic properties of RGO-anatase TiO2 were also compared with that of similar sized anatase TiO2 by transient photovoltage technique, and it was interesting to find that the combination of reduced graphene oxide with anatase TiO2 will significantly increase the photovoltaic response and retard the recombination of electron-hole pairs in the excited anatase TiO2. Electronic supplementary information (ESI) available: AFM image of RGO-anatase TiO2, Raman spectra of GO, GO-amorphous TiO2, RGO-anatase TiO2 and hydrazine reduced graphene, TEM image and XRD pattern of anatase TiO2 nanoparticles. See DOI: 10.1039/c0nr00714e

Wang, Ping; Zhai, Yueming; Wang, Dejun; Dong, Shaojun

2011-04-01

134

The effect of dissolved oxygen on the 1,4-dioxane degradation with TiO2 and Au-TiO2 photocatalysts.  

PubMed

In order to enhance the photocatalytic activity of TiO(2), the recombination of photogenerated electron-hole pairs needs to be suppressed. Noble metals, e.g. Au nanoparticles, have been incorporated with TiO(2) to efficiently separate charge carriers created in/on TiO(2). On the other hand, dissolved oxygen (DO) in an aqueous solution was also known to scavenge the electrons, which avoid the recombination of electrons and holes. In this study, we investigated the combined system of Au nanoparticles incorporated with TiO(2) and DO to gain insight into the relationship between them using a photocatalytic degradation of 1,4-dioxane. The rate constants of 1,4-dioxane photodegradation with respect to TiO(2) catalysts with three different Au loadings, as well as DO levels, indicated the DO dependency is disproportional to the Au loading amount, implying that there is an overlapping function in capturing electrons between Au nanoparticles and DO. PMID:20034741

Youn, Na Kyoung; Heo, Jung Eun; Joo, Oh Shim; Lee, Hyunjoo; Kim, Jaehoon; Min, Byoung Koun

2010-05-15

135

Enhanced photocatalytic performance of Hemin (chloro(protoporhyinato)iron(III)) anchored TiO2 photocatalyst for methyl orange degradation: A surface modification method  

NASA Astrophysics Data System (ADS)

TiO2 was prepared by sol-gel method through the hydrolysis of TiCl4 and its surface derivatization was carried out with molecular catalyst like Hemin (chloro(protoporhyinato)iron(III)). Catalyst was characterized by various analytical techniques like UV-vis spectroscopy, FT-IR, FE-SEM and XRD. The anchoring of Hemin on titania surface is confirmed by FT-IR spectra through the linkage of Odbnd Csbnd Osbnd Ti bond and also by TGA-DSC and elemental analysis. The photocatalytic activity of the surface modified catalyst is tested for the degradation of methyl orange (MO) as a model compound under UV light. The Hemin impregnated TiO2 (H-TiO2) in presence of H2O2 shows an excellent photocatalytic activity compared to pristine TiO2, Hemin, H2O2, TiO2/H2O2, and Hemin/H2O2 systems. The enhancement in the photocatalytic activity is attributed to the presence of iron (III) porphyrin ring on the TiO2 surface, which reduces the electron-hole recombination rate and also by acting as a mediator for continuous production of enriched concentration of hydroxyl radicals along with various other reactive free radicals.

Devi, L. Gomathi; ArunaKumari, M. L.

2013-07-01

136

Synthesis of TiO2 nanosheets via an exfoliation route assisted by a surfactant.  

PubMed

Titanium dioxide (TiO2) is an important material for photovoltaics, photocatalysis, sensors and lithium ion batteries. Various morphologies of TiO2 nanomaterials have been synthesized, including zero-dimensional (0D) nanoparticles, one-dimensional (1D) nanowires and nanotubes, as well as three-dimensional (3D) nanostructures. But the two-dimensional (2D) TiO2 nanostructures, which are expected to have more promising properties and applications, are rarely reported. Herein, we report a surfactant-assisted exfoliation method to synthesize TiO2 2D nanosheets. It has been revealed that tetrabutylammonium hydroxide (hereafter TBAOH) as a surfactant plays a crucial role in retaining the 2D nanosheet structures. Compared with TiO2 nanotubes and anatase TiO2 nanoparticles, the as-prepared TiO2 single layered nanosheets delivered much higher capacities as anodes of the coin-type Li ion cells, with a reversible capacity of 82.2 mA h g(-1) at the 630th cycle at a current density of 2000 mA g(-1). PMID:24958361

Leng, Mei; Chen, Yu; Xue, Junmin

2014-07-10

137

Enhanced photocatalytic performances of CeO2/TiO2 nanobelt heterostructures.  

PubMed

CeO2 /TiO2 nanobelt heterostructures are synthesized via a cost-effective hydrothermal method. The as-prepared nanocomposites consist of CeO2 nanoparticles assembled on the rough surface of TiO2 nanobelts. In comparison with P25 TiO2 colloids, surface-coarsened TiO2 nanobelts, and CeO2 nanoparticles, the CeO2 /TiO2 nanobelt heterostructures exhibit a markedly enhanced photocatalytic activity in the degradation of organic pollutants such as methyl orange (MO) under either UV or visible light irradiation. The enhanced photocatalytic performance is attributed to a novel capture-photodegradation-release mechanism. During the photocatalytic process, MO molecules are captured by CeO2 nanoparticles, degraded by photogenerated free radicals, and then released to the solution. With its high degradation efficiency, broad active light wavelength, and good stability, the CeO2 /TiO2 nanobelt heterostructures represent a new effective photocatalyst that is low-cost, recyclable, and will have wide application in photodegradation of various organic pollutants. The new capture-photodegradation-release mechanism for improved photocatalysis properties is of importance in the rational design and synthesis of new photocatalysts. PMID:23681828

Tian, Jian; Sang, Yuanhua; Zhao, Zhenhuan; Zhou, Weijia; Wang, Dongzhou; Kang, Xueliang; Liu, Hong; Wang, Jiyang; Chen, Shaowei; Cai, Huaqiang; Huang, Hui

2013-11-25

138

Deactivation of the TiO2 photocatalyst by coupling with WO3 and the electrochemically assisted high photocatalytic activity of WO3.  

PubMed

Patterned TiO2 stripes were formed on a sol-gel crystalline WO3 film by using a chemically modified sol-gel method (pat-TiO2/WO3), and the coupling effect on the photocatalytic activity was studied. Although the photoinduced electron transfer from TiO2 to WO3 was confirmed by labeling and visualization of the reduction sites with Ag particles, the photocatalytic activities of TiO2 for both the gas-phase oxidation of CH3CHO and the liquid-phase oxidation of 2-naphthol decreased significantly with the coupling. This finding was rationalized in terms of the decrease in the rate of the electron transfer from the semiconductor-(s) to 02 with the coupling, which was estimated from the kinetic analysis of the photopotential relaxation. When the excited electrons were removed by a SnO2 underlayer, the WO3 film exhibited a high photocatalytic activity exceeding that of TiO2 for the oxidation of 2-naphthol. PMID:15969179

Tada, Hiroaki; Kokubu, Akio; Iwasaki, Mitsunobu; Ito, Seisihro

2004-05-25

139

Photocatalytic degradation of metoprolol tartrate in suspensions of two TiO2-based photocatalysts with different surface area. Identification of intermediates and proposal of degradation pathways.  

PubMed

This study investigates the efficiency of the photocatalytic degradation of metoprolol tartrate (MET), a widely used ?(1)-blocker, in TiO(2) suspensions of Wackherr's "Oxyde de titane standard" and Degussa P25. The study encompasses transformation kinetics and efficiency, identification of intermediates and reaction pathways. In the investigated range of initial concentrations (0.01-0.1 mM), the photocatalytic degradation of MET in the first stage of the reaction followed approximately a pseudo-first order kinetics. The TiO(2) Wackherr induced a significantly faster MET degradation compared to TiO(2) Degussa P25 when relatively high substrate concentrations were used. By examining the effect of ethanol as a scavenger of hydroxyl radicals (OH), it was shown that the reaction with OH played the main role in the photocatalytic degradation of MET. After 240 min of irradiation the reaction intermediates were almost completely mineralized to CO(2) and H(2)O, while the nitrogen was predominantly present as NH(4)(+). Reaction intermediates were studied in detail and a number of them were identified using LC-MS/MS (ESI+), which allowed the proposal of a tentative pathway for the photocatalytic transformation of MET as a function of the TiO(2) specimen. PMID:22035693

Abramovi?, Biljana; Kler, Sanja; Soji?, Daniela; Lauševi?, Mila; Radovi?, Tanja; Vione, Davide

2011-12-30

140

Microwave-assisted synthesis of nanocrystalline TiO2 for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

The main purposes of this study are replacing conventional hydro-thermal method by microwave heating using water as reaction medium to rapidly synthesize TiO2.Titanium tetraisopropoxide (TTIP) was hydrolyzed in water. The solution is subsequently processed with microwave heating for crystal growth. The reaction time could be shortened into few minutes. Then we chose different acids as dispersion agents to prepare TiO2 paste for investigating the effects of dispersion on the power conversion efficiency of dye-sensitized solar cells (DSCs). The photovoltaic performance of the microwave-assisted synthesized TiO2 achieved power conversion efficiency of 6.31% under AM 1.5 G condition (100 mW/cm2). This PCE value is compatible with that of the devices made from commercial TiO2.

Kuo, Ta-Chuan; Guo, Tzung-Fang; Chen, Peter

2012-09-01

141

The synthesis of rutile nano-structured TiO2 composite under low temperature  

NASA Astrophysics Data System (ADS)

In this paper, in order to improve the photocatalytic application of TiO2, the low-density material such as Ps and TiCl4 is proposed to be the raw carrier, and the nana-structured TiO2 composite is obtained by combining the sol-gel technology and layer-by-layer self-assembly methods; The pure rutile nano-structured TiO2 whose diameter is about 0.25mm are prepared under different conditions at low temperature. By being calcined under 450 ? the hollow sphere TiO2 is prepared and its composition, size, structure analysis and characterization are studied by using X ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermal gravimetric analysis (DSC-TG) respectively.

Zhang, Lei; Zheng, Yibo; Dong, Mofei; Li, Simian

2012-11-01

142

Synthesis of nano-sized Al doped TiO 2 powders using thermal plasma  

Microsoft Academic Search

High quality nano-sized Al doped TiO2 powders were prepared using a DC plasma jet. Titanium tetrachloride (TiCl4) and aluminum chloride (AlCl3) were fed into the plasma flame as starting materials, and the ratio of Al to TiO2 was varied from 1 to 8 wt.%. We investigated the effect of process parameters on phase composition, particle size, and optical property by

Ji Eun Lee; Seung-Min Oh; Dong-Wha Park

2004-01-01

143

Synthesis and Characterization of Size-Controlled TiO2 Microspheres with Wormhole Mesoporous Structure  

Microsoft Academic Search

The size-controlled TiO2 microspheres with wormhole mesoporous structure have been synthesized via a salt-assisted sol–gel method. The influences of various precursor concentrations and the addition of different salt ions on the size and on the size distribution of the final microspheres were investigated. Structural characterization indicates that these TiO2 microspheres with the diameters of 60 nm–2 µm are composed of nanocrystals (about

Li Junqi; He Zuoli; Guo Liying; Zhu Zhenfeng

2010-01-01

144

Fabrication of CdS nanowires decorated with TiO 2 nanoparticles for photocatalytic hydrogen production under visible light irradiation  

Microsoft Academic Search

A CdS\\/TiO2 composite photocatalyst consisting of one-dimensional CdS nanowire (NW) with a high crystallinity decorated with nanosized TiO2 particles (NP) was fabricated by solvothermal method and sol–gel synthesis. The new configuration photocatalyst exhibited higher rate of hydrogen production than that of single CdS NW under visible light irradiation (??420nm) from water containing sulfide and sulfite ions as hole scavengers. Physicochemical

Jum Suk Jang; Hyun Gyu Kim; Upendra A. Joshi; Ji Wook Jang; Jae Sung Lee

2008-01-01

145

Polypropylene membrane surface modification by RAFT grafting polymerization and TiO 2 photocatalysts immobilization for phenol decomposition in a photocatalytic membrane reactor  

Microsoft Academic Search

The main technical barriers that impede photocatalytic membrane reactor (PMR) commercialization remain on the post-recovery of the catalyst particles after water treatment. To overcome this problem, surface modification of polypropylene macroporous membrane was performed with the technique of photoinduced reversible addition-fragmentation chain transfer grafting polymerization of acrylic acid. Titanium oxide photocatalysts were introduced to the acrylic acid grafted membrane surface.

Song Yang; Jia-Shan Gu; Hai-Yin Yu; Jin Zhou; Shi-Feng Li; Xiu-Min Wu; Liang Wang

2011-01-01

146

One-pot solvothermal synthesis of graphene-supported TiO2 (B) nanosheets with enhanced lithium storage properties.  

PubMed

A facile process was developed for the synthesis of graphene-supported TiO2 (B) nanosheets (GTBN) composite based on the hydrothermal treatment titanium (III) chloride and graphene oxide in an ethylene glycol. The morphology and microstructure of the composites were examined by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectroscopy. The obtained GTBN show a high thermal stability and the phase transformation of TiO2 (B) to anatase can be prevented by graphene after pyrolysis of GTBN at 350°C for 2h. Furthermore, GTBN exhibited high rate performance and stability of lithium ion batteries, due to the enhanced conductivity of the electrode and accommodation to volume/strain changes during lithium insertion-extraction. PMID:23972503

Zhang, Zhe; Chu, Qingxin; Li, Huiyan; Hao, Jinhui; Yang, Wenshu; Lu, Baoping; Ke, Xi; Li, Jing; Tang, Jilin

2013-11-01

147

Synthesis and Magnetotransport Properties of CrO2-TiO2 Composites  

NASA Astrophysics Data System (ADS)

CrO2-TiO2 composites are synthesized by using a high temperature and high pressure method using CrO3 and H2TiO3 as precursors. The composites consist of large rod-like CrO2 crystals separated by small TiO2 grains. The CrO2 in the composites is very pure and its saturation magnetization is very close to the theoretical value (i.e., 2?B per formula unit). The composites exhibit a large negative magnetoresistance (MR) at 5K. The MR in CrO2-TiO2 composites is mainly attributed to spin-polarized tunneling between CrO2 crystals. The conductivity of the composites is best described by a fluctuation-induced tunneling model below 230K.

Fan, Yin-Bo; Zhang, Cai-Ping; Du, Xiao-Bo; Wen, Ge-Hui; Ma, Hong-An; Jia, Xiao-Peng

2013-03-01

148

One step synthesis of rutile TiO2 nanoparticles at low temperature.  

PubMed

Sphere-like rutile TiO2 nanocrystals have been synthesized by sol-gel method followed by hydrolysis of titanium tetrachloride in deionized water in the presence of ammonium hydroxide as hydrolysis catalyst. The as-prepared TiO2 nanoparticles have single rutile phase with average diameter approximately 26.4 nm. The results show that the temperature has a great influence on the particle size distribution and also crystalline phase (rutile) of TiO2 nanoparticles is consistent with the temperature. Characterization of the as-prepared nanocrystalline powder was carried out by different techniques such as powder X-ray diffraction (XRD), field emission transmission electron microscopy (FE-TEM) and Raman spectroscopy. PMID:22629999

Anwar, M S; Kumar, Shalendra; Ahmed, Faheem; Arshi, Nishat; Lee, Chan Gyu; Koo, Bon Heun

2012-02-01

149

Synthesis of uniform TiO2 nanoparticles with egg albumen proteins as novel biotemplate.  

PubMed

A novel bio-templated route was reported for the fabrication of uniform and well dispersed TiO, nanoparticles using denatured egg albumen (EA) proteins network as template. Anatase TiO2 nanoparticles of ca. 9 nm with narrow size distribution were obtained under employed reaction conditions, as proved by the XRD and TEM results. The as-prepared TiO2 nanoparticles were further characterized by means of XPS, FTIR, TG-DTA and UV-Vis. Based on the characterization results, a possible process of heat-induced denatured protein network as template matrix to fabricate TiO2 nanoparticles was carefully proposed. The method with egg albumen as bio-template provides us a cheap, green and repeatable route for the fabrication of nanoparticles under mild conditions. PMID:21133103

Yan, Jingjing; Wu, Guangjun; Li, Landong; Yu, Aimin; Sun, Xiaohong; Guan, Naijia

2010-09-01

150

Uniform TiO2-SiO2 hollow nanospheres: Synthesis, characterization and enhanced adsorption-photodegradation of azo dyes and phenol  

NASA Astrophysics Data System (ADS)

TiO2-SiO2 hollow nanospheres with remarkable enhanced photocatalytic performance have been fabricated by sol-gel method. The hollow sphere possesses both high phototcatalytic activity and adsorption capability. The as-prepared samples were characterized by XRD, SEM, TEM, FTIR, XPS, BJH and TGA/DSC. The experiment results show that, the photocatalyst calcined at 500 °C with Ti/Si ratio of 5:1 (denoted as 5T/S-500) displayed superiorities in both textural and functional properties with the enhanced degradation efficiency on azo dyes (methylene blue, methyl orange) and phenol. The high adsorption capability of organic poisonous contaminants onto 5T/S-500 in aqueous solution demonstrated that the photocatalyst can remove the contaminants from water effectively even without illumination. The TEM and SEM morphologies demonstrated unique hollow and coarse structure of 5T/S-500. Structural analysis showed that Si was doped into the lattice of TiO2 and SiO2 nanoparticles can work as a surface modifier on TiO2. The surface area of 5T/S-500 is 1105 m2/g, 14.5 times as great as that of the pure hollow TiO2 nanosphere, confirms the effect of SiO2 on the improvement of specific surface area. The high photocatalytic activities and high adsorption ability for organic poisonous contaminants demonstrate that the nanocomposite of TiO2-SiO2 is a promising candidate material for future treatment of contaminated water.

Guo, Na; Liang, Yimai; Lan, Shi; Liu, Lu; Ji, Guijuan; Gan, Shucai; Zou, Haifeng; Xu, Xuechun

2014-06-01

151

Photocatalytic evolution of hydrogen over mesoporous TiO 2 supported NiO photocatalyst prepared by single-step sol–gel process with surfactant template  

Microsoft Academic Search

Photocatalytic activity of mesoporous titania supported nickel oxide photocatalyst synthesized by single-step sol–gel (SSSG) process combined with surfactant-assisted template method was investigated for hydrogen evolution from an aqueous methanol solution, in comparison with one prepared by conventional incipient wetness impregnation (IWI) method. In single-step sol–gel process, nickel precursor was introduced into the titania sol prepared with the aid of a

Thammanoon Sreethawong; Yoshikazu Suzuki; Susumu Yoshikawa

2005-01-01

152

Direct synthesis of a mesoporous TiO2-RuO2 composite through evaporation-induced polymeric micelle assembly.  

PubMed

Here we report a direct synthesis of a mesoporous TiO2-RuO2 composite. Titanium tetraisopropoxide (TTIP) and RuCl3 are used as inorganic precursors for TiO2 and RuO2, respectively. Evaporation-induced assembly of spherical micelles made of an asymmetric poly(styrene-b-2-vinyl pyridine-b-ethylene oxide) triblock copolymer enables the fabrication of a mesoporous TiO2-RuO2 composite with a uniform pore size of 30 nm. PMID:24760227

Bastakoti, Bishnu Prasad; Salunkhe, Rahul R; Ye, Jinhua; Yamauchi, Yusuke

2014-05-14

153

In situ synthesis of TiO2/polyethylene terephthalate hybrid nanocomposites at low temperature  

NASA Astrophysics Data System (ADS)

TiO2 nanoflowers were in situ grown on polyethylene terephthalate (PET) non-woven fabric by hydrolysis of TiCl4 in aqueous solution in the presence of nanocrystal cellulose grafted PET fabric (NCC-g-PET) at a low temperature of 70 °C. Nanocrystal cellulose (NCC) pre-grafted on PET fabric acted as hydrophilic substrate and morphology inducing agent to promote the nucleation and crystal growth of TiO2. Detailed information on the synthetic process was presented. The resulting samples were characterized using FE-SEM, EDS, ATR-IR, Raman microscopy, XRD and TG analysis. The photocatalytic activity of the samples was evaluated by the degradation of orange methyl under solar light. Characteristic results indicate that rutile TiO2 nanoflowers have grown abundantly on PET non-woven fabric, and the established hydrogen bonding strengthens the interfacial interaction between the inorganic particles and the polymeric substrates. The methyl orange decoloration test under natural solar light demonstrates that this TiO2/PET hybrid nanocomposites exhibit excellent self-cleaning performance which is expected to have a good potential for commercialization.

Peng, Xinyan; Ding, Enyong; Xue, Feng

2012-06-01

154

Synthesis of TiO2 nanocoral structures in ever-changing aqueous reaction systems.  

PubMed

A far-from-equilibrium strategy is developed to synthesize coral-like nanostructures of TiO(2) on a variety of surfaces. TiO(2) nanocoral structures consist of anatase base film and rutile nanowire layers, and they are continuously formed on substrates immersed in aqueous TiOSO(4)-H(2)O(2). The sequential deposition of TiO(2) starts with hydrolysis and condensation reactions of titanium peroxocomplexes in the aqueous phase, resulting in deposition of amorphous film. The film serves as adhesive interface on which succeeding growth of rutile nanowires to occur. This initial deposition reaction is accompanied by shift in pH of the reaction media, which is favorable condition for the growth of rutile nanocrystals. During the growth of rutile nanocoral layers, the amorphous base films are transformed to anatase phase. These sequential deposition reactions occur at temperatures as low as 80 °C, and the mild synthetic condition allows the use of a wide range of substrates such as ITO (indium tin oxide), glass, and even organic polymer films. The thickness of nanocoral layer is controllable by repeating the growth reaction of rutile nanocorals. TiO(2) nanocorals show photocatalytic activity as demonstrated by site-specific reduction of Ag(I) ions, which proceeds preferentially on the rutile nanowire layer. The rutile nanowire layer also shows photocatalytic decomposition of acetaldehyde, which is promoted upon increase of the thickness of the nanowire layer. The use of temporally transforming reaction media allows the formation of biphasic TiO(2) nanocoral structures, and the concept of nonequilibrium synthetic approach would be widely applicable to developing structurally graded inorganic nanointerfaces. PMID:22214471

Soejima, Tetsuro; Jin, Ren-Hua; Terayama, Yuki; Takahara, Atsushi; Shiraishi, Takamasa; Ito, Seishiro; Kimizuka, Nobuo

2012-02-01

155

CTAB-assisted synthesis of mesoporous F-N-codoped TiO 2 powders with high visible-light-driven catalytic activity and adsorption capacity  

NASA Astrophysics Data System (ADS)

This article describes the preparation of mesoporous rod-like F-N-codoped TiO 2 powder photocatalysts with anatase phase via a sol-gel route at the temperature of 373 K, using cetyltrimethyl ammonium bromide (CTAB) as surfactant. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectra (UV-vis DRS). The results showed that the photocatalysts possessed a homogeneous pore diameter and a high surface area of 106.3-160.7 m 3 g -1. The increasing CTAB reactive concentration extended the visible-light absorption up to 600 nm. The F-N-codoped TiO 2 powders exhibited significant higher adsorption capacity for methyl orange (MO) than that of Degussa P25 and showed more than 6 times higher visible-light-induced catalytic degradation for MO than that of P25.

Xie, Yi; Zhao, Xiujian; Li, Yuanzhi; Zhao, Qingnan; Zhou, Xuedong; Yuan, Qihua

2008-08-01

156

Water and temperature effects on photo-selective catalytic reduction of nitric oxide on Pd-loaded TiO2 photocatalyst  

Microsoft Academic Search

Photo-selective catalytic reduction (photo-SCR) of nitric oxide (NO) was studied in the presence of water. The incipient wetness impregnation was applied to prepare 1 wt% PdO\\/TiO2 photocatalyst. Steady-state photoreaction was carried out in a continuous-flow photoreactor with 0.55–1.6 v% water at 30–120°C under UV-light intensity of ? 200 mW\\/cm. The C3H8\\/NO molar ratio in the feed ranged from 0.8–16.8 at a volume hourly

Janusz Lasek; Yi-Hui Yu; Jeffrey C. S. Wu

2012-01-01

157

Fabrication of Titanium Dioxide Photocatalyst Coatings by Cold Spray  

Microsoft Academic Search

Titanium dioxide (TiO2) is a promising material for photocatalyst coating. However, it was difficult to fabricate TiO2 coatings which have excellent photocatalytic property by thermal spray processes. Because anatase phase of TiO2 transforms into rutile phase under high temperature i.e. the photocatalytic property of TiO2 declines by heating. In this study, TiO2 photocatalyst coatings were fabricated by cold spray process.

Motohiro Yamada; Yuko Kandori; Kazunori Sato; Masahiro Fukumoto

2009-01-01

158

Synthesis and characterization of La2O3/TiO2-xFx and the visible light photocatalytic oxidation of 4-chlorophenol.  

PubMed

In this work, we investigated the synergetic effect of La and F on the visible light photocatalytic activity of TiO(2) catalysts. La(2)O(3)/TiO(2-x)F(x) photocatalysts were prepared by a simple sol-gel process using tetrabutyl titanate (TBT), La(NO(3))(3) and NH(4)F as precursors. XPS results revealed that La(2)O(3) accumulated on the surface of TiO(2), which enhanced the surface area of TiO(2) and inhibited the recombination of electron-hole pairs. It also showed that two kinds of fluorine species were formed and these increased the acid active sites and enhanced the oxidation potential of the photogenerated holes in the valance band. UV-vis diffuse reflection spectra of La(2)O(3)/TiO(2-x)F(x) showed that intraband gap states were present and these are probably responsible for its absorption of visible light while the intrinsic absorption band was shifted slightly to a longer wavelength. At molar ratios of La and F to Ti of 1.5:100 and 5:100 and after calcination at 500 degrees C, the degradation rate of 4-chlorophenol (4-CP) over the sample was about 1.2-3.0 times higher than that of the other doped samples and undoped TiO(2). The total organic carbon (TOC) removal rates of 4-CP showed that 4-CP was mineralized efficiently in the presence of the sample under visible light illumination. PMID:20149531

Cao, Guangxiu; Li, Yaogang; Zhang, Qinghong; Wang, Hongzhi

2010-06-15

159

Self-organized TiO2 nanotube arrays: synthesis by anodization in an ionic liquid and assessment of photocatalytic properties.  

PubMed

Self-organized TiO(2) nanotube (NT) arrays were produced by anodization in ethylene glycol (EG) electrolytes containing 1-n-butyl-3-methyl-imidazolium tetrafluoroborate (BMI.BF(4)) ionic liquid and water. The morphology of the as-formed NTs was considerably affected by changing the anodization time, voltage, and water and ionic liquid electrolyte concentrations. In general, a nanoporous layer was formed on the top surface of the TiO(2) NTs, except for anodization at 100 V with 1 vol % of BMI.BF(4), where the NT's mouth was revealed. The length and bottom diameter of the NTs as well as the pore diameter of the top layer showed a linear relationship with increased anodization voltage. These TiO(2) NTs were tested as photocatalysts for methyl orange photodegradation and hydrogen evolution from water/methanol solutions by UV light irradiation. The results show that the TiO(2) NTs obtained by anodization in EG/H(2)O/BMI.BF(4) electrolytes are active and efficient for both applications. PMID:21443251

Wender, Heberton; Feil, Adriano F; Diaz, Leonardo B; Ribeiro, Camila S; Machado, Guilherme J; Migowski, Pedro; Weibel, Daniel E; Dupont, Jairton; Teixeira, Sérgio R

2011-04-01

160

Branch Density-Controlled Synthesis of Hierarchical TiO2 Nanobelt and Tunable Three-Step Electron Transfer for Enhanced Photocatalytic Property.  

PubMed

The successful adjustment of phase composition and morphology of hierarchical TiO2 nanobelts, which feature homoepitaxial nanobranches, has been developed via the hydrothermal method and chemical bath deposition technique. Effects of hydrothermal reaction time, titanium butoxide treatment in chemical bath deposition, and calcination temperature are systematically investigated. For the first time, three-step ultrafast electron transfers between the band edges of the engaged phases are realized through the enhanced photocatalytic activity results. Growth mechanism related to branch density control on nanobelt surface under such soft chemical process is discussed in detail on the basis of classical nucleation theory. The current work might provide new insights into the fabrication of one-dimensional homoepitaxial branched TiO2 nanostructures as high performance photocatalysts and facilitate their application in environmental cleanup. PMID:24857888

Sarkar, Debabrata; Chattopadhyay, Kalyan Kumar

2014-07-01

161

Synthesis of capped TiO2 nanocrystals of controlled shape and their use with MEH-PPV to develop nanocomposite films for photovoltaic applications.  

PubMed

The present study presents the synthesis details of titanium dioxide (TiO2) nanoparticles (NPs) of different morphologies using oleic acid (OA) and oleyl amine (OM) as capping agents. Different shapes of NPs, such as nanospheres, nanorods, and nanorhombics, were achieved. In order to develop nanocomposite thin films for photovoltaic cells, these TiO2 NPs were carefully dispersed in 2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene (MEH-PPV) matrix. The properties of synthesized TiO2 NPs and MEH-PPV/TiO2 nanocomposites were characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), UV-Visible spectroscopy, and Photoluminescence technique. Obtained results showed promising properties for photovoltaic devices, especially solar radiation absorption properties and charge transfer at the interface of the conjugated MEH-PPV matrix and TiO2 dispersed NPs. PMID:22755128

Vu, Thi Thuy Duong; Mighri, Frej; Do, Trong-On; Ajji, Abdellah

2012-03-01

162

Synthesis of gold nanoclusters: a fluorescent marker for water-soluble TiO2 nanotubes  

NASA Astrophysics Data System (ADS)

The first example of a water-soluble wrapped titania nanotube (TNT) decorated with fluorescent gold nanoparticles has been prepared. Gold nanoparticles ~ 1.6 nm in diameter were grown on the TiO2 nanotubes using a thiolactic acid linker to control the size. The gold clusters emit at 660 nm in water and were imaged using confocal microscopy. The gold decorated TNTs were suspended in water by wrapping the nanotubes with poly-L-arginine.

Ratanatawanate, Chalita; Yu, Jing; Zhou, Chen; Zheng, Jie; Balkus, Kenneth J., Jr.

2011-02-01

163

Synthesis of TiO2\\/functionalized graphene sheets (FGSs) nanocomposites in super critical CO2  

Microsoft Academic Search

Highly ordered TiO2 nanowire arrays were prepared on the surface of Functionalized Graphene sheets (FGSs) by solgel method using titanium isopropoxide monomer with acetic acid as the polycondensation agent in the green solvent, supercritical carbon dioxide (sc-CO2). Morphology of synthesized materials was studied by SEM and TEM. Optical properties of the nanocomposites studied by UV spectroscopy which showed high absorption

Nasrin Farhangi; Yaocihuatl Medina-Gonzalez; Bo Chen; Paul A. Charpentier

2010-01-01

164

Synthesis of monodisperse TiO2-paraffin core-shell nanoparticles for improved dielectric properties.  

PubMed

Core-shell structures of oxide nanoparticles having a high dielectric constant, and organic shells with large breakdown field are attractive candidates for large electrical energy storage applications. A high growth temperature, however, is required to obtain the dielectric oxide nanoparticles, which affects the process of core-shell formation and also leads to poor control of size, shape, and size-distribution. In this communication, we report a new synthetic process to grow core-shell nanoparticles by means of an experimental method that can be easily adapted to synthesize core-shell structures from a variety of inorganic-organic or inorganic-inorganic materials. Monodisperse and spherical TiO2 nanoparticles were produced at room temperature as a collimated cluster beam in the gas phase using a cluster-deposition source and subsequently coated with uniform paraffin nanoshells using in situ thermal evaporation, prior to deposition on substrates for further characterization and device processing. The paraffin nanoshells prevent the TiO2 nanoparticles from contacting each other and also act as a matrix in which the volume fraction of TiO2 nanoparticles was varied by controlling the thickness of the nanoshells. Parallel-plate capacitors were fabricated using dielectric core-shell nanoparticles having different shell thicknesses. With respect to the bulk paraffin, the effective dielectric constant of TiO2-paraffin core-shell nanoparticles is greatly enhanced with a decrease in the shell thickness. The capacitors show a minimum dielectric dispersion and low dielectric losses in the frequency range of 100 Hz-1 MHz, which are highly desirable for exploiting these core-shell nanoparticles for potential applications. PMID:20359188

Balasubramanian, Balamurugan; Kraemer, Kristin L; Reding, Nicholas A; Skomski, Ralph; Ducharme, Stephen; Sellmyer, David J

2010-04-27

165

TiO2 Hollow Spheres: One-Pot Synthesis and Enhanced Photocatalysis  

NASA Astrophysics Data System (ADS)

Hollow TiO2 microspheres were successfully fabricated by metal salts with low solubility in ethanol acting as intelligent templates using a simple one-pot solvothermal method. Hollow spheres with large diameter were obtained using CuSO4?5H2O as templates while small ones were obtained using Sr(NO3)2 as templates. It is found that titanium precursor plays an important role for the morphology of samples. Solid TiO2 microspheres were prepared by using titanium tetrabutoxide (TBT). In contrast, bowl-like hollow microspheres were obtained by using titanium tetrachloride (TiCl4). Furthermore, the amount of H2O can stimulate the hydrolysis rate of TiCl4 to form solid spheres. Compared with solid microspheres, hollow TiO2 microspheres depending on their interior cavity structure exhibited enhanced photocatalysis efficiency for the UV-light photodegradation of methyl orange. Quantificationally, the apparent photocatalytic degradation pseudo-first-rate constant of the hollow microspheres is 1.25 times of that of the solid ones.

Jia, Changchao; Cao, Yongqiang; Yang, Ping

2013-06-01

166

Synthesis and characterization of Y3+-doped TiO2 nanocomposites for photocatalytic applications.  

PubMed

The TiO(2).[Y(2)O(3)](x) (x = 0.1-0.4) nanocomposites (NCs) with an average particle size of 74 nm were prepared by the method of chemical co-precipitation followed by hydrolysis (CPH). Their visible light photocatalytic activity was investigated for the degradation of congo red (CR) dye. All NCs showed improved degradation as compared to the polycrystalline samples of similar compositions prepared by the solid-state reaction (SSR) route (average particle size of a few micrometers), as well as to the pure TiO(2). The better photocatalytic activity of the NCs was attributed to their smaller particle size. Another comparison of the results with those obtained with Zn(2+)/Fe(3+) ions co-doped TiO(2) NCs, under similar experimental conditions, revealed that in the Y(3+)-doped NCs, particle size might not be the only factor responsible for the improved photocatalytic properties. It was concluded that the Y(3+) ion-mediated suppression of the unwanted e(-)/h(+) recombination could be the possible factor leading to additional enhancement. PMID:19491466

Narayan, Himanshu; Alemu, Hailemichael; Macheli, Lebohang; Thakurdesai, Madhavi; Rao, T K Gundu

2009-06-24

167

Template-directed synthesis, characterization and electrical properties of Au TiO2 Au heterojunction nanowires  

NASA Astrophysics Data System (ADS)

The feasibility of synthesizing metal-oxide-metal (MOM) heterojunction nanowires in the Au-TiO2-Au system is demonstrated. The synthesis method presented here entails sequential electroplating of Au and electro-deposition of amorphous titanium oxide (TiOx) inside nanoholes of anodic aluminium oxide (AAO) templates. This is followed by dissolving the template, and heat-treating the released nanowires, which results in the crystallization of the amorphous TiOx segment into nanocrystalline TiO2. Detailed transmission electron microscopy (TEM) investigation has revealed that the nanocrystalline TiO2 is orthorhombic (columbite) phase primarily. This synthesis method has the potential to provide better control over the characteristics and architectures of the resulting MOM nanowires. The Au-TiO2-Au nanowires were incorporated into single-nanowire devices, fabricated using a direct-write method. Nonlinear current-voltage (I-V) responses were obtained for individual MOM nanowires. The heterojunctions in such MOM nanowires are likely to offer certain advantages over all-oxide nanowires, making the MOM nanowires potentially useful as one-dimensional building blocks in the multifunctional nanoelectronics of the future.

Herderick, Edward D.; Tresback, Jason S.; Vasiliev, Alexander L.; Padture, Nitin P.

2007-04-01

168

Facile synthesis of TiO2/graphene composites for selective enrichment of phosphopeptides  

NASA Astrophysics Data System (ADS)

TiO2/graphene composites were synthesized through a simple one-step hydrothermal reaction and successfully used to selectively capture phosphopeptides from peptide mixtures for matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis.TiO2/graphene composites were synthesized through a simple one-step hydrothermal reaction and successfully used to selectively capture phosphopeptides from peptide mixtures for matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis. Electronic supplementary information (ESI) available: Experimental details, SEM image, and EDXA pattern. See DOI: 10.1039/c2nr11791f

Lu, Jin; Wang, Mengyi; Li, Yan; Deng, Chunhui

2012-02-01

169

Synthesis and characterization of TiO2 nanotube/hydroquinone hybrid structure.  

PubMed

It is shown that 1,4-benzenediol (hydroquinone) and TiO2 nanotubes can form a hybrid structure that is stable in aqueous environment. The incorporation of hydroquinone restores the local structure of nanotubes to anatase-like as evidenced by Raman spectroscopy. Subtle overall structural changes take place upon annealing of the hybrid structure contributing to its stability. The hybrid system shows a broad optical absorption peak extending significantly beyond 700 nm with potential applications in photocatalysis and photoelectrochemistry. PMID:17450779

Jia, Yuanyuan; Kleinhammes, Alfred; Kulkarni, Harsha; McGuire, Kristopher; McNeil, L E; Wu, Yue

2007-02-01

170

Synthesis and Characterization of Sodium Titanate and TiO2 Nanostructures Loaded with Silver Nanoparticles  

NASA Astrophysics Data System (ADS)

Sodium titanate nanostructures loaded with Ag0 nanoparticles were synthesized from anatase TiO2 doped with Ag+ and NaOH(aq) under hydrothermal conditions. Presence of Ag+ ions in reaction mixture prevented the growth of sodium titanate nanotubes. Instead of nanotubes half rolled sodium titanate slabs were formed. HAADF-STEM characterization revealed that Ag0 nanoparticles are homogenously distributed on titanate matrix. By an ion exchange process sodium ions were exchanged with H3O+ in a solution of acetic acid. Further thermal treatment at 400 °C in a reductive atmosphere transformed protonated titanate slabs into TiO2 slabs loaded with Ag0 nanoparticles. The ion exchange process slightly reduced the average diameter of Ag0 nanoparticles when compared to the diameter of Ag0 nanoparticles in the as synthesized sample. The samples were characterized by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD).

Umek, Polona; Gloter, Alexandre; Navio, Cristina; Bittencourt, Carla

2011-12-01

171

Large-surface mesoporous TiO2 nanoparticles: synthesis, growth and photocatalytic performance.  

PubMed

This study demonstrates a facile and effective method to generate mono-dispersed titanium dioxide spheres at ambient conditions. The size of the colloids can be controlled from 60 to 500 nm by optimizing experimental parameters (e.g., concentration, time, and temperature). Anatase TiO(2) can be obtained through titanium glycolate colloids generated in acetone via two ways: water boiling approach and calcination at a high temperature of 500°C. Particle characteristics (shape, size, and size distribution) were measured by advanced techniques, including transmission electron microscope (TEM), thermo-gravimetric analysis (TGA), UV/Vis absorption spectrum, nitrogen gas adsorption and desorption isotherms Brunauer-Emmett-Teller (BET) surface area measurement, and X-ray diffraction technique (XRD). The possible mechanism of nucleation and growth of such colloids was discussed. The role of acetone in the formation and growth of titanium glycolate colloids was also investigated by Fourier transform infrared (FT-IR) spectroscopy. Finally, the photocatalysis performance of such anatase TiO(2) particles was tested and proved to be efficient in degradation of organic dyes (e.g., phenolphthalein and methly orange). PMID:22975400

Yang, Xiaohong; Fu, Haitao; Yu, Aibing; Jiang, Xuchuan

2012-12-01

172

Characterisation of the photocatalyst Pilkington Activ™: a reference film photocatalyst?  

Microsoft Academic Search

Pilkington Glass Activ™ represents a possible suitable successor to P25 TiO2, especially as a benchmark photocatalyst film for comparing other photocatalyst or PSH self-cleaning films. Activ™ is a glass product with a clear, colourless, effectively invisible, photocatalytic coating of titania that also exhibits PSH. Although not as active as a film of P25 TiO2, Activ™ vastly superior mechanical stability, very

Andrew Mills; Anne Lepre; Nicholas Elliott; Sharan Bhopal; Ivan P. Parkin; S. A. O’Neill

2003-01-01

173

Modeling Geometric Arrangements of TiO2-Based Catalyst Substrates and Isotropic Light Sources to Enhance the Efficiency of a Photocatalystic Oxidation (PCO) Reactor  

NASA Technical Reports Server (NTRS)

The closed confined environments of the ISS, as well as in future spacecraft for exploration beyond LEO, provide many challenges to crew health. One such challenge is the availability of a robust, energy efficient, and re-generable air revitalization system that controls trace volatile organic contaminants (VOCs) to levels below a specified spacecraft maximum allowable concentration (SMAC). Photocatalytic oxidation (PCO), which is capable of mineralizing VOCs at room temperature and of accommodating a high volumetric flow, is being evaluated as an alternative trace contaminant control technology. In an architecture of a combined air and water management system, placing a PCO unit before a condensing heat exchanger for humidity control will greatly reduce the organic load into the humidity condensate loop ofthe water processing assembly (WPA) thereby enhancing the life cycle economics ofthe WPA. This targeted application dictates a single pass efficiency of greater than 90% for polar VOCs. Although this target was met in laboratory bench-scaled reactors, no commercial or SBIR-developed prototype PCO units examined to date have achieved this goal. Furthermore, the formation of partial oxidation products (e.g., acetaldehyde) was not eliminated. It is known that single pass efficiency and partial oxidation are strongly dependent upon the contact time and catalyst illumination, hence the requirement for an efficient reactor design. The objective of this study is to maximize the apparent contact time and illuminated catalyst surface area at a given reactor volume and volumetric flow. In this study, a Ti02-based photocatalyst is assumed to be immobilized on porous substrate panels and illumination derived from linear isotropic light sources. Mathematical modeling using computational fluid dynamics (CFD) analyses were performed to investigate the effect of: 1) the geometry and configuration of catalyst-coated substrate panels, 2) porosity of the supporting substrate, and 3) varying the light source and spacing on contact time and illuminated catalyst area.

Richards, Jeffrey T.; Levine, Lanfang H.; Husk, Geoffrey K.

2011-01-01

174

Synthesis of TiO2 Nanosized Powder by Pulsed Wire Discharge  

NASA Astrophysics Data System (ADS)

Nanosized powders of TiO2 have been synthesized by pulsed wire discharge (PWD) using titanium wire in oxygen gas. The relative energy (R, R = Ei/Ev), which is the ratio of the charged energy of the capacitor (Ei) to the vaporization energy of the wire (Ev), was changed from R = 1.9 to 52.1. The X-ray diffraction patterns of nanosized powders synthesized at various relative energies showed that all the samples had peaks of rutile and anatase. The rutile content increased with the increase in the relative energy, and changed from 6 to 84 vol % at 100 kPa. The median particle diameter decreased from 30.9 to 20.4 nm. Control of the rutile content and particle size was possible by varying the relative energy used for PWD.

Tokoi, Yoshinori; Suzuki, Tsuneo; Nakayama, Tadachika; Suematsu, Hisayuki; Jiang, Weihua; Niihara, Koichi

2008-01-01

175

Porous tubular rutile TiO2 nanofibers: synthesis, characterization and photocatalytic properties.  

PubMed

Electrospinning was employed to synthesize tubular TiO2 nanofibers. The as-spun fibers were subjected to heat treatment at 800 degrees C for 1 h in the air. By controlling the polymer concentration, pores measuring 30-60 nm were formed on the side walls of the tubular nanofibers. During annealing, the average nanofiber diameter shrank from 150 nm to 120 nm. The structural properties were characterized by XRD, Raman and FTIR spectroscopy. Further porous and tubular structures were confirmed by SEM and HRTEM. The specific surface area of porous tubular nanofibers (PTNFs) was measured using the Brunauer-Emmett-Teller (BET) method, which revealed a high surface area of 63 m2 g(-1). Photodegradation of methyl orange demonstrated that the PTNFs have higher photocatalytic activity than nonporous nanofibers. This enhanced photocatalytic activity can be attributed to the high surface area of the porous and tubular structures. PMID:24734730

Thirugnanam, Lavanya; Kaveri, Satheesh; Dutta, Mrinal; Jaya, N Victor; Fukata, Naoki

2014-04-01

176

Effect of Nb doping on structural, optical and photocatalytic properties of flame-made TiO2 nanopowder.  

PubMed

TiO(2):Nb nanopowders within a dopant concentration in the range of 0.1-15 at.% were prepared by one-step flame spray synthesis. Effect of niobium doping on structural, optical and photocatalytic properties of titanium dioxide nanopowders was studied. Morphology and structure were investigated by means of Brunauer-Emmett-Teller isotherm, X-ray diffraction and transmission electron microscopy. Diffuse reflectance and the resulting band gap energy were determined by diffuse reflectance spectroscopy. Photocatalytic activity of the investigated nanopowders was revised for the photodecomposition of methylene blue (MB), methyl orange (MO) and 4-chlorophenol under UVA and VIS light irradiation. Commercial TiO(2)-P25 nanopowder was used as a reference. The specific surface area of the powders was ranging from 42.9 m(2)/g for TiO(2):0.1 at.% Nb to 90.0 m(2)/g for TiO(2):15 at.% Nb. TiO(2):Nb particles were nanosized, spherically shaped and polycrystalline. Anatase was the predominant phase in all samples. The anatase-related transition was at 3.31 eV and rutile-related one at 3.14 eV. TiO(2):Nb nanopowders exhibited additional absorption in the visible range. In comparison to TiO(2)-P25, improved photocatalytic activity of TiO(2):Nb was observed for the degradation of MB and MO under both UVA and VIS irradiation, where low doping level (Nb?photocatalyst. PMID:23054731

Michalow, Katarzyna A; Flak, Dorota; Heel, Andre; Parlinska-Wojtan, Magdalena; Rekas, Mieczyslaw; Graule, Thomas

2012-11-01

177

A direct synthesis of B-doped TiO2 and its photocatalytic performance on degradation of RhB  

NASA Astrophysics Data System (ADS)

B-doped TiO2 was synthesized by a direct hydrolyzation of n-tetrabutyl titanate in a solution of boric acid, and was treated by hydro-thermal synthesis. The powder was characterized by X-ray diffraction (XRD), FT-IR, scanning and transmission electron microscopy (SEM and TEM), surface photoviolet spectra, UV-visible absorption spectra and X-ray photoelectron spectroscopy (XPS). Rhodamine B (RhB) degradation was used as a probe reaction to evaluate the photocatalytic activity of B-doped TiO2 under simulate sunlight, and excellent photocatalytic performance was achieved.

Li, Liang; Yang, Yulin; Liu, Xinrong; Fan, Ruiqing; Shi, Yan; Li, Shuo; Zhang, Lingyun; Fan, Xiao; Tang, Pengxiao; Xu, Rui; Zhang, Wenzhi; Wang, Yazhen; Ma, Liqun

2013-01-01

178

Synthesis and application of TiO2 single-crystal nanorod arrays grown by multicycle hydrothermal for dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

TiO2 is a wide band gap semiconductor with important applications in photovoltaic cells. Vertically aligned TiO2 nanorod arrays (NRs) are grown on the fluorine-doped tin oxide (FTO) substrates by a multicycle hydrothermal synthesis process. The samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and selected-area electron diffraction (SAED). It is found that dye-sensitized solar cells (DSSCs) assembled by the as-prepared TiO2 single-crystal NRs exhibit different trends under the condition of different nucleation and growth concentrations. Optimum cell performance is obtained with high nucleation concentration and low growth cycle concentration. The efficiency enhancement is mainly attributed to the improved specific surface area of the nanorod.

Zhu, Jian-Jing; Zhao, Yu-Long; Zhu, Lei; Gu, Xiu-Quan; Qiang, Ying-Huai

2014-04-01

179

Synthesis of capped TiO2 nanocrystals of controlled shape and their use with MEH-PPV conjugated polymer to develop nanocomposite films for photovoltaic applications  

NASA Astrophysics Data System (ADS)

This study presents the synthesis details of titanium dioxide (TiO2) nanoparticles (NPs) of different shapes (nanospheres, nanorods and nanorhombics) using oleic acid (OA) and oleyl amine (OM) as capping agents. In order to develop nanocomposite thin films for photovoltaic cells, these TiO2 NPs were carefully dispersed in 2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene (MEH-PPV) matrix. The properties of synthesized TiO2 NPs and MEH-PPV/TiO2 nanocomposites were characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA), UV-Visible spectroscopy, and Photoluminescence technique. It was found that the shape of NPs and the amount of OA and OM surfactants capped on their surface have an effect on their energy bandgap and also on the dispersion quality of MEH-PPV/TiO2 nanocomposites. Even though there was no evidence of chemical bonding between MEH-PPV matrix and TiO2 dispersed NPs, MEH-PPV/TiO2 nanocomposites showed very promising results for light absorption properties and charge transfer at the interface of the conjugated MEH-PPV matrix and TiO2 dispersed NPs, which are two main characteristics for photovoltaic materials.

Mighri, F.; Duong, Vu Thi Thuy; On, Do Trong; Ajji, A.

2014-05-01

180

Synthesis and photocatalytic properties of porous TiO 2 films prepared by ODA\\/sol–gel method  

Microsoft Academic Search

Porous TiO2 films were deposited on SiO2 pre-coated glass-slides by sol–gel method using octadecylamine (ODA) as template. The amount of ODA in the sol played an important role on the physicochemical properties and photocatalytic performance of the TiO2 films. The films prepared at different conditions were all composed of anatase titanium dioxide crystals, and TiO2 crystalline size got larger with

Wenjie Zhang; Jiawei Bai

181

Aqueous Synthesis and Concentration-Dependent Dermal Toxicity of TiO 2 Nanoparticles in Wistar Rats  

Microsoft Academic Search

A number of dermal toxicological studies using TiO2 nanoparticles exist which are based on the study of various animal models like mice, rabbits etc. However, a well-defined\\u000a study is lacking on the dermal toxic effects of TiO2 nanoparticles on rats, which are the appropriate model for systemic absorption study of nanoparticles. Furthermore, toxicity\\u000a of TiO2 nanoparticles varies widely depending upon

Jyotisree Unnithan; Muneeb U. Rehman; Farhan J. Ahmad; M. Samim

182

Aligned rutile TiO2 nanorods: Facile synthesis and field emission  

NASA Astrophysics Data System (ADS)

By simple two-step technique, first anodization in an ethylene glycol solution and then oxidation in a low-pressure atmosphere by chemical vapor deposition at 750 °C, aligned rutile TiO2 nanorods (TNRs) were successfully synthesized. Furthermore, their growth mechanism and field-emission (FE) property were experimentally investigated. The results indicate that the aligned TNRs are rutile phase with a preferential growth direction of [1 1 0] and their structure parameters such as the aspect ratio and density can be easily adjusted by the anodization times, which are beneficial for optimizing their FE properties. When the anodization time increases from 30 to 480 s, the nanorods show various aspect ratios in a range of 16-28 and different turn-on fields within 1.78-6.46 V/?m. The optimized sample of anodized 120 s exhibits excellent FE properties involving both a low turn-on field of 1.78 V/?m, a high field enhancement factor (4757) and a good FE stability.

Li, Dong-Sheng; Chen, Jian-Biao; Wang, Cheng-Wei; Zhu, Wei-Dong; Zhang, Ling; Li, Yan; Wang, Jian; Zhou, Feng

2013-07-01

183

In situ surface hydrogenation synthesis of Ti(3+) self-doped TiO2 with enhanced visible light photoactivity.  

PubMed

A novel one-step, vapor-fed aerosol flame synthetic process (VAFS) has been developed to prepare Ti(3+) self-doped titanium dioxide (TiO2). The freshly formed TiO2 was in situ surface hydrogenated during the condensation stage by introducing H2 above the flame, and Ti(3+) ions were created near the surface of TiO2. The relative content of Ti(3+) ions near the surface of TiO2 is estimated to be 8%. Because of the high absorption of visible light and suppression of charge recombination, the photocurrent density and decomposition of MB under visible light irradiation were remarkably enhanced. This study demonstrates a simple, potential method to produce Ti(3+) self-doped TiO2 with effective photoactivity in visible light. PMID:24976359

Huo, Junchao; Hu, Yanjie; Jiang, Hao; Li, Chunzhong

2014-07-10

184

Effect of plasma treatment with various gases on nanocrystalline TiO2 for dye-sensitized solar cell (DSSC)  

Microsoft Academic Search

Titanium dioxide (TiO2) photocatalyst with anatase phase has been extensively investigated for Dye-sensitized solar cell (DSSC). The chemical activation of OH group on TiO2 surface can provide valuable electron transfer from sensitizer dye to TiO2. The plasma treatment is suggested as improving hydrophilic property of nano-structured TiO2 surface, and has different effects on TiO2 surface depending on the gas to

Jumi Kim; Min Jae Sin; Hyung Jin Kim; Byungyou Hong

2010-01-01

185

Development of supported boron-doping TiO 2 catalysts by chemical vapor deposition  

Microsoft Academic Search

In this study, supported nonmetal (boron) doping TiO2 coating photocatalysts were prepared by chemical vapor deposition (CVD) to enhance the activity under visible light irradiation\\u000a and avoid the recovering of TiO2. Boron atoms were successfully doped into the lattice of TiO2 through CVD, as evidenced from XPS analysis. B-doped TiO2 coating catalysts showed drastic and strong absorption in the visible

Xing-wang Zhang; Le-cheng Lei

2008-01-01

186

Facile hydrothermal synthesis of TiO2-Bi2WO6 hollow superstructures with excellent photocatalysis and recycle properties.  

PubMed

One-dimensional mesoporous TiO2-Bi2WO6 hollow superstructures are prepared using a hydrothermal method and their photocatalysis and recycle properties are investigated. Experimental results indicate that anatase TiO2 nanoparticles are coupled with hierarchical Bi2WO6 hollow tubes on their surfaces. The TiO2-Bi2WO6 structure has a mesoporous wall and the pores in the wall are on average 21 nm. The hierarchical TiO2-Bi2WO6 heterostructures exhibit the highest photocatalytic activity in comparison with P25, pure Bi2WO6 hollow tube and mechanical mixture of Bi2WO6 tube and TiO2 nanoparticle in the degradation of rhodamine B (RhB) under simulated sunlight irradiation. The as-prepared TiO2-Bi2WO6 heterostructures can be easily recycled through sedimentation and they retains their high photocatalytic activity during the cycling use in the simulated sunlight-driving photodegradation process of RhB. The prepared mesoporous TiO2-Bi2WO6 with hollow superstructure is therefore a promising candidate material for water decontamination use. PMID:24162142

Hou, Ya-Fei; Liu, Shu-Juan; Zhang, Jing-huai; Cheng, Xiao; Wang, You

2014-01-21

187

Preillumination of TiO2 and Ta2O5 photoactive thin films as a tool to tailor the synthesis of composite materials.  

PubMed

Illumination of TiO 2 thin films with UV light is known to induce the transformation of the surface of this material from partially hydrophobic into fully hydrophilic. The present work shows that this transformation is accompanied by other effects that may be used to control the synthesis of composite materials. For this purpose, TiO 2 and Ta 2O 5 transparent thin films with a columnar structure and open pores were prepared by electron evaporation at glancing angles. Transparent TiO 2 thin films with micropores (i.e., pores smaller than 2 nm) prepared by plasma enhanced chemical vapor deposition (PECVD) were also used. All these films became hydrophilic upon UV illumination. Rhodamine 6G and Rhodamine 800 dyes were irreversibly adsorbed within the columns of the TiO 2 and Ta 2O 5 thin films by immersion into a water solution of these molecules. Isolated and aggregated molecules of these two dyes were detected by visible absorption spectroscopy. The infiltration adsorption efficiency was directly correlated with the acidity of the medium, increasing at basic pHs as expected from simple considerations based on the concepts of the point of zero charge (PZC) in colloidal oxides. The infiltration experiments were repeated with columnar TiO 2 and Ta 2O 5 thin films that were subjected to preillumination with UV light. It was found that this treatment produced a modification in the type (isolated or aggregated) and amount of dye molecules incorporated into the pores. Moreover, the selective adsorption of a given dye in preilluminated areas of the films permitted the lithographic coloring of the films. Preillumination also controls the UV induced deposition of silver on the surface of the microporous TiO 2 thin films. It was found that the size distribution of the formed silver nanoparticles was dependent on the preillumination treatment and that a well-resolved surface plasmon resonance at around 500 nm was only monitored in the preilluminated films. A model is proposed to account for the effects induced by UV preillumination on the TiO 2 and Ta 2O 5 oxide surfaces. The possibilities of this type of light treatment for the tailored synthesis of nanocomposite thin films (i.e., dye-oxide, metal nanoparticles-oxide) are highlighted. PMID:18642860

Sánchez-Valencia, Juan R; Borrás, Ana; Barranco, Angel; Rico, Victor J; Espinós, Juan P; González-Elipe, Agustín R

2008-09-01

188

TiO2-SnO2 heterostructures applied to dye photodegradation: The relationship between variables of synthesis and photocatalytic performance  

NASA Astrophysics Data System (ADS)

This paper describes the synthesis of TiO2-SnO2 heterostructures and their application to water decontamination based on the photodegradation of Rhodamine B (RhB). The heterostructures were fabricated through two different routes, a hydrolytic sol gel and the polymeric precursor method, both of which induced the growth of SnO2 on commercial TiO2. The results show that the heterostructures presented higher photoactivity behaviors than commercial TiO2 nanopowders. The achievement of homogeneity during phase formation (i.e., of the SnO2 dispersion over the TiO2 nanoparticles) was a key parameter for obtaining higher photocatalytic activities per unit area. The main degradation mechanism was correlated with the process of rad OH radical generation, which was related to the concentration and nature of the surface hydroxyl groups. Accordingly, the polymeric precursor method was shown to be more adequate for dispersing higher amounts of SnO2 in comparison with the hydrolytic sol gel method. Additionally, the polymeric precursor method delivered higher proportions of bonded surface hydroxyl groups, which were responsible for radical formation; in contrast, the hydrolytic sol gel method demonstrated the highest amount of adsorbed water.

de Mendonça, Vagner R.; Lopes, Osmando F.; Fregonesi, Raul P.; Giraldi, Tania R.; Ribeiro, Caue

2014-04-01

189

Synthesis of biomorphological mesoporous TiO2 templated by mimicking bamboo membrane in supercritical CO2.  

PubMed

A new approach is presented for preparing biomorphological mesoporous TiO2 templated by mimicking bamboo inner shell membrane via supercritical CO2 (SCCO2) transportation through titanium tetrabutyloxide (TTBO). The analysis of wide-angle X-ray powder diffraction (XRD) showed the prepared TiO2 in phase of anatase, and the small-angle XRD revealed the presence of mesopores without periodicity. The product exhibited the shape of crinkled films and extended in two dimensions up to centimeters. The electron microscopic observation showed that the TiO2 films were around 200 nm in thickness, and across the films there were numerous round or ellipse-shaped mesopores, being 10-50 nm in diameter, which were formed by the close packing of TiO2 particles. High-resolution transmission electron microscope (HRTEM) displayed that the single TiO2 particle size was about 12.5 nm. The UV-vis absorption spectrum was transparent in the wavelength of 320-350 nm for suspensions of the prepared mesoporous TiO2 in ethanol at the concentration of 5.0 mg/l. The mesoporous TiO2 prepared with the aid of SCCO2 exhibited an obvious blue shift compared with the TiO2 prepared by sol-gel infiltration. The possible mechanism for the formation of the mesoporous TiO2 is summarized into a biomimetic mineralization pathway. First, TTBO was transported to the membrane surface via SCCO2, and then condensed. Hydrolysis reactions between the functional groups of organic membrane and TTBO took place to form the nuclear TiO2, and the TiO2 seeds grew around the organic membrane into TiO2 mesoporous materials. The approach provides a low-cost and efficient route for the production of ceramics nanomaterials with unique structural features, which may have potential application in designing UV-selective shielding devices [S. Zhao, X.H. Wang, S.B. Xin, Q. Jiang, X.P. Liang, Rare Metal Mater. Eng. 35 (2006) 508-510]. PMID:17689547

Li, Jinhong; Shi, Xiaoying; Wang, Lijuan; Liu, Fei

2007-11-01

190

Synthesis and electrorheological effect of Cr doped TiO2 nanorods with nanocavities in silicone oil suspensions  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) nanorods with nanocavities doped with chromium (Cr) were synthesized by hydrothermal method. The morphology of prepared nanorods was determined by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX). The electrorheological (ER) behaviour of suspensions based on TiO2 was investigated under the steady shear, and the yield stress was chosen as a suitable tool for a comparison of ER performance. Some optimum in level of Cr doping of TiO2 was found.

Almajdalawi, S.; Pavlinek, V.; Mrlik, M.; Cheng, Q.; Sedlacik, M.

2013-02-01

191

Influence of calcination parameters on the synthesis of N-doped TiO2 by the polymeric precursors method  

NASA Astrophysics Data System (ADS)

In this paper, the influence of calcination parameters on the synthesis of N:TiO2 catalysts obtained through the polymeric precursors method was evaluated. The powders were prepared by annealing Ti4+ precursor resins at different temperature-time conditions in air, resulting in powders with different degrees of crystallinity for N doping, which was done by adding urea to the as-prepared powders and calcining in N2 atmosphere. The N doping process resulted in band gap narrowing of TiO2 and, varying annealing temperature and time, can be an alternative method for preferential formation of substitutional N or interstitial N. It was found that the percentage of interstitial N increased with an increase in annealing temperature, resulting in the complete absence of substitutional N at 400 °C. The photocatalytic performance of the powders was evaluated using Rhodamine-B and Atrazine solutions under ultraviolet and visible irradiations. The coefficients revealed that interstitial N had a positive correlation to both ultraviolet and visible photoactivity. In contrast, substitutional N showed a negative correlation. Further, the ratio of substitutional N to interstitial N indicated a strong negative correlation to ultraviolet light photoactivity and no correlation to visible light photoactivity. However, substitutional N should be controlled for better photocatalytic properties.

Dawson, Margaret; Soares, Gabriela Byzynski; Ribeiro, Caue

2014-07-01

192

Photocatalytic degradation of monoethanolamine in wastewater using nanosized TiO2 loaded on clinoptilolite  

NASA Astrophysics Data System (ADS)

The use of titanium dioxide (TiO2) as photocatalyst to degrade the organic compounds is an effective method of oxidation process and has been widely studied in environmental engineering. In this investigation photocatalytic degradation of monoethanolamine (MEA) using TiO2 (in form of anatase) loaded on surface of clinoptilolite (CP) (TiO2-CP) in wastewater was studied. The surface interaction between TiO2 and CP was investigated by means of transmission electron microscope (TEM), atom force microscope (AFM), IR and X-ray diffraction (XRD). Then the effects of some parameters such as pH, amount of photocatalyst, and initial concentration of MEA on degradation percentage of MEA were examined. The obtained results show that the TiO2-CP is an active photocatalyst as compared with TiO2 nanopowders. All these results indicated that this proposed method can be useful for the development of wastewater treatment applications.

Khodadoust, Saeid; Sheini, Azarmidokht; Armand, Nezam

193

Synthesis and characterization of beta barium borate thin films obtained from the BaO–B 2O 3–TiO 2 ternary system  

Microsoft Academic Search

This work reports on the synthesis and the structural and optical characterization of beta barium borate (?-BBO) thin films containing 4, 8 and 16 mol% of titanium oxide (TiO2) deposited on fused silica and silicon (001) substrates using the polymeric precursor method. The thin films were characterized by X-ray diffraction, Raman spectroscopy, atomic force microscopy and scanning electron microscopy techniques.

L. J. Q. Maia; M. I. B. Bernardi; C. A. C. Feitosa; V. R. Mastelaro; A. R. Zanatta; A. C. Hernandes

2004-01-01

194

Synthesis of monodisperse colloidal TiO2 microspheres and performance of their dye-sensitized solar cells  

NASA Astrophysics Data System (ADS)

Monodisperse colloidal TiO2 microspheres with different size have been synthesized via controlled hydrolysis of tetrabutyltitanate (TBOT) in ethanol with addition of a salt solution. The photoelectric conversion performances of dye-sensitized solar cells (DSSCs) based on TiO2 microspheres were investigated. The results revealed that these TiO2 microspheres, which were well dispersed and uniform, and their size became gradually smaller with the increasing KCl concentration. The DSSC based on smaller TiO2 microspheres exhibited an enhanced photocurrent and conversion efficiency, which was attributed to its better absorption properties of dye molecules and superior conductivity. After the further optimization, the total conversion efficiency of DSSC with electrode 2 was 5.72%.

Zhu, Zhenfeng; Zhu, Chunkui; Liu, Hui; Wu, Yingfeng; Chen, Guanhong; Lv, Ting

2014-07-01

195

Synthesis and Non-isothermal Crystallization Behavior of PET\\/Surface-treated TiO2Nanocomposites  

Microsoft Academic Search

Poly(ethylene terephthalate) (PET)\\/TiO2 nanocomposites were prepared by melt-blending PET and surface-treated TiO2. The crystallization behavior and the non-isothermal crystallization kinetics of these composites were investigated by differential scanning calorimetry (DSC). Jeziorny and Mo's methods were applied to describe the kinetics of the non-isothermal crystallization process. It was found that the PET matrix with incorporated surface-treated TiO2 particles has lower crystallization

Xiuling Zhu; Biao Wang; Shiyan Chen; Chaosheng Wang; Yumei Zhang; Huaping Wang

2008-01-01

196

Sonoelectrochemical synthesis of highly photoelectrochemically active TiO2 nanotubes by incorporating CdS nanoparticles  

NASA Astrophysics Data System (ADS)

Self-organized anodic TiO2 nanotube arrays (TiO2NTs) are functionalized with CdS nanoparticle based perfusion and deposition through a single-step sonoelectrodeposition method. Even controlled at 50 °C, CdS nanoparticles with smaller size and more homogeneous distribution are successfully synthesized in dimethyl sulfoxide (DMSO) under ultrasonic irradiation. Moreover, TiO2 nanotubes can be filled with nanoparticles because of the ultrasonic effect. The CdS incorporated TiO2NTs (CdS-TiO2NTs) effectively harvest solar light in the UV as well as the visible light (up to 480 nm) region. Compared with pure TiO2NTs, a more than ninefold enhancement in photocurrent response is observed using the CdS-TiO2NTs. Maximum incident photon to charge carrier efficiency (IPCE) values of 99.95% and 9.85% are observed respectively for CdS-TiO2 nanotubes and pure TiO2NTs. The high value of IPCE observed with the CdS-TiO2NTs is attributed to the increased efficiency of charge separation and transport of electrons. A schematic diagram is proposed to illustrate the possible process of CdS formation in nanotubes under sonochemical and electrochemical conditions.

Wang, Cheng Lin; Sun, Lan; Yun, Hong; Li, Jing; Lai, Yue Kun; Lin, Chang Jian

2009-07-01

197

Sol-gel synthesis and photocatalytic activity of B and Zr co-doped TiO2  

NASA Astrophysics Data System (ADS)

Effects of boron (B) and/or zirconium (Zr) doping on photocatalytic activity of sol-gel derived titania (TiO2) powders were investigated. A conventional, non-hydrous sol-gel technique was applied to synthesize the B, Zr doped/co-doped TiO2 powders. Doping was made at molar ratios of Ti/B=1 and Ti/Zr=10. Sol-gel derived xero-gels were calcined at 500 °C for 3 h. The crystal chemistry and the morphology of the undoped and B, Zr doped/co-doped TiO2 nanoparticles were investigated using X-ray diffractometer and scanning electron microscope. Nano-scale (9-46 nm) TiO2 crystallites were obtained after calcination. Doping and co-doping decreased the crystallite size. Photocatalytic activity was measured through the degradation of methylene blue (MB) under 1 h UV-irradiation using a UV-vis spectrophotometer. Results revealed that B doping into anatase caused the formation of oxygen vacancies, whereas Zr addition caused Ti substitution. Both B and Zr ions had a profound effect on the particle morphology and photocatalytic activity of TiO2. The photocatalytic activity of B and Zr doped TiO2 particles increased from 27% to 77% and 57%, respectively. The best activity (88.5%) was achieved by co-doping.

Kapusuz, Derya; Park, Jongee; Ozturk, Abdullah

2013-07-01

198

Synthesis and characterization of TiO2/SiO2 nano composites for solar cell applications  

NASA Astrophysics Data System (ADS)

The use of titania-silica in photocatalytic process has been proposed as an alternative to the conventional TiO2 catalysts. Mesoporous materials have been of great interest as catalysts because of their unique textural and structural properties. Mesoporous TiO2, SiO2 nanoparticles and TiO2/SiO2 nanocomposites were successfully synthesized by sol-gel method using titanium (IV) isopropoxide, tetra-ethylorthosilicate as starting materials. The synthesized samples are characterized by X-ray diffraction, UV-Vis spectroscopy, Fourier transform infrared spectroscopy, Brunauett-Emmett-Teller and field-dependent photoconductivity. The UV-Vis spectrum of as-synthesized samples shows similar absorption in the visible range. The crystallite size of the as-synthesized samples was calculated by Scherrer's formula. The BET surface area for TiO2/SiO2 nanocomposite is found to be 303 m2/g and pore size distribution has average pore diameter about 10 nm. It also confirms the absence of macropores and the presence of micro and mesopores. The field-dependent photoconductivity of TiO2/SiO2 nanocomposite shows nearly 300 folds more than that of TiO2 nanoparticle for a field of 800 V/cm.

Arun Kumar, D.; Merline Shyla, J.; Xavier, Francis P.

2012-12-01

199

Controllable synthesis of MoO3-deposited TiO2 nanotubes with enhanced lithium-ion intercalation performance  

NASA Astrophysics Data System (ADS)

Well-organized TiO2 nanotube arrays are synthesized by anodic oxidation and then modified with MoO3 via facile electrodeposition for their improved Li-ion intercalation property. All the bare and MoO3-deposited TiO2 nanotubes are cycled at a current of 50 or 200 ?A cm-2. The deposited nanotubes surprisingly deliver twice or even triple areal capacity of the bare ones, as well as better rate capability. For example, the bare nanotubes exhibit an initial capacity of 81.2 ?Ah cm-2 and a final capacity of 59.6 ?Ah cm-2 over 48 electrochemical cycles, while the ones coated by MoO3 using only one deposition cycle displays a nearly doubled initial capacity of 154.9 ?Ah cm-2 and a final capacity of 116.6 ?Ah cm-2. More deposition cycles yield TiO2 nanotubes with higher capacities up to 204.7 ?Ah cm-2. Such improvement could be further optimized by tuning the dimensions of TiO2 nanotubes. An eight-fold increase in the capacity of MoO3/TiO2 nanotube composite anode is achieved easily with larger nanotubes for MoO3 coating. This is attributed to the combination of MoO3 with a high specific capacity and TiO2 nanotubes with large surface area allowing efficient MoO3 deposition and ionic transport inside the anode.

Guan, Dongsheng; Li, Jianyang; Gao, Xianfeng; Yuan, Chris

200

Solvothermal synthesis and enhanced photocatalytic activity of flowerlike nanoarchitectures assembled from anatase TiO2 nanoflakes  

NASA Astrophysics Data System (ADS)

TiO2 nanoflakes assembled flowerlike nanoarchitectures with diameters of 1.70-2.20 ?m were synthesized by a solvothermal reaction of butyl titanate with isopropyl alcohol, HF and H2O at 180 °C for 12 h. The constituent nanoflakes have perfect rectangular shapes with the typical widths of 0.81-0.95 ?m, lengths of 1.04-1.20 ?m and thicknesses of 0.10-0.12 ?m. The constituent nanoflakes are formed due to the selective adsorption of isopropyl alcohol on (0 1 0) surface of anatase TiO2. These anatase TiO2 nanoflakes assemble into flowerlike structures driven by the electrostatic attraction. The as-prepared TiO2 flowerlike nanoarchitectures exhibit enhanced photocatalytic ability to degrade methyl orange dye in comparison with commercial TiO2 powders. The photodegradation of methyl orange dye catalyzed by the anatase TiO2 nanoflake assembled flowerlike nanostructures fits a pseudo first-order reaction.

Cui, Meng; Tian, Sha; Zhao, Hua; Jin, Rong; Chen, Yan; Liu, Bin; Yang, Heqing

2012-07-01

201

Electrochemical synthesis and characterization of TiO2 nanoparticles and their use as a platform for flavin adenine dinucleotide immobilization and efficient electrocatalysis  

NASA Astrophysics Data System (ADS)

Here, we report the electrochemical synthesis of TiO2 nanoparticles (NPs) using the potentiostat method. Synthesized particles have been characterized by using x-ray diffraction (XRD) studies, atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results revealed that the TiO2 film produced was mainly composed of rutile and that the particles are of a size in the range of 100 ± 50 nm. TiO2 NPs were used for the modification of a screen printed carbon electrode (SPE). The resulting TiO2 film coated SPE was used to immobilize flavin adenine dinucleotide (FAD). The flavin enzyme firmly attached onto the metal oxide surface and this modified electrode showed promising electrocatalytic activities towards the reduction of hydrogen peroxide (H2O2) in physiological conditions. The electrochemistry of FAD confined in the oxide film was investigated. The immobilized FAD displayed a pair of redox peaks with a formal potential of -0.42 V in pH 7.0 oxygen-free phosphate buffers at a scan rate of 50 mV s-1. The FAD in the nanostructured TiO2 film retained its bioactivity and exhibited excellent electrocatalytic response to the reduction of H2O2, based on which a mediated biosensor for H2O2 was achieved. The linear range for the determination of H2O2 was from 0.15 × 10-6 to 3.0 × 10-3 M with the detection limit of 0.1 × 10-6 M at a signal-to-noise ratio of 3. The stability and repeatability of the biosensor is also discussed.

Ashok Kumar, S.; Lo, Po-Hsun; Chen, Shen-Ming

2008-06-01

202

Optimization of CdS\\/TiO 2 nano-bulk composite photocatalysts for hydrogen production from Na 2S\\/Na 2SO 3 aqueous electrolyte solution under visible light ( ? ? 420 nm)  

Microsoft Academic Search

A CdS\\/TiO2 nano-bulk composite photocatalyst consisting of bulky CdS with a high crystallinity decorated with nanosized TiO2 particles was fabricated by precipitation method and sol–gel synthesis. This configuration of the composite photocatalyst exhibited a very high rate of hydrogen production under visible light irradiation (??420nm) from water containing sulfide and sulfite as hole scavengers. In this work, we investigated the

Jum Suk Jang; Sang Min Ji; Sang Won Bae; Hyo Chang Son; Jae Sung Lee

2007-01-01

203

Modified microwave method for the synthesis of visible light-responsive TiO2/MWCNTs nanocatalysts  

PubMed Central

Recently, TiO2/multi-walled carbon nanotube (MWCNT) hybrid nanocatalysts have been a subject of high interest due to their excellent structures, large surface areas and peculiar optical properties, which enhance their photocatalytic performance. In this work, a modified microwave technique was used to rapidly synthesise a TiO2/MWCNT nanocatalyst with a large surface area. X-ray powder diffraction, field-emission scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller measurements were used to characterise the structure, morphology and the surface area of the sample. The photocatalytic activity of the hybrid nanocatalysts was evaluated through a comparison of the degradation of methylene blue dye under irradiation with ultraviolet and visible light. The results showed that the TiO2/MWCNT hybrid nanocatalysts degraded 34.9% of the methylene blue (MB) under irradiation with ultraviolet light, whereas 96.3% of the MB was degraded under irradiation with visible light.

2013-01-01

204

TiO 2 nanopowders doped with boron and nitrogen for photocatalytic applications  

NASA Astrophysics Data System (ADS)

TiO 2-based systems have attracted an increasing interest for their potential use as photocatalysts under visible-light irradiation. In this context, the present work was dedicated to the tailored synthesis of TiO 2 nanopowders doped with boron, nitrogen or both species for the photocatalytic degradation of organic dyes. In particular, the systems were synthesized by a sol-gel route starting from titanium(IV) butoxide as a Ti source and thoroughly characterized by the combined use of N 2 physisorption, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-Vis reflectance spectroscopy and temperature-programmed oxidation (TPO). Finally, the photocatalytic performances in the decomposition of the azo-dye methyl orange (MO) were investigated. The obtained results suggest that both dopants promote the photocatalytic activity with respect to pure TiO 2 systems. Nevertheless, while our surface N-doping does not appreciably modify the titania structure and texture, B incorporation inhibits the TiO 2 crystallite growth and induces an increase in the surface area. As regards the codoped systems, a remarkable reactivity improvement was observed only when B is present in excess with respect to N. A rational interpretation of the observed behaviour was attempted by calculations based on the density functional theory (DFT). We suggest that the presence of B in molar excess with respect to N generates reactive Ti(III) sites, which, in turn, might induce the formation of reactive superoxide species.

Gombac, V.; De Rogatis, L.; Gasparotto, A.; Vicario, G.; Montini, T.; Barreca, D.; Balducci, G.; Fornasiero, P.; Tondello, E.; Graziani, M.

2007-10-01

205

Microwave-induced synthesis of porous single-crystal-like TiO2 with excellent lithium storage properties.  

PubMed

Porous anatase TiO(2) single crystal architectures with large specific surface area and remarkable crystalline phase-stability were fabricated via a green microwave-assisted process. Ionic liquid was chosen as both an essential structure-directing agent for the formation of the {001} facets exposed TiO(2) and an etching agent source for selective erosion of the exposed {001} facets, leading to robust porous framework with exposed {101} facets. These porous anatase single crystals were thermally stable up to 800 °C, indicating excellent structure stability. The product showed stable cyclability at high current rate, better reversibility, and high Coulumbic efficiency of 100% for lithium storage. PMID:22329597

Zhang, Dieqing; Wen, Meicheng; Zhang, Peng; Zhu, Jian; Li, Guisheng; Li, Hexing

2012-03-01

206

Molten salt synthesis of SrTiO 3 nanocrystals using nanocrystalline TiO 2 as a precursor  

Microsoft Academic Search

A molten salt method was proposed to synthesize SrTiO3 nanocrystals in the eutectic NaCl–KCl at 700°C for 6h, by using the homemade TiO2 nanocrystals and commercial Sr(NO3)2 powder as raw materials. Besides, a control experiment with the commercial TiO2 submicron-sized crystallites as a precursor was also conducted. The structure and composition of the obtained products were characterized by powder X-ray

Tian Xi Wang; Shuang Zhi Liu; Jun Chen

2011-01-01

207

One-pot hydrothermal synthesis and enhanced photocatalytic activity of trifluoroacetic acid modified TiO 2 hollow microspheres  

Microsoft Academic Search

Trifluoroacetic acid (TFA) modified TiO2 (TFA-TiO2) hollow microspheres were prepared by one-pot hydrothermal treatment of Ti(SO4)2 in the presence of TFA at 180°C for 12h. The prepared samples were characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption–desorption isotherms and Fourier transform infrared. The production rates of OH on the surface of UV-illuminated TiO2 were

Jiaguo Yu; Lei Shi

2010-01-01

208

One-step synthesis of TiO2/CdS nanocomposites by using microwave irradiation of a TiO2 + Cd2+-mercaptopropionic acid aqueous solution  

NASA Astrophysics Data System (ADS)

A novel and simple microwave-assisted hydrothermal method for synthesizing high-quality TiO2/CdS nanocomposites was developed using TiO2 (P-90), CdCl2, and mercaptopropionic acid (MPA). The optical properties and the physical characteristics of the synthesized TiO2/CdS nanocrystals (NCs) depended on the conditions of microwave irradiation. Samples prepared with the same concentration of precursor were treated at different temperatures from 150 °C to 250 °C by using the microwave power. Consequently, the crystal structure of TiO2/CdS transformed from cubic to hexagonal. Transmission electron microscopy and energy-dispersive X-ray spectroscopy techniques confirmed that the fabricated TiO2/CdS were composed of heterogeneously bonded nanostructures. Analysis of the optical properties showed that the UV absorption spectra had a strong red-shift when the microwave heating temperature increased, which caused an increase in the size of the CdS NCs. The mean radius of the CdS NCs combined with TiO2 tended to increase from 3.7 nm to 13.1 nm. Photoluminescence (PL) measurements were used to investigate the PL peak of the fabricated TiO2/CdS under microwave irradiation at 250 °C, and they revealed a 24 nm Stoke's shift from the absorption peak.

Ha, Sung Yong; Kim, Hee Jin; Nam, Sungmo; Oh, Seong Yong; Lim, Changhwan; Kim, Il Gon; Yoo, Dong Sun; Park, Sang Yeup

2014-02-01

209

Synthesis and characterization of a mixed phase of anatase TiO2 and TiO2(B) by low pressure chemical vapour deposition (LPCVD) for high photocatalytic activity  

NASA Astrophysics Data System (ADS)

This project is concerned with enhancing photocatalytic activity by preparing a mixed phase of nano-sized TiO2. TiO2 thin films were synthesized by using Low Pressure Chemical Vapour Deposition (LPCVD). Titanium isopropoxide and N2 gas were used as the precursor and carrier gas respectively. The effects of reaction temperature, carrier gas flow rate and deposited area were studied. TiO2 thin films with nano-sized TiO2 particles were obtained under suitable conditions and SEM, TEM, powder XRD and Raman spectroscopy were employed to characterize the phase and physical appearance of synthesized materials. Preliminary results show that a dual phase (TiO2(B) and anatase) thin film nanopowder was successfully prepared by LPCVD with needle- and polygonal plate-shape crystallites respectively. This thin film deposit produced a preferred orientation of TiO2(B) needles in the [001] direction of average crystallite size 50-80 nm in length and 5-10 nm in width, whilst the crystallite size of anatase polygonal-plates was around 200 nm. The optimal LPCVD condition for preparing this mixed phase of TiO2 was 600°C with a 1 mL/s N2 flow rate.

Chimupala, Y.; Hyett, G.; Simpson, R.; Brydson, R.

2014-06-01

210

Synthesis of SUB-10 NM TiO2 Nanowires for the Application of Dye-Sensitized Solar Cells  

NASA Astrophysics Data System (ADS)

Highly oriented single-crystalline rutile TiO2 nanowires on transparent conductive fluorine-doped tin oxide (FTO) substrates are prepared by low-temperature hydrothermal method. The small lattice mismatch between FTO substrate and rutile TiO2 promote the epitaxial nucleation and growth of rutile TiO2 nanowires on FTO, with the diameter of 4-6 nm. Due to Van der waals force, the ultrafine nanowires tend to gather together, forming nanowire bundles. Using the ultrafine nanowire bundle array as the photoanode and ruthenium complex (N719) as the sensitizer, dye-sensitized solar cells (DSSCs) are assembled. The effect of the TiO2 nanowire gathering on the power conversion of the DSSCs has been investigated. Experimental result shows that the light-to-electricity conversion efficiency is increased by reducing the gathering of the nanowires through introducing toluene into reactant precursors. The DSSCs based on the bundles with smallest average width (i.e., least nanowire gathering) show the highest power conversion efficiency of 3.70%. The relatively high energy conversion efficiency is contributed to the large surface area, which enhances the adsorption of dye molecules.

Liu, Jun; Liu, Zhen; Lin, Kangbao; Wei, Aixiang

2013-04-01

211

Synthesis of molecular imprinted polymer modified TiO 2 nanotube array electrode and their photoelectrocatalytic activity  

NASA Astrophysics Data System (ADS)

A tetracycline hydrochloride (TC) molecularly imprinted polymer (MIP) modified TiO 2 nanotube array electrode was prepared via surface molecular imprinting. Its surface was structured with surface voids and the nanotubes were open at top end with an average diameter of approximately 50 nm. The MIP-modified TiO 2 nanotube array with anatase phase was identified by XRD and a distinguishable red shift in the absorption spectrum was observed. The MIP-modified electrode also exhibited a high adsorption capacity for TC due to its high surface area providing imprinted sites. Photocurrent was generated on the MIP-modified photoanode using the simulated solar spectrum and increased with the increase of positive bias potential. Under simulated solar light irradiation, the MIP-modified TiO 2 nanotube array electrode exhibited enhanced photoelectrocatalytic (PEC) activity with the apparent first-order rate constant being 1.2-fold of that with TiO 2 nanotube array electrode. The effect of the thickness of the MIP layer on the PEC activity was also evaluated.

Lu, Na; Chen, Shuo; Wang, Hongtao; Quan, Xie; Zhao, Huimin

2008-10-01

212

Photocatalytic degradation of methyl orange over nitrogen-fluorine codoped TiO2 nanobelts prepared by solvothermal synthesis.  

PubMed

Anatase type nitrogen-fluorine (N-F) codoped TiO(2) nanobelts were prepared by a solvothermal method in which amorphous titania microspheres were used as the precursors. The as-prepared TiO(2) nanobelts are composed of thin narrow nanobelts and it is noted that there are large amount of wormhole-like mesopores on these narrow nanobelts. Photocatalytic activity of the N-F codoped TiO(2) nanobelts was measured by the reaction of photocatalytic degradation of methyl orange. Results indicate that the photocatalytic activity of the N-F codoped TiO(2) nanobelts is higher than that of P25, which is mainly ascribed to wormhole-like mesopores like prison, larger surface area, and enhanced absorption of light due to N-F codoping. Interestingly, it is also found that the photocatalytic activity can be further enhanced when tested in a new testing method because more photons can be captured by the nanobelts to stimulate the formation of the hole-electron pair. PMID:23148575

He, Zuoli; Que, Wenxiu; Chen, Jing; Yin, Xingtian; He, Yucheng; Ren, Jiangbo

2012-12-01

213

Detection of active oxidative species in TiO 2 photocatalysis using the fluorescence technique  

Microsoft Academic Search

The active oxidative species (mainly corresponding to hydroxyl radicals (· OH)) produced on TiO2 film photocatalyst in aerated aqueous solution have been quantitatively investigated by measuring the fluorescence derived by the reaction with either coumarin or terephthalic acid. Upon UV light illumination, coumarin in aqueous solution and terephthalic acid in NaOH solution were converted on the TiO2 film photocatalyst to

Ken-ichi Ishibashi; Akira Fujishima; Toshiya Watanabe; Kazuhito Hashimoto

2000-01-01

214

Catalytic synthesis of 2-(N-benzyl-N-phenylamino) phenol by mesoporous Pd-doped TiO2: an environmentally benign approach  

NASA Astrophysics Data System (ADS)

A facile and environmentally route for catalytic Synthesis of 2-(N-benzyl-N-phenylamino) phenol under UV irradiation conditions has been developed in the presence of a catalytic amount of mesoporous Pd-doped TiO2 (Pd/TiO2) based on a ionic liquid process to fabricate. The particles were characterized with XRD, TEM and XPS. The FT-IR and HNMR spectra confirmed the expected function groups and the structure of 2-(N-benzyl-N-phenylamino) phenol synthesized.

Wang, Huqun; Hu, Tiegang; Yang, Xiaofeng; Yan, Junping; Xiong, Weifeng; Zhang, Zhimin

2013-03-01

215

Synthesis of the double-shell anatase-rutile TiO2 hollow spheres with enhanced photocatalytic activity  

NASA Astrophysics Data System (ADS)

A novel double-shell TiO2 hollow sphere with an inner anatase shell and an outer rutile shell was synthesized by a simple sol-gel method and silica protected calcination process. The structure and formation mechanism was proposed based on characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The double-shell spheres have a uniform diameter of 360 nm and a typical yolk-shell structure. Moreover, the double-shell TiO2 hollow spheres possess a large specific surface area (169 m2 g-1). Due to the high surface area, multiple light reflection and beneficial electron conduction between the inner anatase and outer rutile shell of this special structure, the as-prepared double-shell TiO2 catalysts show remarkably enhanced photoactivity compared to the commercial P25 catalyst. In particular, rhodamine B molecules can be completely decomposed in the presence of the double-shell spheres after 60 minutes of irradiation with UV light. In addition, the high activity is retained after five cycles, indicating the stability and reusability of the double-shell catalyst.A novel double-shell TiO2 hollow sphere with an inner anatase shell and an outer rutile shell was synthesized by a simple sol-gel method and silica protected calcination process. The structure and formation mechanism was proposed based on characterization using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The double-shell spheres have a uniform diameter of 360 nm and a typical yolk-shell structure. Moreover, the double-shell TiO2 hollow spheres possess a large specific surface area (169 m2 g-1). Due to the high surface area, multiple light reflection and beneficial electron conduction between the inner anatase and outer rutile shell of this special structure, the as-prepared double-shell TiO2 catalysts show remarkably enhanced photoactivity compared to the commercial P25 catalyst. In particular, rhodamine B molecules can be completely decomposed in the presence of the double-shell spheres after 60 minutes of irradiation with UV light. In addition, the high activity is retained after five cycles, indicating the stability and reusability of the double-shell catalyst. Electronic supplementary information (ESI) available: UV-vis diffuse reflection spectra and the summarisation of BET surface and average pore size. See DOI: 10.1039/c3nr04043g

Li, Shunxing; Chen, Jie; Zheng, Fengying; Li, Yancai; Huang, Fuying

2013-11-01

216

Photocatalytic CO2 reduction using a molecular cobalt complex deposited on TiO2 nanoparticles.  

PubMed

Hybrid photocatalysts were prepared by depositing a macrocyclic cobalt complex on TiO2 surfaces. Upon UV light irradiation, photoexcited electrons in TiO2 nanoparticles were transferred to the surface cobalt catalyst for CO2 reduction. PMID:24781709

Jin, Tong; Liu, Chao; Li, Gonghu

2014-06-14

217

Large-Scale Synthesis of Transition-Metal-Doped TiO2 Nanowires with Controllable Overpotential  

SciTech Connect

Practical implementation of one-dimensional semiconductors into devices capable of exploiting their novel properties is often hindered by low product yields, poor material quality, high production cost, or overall lack of synthetic control. Here, we show that a molten-salt flux scheme can be used to synthesize large quantities of high-quality, single-crystalline TiO2 nanowires with controllable dimensions. Furthermore, in situ dopant incorporation of various transition metals allows for the tuning of optical, electrical, and catalytic properties. With this combination of control, robustness, and scalability, the molten-salt flux scheme can provide high-quality TiO2 nanowires to satisfy a broad range of application needs from photovoltaics to photocatalysis.

Liu, Bin; Chen, HaoMing; Liu, Chong; Andrews, Sean; Han, Chris; Yang, Peidong

2013-03-13

218

Synthesis, characterization and microwave absorption property of doped polyaniline nanocomposites containing TiO 2 nanoparticles and carbon nanotubes  

Microsoft Academic Search

As nanomaterial possessing moderate conductivity, magnetic and dielectric property, novel hexanoic acid (HA)-doped polyaniline (PAni) nanocomposites containing TiO2 nanoparticles (dielectric filler) and carbon nanotubes, CNTs (magnetic fillers such as single-walled carbon nanotube, SWNT and multi-walled carbon nanotube, MWNT) were prepared by template free method. The PAni were characterized by UV, FTIR, X-ray diffraction (XRD), thermogravimetric (TGA) and scanning electron microscopy

Sook Wai Phang; Masato Tadokoro; Jiro Watanabe; Noriyuki Kuramoto

2008-01-01

219

Surfactant\\/co-polymer template hydrothermal synthesis of thermally stable, mesoporous TiO 2 from TiOSO 4  

Microsoft Academic Search

Industrial TiOSO4 solution was used as inorganic precursor to prepare mesoporous titania via composite template route, using cetyl-trimethylammonium bromide (CTAB) and tri-block copolymer EO20PO70EO20 (P-123) as structure-directing agents (SDA) under high acidic conditions. Mesoporous TiO2 with high thermal stability was obtained via controlling the hydrolysis and condensation rate of industrial TiOSO4 solution by adjusting the pH value and post hydrothermal

Congxue Tian; Zhao Zhang; Jun Hou; Ni Luo

2008-01-01

220

Sol-gel synthesis and characterization of nanostructured TiO2/gamma-Al2O3 composite membranes.  

PubMed

Nanostructured TiO2/gamma-Al2O3 composite membranes with various compositions were prepared by sol-gel method. The structural and textural properties of the composite membranes could be modified by the mixing ratio of boehmite sol and titania sol, and calcination temperature. The existence of alumina in the composite membranes retarded anatase-to-rutile phase transformation, resulting in stabilization of textural properties. Defect-free composite membranes were confirmed by gas permeation test. PMID:22103175

Kwon, Hyuk Taek; Kim, Jinsoo

2011-08-01

221

Synthesis of titanium carbide from a composite of TiO 2 nanoparticles\\/methyl cellulose by carbothermal reduction  

Microsoft Academic Search

Titanium carbide (TiC) was synthesized from a composite constituted of nano-sized TiO2 particles (ca. 5 nm in diameter) and methyl cellulose (MC) via carbothermal reduction in an Ar flow. The composite was converted into titanium oxycarbide by heating at 1050°C. With the increase of heating temperature, the lattice parameter of the titanium oxycarbide phase increased while the oxygen content in

Yasuo Gotoh; Kensaku Fujimura; Mikio Koike; Yutaka Ohkoshi; Masanobu Nagura; Kensuke Akamatsu; Shigehito Deki

2001-01-01

222

First-principles study on anatase TiO2 codoped with nitrogen and praseodymium  

Microsoft Academic Search

The crystal structures, electronic structures and optical properties of nitrogen or\\/and praseodymium doped anatase TiO2 were calculated by first principles with the plane-wave ultrasoft pseudopotential method based on density functional theory. Highly efficient visible-light-induced nitrogen or\\/and praseodymium doped anatase TiO2 nanocrystal photocatalyst were synthesized by a microwave chemical method. The calculated results show that the photocatalytic activity of TiO2 can

Pan Gao; Jing Wu; Qing-Ju Liu; Wen-Fang Zhou

2010-01-01

223

Kinetics and mechanism of TNT degradation in TiO 2 photocatalysis  

Microsoft Academic Search

The photocatalytic degradation of TNT in a circular photocatalytic reactor, using a UV lamp as a light source and TiO2 as a photocatalyst, was investigated. The effects of various parameters such as the initial TNT concentration, and the initial pH on the TNT degradation rate of TiO2 photocatalysis were examined. In the presence of both UV light illumination and TiO2

Hyun-Seok Son; So-Jin Lee; Il-Hyoung Cho; Kyung-Duk Zoh

2004-01-01

224

Synthesis and photoelectrochemical response of CdS quantum dot-sensitized TiO2 nanorod array photoelectrodes  

PubMed Central

A continuous and compact CdS quantum dot-sensitive layer was synthesized on TiO2 nanorods by successive ionic layer adsorption and reaction (SILAR) and subsequent thermal annealing. The thickness of the CdS quantum dot layer was tuned by SILAR cycles, which was found to be closely related to light absorption and carrier transformation. The CdS quantum dot-sensitized TiO2 nanorod array photoelectrodes were characterized by scanning electron microscopy, X-ray diffraction, ultraviolet–visible absorption spectroscopy, and photoelectrochemical property measurement. The optimum sample was fabricated by SILAR in 70 cycles and then annealed at 400°C for 1 h in air atmosphere. A TiO2/CdS core-shell structure was formed with a diameter of 35 nm, which presented an improvement in light harvesting. Finally, a saturated photocurrent of 3.6 mA/cm2 was produced under the irradiation of AM1.5G simulated sunlight at 100 mW/cm2. In particular, the saturated current density maintained a fixed value of approximately 3 mA/cm2 without decadence as time passed under the light conditions, indicating the steady photoelectronic property of the photoanode.

2013-01-01

225

CuInS2 quantum dot-sensitized TiO2 nanorod array photoelectrodes: synthesis and performance optimization  

NASA Astrophysics Data System (ADS)

CuInS2 quantum dots (QDs) were deposited onto TiO2 nanorod arrays for different cycles by using successive ionic layer adsorption and reaction (SILAR) method. The effect of SILAR cycles on the light absorption and photoelectrochemical properties of the sensitized photoelectrodes was studied. With optimization of CuInS2 SILAR cycles and introduction of In2S3 buffer layer, quantum dot-sensitized solar cells assembled with 3-?m thick TiO2 nanorod film exhibited a short-circuit current density ( I sc) of 4.51 mA cm-2, an open-circuit voltage ( V oc) of 0.56 V, a fill factor (FF) of 0.41, and a power conversion efficiency ( ?) of 1.06%, respectively. This study indicates that SILAR process is a very promising strategy for preparing directly anchored semiconductor QDs on TiO2 nanorod surface in a straightforward but controllable way without any complicated fabrication procedures and introduction of a linker molecule.

Zhou, Zhengji; Yuan, Shengjie; Fan, Junqi; Hou, Zeliang; Zhou, Wenhui; Du, Zuliang; Wu, Sixin

2012-11-01

226

Synthesis and characterisations of Au-nanoparticle-doped TiO2 and CdO thin films  

NASA Astrophysics Data System (ADS)

In the present study, pure and gold nanoparticle (Au NP)-doped titanium dioxide (TiO2) and cadmium oxide (CdO) thin film were prepared by the sol–gel method, and the effect of Au NP doping on the optical, structural and morphological properties of these thin films was investigated. The prepared thin films were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and ultraviolet–visible–near infrared (UV–Vis–NIR) spectra. While the optical band increases from 3.62 to 3.73 for TiO2 thin films, it decreases from 2.20 to 1.55 for CdO thin films with increasing Au doping concentration. Analysis of XRD indicates that the intensities of peaks of the crystalline phase have increased with the increasing Au NP concentrations in all thin films. SEM images demonstrate that the surface morphologies of the samples were affected by the incorporation of Au NPs. Consequently, the most significant results of the present study are that the Au NPs can be used to modify the optical, structural and morphological properties of TiO2 and CdO thin films.

Gültekin, Aytaç; Karanfil, Gamze; Özel, Faruk; Ku?, Mahmut; Say, Ridvan; Sönmezo?lu, Sava?

2014-06-01

227

A simple, template-free route for the synthesis of bicrystalline mesoporous TiO2 materials.  

PubMed

A simple, low-temperature and green template-free synthetic route has been used to prepare mesoporous TiO2 with anatase and brookite bicrystalline framework. This route combines a quick hydrolysis at ambient temperature and sequent hydrothermal treatment at 80-180 egrees C without further calcination. The resultant materials were characterized by XRD, TEM and nitrogen adsorption. It was found that the wormhole-like mesostructure and the bicrystalline framework could be formed in the hydrothermal treatment, and high surface areas of 160-250 m2 x g(-1) could be obtained due to the avoidance of calcination at high temperature. The effect of hydrothermal temperature on mesoporosity and crystallinity was also investigated and discussed. The as-prepared TiO2 samples exhibited higher photocatalytic activities than pure anatase TiO2 and corresponding calcined samples in the degradation of methyl orange, which can be attributed to the combined effect of composite crystalline phase and high surface area. PMID:19908583

Su, Zhili; Yang, Chun

2009-11-01

228

CuInS2 quantum dot-sensitized TiO2 nanorod array photoelectrodes: synthesis and performance optimization.  

PubMed

CuInS2 quantum dots (QDs) were deposited onto TiO2 nanorod arrays for different cycles by using successive ionic layer adsorption and reaction (SILAR) method. The effect of SILAR cycles on the light absorption and photoelectrochemical properties of the sensitized photoelectrodes was studied. With optimization of CuInS2 SILAR cycles and introduction of In2S3 buffer layer, quantum dot-sensitized solar cells assembled with 3-?m thick TiO2 nanorod film exhibited a short-circuit current density (Isc) of 4.51 mA cm-2, an open-circuit voltage (Voc) of 0.56 V, a fill factor (FF) of 0.41, and a power conversion efficiency (?) of 1.06%, respectively. This study indicates that SILAR process is a very promising strategy for preparing directly anchored semiconductor QDs on TiO2 nanorod surface in a straightforward but controllable way without any complicated fabrication procedures and introduction of a linker molecule. PMID:23181940

Zhou, Zhengji; Yuan, Shengjie; Fan, Junqi; Hou, Zeliang; Zhou, Wenhui; Du, Zuliang; Wu, Sixin

2012-01-01

229

Tuning TiO2 nanoparticle morphology in graphene-TiO2 hybrids by graphene surface modification  

NASA Astrophysics Data System (ADS)

We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as a shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shapes and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted truncated bipyramids, bonded to graphene via the {100} facets. Belted truncated bipyramids formed on unfunctionalized GNP too, however the NPs were more irregular and rounded. These effects were ascribed to pH variations in the proximity of the functionalized GNP sheets, due to the high density of COOH or NH2 groups. Because of the different reactivity of anatase {100} and {101} crystalline facets, we hypothesize that the hybrid materials will behave differently as photocatalysts, and that the COOH-GNP-TiO2 hybrids will be better photocatalysts for water splitting and H2 production.We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as a shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shapes and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted truncated bipyramids, bonded to graphene via the {100} facets. Belted truncated bipyramids formed on unfunctionalized GNP too, however the NPs were more irregular and rounded. These effects were ascribed to pH variations in the proximity of the functionalized GNP sheets, due to the high density of COOH or NH2 groups. Because of the different reactivity of anatase {100} and {101} crystalline facets, we hypothesize that the hybrid materials will behave differently as photocatalysts, and that the COOH-GNP-TiO2 hybrids will be better photocatalysts for water splitting and H2 production. Electronic supplementary information (ESI) available: Statistical analysis of the D : G intensity ratio, additional XPS analysis and TEM micrographs. See DOI: 10.1039/c4nr01322k

Sordello, Fabrizio; Zeb, Gul; Hu, Kaiwen; Calza, Paola; Minero, Claudio; Szkopek, Thomas; Cerruti, Marta

2014-05-01

230

Synthesis and Characterization of Poly(oxyethylene methacrylate) Coated TiO2 Nanoparticles via Surface Thiol-Lactam Initiated Radical Polymerization  

Microsoft Academic Search

Poly(oxyethylene methacrylate) (POEM) anchored TiO2 nanoparticles were synthesized via the surface thiol-lactam initiated radical polymerization of POEM in the presence of thiol functionalized TiO2 nanoparticles. The grafting of POEM onto the surface of TiO2 nanoparticles was investigated by FT-IR, XPS, EDX, TGA, XRD, and TEM analyses. The experimental findings suggested that a strong interaction prevailed between grafted POEM and TiO2

Long Giang Bach; Seong-Soo Hong; Ha Soo Hwang; Hyun Gyu Kim; Kwon Taek Lim

2012-01-01

231

TiO2 Nanorods: A Facile Size- and Shape-Tunable Synthesis and Effective Improvement of Charge Collection Kinetics for Dye-Sensitized Solar Cells.  

PubMed

In this paper, we present a novel, high-yield, and cost-effective hydrothermal method for the preparation of single crystal-like anatase TiO2 nanorods (NRs) with specific {101} exposed crystal planes and preferred [001] growth direction, which is governed by the "oriented attachment" mechanism. The successful synthesis of TiO2 NRs and fine tuning on their size and shape could be easily accomplished by adjusting the solvent compositions. The salient feature of these NRs, in lieu of traditional nanoparticles as building blocks of photoanodes in dye-sensitized solar cell (DSSC) system, rests with their significantly reduced grain boundaries. The electron diffusion and recombination kinetics have been critically compared for the first time with respect to the size and shape of the novel building blocks. A high efficiency of 8.87% has finally been achieved for DSSC based on long-thin NRs rather than short-thin or long-thick NRs, which possesses balanced optimizations on charge collection and light-harvesting properties. PMID:24833257

Zhang, Wenjun; Xie, Yan; Xiong, Dehua; Zeng, Xianwei; Li, Zhihong; Wang, Mingkui; Cheng, Yi-Bing; Chen, Wei; Yan, Keyou; Yang, Shihe

2014-06-25

232

A simple synthesis and room-temperature magnetic behavior of Co-doped anatase TiO 2 nanoparticles  

NASA Astrophysics Data System (ADS)

Co-doped anatase TiO 2 (i.e. Ti 0.93Co 0.07O 2) nanoparticles have been synthesized by a simple chemical route using titanium(diisoproproxide) bis(2, 4-pentanedionate) 75 wt% in 2-propanol, cobalt (II) acetate tetrahydrate and polyvinyl pyrrolidone (PVP) as the starting chemicals. The nanoparticles were obtained after calcination of the precursor at 823 K for 3 h. The morphology of the nanoparticles was revealed by TEM. The particle sizes obtained from TEM and X-ray line broadening were ˜10-15 and 27 nm, respectively. The XRD and FT-IR results indicated that the synthesized Ti 0.93Co 0.07O 2 nanoparticles have the pure anatase TiO 2 structure without any significant change in the structure that would have been affected by Co substitution. Room temperature magnetization results showed a ferromagnetic behavior of the Ti 0.93Co 0.07O 2 nanoparticles, having their hysteresis loop in the range of -2500 Oe

Maensiri, Santi; Laokul, Paveena; Klinkaewnarong, Jutharatana

2006-07-01

233

Synthesis of TiO2/WO3 nanoparticles via sonochemical approach for the photocatalytic degradation of methylene blue under visible light illumination.  

PubMed

Through an ultrasound assisted method, TiO2/WO3 nanoparticles were synthesized at room temperature. The XRD pattern of as-prepared TiO2/WO3 nanoparticles matches well with that of pure monoclinic WO3 and rutile TiO2 nanoparticles. TEM images show that the prepared TiO2/WO3 nanoparticles consist of mixed square and hexagonal shape particles about 8-12nm in diameter. The photocatalytic activity of TiO2/WO3 nanoparticles was tested for the degradation of a wastewater containing methylene blue (MB) under visible light illumination. The TiO2/WO3 nanoparticles exhibits a higher degradation rate constant (6.72×10(-4)s(-1)) than bare TiO2 nanoparticles (1.72×10(-4)s(-1)) under similar experimental conditions. PMID:24629580

Anandan, Sambandam; Sivasankar, Thirugnanasambandam; Lana-Villarreal, Teresa

2014-11-01

234

Adsorption properties and photocatalytic activity of TiO2/activated carbon fiber composite  

NASA Astrophysics Data System (ADS)

Photocatalysts of titanium dioxide (TiO2) and TiO2/activated carbon fiber (TiO2/ACF) composite were prepared by sol-gel method, followed by calcining the pure TiO2 sols and the TiO2/ACF sols at 500°C for 2 h in a N2 atmosphere, respectively. These photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and N2 adsorption-desorption isotherms measurement. Batch experiments were conducted to study the adsorption property of TiO2/ACF composite using methylene blue as adsorbate. The adsorption data obtained from different batch experiments were analyzed using pseudo-second-order kinetic model, the experimental data can be adequately described by the pseudo-second-order equation. The photodecomposition behavior of TiO2/ACF was investigated in aqueous solution using methylene blue as target pollutant. It was found that methylene blue could be removed rapidly from water by TiO2/ACF, the photocatalytic decomposition was obviously improved when the photocatalyst was used. Kinetics analysis revealed that the photocatalytic decomposition reaction can be described well by a first-order rate equation.

Yao, Shuhua; Song, Shuangping; Shi, Zhongliang

2014-06-01

235

Decomposition of water in the separate evolution of hydrogen and oxygen using visible light-responsive TiO 2 thin film photocatalysts: Effect of the work function of the substrates on the yield of the reaction  

Microsoft Academic Search

The development of visible light-responsive TiO2 thin films (vis-TiO2) was successfully carried out by applying a radio-frequency magnetron sputtering (RF-MS) deposition method. The Pt-loaded vis-TiO2 thin films clearly showed high potential for the decomposition of water into H2 and O2 by the evolution of H2 from methanol\\/water as well as O2 from a silver nitrate\\/water system under both UV and

Masaaki Kitano; Koichiro Tsujimaru; Masakazu Anpo

2006-01-01

236

Synthesis and characterization of the air-water interfacial TiO2/ZrO2 binary oxide film.  

PubMed

TiO(2)/ZrO(2) binary oxide film was self-assembled using anionic surfactant (sodium dodecyl sulfonate (SDS)) as template and obtained at the air-water interface. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to characterize the obtained film. The film was composed of many lamellar nanorods with a d spacing of 3.2 nm, and the lamellas were perpendicular to the lengthwise position of the rods. The energy-dispersive spectrum (EDS) was used for determining the titanium/zirconium atomic ratio. After being calcined, the sample decomposed to a mixture of anatase titania and tetragonal zirconia, and all the lamellar structure was broken. PMID:17367800

Kan, Chun; Liu, Xiaoheng; Duan, Guorong; Wang, Xin; Yang, Xujie; Lu, Lude

2007-06-15

237

Synthesis of uniformly dispersed anatase nanoparticles inside mesoporous silica thin films via controlled breakup and crystallization of amorphous TiO2 deposited using atomic layer deposition.  

PubMed

Amorphous titanium dioxide was introduced into the pores of mesoporous silica thin films with 75% porosity and 12 nm average pore diameter via Atomic Layer Deposition (ALD) using alternating pulses of tetrakis(dimethylamino)titanium and water. Calcination provoked fragmentation of the deposited amorphous TiO2 phase and its crystallization into anatase nanoparticles inside the nanoporous film. The narrow particle size distribution of 4 ± 2 nm and the uniform dispersion of the particles over the mesoporous silica support were uniquely revealed using electron tomography. These anatase nanoparticle bearing films showed photocatalytic activity in methylene blue degradation. This new synthesis procedure of the anatase nanophase in mesoporous silica films using ALD is a convenient fabrication method of photocatalytic coatings amenable to application on very small as well as very large surfaces. PMID:23636429

Sree, Sreeprasanth Pulinthanathu; Dendooven, Jolien; Masschaele, Kasper; Hamed, Heidari M; Deng, Shaoren; Bals, Sara; Detavernier, Christophe; Martens, Johan A

2013-06-01

238

Synthesis of uniformly dispersed anatase nanoparticles inside mesoporous silica thin films via controlled breakup and crystallization of amorphous TiO2 deposited using atomic layer deposition  

NASA Astrophysics Data System (ADS)

Amorphous titanium dioxide was introduced into the pores of mesoporous silica thin films with 75% porosity and 12 nm average pore diameter via Atomic Layer Deposition (ALD) using alternating pulses of tetrakis(dimethylamino)titanium and water. Calcination provoked fragmentation of the deposited amorphous TiO2 phase and its crystallization into anatase nanoparticles inside the nanoporous film. The narrow particle size distribution of 4 +/- 2 nm and the uniform dispersion of the particles over the mesoporous silica support were uniquely revealed using electron tomography. These anatase nanoparticle bearing films showed photocatalytic activity in methylene blue degradation. This new synthesis procedure of the anatase nanophase in mesoporous silica films using ALD is a convenient fabrication method of photocatalytic coatings amenable to application on very small as well as very large surfaces.

Sree, Sreeprasanth Pulinthanathu; Dendooven, Jolien; Masschaele, Kasper; Hamed, Heidari M.; Deng, Shaoren; Bals, Sara; Detavernier, Christophe; Martens, Johan A.

2013-05-01

239

TiO_{2}.  

PubMed

Using first-principles density functional theory calculations, we explore the chemical activity of epitaxial heterostructures of TiO_{2} anatase on strained polar SrTiO_{3} films focusing on the oxygen evolution reaction (OER), the bottleneck of water splitting. Our results show that the reactivity of the TiO_{2} surface is tuned by electric dipoles dynamically induced by the adsorbed species during the intermediate steps of the reaction while the initial and final steps remain unaffected. Compared to the OER on unsupported TiO_{2}, the combined effects of the dynamically induced dipoles and epitaxial strain strongly reduce rate-limiting thermodynamic barriers and significantly improve the efficiency of the reaction. PMID:24877949

Lee, Jun Hee; Selloni, Annabella

2014-05-16

240

"Suspended" Pt nanoparticles over TiO2 nanotubes for enhanced photocatalytic H2 evolution.  

PubMed

In the present work we introduce a technique to form a photocatalyst based on Pt nanoparticles suspended over the mouth of anodic TiO2 nanotubes. These structures are obtained by decorating the top end of highly ordered TiO2 nanotubes with a web of TiO2 nanofibrils, followed by sputter deposition of a minimum amount of Pt. A subsequent thermal dewetting step forms 3-6 nm-sized Pt nanoparticles along the nanofibrils. These structures, when compared to conventional Pt decoration techniques of TiO2 nanotubes, show strongly enhanced photocatalytic H2 evolution efficiency. PMID:25019463

Nguyen, Nhat Truong; Yoo, JeongEun; Altomare, Marco; Schmuki, Patrik

2014-07-29

241

Ultrathin TiO2 layer coated-CdS spheres core-shell nanocomposite with enhanced visible-light photoactivity.  

PubMed

Development of various strategies for controllable fabrication of core-shell nanocomposites (CSNs) with highly active photocatalytic performance has been attracting ever-increasing research attention. In particular, control of the ultrathin layer TiO2 shell in constructing CSNs in an aqueous phase is a significant but technologically challenging issue. Here, this paper demonstrates the interface assembly synthesis of CdS nanospheres@TiO2 core-shell photocatalyst via the electrostatic interaction of negatively charged water-stable titania precursor with positively charged CdS nanospheres (CdS NSPs), followed by the formation of the ultrathin-layer TiO2 shell through a facile refluxing process in aqueous phase. The as-formed CdS NSPs@TiO2 core-shell nanohybrid exhibits a high visible-light-driven photoactivity for selective transformation and reduction of heavy metal ions. The ultrathin TiO2 layer coated on CdS NSPs results in excellent light transmission property, enhanced adsorption capacity, and improved transfer of charge carriers and lifespan of photoinduced electron-hole pairs, which would prominently contribute to the significant photoactivity enhancement. It is anticipated that this facile aqueous-phase synthesis strategy could be extended to design a variety of more efficient CSN photocatalysts with controllable morphology toward target applications in diverse photoredox processes. PMID:24245797

Chen, Zhang; Xu, Yi-Jun

2013-12-26

242

Designed synthesis and stacking architecture of solid and mesoporous TiO(2) nanoparticles for enhancing the light-harvesting efficiency of dye-sensitized solar cells.  

PubMed

We fabricated solid and mesoporous TiO2 nanoparticles (NPs) with relatively large primary sizes of approximately 200 nm via inorganic templates for aero-sol-gel and subsequent aqueous-washing processes. The amount of dye molecules adsorbed by the internal pores in the mesoporous TiO2 NPs was increased by creating the nanopores within the solid TiO2 NPs. Simultaneously, the light-scattering effect of the mesoporous TiO2 NPs fabricated by this approach was secured by maintaining their spherical shape and relatively large average size. By precisely accumulating the fabricated solid or mesoporous 200 nm diameter TiO2 NPs on top of a conventional 25 nm diameter TiO2 NP-based underlayer, we could systematically examine the effect of the solid and mesoporous TiO2 NPs on the photovoltaic performance of dye-sensitized solar cells (DSSCs). Consequently, the stacking architecture of the mesoporous TiO2 NP-based overlayer, which functioned as both a light-scattering and dye-supporting medium, on top of a conventional solid TiO2 NP-based underlayer in a DSSC photoelectrode (i.e., double-layer structures) was found to be very promising for significantly improving the photovoltaic properties of conventional solid TiO2 NP single-layer-based DSSCs. PMID:24377279

Ahn, Ji Young; Moon, Kook Joo; Kim, Ji Hoon; Lee, Sang Hyun; Kang, Jae Wook; Lee, Hyung Woo; Kim, Soo Hyung

2014-01-22

243

Tuning TiO2 nanoparticle morphology in graphene-TiO2 hybrids by graphene surface modification.  

PubMed

We report the hydrothermal synthesis of graphene (GNP)-TiO2 nanoparticle (NP) hybrids using COOH and NH2 functionalized GNP as a shape controller. Anatase was the only TiO2 crystalline phase nucleated on the functionalized GNP, whereas traces of rutile were detected on unfunctionalized GNP. X-Ray Photoelectron spectroscopy (XPS) showed C-Ti bonds on all hybrids, thus confirming heterogeneous nucleation. GNP functionalization induced the nucleation of TiO2 NPs with specific shapes and crystalline facets exposed. COOH functionalization directed the synthesis of anatase truncated bipyramids, bonded to graphene sheets via the {101} facets, while NH2 functionalization induced the formation of belted truncated bipyramids, bonded to graphene via the {100} facets. Belted truncated bipyramids formed on unfunctionalized GNP too, however the NPs were more irregular and rounded. These effects were ascribed to pH variations in the proximity of the functionalized GNP sheets, due to the high density of COOH or NH2 groups. Because of the different reactivity of anatase {100} and {101} crystalline facets, we hypothesize that the hybrid materials will behave differently as photocatalysts, and that the COOH-GNP-TiO2 hybrids will be better photocatalysts for water splitting and H2 production. PMID:24821216

Sordello, Fabrizio; Zeb, Gul; Hu, Kaiwen; Calza, Paola; Minero, Claudio; Szkopek, Thomas; Cerruti, Marta

2014-05-29

244

Synthesis of mixed ZrO 2–TiO 2 oxides by sol–gel: Microstructural characterization and infrared spectroscopy studies of NO x  

Microsoft Academic Search

Single ZrO2, TiO2 and mixed ZrO2–TiO2 oxides with various Zr:Ti ratio (90:10, 50:50 and 10:90) were prepared by the sol–gel method. The samples were characterized by DSC, nitrogen adsorption, SEM, XRD, molecular simulation and DRIFT. According to the ZrO2\\/TiO2 ratio, the experimental results reveal that the TiO2 loading into ZrO2 had effects on shifts of exothermic peaks towards higher temperature,

R. Pérez-Hernández; D. Mendoza-Anaya; M. E. Fernández; A. Gómez-Cortés

2008-01-01

245

Synthesis and characterization of nano TiO2-SiO2: PVA composite - a novel route  

NASA Astrophysics Data System (ADS)

A novel, simple, less time consuming and cost-effective sol-gel method has been developed to synthesize nano titania-silica with polyvinyl alcohol (PVA) composite relatively at low temperature in acidic pH. Titania sol is prepared by hydrolysis of titanium tetrachloride and was mixed with silicic acid and tetrahydrofuran mixture. The reaction was carried out under vigorous stirring for 6 h and dried at room temperature with the addition of PVA solution. The resulting powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FT-IR), UV-visible spectroscopy and thermal techniques. The grain size of the particles was calculated by X-ray diffraction; surface morphology and chemical composition were determined from scanning electron microscopy-energy dispersive spectroscopy; metal oxide stretching was confirmed from FT-IR spectroscopy; bandgap was calculated using UV-visible spectroscopy, and thermal stability of the prepared composite was determined by thermogravimetric/differential thermal analysis. Since TiO2 got agglomerated on the surface of SiO2, effective absorptive sites increase which in turn increase the photocatalytic efficiency of the resulting composite.

Venckatesh, Rajendran; Balachandaran, Kartha; Sivaraj, Rajeshwari

2012-07-01

246

Synthesis and characterization of Pt-MoO x -TiO2 electrodes for direct ethanol fuel cells  

NASA Astrophysics Data System (ADS)

To enhance the CO-tolerance performance of anode catalysts for direct ethanol fuel cells, carbon nanotubes were modified by titanium dioxide (donated as CNTs@TiO2) and subsequently served as the support for the preparation of Pt/CNTs@TiO2 and Pt-Mo/CNTs@TiO2 electrocatalysts via a UV-photoreduction method. The physicochemical characterizations of the catalysts were carried out by using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy of adsorbed probe ammonia molecules. The electrocatalytic properties of the catalysts for methanol oxidation were investigated by the cyclic voltammetry technique. The results show that Pt-Mo/CNTs@TiO2 electrode exhibits the highest performance in all the electrodes. It is explained that, the structure, the oxidation states, and the acid-base properties of the catalysts are influenced due to the strong interaction between Ti and Mo species by adding TiO2 and MoO x to the Pt-based catalysts.

Wang, Xiu-Yu; Zhang, Jing-Chang; Cao, Xu-Dong; Jiang, Yuan-Sheng; Zhu, Hong

2011-10-01

247

Synthesis of TiO2 nano-powders prepared from purified sulphate leach liquor of red mud.  

PubMed

The research work presented in this paper is focused on the development of a purification process of red mud sulphate leach liquor for the recovery of titanium oxide (TiO(2)) nano-powders in the form of anatase. Initially, titanium was extracted over iron and aluminium from the leach liquor by solvent extraction using Cyanex 272 in toluene, at pH: 0.3 and T: 25°C, with 40% extractant concentration. Stripping of the loaded, with titanium, organic phase was carried out by diluted HCl (3 mol/L) at ambient temperature. Finally, the recovery of titanium nano-powder, in the form of anatase, was performed by chemical precipitation at pH: 6 and T: 95°C, using 10 wt% MgO pulp as neutralizing agent. The produced precipitates were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric/differential thermal analysis (TGA/DTA). Their morphological characteristics and microstructure were studied by scanning electron microscopy (SEM). High grade titanium white precipitate, in the form of anatase, was obtained. Iron concentration in the precipitate did not exceed 0.3%, whereas no aluminium was detected. PMID:21868153

Tsakiridis, P E; Oustadakis, P; Katsiapi, A; Perraki, M; Agatzini-Leonardou, S

2011-10-30

248

Study on Molecular Contamination Prevention by Using Photocatalysts under Vacuum Conditions  

Microsoft Academic Search

To better understand the characteristics for preventing organic contaminants from accumulating on the critical surfaces of spacecraft, we studied on the effective prevention of molecular contaminants by using photocatalysts under ultraviolet irradiation and vacuum conditions. Squalene, tetra-methyl tetra-phenyl tri-siloxane, oleamide and diethylhexyl phthalate were used as model contaminants. TiO2 particles and TiO2-coated substrates were used as photocatalysts. TiO2 was effective

Fumitaka Urayama; Mutsuhisa Furukawa; Kiyoshi Ozawa; Masahiro Tosa; Hideo Kimura

2007-01-01

249

Photodegradation of nalidixic acid assisted by TiO(2) nanorods/Ag nanoparticles based catalyst.  

PubMed

Two different nanosized TiO2-based catalysts supported onto glass with tailored photocatalytic properties upon irradiation by UV light were successfully employed for the degradation of nalidixid acid, a widely diffused antibacterial agent of environmental relevance known to be non-biodegradable. Anatase rod-like TiO2 nanocrystals (TiO2NRs) and a semiconductor oxide-noble metal nanocomposite TiO2 NRs/Ag nanoparticles (NPs), synthesized by colloidal chemistry routes, were cast onto glass slide and employed as photocatalysts. A commercially available catalyst (TiO2 P25), also immobilized onto a glass slide, was used as a reference material. It was found that both TiO2 NRs/Ag NPs composite and TiO2 NRs demonstrated a photocatalytic efficiency significantly higher than the reference TiO2 P25. Specifically, TiO2 NRs/Ag NPs showed a photoactivity in nalidixic acid degradation 14 times higher than TiO2 P25 and 4 times higher than bare TiO2 NRs in the first 60min of reaction. Several by-products were identified by HPLC-MS along the nalidixic acid degradation, thus getting useful insight on the degradation pathway. All the identified by-products resulted completely removed after 6h of reaction. PMID:23466278

Petronella, F; Diomede, S; Fanizza, E; Mascolo, G; Sibillano, T; Agostiano, A; Curri, M L; Comparelli, R

2013-05-01

250

Synthesis and Microstructure Evolution of Nano-Titania Doped Silicon Coatings  

Microsoft Academic Search

The Anatase phase of Titania (TiO2) in nanocrystalline form is a well known photocatalyst. Photocatalysts are commercially used to accelerate photoreactions\\u000a and increase photovoltaic efficiency such as in solar cells. This study investigates the in-flight synthesis of Titania and\\u000a its doping into a Silicon matrix resulting in a catalyst-dispersed coating. A liquid precursor of Titanium Isopropoxide and\\u000a ethanol was coaxially

N. A. Moroz; H. Umapathy; P. Mohanty

2010-01-01

251

Photocatalytic decolorization of anthraquinonic dye by TiO 2 thin film under UVA and visible-light irradiation  

Microsoft Academic Search

In this investigation, the effectiveness of using photocatalytic sol–gel TiO2 thin film to decolorize anthraquinonic dye Acid Blue 80 was evaluated experimentally. The TiO2 photocatalysts synthesized were characterized by DSC–TG, XRD, HRTEM, UV–vis spectra, SEM, and XPS. The experimental results showed that a TiO2 thin film formed without high temperature calcination could effectively perform photocatalytic decolorization under UVA irradiation. After

C. H. Ao; M. K. H. Leung; Ringo C. W. Lam; Dennis Y. C. Leung; Lilian L. P. Vrijmoed; W. C. Yam; S. P. Ng

2007-01-01

252

Vapor-phase hydrothermal synthesis of rutile TiO2 nanostructured film with exposed pyramid-shaped (111) surface and superiorly photoelectrocatalytic performance.  

PubMed

Rutile TiO2 nanostructured film with exposed pyramid-shaped (111) surface was successfully fabricated using metal titanium foil as substrate through a facile vapor-phase hydrothermal method. The fabricated rutile TiO2 film was composed of vertically aligned rod-like structures with diameters ranged from 400 to 700nm and thickness of ca. 2.0?m. The obtained rutile TiO2 film as photoanode exhibited excellent photoelectrocatalytic activity toward water oxidation and rhodamine B decolorization under UV illumination, which was more than 3.5 and 1.2 times of that obtained by highly ordered anatase TiO2 nanotube array film photoanode under the same experimental conditions, respectively. The excellent photoelectrocatalytic performance of the rutile TiO2 film photoanode could be due to the superior photoelectron transfer property and the high oxidative capability of {111} crystal facets. The superior photoelectron transfer capability of the photoanodes was manifested by the inherent resistance (R0) of the photoanodes using a simple photoelectrochemical method. The calculated R0 values were 50.5 and 86.2? for the rutile TiO2 nanostructured film and anatase TiO2 nanotube array film, respectively. Lower R0 value of the rutile TiO2 photoanode indicated a superior photoelectron transfer capability owing to good single crystal property of the rod-like rutile nanostructure. Almost identical valence band level (1.94eV) of the rutile TiO2 nanostructured film and anatase TiO2 nanotube array film (meaning a similar oxidation capability) further confirmed the significant role of photoelectron transfer capability and exposed high-energy {111} crystal facets for improved photoelectrocatalytic performance of the rutile TiO2 nanostructured film photoanode. PMID:24935189

Chen, Jiangyao; Zhang, Haimin; Liu, Porun; Wang, Yun; Liu, Xiaolu; Li, Guiying; An, Taicheng; Zhao, Huijun

2014-09-01

253

Sol-flame synthesis of cobalt-doped TiO2 nanowires with enhanced electrocatalytic activity for oxygen evolution reaction.  

PubMed

Doping nanowires (NWs) is of crucial importance for a range of applications due to the unique properties arising from both impurities' incorporation and nanoscale dimensions. However, existing doping methods face the challenge of simultaneous control over the morphology, crystallinity, dopant distribution and concentration at the nanometer scale. Here, we present a controllable and reliable method, which combines versatile solution phase chemistry and rapid flame annealing process (sol-flame), to dope TiO2 NWs with cobalt (Co). The sol-flame doping method not only preserves the morphology and crystallinity of the TiO2 NWs, but also allows fine control over the Co dopant profile by varying the concentration of Co precursor solution. Characterizations of the TiO2:Co NWs show that Co dopants exhibit 2+ oxidation state and substitutionally occupy Ti sites in the TiO2 lattice. The Co dopant concentration significantly affects the oxygen evolution reaction (OER) activity of TiO2:Co NWs, and the TiO2:Co NWs with 12 at% of Co on the surface show the highest OER activity with a 0.76 V reduction of the overpotential with respect to undoped TiO2 NWs. This enhancement of OER activity for TiO2:Co NWs is attributed to both improved surface charge transfer kinetics and increased bulk conductivity. PMID:24820239

Cai, Lili; Cho, In Sun; Logar, Manca; Mehta, Apurva; He, Jiajun; Lee, Chi Hwan; Rao, Pratap M; Feng, Yunzhe; Wilcox, Jennifer; Prinz, Fritz B; Zheng, Xiaolin

2014-05-28

254

One-pot synthesis of N-F-Cr-doped anatase TiO2 microspheres with nearly all-(001) surface for enhanced solar absorption  

NASA Astrophysics Data System (ADS)

The synthesis and clarifications in structure-property relationship for anatase TiO2 crystals exposing (001) facets have attracted much attention. In this paper, a novel titania microsphere with nearly all-(001) surface was synthesized by hydrothermal treatment of a thermal sprayed TiN/Ti coating with HF aqueous solution containing chromium powders. Unlike the conventional (001)-facet exposed anatase crystals, which are highly truncated bipyramids, the crystal achieved in the current investigation is drum-like with a round cross section. The formation of the drum-like crystals was contributed to a balance between the erosion and precipitation of anatase single crystallites. The Cr-doping in anatase was believed to increase the surface deficiency which enhanced the erosion procedure, leading to the drum-like crystals. The XPS analysis confirmed the incorporations of N, F and Cr in the microsized anatase crystals through the one-pot reaction, which led to a significantly enhanced solar absorption. The UV-Vis diffuse reflectance revealed a band-to-band red-shift of the band gap of the anatase crystals to 1.60 eV, which is contributed mainly to the homogeneous Cr-doping.The synthesis and clarifications in structure-property relationship for anatase TiO2 crystals exposing (001) facets have attracted much attention. In this paper, a novel titania microsphere with nearly all-(001) surface was synthesized by hydrothermal treatment of a thermal sprayed TiN/Ti coating with HF aqueous solution containing chromium powders. Unlike the conventional (001)-facet exposed anatase crystals, which are highly truncated bipyramids, the crystal achieved in the current investigation is drum-like with a round cross section. The formation of the drum-like crystals was contributed to a balance between the erosion and precipitation of anatase single crystallites. The Cr-doping in anatase was believed to increase the surface deficiency which enhanced the erosion procedure, leading to the drum-like crystals. The XPS analysis confirmed the incorporations of N, F and Cr in the microsized anatase crystals through the one-pot reaction, which led to a significantly enhanced solar absorption. The UV-Vis diffuse reflectance revealed a band-to-band red-shift of the band gap of the anatase crystals to 1.60 eV, which is contributed mainly to the homogeneous Cr-doping. Electronic supplementary information (ESI) available: 4 figures to support our discussion. See DOI: 10.1039/c1nr10737b

Wu, Jin-Ming; Tang, Mei-Lan

2011-09-01

255

TiO2@C core-shell nanoparticles formed by polymeric nano-encapsulation  

PubMed Central

TiO2 semiconducting nanoparticles are known to be photocatalysts of moderate activity due to their high band-gap and high rate of electron-hole recombination. The formation of a shell of carbon around the core of TiO2, i.e., the formation of TiO2@C nanoparticles, is believed to partly alleviate these problems. It is usually achieved by a hydrothermal treatment in a presence of a sugar derivative. We present here a novel method for the formation of highly uniform C shell around TiO2 nanoparticles. For this purpose, TiO2 nanoparticles were dispersed in water using an oligomeric dispersant prepared by Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization. Then the nanoparticles were engaged into an emulsion polymerization of acrylonitrile, resulting in the formation of a shell of polyacrylonitrile (PAN) around each TiO2 nanoparticles. Upon pyrolysis, the PAN was transformed into carbon, resulting in the formation of TiO2@C nanoparticles. The structure of the resulting particles was elucidated by X-Ray diffraction, FTIR, UV-VIS and Raman spectroscopy as well as TEM microscopy. Preliminary results about the use of the TiO2@C particles as photocatalysts for the splitting of water are presented. They indicate that the presence of the C shell is responsible for a significant enhancement of the photocurrent.

Vasei, Mitra; Das, Paramita; Cherfouth, Hayet; Marsan, Benoit; Claverie, Jerome P.

2014-01-01

256

Enhanced photocatalytic activity of In2O3-decorated TiO2  

NASA Astrophysics Data System (ADS)

Titania (TiO2)-based photocatalysts decorated with different amounts of indium oxide (In2O3) were prepared by a pore impregnating method and characterized by the Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The separation efficiency of photogenerated charges was investigated using benzoquinone (BQ) as scavenger. The activities of the photocatalysts were evaluated by decolorization of methyl orange (MO) aqueous solution under ultraviolet-light irradiation. Compared to TiO2, In2O3/TiO2 composites show improved photocatalytic performance due to the coupling effect of TiO2 and In2O3, which greatly improves the separation of photogenerated electrons and holes.

Zhong, Junbo; Li, Jianzhang; Zeng, Jun; He, Xiyang; Huang, Shengtiang; Jiang, Weidong; Li, Minjiao

2013-09-01

257

Enhanced photocatalytic activity of In2O3-decorated TiO2  

NASA Astrophysics Data System (ADS)

Titania (TiO2)-based photocatalysts decorated with different amounts of indium oxide (In2O3) were prepared by a pore impregnating method and characterized by the Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and X-ray photoelectron spectroscopy (XPS). The separation efficiency of photogenerated charges was investigated using benzoquinone (BQ) as scavenger. The activities of the photocatalysts were evaluated by decolorization of methyl orange (MO) aqueous solution under ultraviolet-light irradiation. Compared to TiO2, In2O3/TiO2 composites show improved photocatalytic performance due to the coupling effect of TiO2 and In2O3, which greatly improves the separation of photogenerated electrons and holes.

Zhong, Junbo; Li, Jianzhang; Zeng, Jun; He, Xiyang; Huang, Shengtiang; Jiang, Weidong; Li, Minjiao

2014-06-01

258

Synthesis and characterization of TiO 2/Fe 2O 3 core-shell nanocomposition film and their photoelectrochemical property  

NASA Astrophysics Data System (ADS)

TiO 2/Fe 2O 3 core-shell nanocomposition film has been fabricated via two-step method. TiO 2 nanorod arrays are synthesized by a facile hydrothermal method, and followed by Fe 2O 3 nanoparticles deposited on TiO 2 nanorod arrays through an ordinary chemical bath deposition. The phase structures, morphologies, particle size, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and ultraviolet-visible (UV-vis) spectrophotometer. The results confirm that Fe 2O 3 nanoparticles of mean size ca. 10 nm coated on the surface of TiO2 NRs. After depositing Fe 2O 3, UV-vis absorption property is induces the shift to the visible-light range, the annealing temperature of 600 °C is the best condition for UV-vis absorption property of TiO 2/Fe 2O 3 nanocomposite film, and increasing Fe content, optical activity are enhanced one by one. The photoelectrochemical (PEC) performances of the as-prepared composite nanorods are determined by measuring the photo-generated currents under illumination of UV-vis light. The TiO 2 NRs modified by Fe 2O 3 show the photocurrent value of 1.36 mA/cm 2 at 0 V vs Ag/AgCl, which is higher than those of unmodified TiO 2 NRs.

Zhao, Hui; Fu, Wuyou; Yang, Haibin; Xu, Yang; Zhao, Wenyan; Zhang, Yanyan; Chen, Hui; Jing, Qiang; Qi, Xuefeng; Cao, Jing; Zhou, Xiaoming; Li, Yixing

2011-08-01

259

Photodestruction of dichloroacetic acid catalyzed by nano-sized TiO 2 particles  

Microsoft Academic Search

The photocatalytic activity of TiO2 nanoparticles of different size has been studied by following the photodegradation of dichloroacetic acid (DCA), and was tested by measuring the initial rate of the H+ and Cl? ion formation. The catalyst efficiency was found to be in correlation with the specific surface area of the semiconductor particles. The efficiency of the nanocrystalline TiO2 photocatalyst

D. W Bahnemann; S. N Kholuiskaya; R Dillert; A. I Kulak; A. I Kokorin

2002-01-01

260

TiO2 Photocatalysis: A Historical Overview and Future Prospects  

Microsoft Academic Search

Photocatalysis has recently become a common word and various products using photocatalytic functions have been commercialized. Among many candidates for photocatalysts, TiO2 is almost the only material suitable for industrial use at present and also probably in the future. This is because TiO2 has the most efficient photoactivity, the highest stability and the lowest cost. More significantly, it has been

Kazuhito Hashimoto; Hiroshi Irie; Akira Fujishima

2005-01-01

261

A method for large-scale synthesis of Al-doped TiO2 nanopowder using pulse-modulated induction thermal plasmas with time-controlled feedstock feeding  

NASA Astrophysics Data System (ADS)

A unique method of large-scale synthesis of Al-doped TiO2 nanopowder was developed, using 20 kW Ar–O2 pulse-modulated induction thermal plasmas (PMITP) with time-controlled feedstock feeding (TCFF). This PMITP–TCFF method is characterized by intermittent feedstock powder feeding synchronized with modulation of the power of the PMITP. The method enables heavy-load feeding of raw material powder to the thermal plasmas for complete evaporation. The nanopowder synthesized was analysed using different methods including field emission scanning electron microscopy, x-ray diffraction (XRD) spectroscopy, bright-field transmission electron microscopy (TEM), TEM/energy dispersive x-ray (EDX) mapping, x-ray photoelectron spectroscopy, and spectrophotometry. The results showed that Al-doped TiO2 nanopowder can be synthesized with mean diameters of 50–60 nm. The Al doping in TiO2 was confirmed from the constituent structure in the XRD spectra, the uniform presence of Al in the nanopowder in the TEM/EDX mapping, the chemical shift in the x-ray photoelectron spectra, and the absorption edge shift in the optical properties. The rate of production of the Al-doped TiO2 nanopowder was estimated as 400 g h?1.

Kodama, Naoto; Tanaka, Yasunori; Kita, K.; Uesugi, Y.; Ishijima, T.; Watanabe, S.; Nakamura, K.

2014-05-01

262

Facile synthesis of anatase TiO(2) quantum-dot/graphene-nanosheet composites with enhanced electrochemical performance for lithium-ion batteries.  

PubMed

A facile method to synthesize well-dispersed TiO2 quantum dots on graphene nanosheets (TiO2 -QDs/GNs) in a water-in-oil (W/O) emulsion system is reported. The TiO2 /graphene composites display high performance as an anode material for lithium-ion batteries (LIBs), such as having high reversible lithium storage capacity, high Coulombic efficiency, excellent cycling stability, and high rate capability. The excellent electrochemical performance and special structure of the composites thus offer a way to prepare novel graphene-based electrode materials for high-energy-density and high-power LIBs. PMID:24347361

Mo, Runwei; Lei, Zhengyu; Sun, Kening; Rooney, David

2014-04-01

263

Preparation and characterization of visible light responsive Fe 2O 3–TiO 2 composites  

Microsoft Academic Search

In this study we present the effects of iron oxide (Fe2O3) on titanium dioxide (TiO2) in synthesising visible-light reactive photocatalysts. A Fe2O3–TiO2 composite photocatalyst was synthesized from Fe2(SO4)3 and Ti(SO4)2 by a ethanol-assisted hydrothermal method. The preparation conditions were optimized through the investigation of the effects of hydrothermal temperature and time as well as molar ratio of Ti to Fe

Hong Liu; H. K. Shon; Xuan Sun; S. Vigneswaran; Hao Nan

2011-01-01

264

The structural, physical and photocatalytic properties of the mesoporous Cr-doped TiO 2  

Microsoft Academic Search

A visible-light-active mesoporous Cr-doped TiO2 photocatalyst with worm-like channels was synthesized using an evaporation-induced self-assembly approach and characterized by X-ray powder diffraction, nitrogen adsorption–desorption, X-ray photoelectron spectroscopy, transmission electron microscope, and UV–vis diffuse reflectance, respectively. The effect of Cr3+ doping concentration on the photocatalytic activity of mesoporous TiO2 was investigated from 0.1 to 1mol%. The characterizations indicated that the photocatalysts

Xiaoxing Fan; Xinyi Chen; Shaopeng Zhu; Zhaosheng Li; Tao Yu; Jinhua Ye; Zhigang Zou

2008-01-01

265

Visible-Light-Driven Oxidation of Primary C-H Bonds over CdS with Dual Co-catalysts Graphene and TiO2  

NASA Astrophysics Data System (ADS)

Selective activation of primary C-H bonds for fine chemicals synthesis is of crucial importance for the sustainable exploitation of available feedstocks. Here, we report a viable strategy to synthesize ternary GR-CdS-TiO2 composites with an intimate spatial integration and sheet-like structure, which is afforded by assembling two co-catalysts, graphene and TiO2, into the semiconductor CdS matrix with specific morphology as a visible light harvester. The GR-CdS-TiO2 composites are able to serve as a highly selective visible-light-driven photocatalyst for oxidation of saturated primary C-H bonds using benign oxygen as oxidant under ambient conditions. This work demonstrates a wide, promising scope of adopting co-catalyst strategy to design more efficient semiconductor-based photocatalyst toward selective activation of C-H bonds using solar light and molecular oxygen.

Yang, Min-Quan; Zhang, Yanhui; Zhang, Nan; Tang, Zi-Rong; Xu, Yi-Jun

2013-11-01

266

Template?Free Sol?Gel Synthesis of Hierarchically Macro? and Mesoporous Monolithic TiO2  

Microsoft Academic Search

Monolithic titania exhibiting a hierarchical, bimodal meso?macroporosity has been prepared through a template free sol?gel synthesis route. The macropore diameter can be controllably varied in the range 0.4–4 µm still maintaining a narrow pore size distribution. The macropores form as a consequence of parallel gelation and microscopic phase separation, where their relative kinetics determine the macropore diameter. We utilize the chelating

Stefan Backlund; Jarl B. Rosenholm; Mika Lindén

2007-01-01

267

Enhanced photocatalytic properties of nanoclustered P-doped TiO2 films deposited by advanced atmospheric plasma jet.  

PubMed

A facile preparation of P-doped TiO2 nanoclusters onto fluorine-doped tin oxide (FTO) glass by an advanced atmospheric plasma jet (AAP jet) is reported here. Titanium tetrachloride (TiCl4) and phosphorus trichloride (PCl3) were used as precursors. Radio frequencies were used to generate plasma at fix powder with Argon as carrier gas. Films were deposited at 500 degrees C for 10 minutes. For comparison, as-prepared, annealed and deposited at 500 degrees C samples were studied for chemical/physical properties by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Optical properties were studied by using UV-Vis spectroscopy which indicated a reduction in optical band with P-doping. The rhodamine B (Rh-B) degradation by P-doped TiO2 deposited at 500 degrees C showed enhanced degradation efficiency than that of annealed TiO2. The suggested deposition method appears to be suitable for the synthesis of photocatalyst with proper control over dopants. PMID:23035425

Seo, Hyung-Kee; Elliott, C Michael; Ansari, S G

2012-09-01

268

Polymeric micelle assembly for the direct synthesis of platinum-decorated mesoporous TiO(2) toward highly selective sensing of acetaldehyde.  

PubMed

Platinum-decorated mesoporous TiO2 is synthesized by the self-assembly of polymeric micelles of an asymmetric triblock copolymer with three chemically distinct units in an acidic tetrahydrofuran solution. The strong hydrophobic interaction of platinum(II) 2,4-pentanedionate with a polystyrene core and electrostatic interaction of titanium tetraisopropoxide with a poly(vinylpyridine) shell enable us to directly synthesize crystalline mesoporous TiO2 with platinum nanoparticles. A thermally stable block copolymer prevents collapse of the ordered mesostructure during the calcination process. The platinum source is in situ reduced to form the platinum nanoparticles on the TiO2 walls. The sensing performance of platinum-decorated mesoporous TiO2 is studied in detail using a quartz crystal microbalance technique, and it is found that it shows excellent sensitivity for acetaldehyde. PMID:24372099

Bastakoti, Bishnu Prasad; Torad, Nagy L; Yamauchi, Yusuke

2014-01-22

269

Preparation of mesoporous TiO2/CNT nanocomposites by synthesis of mesoporous titania via EISA and their photocatalytic degradation under visible light irradiation  

NASA Astrophysics Data System (ADS)

Stabilized mesoporous TiO2 was synthesized by evaporation induced self assembly (EISA) method and mechanically incorporated into single-walled carbon nanotubes (SWCNT) with different ratios. The physicochemical properties of the nanocomposites (mesoporous TiO2/SWCNT) materials were investigated by Brunauer-Emmett-Teller (BET) measurement, X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDX), photoluminescence (PL) and ultraviolet-visible (UV-Vis) spectroscopy measurements. The catalytic activity of mesoporous TiO2 and nanocomposites were assessed by examining the degradation of rhodamine B as model aqueous solution under visible light. CNTs are facilitating the photocatalytic activity of mesoporous TiO2 in the degradation of rhodamine B efficiently.

Rajasekar, K.; Thennarasu, S.; Rajesh, R.; Abirami, R.; Balkis Ameen, K.; Ramasubbu, A.

2013-12-01

270

Facile one-step synthesis of inorganic-framework molecularly imprinted TiO2/WO3 nanocomposite and its molecular recognitive photocatalytic degradation of target contaminant.  

PubMed

Inorganic-framework molecularly imprinted TiO2/WO3 nanocomposites with molecular recognitive photocatalytic activity were first prepared successfully by a facile one-step sol-gel method using 2-nitrophenol and 4-nitrophenol as template molecules, and tetrabutyl orthotitanate as titanium source as well as the precursor of functional monomer which could complex with template molecules. The template molecules could be completely removed by means of high-temperature calcination, avoiding the traditional extraction procedures that are time- as well as solvent-consuming. Compared to nonimprinted TiO2/WO3, the molecularly imprinted TiO2/WO3 shows a much higher adsorption capacity and selectivity toward the template molecules. The enhancement in terms of adsorption capacity and selectivity can be attributed to the chemical interaction between target molecules and imprinted cavities, as well as size matching between imprinted cavities and target molecules. The photocatalytic activity of molecularly imprinted TiO2/WO3 toward the target molecules is more than two times that of non-imprinted TiO2/WO3, a result of selective adsorption of target molecules on molecularly imprinted TiO2/WO3. The formation pathway of intermediate products in 2-nitrophenol and 4-nitrophenol degradation process was provided. Moreover, molecularly imprinted TiO2/WO3 exhibits high stability. The results indicate that inorganic-framework molecularly imprinted TiO2/WO3 nanocomposites have a promising prospect in the treatment of wastewater for irrigation. PMID:23746077

Luo, Xubiao; Deng, Fang; Min, Lujuan; Luo, Shenglian; Guo, Bin; Zeng, Guisheng; Au, Chaktong

2013-07-01

271

The effect of TiO2 nanostructures on self-degrading polyurethane foams  

NASA Astrophysics Data System (ADS)

Waste polyurethane foams are becoming a serious environmental problem due to their low degradation rates upon exposure to the environment. By adding TiO2 nanostructures as a photocatalyst, we can simultaneously enhance mechanical properties during use for higher performance applications, while enhancing degradation when exposed to light when placed in landfills. In this work, we integrated anatase TiO2 nanoparticles into polyurethane foams using a unique bifunctional monomer approach and studied the photodegradation ability and mechanism in a weathering chamber simulating natural environmental conditions. We found that the TiO2 nanoparticles increased the degradation rate in a significant manner showing the utility of this approach.

Chen, Chao; Charpentier, Paul A.

2014-03-01

272

Physical property and photo-catalytic activity of sulfur doped TiO 2 catalysts responding to visible light  

Microsoft Academic Search

The S-doping caused the photon-to-carrier conversion in the energy region below the band gap of pure TiO2. The photocatalyst applications of the S-doped TiO2, therefore, are of great importance. Synthesized S-doped TiO2 powders were characterized by SEM, EDS, XRD, UV–vis, FT-IR and Raman spectroscopy tests. The photocatalytic activity of S-doped TiO2 powder and Degussa p-25 was evaluated using UV–vis absorption

Sang-Hun Nam; Tae Kwan Kim; Jin-Hyo Boo

273

Diatom-templated TiO2 with enhanced photocatalytic activity: biomimetics of photonic crystals  

NASA Astrophysics Data System (ADS)

The siliceous frustules with sophisticated optical structure endow diatoms with superior solar light-harvesting abilities for effective photosynthesis. The preserved frustules of diatom ( Cocconeis placentula) cells, as biophotonic crystals, were thus employed as both hard templates and silicon resources to synthesize TiO2 photocatalyst. Characterizations by a combination of physicochemical techniques proved that the bio-inspired sample is TiO2-coated SiO2 with biogenic C self-doped in. It was found that the synthesized composites exhibited similar morphologies to the original diatom templates. In comparison with commercial Degussa P25 TiO2, the C-doped TiO2/SiO2 catalyst exhibited more light absorption in the visible region and higher photocatalytic efficiency for photodegradation of rhodamine B under visible light due to the biomorphic hierarchical structures, TiO2 coating and C-doping.

He, Jiao; Chen, Daomei; Li, Yongli; Shao, Junlong; Xie, Jiao; Sun, Yuejuan; Yan, Zhiying; Wang, Jiaqiang

2013-11-01

274

Effect of void structure of photocatalyst paper on VOC decomposition.  

PubMed

TiO2 powder-containing paper composites, called TiO2 paper, were prepared by a papermaking technique, and their photocatalytic efficiency was investigated. The TiO2 paper has a porous structure originating from the layered pulp fiber network, with TiO2 powders scattered on the fiber matrix. Under UV irradiation, the TiO2 paper decomposed gaseous acetaldehyde more effectively than powdery TiO2 and a pulp/TiO2 mixture not in paper form. Scanning electron microscopy and mercury intrusion analysis revealed that the TiO2 paper had characteristic unique voids ca. 10 microm in diameter, which might have contributed to the improved photocatalytic performance. TiO2 paper composites having different void structures were prepared by using beaten pulp fibers with different degrees of freeness and/or ceramic fibers. The photodecomposition efficiency was affected by the void structure of the photocatalyst paper, and the initial degradation rate of acetaldehyde increased with an increase in the total pore volume of TiO2 paper. The paper voids presumably provided suitable conditions for TiO2 catalysis, resulting in higher photocatalytic performance by TiO2 paper than by TiO2 powder and a pulp/TiO2 mixture not in paper form. PMID:17166561

Fukahori, Shuji; Iguchi, Yumi; Ichiura, Hideaki; Kitaoka, Takuya; Tanaka, Hiroo; Wariishi, Hiroyuki

2007-02-01

275

Beta zeolite supported sol-gel TiO2 materials for gas phase photocatalytic applications.  

PubMed

Beta zeolite supported sol-gel TiO(2) photocatalytic materials were prepared according to a sol-gel route in which high specific surface area Beta zeolite powder was incorporated into the titanium isopropoxide sol during the course of the sol-gel process. This led to an intimate contact between the zeolite surface and the TiO(2) precursors, and resulted in the anchorage of large amounts of dispersed TiO(2) nanoparticles and in the stabilization of TiO(2) in its anatase form, even for high TiO(2) wt. contents and high calcination temperatures. Taking the UV-A photocatalytic oxidation of methanol as gas phase target reaction, high methanol conversions were obtained on the Beta zeolite supported TiO(2) photocatalysts when compared to bulk sol-gel TiO(2), despite lower amounts of TiO(2) within the photoactive materials. The methanol conversion was optimum for about 40 wt.% TiO(2) loading and calcination temperatures of 500-600°C. PMID:21177024

Lafjah, Mama; Djafri, Fatiha; Bengueddach, Abdelkader; Keller, Nicolas; Keller, Valérie

2011-02-28

276

Study on Molecular Contamination Prevention by Using Photocatalysts under Vacuum Conditions  

NASA Astrophysics Data System (ADS)

To better understand the characteristics for preventing organic contaminants from accumulating on the critical surfaces of spacecraft, we studied on the effective prevention of molecular contaminants by using photocatalysts under ultraviolet irradiation and vacuum conditions. Squalene, tetra-methyl tetra-phenyl tri-siloxane, oleamide and diethylhexyl phthalate were used as model contaminants. TiO2 particles and TiO2-coated substrates were used as photocatalysts. TiO2 was effective in weight losses of all organics under the conditions. Transmittance of the TiO2-coated substrates increased depending on UV irradiation time.

Urayama, Fumitaka; Furukawa, Mutsuhisa; Ozawa, Kiyoshi; Tosa, Masahiro; Kimura, Hideo

277

Photocatalytic oxidation of water on TiO 2-coated WO 3 particles by visible light using Iron(III) ions as electron acceptor  

Microsoft Academic Search

Photocatalytic oxidation of water on TiO2-coated WO3 particles was studied using iron(III) ions as the electron acceptor with the aim of constructing a photochemical energy conversion system. Although WO3 photocatalysts can utilize part of visible light, the reaction was decelerated as the concentration of iron(II) ions in solution increased. This was a marked contrast with the reaction using TiO2 photocatalysts,

Teruhisa Ohno; Fumihiro Tanigawa; Kan Fujihara; Shinobu Izumi; Michio Matsumura

1998-01-01

278

Large scale synthesis of FeS coated Fe nanoparticles as reusable magnetic photocatalysts  

NASA Astrophysics Data System (ADS)

The FeS coated Fe nanoparticles were prepared by using high temperature reactions between the commercial Fe nanoparticles and the S powders in a sealed quartz tube. The simple method developed in this work is effective for large scale synthesis of FeS/Fe nanoparticles with tunable shell/core structures, which can be obtained by controlling the atomic ratio of Fe to S. The structural, magnetic and photocatalytic properties of the nanoparticles were investigated systematically. The good photocatalytic performance originating from the FeS shell in degradation of methylene blue under visible light and the high saturation magnetization originating from the ferromagnetic Fe core make the FeS/Fe nanoparticles a good photocatalyst that can be collected and recycled easily with a magnet. An exchange bias up to 11 mT induced in Fe by FeS was observed in the Fe/FeS nanoparticles with ferro/antiferromagnetic interfaces. The enhanced coercivity up to 32 mT was ascribed to the size effect of Fe core.

Feng, He; Si, Ping-Zhan; Xiao, Xiao-Fei; Jin, Chen-Hao; Yu, Sen-Jiang; Li, Zheng-Fa; Ge, Hong-Liang

2013-09-01

279

Interface actions between TiO2 and porous diatomite on the structure and photocatalytic activity of TiO2-diatomite  

NASA Astrophysics Data System (ADS)

TiO2-diatomite photocatalysts were prepared by sol-gel process with various pre-modified diatomite. In order to obtain diatomite with different surface characteristics, two modification approaches including calcination and phosphoric acid treatment on the micro-structure of diatomite are introduced. The photocatalysts were characterized by XRD, XPS, nitrogen adsorption-desorption isotherms and micromorphology analysis. The results indicate that, compared with pure TiO2, the anatase-to-rutile phase transition temperature of TiO2 loaded on diatomite carrier is significantly increased to nearly 900 °C, depending on the different pretreatment method of diatomite. The photocatalytic activities of different samples were evaluated by their degradation rate of methyl orange (MO) dye under UV and visible-light irradiation. The samples prepared by phosphoric acid pretreatment method exhibit the highest photocatalytic activity. After 90 min of UV irradiation, about 90% of MO is decomposed by the best effective photocatalyst. And after 8 h visible-light irradiation, nearly 60% of MO is decomposed by the same sample. Further mechanism investigation reveals that the H3PO4 pretreatment process can obviously change the surface features of diatomite carrier, cause the formation of Si-O-Ti bond, increase the binding strength between TiO2 and diatomite, restrain crystal growth of loaded TiO2, and thus form thermal-stable mesoporous structure at the granular spaces. It helps to build micro-, meso- and macro-porous hierarchical porous structure in TiO2-diatomite, and improves the charge and mass transfer efficiency during catalyzing process, resulting in the significantly increased photocatalytic activity of TiO2-diatomite pretreated by phosphoric acid.

Xia, Yue; Li, Fangfei; Jiang, Yinshan; Xia, Maosheng; Xue, Bing; Li, Yanjuan

2014-06-01

280

High-performance titanium dioxide photocatalyst on ordered mesoporous carbon support  

NASA Astrophysics Data System (ADS)

Anatase TiO 2 photocatalysts supported with the ordered mesoporous carbon, CMK-3, were synthesized by the incorporation of TiO 2 into CMK-3 followed by heating at 700 °C. The structural properties of the TiO 2 on CMK-3 were investigated by X-ray diffraction, nitrogen physisorption and electron microscopy techniques. In particular, TiO 2 was observed both inside and the external surface of CMK-3. The photocatalytic activity of TiO 2 on CMK-3 under UV-light exhibited higher efficiency in removing the Rhodamine 6G dye solution than the commercial photocatalyst P25 and TiO 2 on activated carbon. It was attributed to the synergistic effect of large surface area adsorption provided by mesoporous CMK-3 and the distinctive location of TiO 2 on the external surface of CMK-3.

Park, In-Soo; Choi, Sun Young; Ha, Jeong Sook

2008-05-01

281

Microwave assisted hydrothermal synthesis of Ag/AgCl/WO{sub 3} photocatalyst and its photocatalytic activity under simulated solar light  

SciTech Connect

Simulated solar light responsive Ag/AgCl/WO{sub 3} composite photocatalyst was synthesized by microwave assisted hydrothermal process. The synthesized powders were characterized by X-Ray Diffraction (XRD) spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Diffuse Reflectance Spectroscopy (UV-Vis DRS), and BET surface area analyzer to investigate the crystal structure, morphology, chemical composition, optical properties and surface area of the composite photocatalyst. This photocatalyst exhibited higher photocatalytic activity for the degradation of rhodamine B under simulated solar light irradiation. Dye degradation efficiency of composite photocatalyst was found to be increased significantly as compared to that of the commercial WO{sub 3} nanopowder. Increase in photocatalytic activity of the photocatalyst was explained on the basis of surface plasmon resonance (SPR) effect caused by the silver nanoparticles present in the composite photocatalyst. Highlights: Black-Right-Pointing-Pointer Successful synthesis of Ag/AgCl/WO{sub 3} nanocomposite. Black-Right-Pointing-Pointer Photocatalytic experiment was performed under simulated solar light. Black-Right-Pointing-Pointer Nanocomposite photocatalyst was very active as compared to WO{sub 3} commercial powder. Black-Right-Pointing-Pointer SPR effect due to Ag nanoparticles enhanced the photocatalytic activity.

Adhikari, Rajesh; Gyawali, Gobinda [Research Center for Eco-Multifunctional Nano Materials, Sun Moon University (Korea, Republic of); Sekino, Tohru [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University (Japan); Wohn Lee, Soo, E-mail: swlee@sunmoon.ac.kr [Department of Environmental Engineering, Sun Moon University (Korea, Republic of)

2013-01-15

282

Synthesis of 3D hierarchical porous TiO2/InVO4 nanocomposites with enhanced visible-light photocatalytic properties  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) hierarchical porous TiO2/InVO4 nanocomposites were fabricated by loading TiO2 nanoparticles on the surface of porous InVO4 microspheres. X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis spectroscopy and photoluminescence spectroscopy (PL) were adopted to analyze the structure-property relationship of samples. The results show that the surface of as-prepared TiO2/InVO4 nanocomposites are composed of uniformly interconnected bi-phase nanocrystals, forming a close interface between these two components, which is favorable for the highly efficient interparticle electron transfer to achieve enhanced photocatalytic properties. However, the adsorption ability is decreased due to the loading of TiO2 nanoparticles on the surface of InVO4. Therefore, under the joint action of these factors, the TiO2/InVO4 nanocomposites achieve the best photocatalytic activity when the mole ratio of In:Ti reaches 4:1, and the visible-light photocatalytic activity is about as 3.3 times high as that of pure InVO4 without modification.

Shen, Jianchao; Yang, Hui; Feng, Yu; Cai, Qifeng; Shen, Qianhong

2014-06-01

283

Photocatalytic degradation of acetaminophen in modified TiO2 under visible irradiation.  

PubMed

This study investigated the photocatalytic degradation of acetaminophen (ACT) in synthetic titanium dioxide (TiO2) solution under a visible light (? >440 nm). The TiO2 photocatalyst used in this study was synthesized via sol-gel method and doped with potassium aluminum sulfate (KAl(SO4)2) and sodium aluminate (NaAlO2). The influence of some parameters on the degradation of acetaminophen was examined, such as initial pH, photocatalyst dosage, and initial ACT concentration. The optimal operational conditions were also determined. Results showed that synthetic TiO2 catalysts presented mainly as anatase phase and no rutile phase was observed. The results of photocatalytic degradation showed that LED alone degraded negligible amount of ACT but with the presence of TiO2/KAl(SO4)2, 95% removal of 0.10-mM acetaminophen in 540-min irradiation time was achieved. The synthetic TiO2/KAl(SO4)2 presented better photocatalytic degradation of acetaminophen than commercially available Degussa P-25. The weak crystallinity of synthesized TiO2/NaAlO2 photocatalyst showed low photocatalytic degradation than TiO2/KAl(SO4)2. The optimal operational conditions were obtained in pH 6.9 with a dose of 1.0 g/L TiO2/KAl(SO4)2 at 30 °C. Kinetic study illustrated that photocatalytic degradation of acetaminophen fits well in the pseudo-first order model. Competitive reactions from intermediates affected the degradation rate of ACT, and were more obvious as the initial ACT concentration increased. PMID:23888349

Dalida, Maria Lourdes P; Amer, Kristine Marfe S; Su, Chia-Chi; Lu, Ming-Chun

2014-01-01

284

A novel approach for the synthesis of visible-light-active nanocrystalline N-doped TiO2 photocatalytic hydrosol  

NASA Astrophysics Data System (ADS)

A visible-light-active nitrogen doped nanocrystalline titanium dioxide (N-TiO2) hydrosol was prepared by precipitation-peptization method and following with hydrothermal crystallization at 110 °C holding for 6 h. XPS results show that nitrogen ions have been doped into the TiO2 lattice successfully and the UV-Vis absorption spectra indicate that the light absorption edge of the N-doped TiO2 has been red-shifted into visible light region. The photocatalytic performance of the N-doped TiO2 thin film prepared from the synthesized hydrosol was evaluated by photodegrading the gaseous formaldehyde (HCHO) under visible light irradiation. The photodegradation ratio of HCHO reached up to 90% within 24 h and the degradation ratio was stable for ten degradation cycles, indicating the prepared hydrosol has good reusable performance in photodegrading gaseous pollutants.

Liu, Wen-Xiu; Jiang, Peng; Shao, Wei-Na; Zhang, Jun; Cao, Wen-Bin

2014-07-01

285

Synthesis of TiO2(110) ultra-thin films on W(100) and their reactions with H2O  

NASA Astrophysics Data System (ADS)

We present a study of the growth and reactivity of ultra-thin films of TiO2 grown on W(100). Three approaches to film growth are investigated, each resulting in films that show order in low-energy diffraction (LEED) and a low level of non-stoichiometry in X-ray photoelectron spectroscopy (XPS). H2O is used as a probe of the reactivity of the films, with changes in the Ti 2p and O 1s core levels being monitored by XPS. Evidence for the dissociation of H2O on the TiO2(110) ultra-thin film surface is adduced. These results are discussed with reference to related studies on native TiO2(110).

Matharu, J.; Cabailh, G.; Thornton, G.

2013-10-01

286

CCMR: Synthesis of Nanosized Titanium-Chromium nitride Powders by Ammonolysis of Co-precipitated TiO2/Cr2O3 Precursors  

NSDL National Science Digital Library

Nanocrystalline bimetallic metal nitride, Ti0.5Cr0.5N was synthesized by ammonolysis at 800°C for 14 hours of the nanozide TiO2/Cr2O3 precursor powder. TiO2/Cr2O3 nanopowder resulting from the coprecipitation method. The precursor and the resulting nitrides were characterized by X-Ray diffraction analysis and scanning electron microscope (SEM). The corrosion stability was analyzed by the thermal gravimetric analysis (TGA). The results indicated that the precursor solution contains TiO2 and K2CrO7. The final product is TiN and CrN with an average particle size of 30nm.

Hernã¡ndez Rivera, Mayra

2010-08-15

287

A bio-inspired inner-motile photocatalyst film: a magnetically actuated artificial cilia photocatalyst  

NASA Astrophysics Data System (ADS)

A new type of inner-motile photocatalyst film is explored to enhance photocatalytic performance using magnetically actuated artificial cilia. The inner-motile photocatalyst film is capable of generating flow and mixing on the microscale because it produces a motion similar to that of natural cilia when it is subjected to a rotational magnetic field. Compared with traditional photocatalyst films, the inner-motile photocatalyst film exhibits the unique ability of microfluidic manipulation. It uses an impactful and self-contained design to accelerate interior mass transfer and desorption of degradation species. Moreover, the special cilia-like structures increase the surface area and light absorption. Consequently, the photocatalytic activity of the inner-motile photocatalyst film is dramatically improved to approximately 3.0 times that of the traditional planar film. The inner-motile photocatalyst film also exhibits high photocatalytic durability and can be reused several times with ease. Furthermore, this feasible yet versatile platform can be extended to other photocatalyst systems, such as TiO2, P25, ZnO, and Co3O4 systems, to improve their photocatalytic performance.A new type of inner-motile photocatalyst film is explored to enhance photocatalytic performance using magnetically actuated artificial cilia. The inner-motile photocatalyst film is capable of generating flow and mixing on the microscale because it produces a motion similar to that of natural cilia when it is subjected to a rotational magnetic field. Compared with traditional photocatalyst films, the inner-motile photocatalyst film exhibits the unique ability of microfluidic manipulation. It uses an impactful and self-contained design to accelerate interior mass transfer and desorption of degradation species. Moreover, the special cilia-like structures increase the surface area and light absorption. Consequently, the photocatalytic activity of the inner-motile photocatalyst film is dramatically improved to approximately 3.0 times that of the traditional planar film. The inner-motile photocatalyst film also exhibits high photocatalytic durability and can be reused several times with ease. Furthermore, this feasible yet versatile platform can be extended to other photocatalyst systems, such as TiO2, P25, ZnO, and Co3O4 systems, to improve their photocatalytic performance. Electronic supplementary information (ESI) available: Additional data including details of the fabrication scheme, TEM images of TiO2 deposited on G-COOH, optical microscopy images and mechanical properties of the artificial cilia, details of the mixing performance of actuated cilia, schematic drawing of the experimental setup for the photocatalytic test, photocatalytic kinetics curves, and the efficiency and generality of the new inner-motile photocatalyst film. See DOI: 10.1039/c4nr00644e

Zhang, Dunpu; Wang, Wei; Peng, Fengping; Kou, Jiahui; Ni, Yaru; Lu, Chunhua; Xu, Zhongzi

2014-04-01

288

Electron transfers in a TiO2-containing MOR zeolite: synthesis of the nanoassemblies and application using a probe chromophore molecule.  

PubMed

New assemblies constituted by a microporous matrix of mordenite (MOR) zeolite on which TiO2 nanoclusters are deposited were synthesized using ionic oxalate complexes and TiCl3 titanium precursors. The samples were used to investigate the transfer of electrons produced by spontaneous or photo-induced ionization of a guest molecule (t-stilbene, t-St) occluded in the porous volume towards the conduction band of a conductive material placed nearby, in the pores or at least close to their entrance. The reaction mechanisms were compared in these Ti-rich solids and in a Ti-free mordenite sample. The characterization by XRD, N2 physisorption, TEM, XPS and DRIFT spectroscopy of the supramolecular TiO2/MOR systems before t-St adsorption showed the preservation of the crystalline structure after Ti addition and thermal activation treatments. They also revealed that titanium is mainly located at the external surface of the zeolite grains, in the form of highly dispersed and/or aggregated anatase. After incorporation of the guest molecule in the new assemblies, diffuse reflectance UV-visible and EPR spectroscopies indicate that the electron transfer processes are similar with and without TiO2 but strongly stabilized t-St?(+) radicals are detected in the TiO2-MOR samples whereas such species were never detected earlier in TiO2-free mordenite using these techniques. The stabilization process is found to be more efficient in the sample prepared with TiCl3 as the precursor than with titanium oxalates. It is proposed that the proximity of TiO2 with the formed t-St?(+) radicals provokes the stabilization of the radical through capture of the ejected electron by the semi-conductor and that confinement effects can also play a role. PMID:24866869

Legrand, A; Moissette, A; Hureau, M; Casale, S; Massiani, P; Vezin, H; Mamede, A S; Batonneau-Gener, I

2014-06-11

289

Photocatalytic Destruction of an Organic Dye Using TiO2 and Solar Energy.  

ERIC Educational Resources Information Center

Describes a general chemistry experiment that is carried out in sunlight to illustrate the ability of TiO2 to act as a photocatalyst by mineralizing an organic dye into carbon dioxide. Details about the construction of the reactor system used to perform this experiment are included. (DDR)

Giglio, Kimberly D.; And Others

1995-01-01

290

Plasmon-induced photoelectrochemistry at metal nanoparticles supported on nanoporous TiO2.  

PubMed

Nanoporous TiO(2) films loaded with gold and silver nanoparticles exhibit negative potential changes and anodic currents in response to visible light irradiation, so that the films would potentially be applicable to inexpensive photovoltaic cells, photocatalysts and simple plasmon sensors. PMID:15306895

Tian, Yang; Tatsuma, Tetsu

2004-08-21

291

Designed synthesis of SiO2/TiO2 core/shell structure as light scattering material for highly efficient dye-sensitized solar cells.  

PubMed

SiO2/TiO2 core/shell nanoparticles (STCS-NPs) with diameters of 110, 240, and 530 nm were fabricated to investigate the influence of the size and refractive index of light-scattering particles on light-scattering properties. The optical properties of STCS-NPs were evaluated and compared with SiO2-NPs and TiO2-NPs. The structure of STCS-NPs, consisting of a low refractive index core and high refractive index shell, provides efficient light scattering. The optimized anode film with STCS-NPs had ca. 20% improved power conversion efficiency (PCE). PMID:23635382

Son, Suim; Hwang, Sun Hye; Kim, Chanhoi; Yun, Ju Young; Jang, Jyongsik

2013-06-12

292

Synthesis, magnetic and microwave absorbing properties of core-shell structured MnFe 2O 4\\/TiO 2 nanocomposites  

Microsoft Academic Search

The core-shell MnFe2O4–TiO2 nano-composites were prepared by hydrolysis of titanium butoxide precursor in the presence of MnFe2O4 nanoparticles that were synthesized via the pyrolysis of polyacrylate salt precursor prepared by in situ polymerization of the metal salts and acrylate acid. The magnetic properties of the MnFe2O4 and MnFe2O4–TiO2 composites measured at the maximum magnetic field of 10kOe and room temperature

Hong-Mei Xiao; Xian-Ming Liu; Shao-Yun Fu

2006-01-01

293

Enhance the photocatalytic activity for the degradation of organic contaminants in water by incorporating TiO 2 with zero-valent iron  

Microsoft Academic Search

Titanium dioxide (TiO2) has become the most popular photocatalyst in treating persistent organic pollutants. The main disadvantage of TiO2 is the diminishing photocatalytic activity over time due to the electron–hole pair recombination. Many studies have aimed to prolong the photocatalytic life of TiO2. Among them, incorporation of zero-valent iron (ZVI) is one of the approaches. In this study, a novel

Wen-Pin Hsieh; Jill Ruhsing Pan; Chihping Huang; Yu-Chun Su; Ya-Ju Juang

2010-01-01

294

Samarium-doped mesoporous TiO2 nanoparticles with improved photocatalytic performance for elimination of gaseous organic pollutants  

NASA Astrophysics Data System (ADS)

Mesoporous TiO2 doped with different amounts of Sm were prepared via a sol-gel route with Pluronic P123 as template. The materials were characterized by X-ray diffraction, transmission electron microscopy, and N2 sorption experiments, etc. The photocatalytic activity of the mesoporous TiO2 was tested in elimination of gaseous methanol and acetone. The Sm doped mesoporous TiO2 have higher activity than those of the commercial photocatalyst (Degussa, P25) and Sm doped TiO2 counterparts without mesopore structure under ultraviolet light irradiation. A possible mechanism was proposed to account for the high photocatalytic activity of the Sm doped mesoporous TiO2. The superior activity of the Sm doped mesoporous TiO2 may be attributed to the synergic effect of the high surface area, mesopore structure and doped Sm species.

Tang, Jianting; Chen, Xiaomiao; Liu, Yu; Gong, Wei; Peng, Zhenshan; Cai, Tiejun; Luo, Lianjing; Deng, Qian

2013-01-01

295

A high-stability silica–clay composite: Synthesis, characterization and combination with TiO 2 as a novel photocatalyst for Azo dye  

Microsoft Academic Search

A novel micro-mesopores composite material has successfully been synthesized at basic hydrothermal conditions using natural mineral montmorillonite (MMT) and tetraethoxysilane (TEOS). Two surfactants, cetyltrimethyl ammonium bromide (CTAB) and polyethylene glycol (PEG), have been employed in order to shape the pores in the composite. The resultant silica–clay has large surface area (472m2\\/g) and high hydrothermal stability, which makes it a potentially

Fangfei Li; Yinshan Jiang; Maosheng Xia; Mengmeng Sun; Bing Xue; Xuehong Ren

2009-01-01

296

Low-temperature hydrothermal synthesis of N-doped TiO2 from small-molecule amine systems and their photocatalytic activity.  

PubMed

Nitrogen-doped TiO2 nanopowders have been successfully synthesized by a one-step hydrothennal route under soft-chemistry conditions (150 degrees, 8 h) without high-temperature calcination using seven different types of nitrogen dopants: methylamine, ethylamine, diethylamine, ethylenediamine, triethylamine, triethanolamine and ammonia. X-ray diffraction, transmission electron microscopy, ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption isothenns and Fourier transform infrared spectroscopy were used to analyse the as-synthesized TiO2 powders. The results indicated that nitrogen was doped effectively and the structure and morphology of the titania samples were strongly influenced by the nitrogen sources. Among the investigated nitrogen sources, the diethylamine system was clearly superior to the other small-molecule amine or ammonia systems due to the broad-spectrum response (between 400 and 700 nm) of the interstitial nitrogen-doped TiO2 nanopowders. The diethylamine N-doped TiO2 had the largest pore volume (0.39 ml x g(-1)) and showed a well-aligned anatase phase. The visible-light photocatalytic degradation of liquid X-3B used as a probe reaction demonstrated that the removal rate over the diethylamine material reached 99.7% in 90 min. PMID:24617053

Bao, Nan; Niu, Jun-Jian; Li, Yuan; Wu, Guo-Lin; Yu, Xiao-Hong

2013-01-01

297

Viable method for the synthesis of biphasic TiO2 nanocrystals with tunable phase composition and enabled visible-light photocatalytic performance.  

PubMed

Here we demonstrate a facile method to synthesize high-surface-area TiO(2) nanoparticles in aqueous-ethanol system with tunable brookite/rutile and brookite/anatase ratio possessing high surface area that exhibits enhanced photoactivity. Titanium tetrachloride (TiCl(4)) is used as the metal precursor of choice and the tuning of phase compositions are achieved by varying the water:ethanol ratio, used as mixed solvent system. The synthesized samples were characterized in detail using X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), BET nitrogen sorption measurements, and UV-vis diffuse reflectance spectroscopy (UV-DRS). The photocatalytic activity of biphasic TiO(2) nanocrystals was evaluated by following the degradation kinetics of rhodamine-B dye in aqueous solution and under visible light. Mixed-phase TiO(2) nanostructures composing 83% brookite and 17% of rutile exhibited superior photoactivity when compared to Degussa P25 and phase-pure anatase nanocrystals. The exceptional photocatalytic activity of the synthesized nanostructures can be elucidated on the account of their large surface area and biphasic composition. On the basis of the detailed investigation reported herein, we conclude that tuning the ethanol volume in the mixed-solvent reaction system holds the key to tailor and control the final TiO(2) phase obtained. PMID:22339883

Boppella, Ramireddy; Basak, Pratyay; Manorama, Sunkara V

2012-03-01

298

Solar photocatalytic activity of TiO2 modified with WO3 on the degradation of an organophosphorus pesticide.  

PubMed

In this study, the solar photocatalytic activity (SPA) of WO3/TiO2 photocatalysts synthesized by the sol-gel method with two different percentages of WO3 (2 and 5%wt) was evaluated using malathion as a model contaminant. For comparative purpose bare TiO2 was also prepared by sol-gel process. The powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, diffuse reflectance UV-vis spectroscopy (DRUV-vis), specific surface area by the BET method (SSABET), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and scanning transmission electron microscopy with a high annular angle dark field detector (STEM-HAADF). The XRD, Raman, HRTEM and STEM-HAADF analyses indicated that WO3 was present as a monoclinic crystalline phase with nanometric cluster sizes (1.1 ± 0.1 nm for 2% WO3/TiO2 and 1.35 ± 0.3 nm for 5% WO3/TiO2) and uniformly dispersed on the surface of TiO2. The particle size of the materials was 19.4 ± 3.3 nm and 25.6 ± 3 nm for 2% and 5% WO3/TiO2, respectively. The SPA was evaluated on the degradation of commercial malathion pesticide using natural solar light. The 2% WO3/TiO2 photocatalyst exhibited the best photocatalytic activity achieving 76% of total organic carbon (TOC) abatement after 300 min compared to the 5% WO3/TiO2 and bare TiO2 photocatalysts, which achieved 28 and 47% mineralization, respectively. Finally, experiments were performed to assess 2% WO3/TiO2 catalyst activity on repeated uses; after several successive cycles its photocatalytic activity was retained showing long-term stability. PMID:23993423

Ramos-Delgado, N A; Gracia-Pinilla, M A; Maya-Treviño, L; Hinojosa-Reyes, L; Guzman-Mar, J L; Hernández-Ramírez, A

2013-12-15

299

Synthesis of Nanostructured and Nanoporous TiO2-AgO Mixed Oxide Derived from a Particulate Sol-Gel Route: Physical and Sensing Characteristics  

NASA Astrophysics Data System (ADS)

Nanocrystalline TiO2-AgO thin films and powders were prepared by an aqueous particulate sol-gel route at the low temperature of 573 K (300 °C). Titanium tetraisopropoxide and silver nitrate were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the phase composition of the mixed oxide depends upon the annealing temperature, being a mixture of TiO2 and AgO in the range 573 K to 773 K (300 °C to 500 °C) and a mixture of TiO2, AgO, and Ag2O at 973 K (700 °C). Furthermore, one of the smallest crystallite sizes was obtained for TiO2-AgO mixed oxide, being 4 nm at 773 K (500 °C). Field emission-scanning electron microscopic (FE-SEM) and atomic force microscopic (AFM) images revealed that the deposited thin films had nanostructured and nanoporous morphology with columnar topography. Thin films produced under optimized conditions showed excellent microstructural properties for gas sensing applications. They exhibited a remarkable response toward low concentrations of CO gas ( i.e., 25 ppm) at low operating temperature of 473 K (200 °C), resulting in an increase of the thermal stability of sensing films as well as a decrease in their power consumption. Furthermore, TiO2-AgO sensors follow the power law for the detection of CO gas.

Mohammadi, M. R.; Fray, D. J.

2011-08-01

300

Laser deposition of TiO2 for urethral catheter  

NASA Astrophysics Data System (ADS)

Catheters and medicals tubes are widely used to introduce pharmaceuticals and nutrients into arteries and veins, and to drain fluids or urine from urethra or the digestive organs. It is well known that illuminated TiO2 photocatalysts can decompose most noxious or toxic organic compounds. We studied the properties of titanium dioxide layers created by pulsed laser deposition from pure titanium and titanium dioxide targets with the goal to develop urethral catheter using TiO2 coated plastic tube. To reach crystalline structure at low substrate temperatures the radio-frequency discharge between the target and the substrate was implemented. The crystalline structure of layers was determined by X-ray diffraction and Fourier Transform Infrared Spectroscopy. Morphology was studied by atomic force microscopy (AFM). Using RF discharge, mixture of anatase and rutile was found at substrate temperature of 90°C (which was reached only by RF discharge).

Jelínek, Miroslav; Remsa, Jan; Zezulová, Markéta

2010-10-01

301

Preparation and characterization of tungsten-loaded titanium dioxide photocatalyst for enhanced dye degradation  

Microsoft Academic Search

Tungsten-loaded TiO2 photocatalyst has been successfully prepared and characterized. TEM analysis showed that the photocatalysts were nanosize with the tungsten species forming layers of coverage on the surface of TiO2, but not in clustered form. This was confirmed by XRD and FT-Raman analyses where tungsten species were well dispersed at lower loading (<6.5mol%), but were in crystalline WO3 at higher

Saepurahman; M. A. Abdullah; F. K. Chong

2010-01-01

302

New Paradigms for Active Site Engineering in Titanium Dioxide Photocatalysts  

NASA Astrophysics Data System (ADS)

The common trends in the synthesis of new TiO2 photocatalysts are based on the premise that increasing the area of high index facets results in higher photocatalytic activity. Nevertheless, there exist a number of catalysts, that, due to their peculiar morphology which does not mirror the crystal symmetry, possess sites or properties which fall outside of the realm of this general paradigm. A new universe of possibilities becomes available by considering structures which have been deposited under conditions very far from equilibrium (i.e. plasmas), or which have received a post-synthesis process that alters the energetics or geometries of the sites. A new framework for understanding these materials and tools to categorize the types of sites they present is not yet in place. In this Thesis we consider three types of systems and with each one introduce a new concept in the synthesis of materials that could open research directions that transcend and complete the limitations of the single-crystal framework. We introduce the concept of parent morphologies for TiO2 nanorods that are produced by collapsing a nanotube structure. We analyze in detail the properties of acetaldehyde adsorption at environmentally relevant pressures setting the stage for practical applications, and use HRTEM to reveal the orientation of the crystallite within the rod. We show that a unique structure results from this procedure yielding (100) rods. We discuss the use of parent structures with different crystal orientations as a viable route to produce highly energetic metastable configurations. Next, we discuss the interaction between crystal domains in TiO2 thin films. We introduce the use of X-ray goniometry to analyze the degree of crystallite orientation in films deposited with magnetron sputtering, constituting the first analysis of crystallite orientation in TiO2 films for photocatalysis. We find the degree of orientation to be an excellent predictor of reactivity. We investigate organic-semiconductor active sites with the third system, TiO2 surfaces functionalized with salicylate derivatives. We analyze the adsorption of CO2 and track the electron dynamics using EPR. We demonstrate that the adsorption of CO2 creates a surface state and postulate its importance in the charge transfer to CO2.

Finkelstein Shapiro, Daniel

303

Surface modification of nanometer size TiO 2 with salicylic acid for photocatalytic degradation of 4-nitrophenol  

Microsoft Academic Search

The efficiency of photocatalytic reactions was limited by the wide band-gap of TiO2 and the high degree of electron–hole recombination inherent in photocatalytic process, as well as by the limited adsorption capability of photocatalysts. In order to increase the overall efficiency, the surface of nanometer size TiO2 was simply and fast modified by chemical adsorption in saturated solution of salicylic

Li Shun-Xing; Zheng Feng-Ying; Cai Wen-Lian; Han Ai-Qin; Xie Yu-Kun

2006-01-01

304

Synthesis of dandelion-like TiO2 microspheres as anode materials for lithium ion batteries with enhanced rate capacity and cyclic performances  

NASA Astrophysics Data System (ADS)

Dandelion-like TiO2 microspheres consisting of numerous rutile single-crystalline nanorods were synthesized for the first time by a hydrothermal method. Their crystal structure, morphology and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and galvanostatic charge and discharge tests. The results show that the synthesized TiO2 microspheres exhibit good rate and cycle performances as anode materials of lithium ion batteries. It can be found that the dandelion-like structure provides a larger specific surface area and the single-crystalline nanorod provides a stable structure and fast pathways for electron and lithium ion transport, which contribute to the rate and cycle performances of the battery.

Yi, Jin; Liu, Yan-lin; Wang, Yuan; Li, Xiao-ping; Hu, She-jun; Li, Wei-shan

2012-11-01

305

Kinetic evaluation of combustion synthesis 3TiO 2 + 7Al ? 3TiAl + 2Al 2O 3 using non-isothermal DSC method  

Microsoft Academic Search

In situ process has been utilized to fabricate TiAl\\/Al2O3 composites, with thermodynamically compatible matrices and reinforcements being obtained, through displacement reaction between TiO2 and Al. However, the reaction involves intermediate steps between the starting and final materials, affecting the final phases and consequently the properties. In this paper, a model-free Kissinger-type method is applied to the non-isothermal differential scanning calorimetry

Run-hua Fan; Bing Liu; Jing-de Zhang; Jian-qiang Bi; Yan-sheng Yin

2005-01-01

306

Rapid Synthesis of Nanocrystalline TiO 2\\/SnO 2 Binary Oxides and Their Photoinduced Decomposition of Methyl Orange  

Microsoft Academic Search

A rapid and simple method, the so-called stearic acid method (SAM) was developed to prepare nanostructured TiO2\\/SnO2 binary oxides by combustion of stearic acid precursors. The preparative process was studied by Fourier transform infrared spectroscopy (FT-IR). During the preparative process, metal precursors were dispersed in stearic acid at molecular level. Microstructure of the samples was investigated by X-ray diffraction (XRD),

Juan Yang; Dan Li; Xin Wang; Xujie Yang; Lude Lu

2002-01-01

307

In situ controllable synthesis platinum nanocrystals on TiO2 by novel polyol-process combined with light induced photocatalysis oxidation.  

PubMed

Clean Pt/TiO(2) with highly dispersed controlled Pt nanocrystals was prepared by a novel approach combining an in situ polyol process with light induced photocatalysis oxidation. The interaction between TiO(2) and Pt under the assistance of surfactants hinders the agglomeration. The preference to form three dimensional clusters as the cluster size increases enables the formation of controlled Pt nanocrystals. PMID:22910980

Jiang, Zhi; Guo, Hongyan; Jiang, Zheng; Chen, Guosheng; Xia, Longfei; Shangguan, Wenfeng; Wu, Xiaojun

2012-10-01

308

(0 0 1) Facet-exposed anatase-phase TiO2 nanotube hybrid reduced graphene oxide composite: Synthesis, characterization and application in photocatalytic degradation  

NASA Astrophysics Data System (ADS)

Reduced graphene oxide (RGO) and TiO2 nanotube (TNT) with (0 0 1) facet-exposed anatase phase are covalently bonded together to synthesize TNT hybrid RGO (RGO-TNT) through consecutive process such as hydrothermal reaction, HCl washing, lyophilization and heat treatment with graphene oxide (GO), TiO2 powder and high concentration NaOH solution as the starting materials. The TNT with the diameter between 10 and 20 nm characterized by high resolution transmission electron microscopy (HRTEM) is in anatase phase proven by X-ray diffraction (XRD) and HRTEM. Additionally, the more active (0 0 1) facet is exposed identified by HRTEM. More significantly, TNT is bridged to RGO by CTi bond by the measurement of X-ray photoelectron spectroscopy (XPS). The photoluminescence (PL) spectra has testified that RGO in RGO-TNT can transfer and accept photoelectrons from TNT. The photocatalytic activity of RGO-TNT for degrading methylene blue (MB) is enhanced by contrast with pure TNT, and changeable by adjusting the mass ratios of GO to TiO2 powder. Simultaneously, lyophilization is benefit for maintaining the high active surface area of RGO-TNT, which is deeply in relationship with a higher photocatalytic activity. After four running cycles of photocatalytic degradation, RGO-TNT has shown a high stability and perfect reproducibility.

Zhou, Xun; Shi, Tiejun; Wu, Jing; Zhou, Haiou

2013-12-01

309

A maskless synthesis of TiO2-nanofiber-based hierarchical structures for solid-state dye-sensitized solar cells with improved performance  

PubMed Central

TiO2 hierarchical nanostructures with secondary growth have been successfully synthesized on electrospun nanofibers via surfactant-free hydrothermal route. The effect of hydrothermal reaction time on the secondary nanostructures has been studied. The synthesized nanostructures comprise electrospun nanofibers which are polycrystalline with anatase phase and have single crystalline, rutile TiO2 nanorod-like structures growing on them. These secondary nanostructures have a preferential growth direction [110]. UV–vis spectroscopy measurements point to better dye loading capability and incident photon to current conversion efficiency spectra show enhanced light harvesting of the synthesized hierarchical structures. Concomitantly, the dye molecules act as spacers between the conduction band electrons of TiO2 and holes in the hole transporting medium, i.e., spiro-OMeTAD and thus enhance open circuit voltage. The charge transport and recombination effects are characterized by electrochemical impedance spectroscopy measurements. As a result of improved light harvesting, dye loading, and reduced recombination losses, the hierarchical nanofibers yield 2.14% electrochemical conversion efficiency which is 50% higher than the efficiency obtained by plain nanofibers.

2014-01-01

310

Decomposition of formaldehyde by EPD photocatalyst filters in HVAC  

Microsoft Academic Search

This study used electrophoretic deposition (EPD) to apply titanium oxide (TiO2) coating on stainless steel filters and investigated the effectiveness of photocatalytic oxidation of formaldehyde by TiO2 under various conditions of heating ventilation air conditioning (HVAC). The results showed photocatalytic efficiency could reach 35.59% at 21°C and 36.39% at 26°C with 7 photocatalyst filters and 5 UVC lamps, the overall

Chien-Chih Chen; Ching-Song Jwo; Tun-Ping Teng

2011-01-01

311

Synthesis of visible light-activated TiO{sub 2} photocatalyst via surface organic modification  

SciTech Connect

A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to sol-gel-hydrothermal synthesized TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex that was confirmed by the FT-IR and XPS spectra. Due to the existence of surface complex, the absorption edge of as-prepared TDI-modified TiO{sub 2} nanomaterial extended well into visible region. Compared with unmodified TiO{sub 2} and Degussa P25, the TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation. - Graphical abstract: A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex. The TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation.

Jiang Dong [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China)], E-mail: jdred@sxicc.ac.cn; Xu Yao [Key Laboratory of Carbon Material, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)], E-mail: xuyao@sxicc.ac.cn; Hou Bo [Key Laboratory of Carbon Material, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Wu Dong [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Sun Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)], E-mail: yhsun@sxicc.ac.cn

2007-05-15

312

Rational Design and Synthesis of Freestanding Photoelectric Nanodevices as Highly Efficient Photocatalysts  

PubMed Central

Photocatalysts are of significant interest for solar energy harvesting and conversion into chemical energy. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here we report the rational design of a new generation of freestanding photoelectric nanodevices as highly efficient and stable photocatalysts by integrating a nanoscale photodiode with two redox catalysts in a single nanowire heterostructure. We show that a platinum-silicon-silver nanowire heterostructure can be synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. We further demonstrated that the Schottky diodes exhibited pronounced photovoltaic effect with nearly unity internal quantum efficiency, and that the integrated nanowire heterostructures could be used as highly efficient photocatalysts for a wide range of thermodynamically downhill and uphill reactions including photocatalytic degradation of organic dyes, reduction of metal ions and carbon dioxide using visible light. Our studies for the first time demonstrated the integration of multiple distinct functional components into a single nanostructure to form a standalone active nanosystem, and for the first time successfully realized a photoelectric nanodevice that is both highly efficient and highly stable throughout the entire solar spectrum. It thus opens a rational avenue to design and synthesize a new generation of photoelectric nanosystems with unprecedented efficiency and stability, and will impact broadly in areas including environmental remediation and solar fuel production.

Qu, Yongquan; Liao, Lei; Cheng, Rui; Wang, Yue; Lin, Yung-chen; Huang, Yu; Duan, Xiangfeng

2010-01-01

313

Chromium incorporation into TiO2 at high pressure  

NASA Astrophysics Data System (ADS)

Chromium incorporation into TiO2 up to 3 GPa at 1300 °C and 900 °C has been studied by XRD as well as TEM. A CaCl2 type TiO2 polymorph has been observed in the quenched samples from high pressure. Two different mechanisms of solubility occur in the recovered samples. Chromium replaces titanium on normal octahedral sites but it also occupies interstitial octahedral sites, especially in the samples recovered from higher pressures. Interstitial chromium is responsible for an orthorhombic distortion of the TiO2 rutile structure in the quenched samples and gives rise to a (1 1 0) twinned CaCl2-structured polymorph. This phase is very likely the result of temperature quench at high pressure. The formation of this phase is directly related to the chromium content of the TiO2 grains. Chromium solubility in TiO2 increases with increasing the synthesis pressure. TiO2 is able to accommodate up to 15.3 wt% Cr2O3 at 3 GPa and 1300 °C, compared to 5.7 wt% at atmospheric pressure at the same temperature.

Escudero, Alberto; Langenhorst, Falko

2012-06-01

314

Electrochromic devices based on surface-modified nanocrystalline TiO 2 thin-film electrodes  

Microsoft Academic Search

Nanocrystalline TiO2 thin film electrodes on conductive glass were modified with monolayers of different electrochromic compounds (mono-, di- and trimeric N,N?-dialkyl- or-diphenyl-4,4?-bipyridinium salts) equipped with TiO2 anchoring groups (An=benzoate, salicylate, phosphonate). The synthesis of these compounds is reported. Different approaches have been studied to increase the surface concentration ?CS of electrochemically active coloring centers (CS) on TiO2. The electrodes were

F. Campus; P. Bonhôte; M. Grätzel; S. Heinen; L. Walder

1999-01-01

315

Thermal evolution of structure and photocatalytic activity in polymer microsphere templated TiO2 microbowls  

NASA Astrophysics Data System (ADS)

Polystyrene cross-linked divinyl benzene (PS-co-DVB) microspheres were used as an organic template in order to synthesize photocatalytic TiO2 microspheres and microbowls. Photocatalytic activity of the microbowl surfaces were demonstrated both in the gas phase via photocatalytic NO(g) oxidation by O2(g) as well as in the liquid phase via Rhodamine B degradation. Thermal degradation mechanism of the polymer template and its direct influence on the TiO2 crystal structure, surface morphology, composition, specific surface area and the gas/liquid phase photocatalytic activity data were discussed in detail. With increasing calcination temperatures, spherical polymer template first undergoes a glass transition, covering the TiO2 film, followed by the complete decomposition of the organic template to yield TiO2 exposed microbowl structures. TiO2 microbowl systems calcined at 600 °C yielded the highest per-site basis photocatalytic activity. Crystallographic and electronic properties of the TiO2 microsphere surfaces as well as their surface area play a crucial role in their ultimate photocatalytic activity. It was demonstrated that the polymer microsphere templated TiO2 photocatalysts presented in the current work offer a promising and a versatile synthetic platform for photocatalytic DeNOx applications for air purification technologies.

Erdogan, Deniz Altunoz; Polat, Meryem; Garifullin, Ruslan; Guler, Mustafa O.; Ozensoy, Emrah

2014-07-01

316

Enhanced inactivation of bacteria with silver-modified mesoporous TiO 2 under weak ultraviolet irradiation  

Microsoft Academic Search

The efficient antibacterial activity of silver-modified mesoporous TiO2 materials with different silver contents were investigated under weak ultraviolet light (UVA) (200?W) irradiation using Escherichia coli (E. coli) as a model strain. The comparison with the antibacterial results of three silver-modified TiO2 photocatalysts indicated that sample TiO2–Ag2.0% with 2.0wt.% of Ag exhibited the highest antibacterial activity with 108–109CFU\\/mL E. coli being

Jizhen Ma; Zhigang Xiong; T. David Waite; Wun Jern Ng; X. S. Zhao

2011-01-01

317

Mechanochemical preparation of sulfur-doped nanosized TiO 2 and its photocatalytic activity under visible light  

Microsoft Academic Search

In order to make nanosized TiO2 photocatalyst responsive to visible light and effectively utilize solar energy, we have, for the first time, prepared S-doped\\u000a nanosized TiO2 by a mechanochemical method with hydrolysis of TiCl4. The as-prepared S-doped nanosized TiO2 possesses strong absorption for visible light of 400–650 nm and shows high photocatalytic activity for decomposition of methylene\\u000a blue under irradiation

Zhou Zhiqiang; Zhang Xianyou; Wu Ze; Dong Limin

2005-01-01

318

Current Progress on Persistent Fluorescence-Assisted Composite Photocatalysts  

NASA Astrophysics Data System (ADS)

Long afterglow phosphors-assisted novel photocatalysts appear to be a series of promising functional materials, which have high utilization efficiency of solar light in practical application of environmental purifications. In this review paper, the recent progress on fluorescence-assisted composite type photocatalysts includes TiO2-based and Ag3PO4-based fluorescence photocatalyst composites with full-time active photocatalytic properties is reviewed. This fundamental understanding shows that excellent visible light induced photocatalysts coupled with an appropriate amount of long afterglow phosphors could continuously degrade pollutants in air and solution not only under light irradiation, but also after turning off the lamp irradiation for several hours, indicating the possibility of a full-time-active highly efficient photocatalysts system. A promising strategy involving coupling of a highly efficient visible light responsive photocatalyst with an appropriate long afterglow phosphor might be established.

Li, Huihui; Yin, Shu; Wang, Yuhua; Sato, Tsugio

2013-12-01

319

Enhanced photocatalytic activity of TiO2 nanobarbed fibers treated with atmospheric pressure plasma using O2 gas  

NASA Astrophysics Data System (ADS)

TiO2 nanobarbed fibers (NBFs) were prepared by growing rutile TiO2 nanorods on anatase TiO2 nanofibers via electrospinning and hydrothermal reaction processes. There was a large increase in the photocatalytic activity of O2-plasma-treated (OP)-TiO2 NBFs relative to that of the TiO2 NBFs; this is due to the hydroxylation of the surface of the TiO2 NBFs by OP treatment. The repeatability of the photocatalytic activity of the OP-TiO2 NBFs was found to be high and the decolorization rate after ten cycles was 88.3% of the initial value. These results indicate that OP-TiO2 NBFs have great potential for use as a photocatalyst.

Lee, Hyun-Uk; Ahn, Kyun; Jeong, Se-Young; Cho, Chae-Ryong; Kim, Jong-Pil; Bae, Jong-Seong; Kim, Hyun-Gyu; Kwon, Se-Hun; Lee, Hyung Woo

2010-11-01

320

Sterilization effect of UV light on Bacillus spores using TiO(2) films depends on wavelength.  

PubMed

UV light and photocatalysts such as titanium dioxide (TiO(2)) and silver (Ag) are useful for disinfection of water and surfaces. However, the effect of UV wavelength on photocatalytic disinfection of spores is not well understood. Inactivation of Bacillus spores has been examined using different UV wavelengths and TiO(2) or TiO(2)/Ag composite materials. The level of UVA disinfection of Bacillus anthracis and Bacillus brevis vegetative cells increased with the presence of the TiO(2) and Ag photocatalysts, but had little effect on their spores. B. brevis spores were slightly more sensitive to UVB and UVC than the spores of B. atrophaeus. Photocatalytic sterilization against spores was strongest in UVC and UVB and weakest in UVA. The rate of inactivation of Bacillus spores was significantly increased by the presence of TiO(2), but was not markedly different from that induced by the presence of Ag. Therefore, TiO(2)/Ag plus UVA can be used for the sterilization of vegetative cells, while TiO(2) and UVC are effective against spores. PMID:22449993

Nhung, Le Thi Tuyet; Nagata, Hirofumi; Takahashi, Akira; Aihara, Mutsumi; Okamoto, Toshihiro; Shimohata, Takaaki; Mawatari, Kazuaki; Akutagawa, Masatake; Kinouchi, Yhosuke; Haraguchi, Masanobu

2012-01-01

321

Synthesis of a Highly Efficient BiOCl Single-Crystal Nanodisk Photocatalyst with Exposing {001} Facets.  

PubMed

BiOCl is known as a highly efficient photocatalyst for degradation of pollutants. However, effective methods for fabricating BiOCl nanomaterials with well-defined facets are still lacking. In this work, a facile synthetic method was developed for the fabrication of BiOCl nanodisks with exposed {001} facets. The central feature of this approach was the use of water as the hydrolysis agent and ethylene glycol as the crystal growth inhibitor agent to tune the growth of BiOCl nanomaterial. With this approach, the size and shape of BiOCl nanostructures could be effectively tuned through adjusting the volume ratio of ethylene glycol/H2O. In addition, the mechanism of the crystal growth in this fabrication process was elucidated. The as-prepared BiOCl nanodisks with exposed {001} facets exhibited an excellent photocatalytic activity towards Rhodamine B degradation under both ultraviolet and visible light irradiations. These findings shed light on the deep understanding of formation mechanisms of BiOCl nanodisks and provide an efficient and facile method for the synthesis of high active photocatalyst. PMID:24797177

Zhang, Xing; Wang, Xin-Bo; Wang, Li-Wei; Wang, Wei-Kang; Long, Lu Lu; Li, Wen-Wei; Yu, Han-Qing

2014-05-28

322

Enhancing selective decomposition of ibuprofen onto porous TiO2 nanoparticles  

NASA Astrophysics Data System (ADS)

Advanced oxidation technologies have gained tremendous attention for water treatment purposes after demonstration of insufficient efficiency of conventional systems for removal of many emerging chemicals of concern. Among AOTs, a TiO2-UV system is one of the most promising approaches due to its green properties and its effectiveness in generation of extremely oxidizing species such as hydroxyl radicals. However it has been demonstrated that non-selectivity of HRs in decomposition of organic compounds results in parallel decomposing of naturally abundant organic matter (NOM) along with toxic target contaminant, which significantly decreases the decomposition rate of target contaminants. Despite a great amount of researches conducted on TiO2 photocatalysts, limited success has been achieved in enhancing selectivity of TiO2 photocatalytic oxidation. In this study, a novel approach for suppressing the adverse effect of co-existing organics such as NOM has been proposed. Physical access of competing compounds was restrained through manipulation of the porous structure of TiO2 photocatalysts. An advanced templating method was employed to create a porous structure across TiO2 nanoparticles. In this study Ibuprofen as a target contaminant was decomposed in the presence of humic acid as competing NOM. Porous particles demonstrated significant improvement in selective decomposition of ibuprofen in the presence of humic acid as competing species. In the second phase of the study, a comprehensive study was conducted through changing the porous structure and size of co-existing organics in competing and non-competing conditions. The photocatalytic results, in correlation with material characterization demonstrated beneficial role of the controlled porous structure on adsorption followed by decomposition of organic species onto TiO2 photocatalysts.

Zakersalehi, Abolfazl

323

Synthesis and characterization of maleimide-functionalized polystyrene-SiO2/TiO2 hybrid nanocomposites by sol-gel process  

NASA Astrophysics Data System (ADS)

Maleimide-functionalized polystyrene (PSMA-SiO2/TiO2) hybrid nanocomposites were prepared by sol-gel reaction starting from tratraethoxysilane (TEOS) and titanium isopropoxide in the solution of polystyrene maleimide in 1,4-dioxane. The hybrid films were obtained by the hydrolysis and polycondensation of TEOS and titanium isopropoxide in maleimide-functionalized polystyrene solution followed by the Michael addition reaction. The transparency of polymer (PSMA-SiO2/TiO2) hybrid was prepared from polystyrene titanium isopropoxide using the ?-aminopropyltriethoxy silane as crosslinking agent by in situ sol-gel process via covalent bonding between the organic-inorganic hybrid nanocomposites. The maleimide-functionalized polystyrene was synthesized by Friedel-Crafts reaction from N-choloromethyl maleimide. The FTIR spectroscopy data conformed the occurrence of Michael addition reaction between the pendant maleimide moieties of the styrene and ?-aminopropyltriethoxysilane. The chemical structure and morphology of PSMA-SiO2/TiO2 hybrid nanocomposites were characterized by FTIR, nuclear magnetic resonance (NMR), 13 C NMR, SEM, XRD, and TEM analyses. The results also indicate that the inorganic particles are much smaller in the ternary systems than in the binary systems; the shape of the inorganic particles and compatibility for maleimide-functionalized polystrene and inorganic moieties are varied with the ratio of the inorganic moieties in the hybrids. Furthermore, TGA and DSC results indicate that the thermal stability of maleimide-functionalized polystyrene was enhanced through the incorporation of the inorganic moieties in the hybrid materials.

Ramesh, Sivalingam; Sivasamy, Arumugam; Kim, Joo-Hyung

2012-06-01

324

Synthesis and characterization of C-doped TiO2 thin films for visible-light-induced photocatalytic degradation of methyl orange  

NASA Astrophysics Data System (ADS)

C-TiO2 thin films were synthesized by a modified sol-gel route based on the self-assembly technique exploiting Tween80 (T80) as a pore directing agent and carbon source. The effect of calcination time on the photocatalytic activity of C-doped TiO2 catalyst was studied. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transforms infrared (FTIR), UV-vis diffuse reflectance spectroscopy, and photoluminescence spectra (PL). The XRD results showed that C-TiO2 sample calcined at 400 °C for various times exhibited anatase phase and no other crystal phase was identified. C-TiO2 exhibited a shift in an absorption edge of samples in the visible region than that of conventional or reference TiO2. The XPS results showed an existence of C in the TiO2 catalysts and C might be existed as COTi group. Moreover, the C-TiO2 thin film calcined at 400 °C for 30 min showed the lowest PL intensity due to a decrease in the recombination rate of photogenerated electrons and holes under UV light irradiation. Also the photocatalytic activity of synthesized catalyst was evaluated by decomposition of methyl orange (MO) under visible light irradiation. The results showed that the optimum preparations of C-TiO2 thin films were found to be under calcination temperature of 400, calcination time of 30 min, and with preparation 9 layers film.

Hassan, Mohamed Elfatih; Cong, Longchao; Liu, Guanglong; Zhu, Duanwei; Cai, Jianbo

2014-03-01

325

Synthesis and characterization of maleimide-functionalized polystyrene-SiO2/TiO2 hybrid nanocomposites by sol-gel process  

PubMed Central

Maleimide-functionalized polystyrene (PSMA-SiO2/TiO2) hybrid nanocomposites were prepared by sol–gel reaction starting from tratraethoxysilane (TEOS) and titanium isopropoxide in the solution of polystyrene maleimide in 1,4-dioxane. The hybrid films were obtained by the hydrolysis and polycondensation of TEOS and titanium isopropoxide in maleimide-functionalized polystyrene solution followed by the Michael addition reaction. The transparency of polymer (PSMA-SiO2/TiO2) hybrid was prepared from polystyrene titanium isopropoxide using the ?-aminopropyltriethoxy silane as crosslinking agent by in situ sol–gel process via covalent bonding between the organic–inorganic hybrid nanocomposites. The maleimide-functionalized polystyrene was synthesized by Friedel-Crafts reaction from N-choloromethyl maleimide. The FTIR spectroscopy data conformed the occurrence of Michael addition reaction between the pendant maleimide moieties of the styrene and ?-aminopropyltriethoxysilane. The chemical structure and morphology of PSMA-SiO2/TiO2 hybrid nanocomposites were characterized by FTIR, nuclear magnetic resonance (NMR), 13?C NMR, SEM, XRD, and TEM analyses. The results also indicate that the inorganic particles are much smaller in the ternary systems than in the binary systems; the shape of the inorganic particles and compatibility for maleimide-functionalized polystrene and inorganic moieties are varied with the ratio of the inorganic moieties in the hybrids. Furthermore, TGA and DSC results indicate that the thermal stability of maleimide-functionalized polystyrene was enhanced through the incorporation of the inorganic moieties in the hybrid materials.

2012-01-01

326

Synthesis of TiO2 hollow nanofibers by co-axial electrospinning and its superior lithium storage capability in full-cell assembly with olivine phosphate  

NASA Astrophysics Data System (ADS)

We report the formation and extraordinary Li-storage properties of TiO2 hollow nanofibers by co-axial electrospinning in both the half-cell and full-cell configurations. Li-insertion properties are first evaluated as anodes in the half-cell configuration (Li/TiO2 hollow nanofibers) and we found that reversible insertion of ~0.45 moles is feasible at a current density of 100 mA g-1. The half-cell displayed a good cyclability and retained 84% of its initial reversible capacity after 300 galvanostatic cycles. The full-cell is fabricated with a commercially available olivine phase LiFePO4 cathode under optimized mass loading. The LiFePO4/TiO2 hollow nanofiber cell delivered a reversible capacity of 103 mA h g-1 at a current density of 100 mA g-1 with an operating potential of ~1.4 V. Excellent cyclability is noted for the full-cell configuration, irrespective of the applied current densities, and it retained 88% of reversible capacity after 300 cycles in ambient conditions at a current density of 100 mA g-1.We report the formation and extraordinary Li-storage properties of TiO2 hollow nanofibers by co-axial electrospinning in both the half-cell and full-cell configurations. Li-insertion properties are first evaluated as anodes in the half-cell configuration (Li/TiO2 hollow nanofibers) and we found that reversible insertion of ~0.45 moles is feasible at a current density of 100 mA g-1. The half-cell displayed a good cyclability and retained 84% of its initial reversible capacity after 300 galvanostatic cycles. The full-cell is fabricated with a commercially available olivine phase LiFePO4 cathode under optimized mass loading. The LiFePO4/TiO2 hollow nanofiber cell delivered a reversible capacity of 103 mA h g-1 at a current density of 100 mA g-1 with an operating potential of ~1.4 V. Excellent cyclability is noted for the full-cell configuration, irrespective of the applied current densities, and it retained 88% of reversible capacity after 300 cycles in ambient conditions at a current density of 100 mA g-1. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01128c

Zhang, X.; Aravindan, V.; Kumar, P. Suresh; Liu, H.; Sundaramurthy, J.; Ramakrishna, S.; Madhavi, S.

2013-06-01

327

Synthesis of a SiO2/TiO2 hybrid boronate affinity monolithic column for specific capture of glycoproteins under neutral conditions.  

PubMed

A unique boronate-functionalized SiO2/TiO2 hybrid monolithic column was synthesized by a facile approach. Although a conventional boronic acid, 4-vinylphenylboronic acid, was used as the affinity ligand, the prepared monolithic column exhibited specific capacity to capture glycoproteins including antibodies in aqueous solution at neutral pH. With the incorporation of titania, the monolith was highly hydrophilic, and the procedure of affinity chromatography could be performed under aqueous organic-solvent-free conditions. PMID:24448390

Yang, Qin; Huang, Dihui; Zhou, Ping

2014-03-01

328

On the preparation of TiO2-sepiolite hybrid materials for the photocatalytic degradation of TCE: influence of TiO2 distribution in the mineralization.  

PubMed

Hybrid structured photocatalysts based on sepiolite, an adsorbent, and TiO2 were prepared by extrusion of ceramic dough and conformed as plates. The influence of the photocatalyst configuration was studied either by including TiO2 in the extrusion process (incorporated materials) or by coating the sepiolite plates with a TiO2 film (coated materials). The influence of the OH- surface concentration in the photocatalytic performance was studied by treating the ceramic plates at different temperatures. The samples were characterized by N2 adsorption-desorption, MIP, SEM, XRD, and UV-vis-NIR spectroscopy and tested in the photocatalytic degradation of trichloroethylene (TCE) as a target VOC molecule. Most of the catalysts presented high photoactivity, but considerable differences were observed when the CO2 selectivity was analyzed. The results demonstrate that there is a significant effect of the catalyst configuration on the selectivity of the process. An intimate contact between the sepiolite fibers and TiO2 particles for incorporated materials with a corncob-like structure favored the migration of nondesirable reaction products such as COCl2 and dichloroacetyl chloride (DCAC) to the adsorbent, reacting with OH- groups of the adsorbent and favoring the TCE mimeralization. PMID:18767641

Suárez, Silvia; Coronado, Juan M; Portela, Raquel; Martín, Juan Carlos; Yates, Malcolm; Avila, Pedro; Sánchez, Benigno

2008-08-15

329

Ionic Liquid Assisted Chemical Strategy to TiO2 Hollow Nanocube Assemblies with Surface-Fluorination and Nitridation and High Energy Crystal Facet Exposure for Enhanced Photocatalysis.  

PubMed

Realization of anionic nonmetal doping and high energy crystal facet exposure in TiO2 photocatalysts has been proven to be an effective approach for significantly improving their photocatalytic performance. A facile strategy of ionic liquid assisted etching chemistry by simply hydrothermally etching hollow TiO2 spheres composed of TiO2 nanoparticles with an ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate without any other additives is developed to create highly active anatase TiO2 nanocubes and TiO2 nanocube assemblies. With this one-pot ionic liquid assisted etching process, the surface-fluorination and nitridation and high energy {001} crystal facets exposure can be readily realized simultaneously. Compared with the benchmark materials of P25 and TiO2 nanostructures with other hierarchical architectures of hollow spheres, flaky spheres, and spindles synthesized by hydrothermally etching hollow TiO2 spheres with nonionic liquid of NH4F, the TiO2 nanocubes and TiO2 nanocube assemblies used as efficient photocatalysts show super high photocatalytic activity for degradation of methylene blue, methyl orange, and rhodamine B, due to their surface-fluorination and nitridation and high energy crystal facet exposure. The ionic liquid assisted etching chemistry is facile and robust and may be a general strategy for synthesizing other metal oxides with high energy crystal facets and surface doping for improving photocatalytic activity. PMID:24881462

Yu, Shengli; Liu, Baocang; Wang, Qin; Gao, Yuxi; Shi, Ying; Feng, Xue; An, Xiaoting; Liu, Lixia; Zhang, Jun

2014-07-01

330

Synthesis of TiO2 hollow nanofibers by co-axial electrospinning and its superior lithium storage capability in full-cell assembly with olivine phosphate.  

PubMed

We report the formation and extraordinary Li-storage properties of TiO2 hollow nanofibers by co-axial electrospinning in both the half-cell and full-cell configurations. Li-insertion properties are first evaluated as anodes in the half-cell configuration (Li/TiO2 hollow nanofibers) and we found that reversible insertion of ~0.45 moles is feasible at a current density of 100 mA g(-1). The half-cell displayed a good cyclability and retained 84% of its initial reversible capacity after 300 galvanostatic cycles. The full-cell is fabricated with a commercially available olivine phase LiFePO4 cathode under optimized mass loading. The LiFePO4/TiO2 hollow nanofiber cell delivered a reversible capacity of 103 mA h g(-1) at a current density of 100 mA g(-1) with an operating potential of ~1.4 V. Excellent cyclability is noted for the full-cell configuration, irrespective of the applied current densities, and it retained 88% of reversible capacity after 300 cycles in ambient conditions at a current density of 100 mA g(-1). PMID:23712615

Zhang, X; Aravindan, V; Kumar, P Suresh; Liu, H; Sundaramurthy, J; Ramakrishna, S; Madhavi, S

2013-07-01

331

The synthesis of mesoporous TiO2/SiO2/Fe2O3 hybrid particles containing micelle-induced macropores through an aerosol based process.  

PubMed

Mesoporous SiO(2)/TiO(2)/Fe(2)O(3) particles containing macropores of about 50 nm in diameter have been prepared by an aerosol process using cetyltrimethylammonium bromide (CTAB) as a templating agent. In contrast to the traditional templating effect of CTAB to form ordered mesoporous silicas, the morphology here is vastly different due to the presence of precursor iron salts. The particles have mesoporosity templated by CTAB but additionally have large voids leading to a combined macroporous and mesoporous structure. The morphology is explained through the formation of colloidal structures containing species such as CTA(+)X(-1)Fe(3+) colloids in the aerosol droplets, indicating of a salt bridging effect. This dual porosity has applied implications, as the macropores provide easy entry to the particle interior in potentially diffusion limited situations. Furthermore, the particles encapsulate Fe(2)O(3) and contain TiO(2) leading to the dual functional properties of magnetic response and photocatalytic activity. PMID:21500812

Li, Xiangcun; John, Vijay T; Zhan, Jingjing; He, Gaohong; He, Jibao; Spinu, Leonard

2011-05-17

332

Synthesis of Rutile-Type TiO2-SnO2 Solid Solution Nanoparticles by "Forced Co-Hydrolysis" under Hydrothermal Conditions  

NASA Astrophysics Data System (ADS)

Rutile-type TiO2-SnO2 solid solution nanoparticles were synthesized via "forced co-hydrolysis" of precursor solutions of TiCl4 and SnCl4 under hydrothermal conditions at 180~240 °C for 10 h. The lattice parameters a0 and c0 of rutile (Ti, Sn)O2 solid solutions changed according to the Vegard's Law. Rutile-type complete solid solutions in the system TiO2-SnO2 were directly formed in all composition ranges at 240 °C. The crystallite size of solid solutions containing more than 20 mol% SnO2 was maintained in the range of 10 to14 nm by the control of crystallite growth of rutile-type solid solutions owing to the presence of SnO2. The specific surface area of rutile-type solid solutions corresponded well to the change in crystallite size. The rutile-type solid solutions were metastable and decomposed into Ti and Sn rich phases via heat treatment at 1200 °C.

Hirano, Masanori; Kono, Takeshi

2011-10-01

333

Morphology and Structure of ZrO2/TiO2/SiO2 Nanocomposites Obtained by Synthesis on Carbon Microfiber  

NASA Astrophysics Data System (ADS)

We present novel nanomaterials based on Ti, Zr, and Si oxides, synthesized by the template method on a carbon fiber support. We have studied their structural and morphological properties. All the oxide fibers obtained have an extended surface formed from nanoparticle aggregates. We show that by selecting the components and varying their ratios, we can change the microorganization of the fiber surface and the structure of the composites. Due to microstress arising in the lattice, rearrangement of the structure of the composite is accompanied by a decrease in the fiber length and diameter. Increasing the amount of stabilizing additives of SiO2 in the titanium dioxide reduces the size of the nanoparticles and inhibits their growth, and makes it possible to stabilize the structure of the TiO2 nanoparticles in the anatase phase. At the same time, the presence of ZrO2 in the composition of the composites allows us to modify the particles at the reactive interface between the components and to obtain a fiber composite with a new crystal structure. For a low ZrO2 concentration (~10 wt.%), the structure of the oxide fibers is formed by TiO2 nanoparticles of the anatase modification, coated with an amorphous mixture of the oxides SiO2 and ZrO2. When the ZrO2 concentration is increased (~50.5 wt.%), we observe formation of nanoparticles with the structure of the orthorhombic phase of the compound ZrTiO4.

Zheleznov, V. V.; Sushkov, Yu. V.; Voit, E. I.; Kuryavyi, V. G.

2013-09-01

334

Linear correlation between inactivation of E. coli and OH radical concentration in TiO 2 photocatalytic disinfection  

Microsoft Academic Search

The biocidal action of the TiO2 photocatalyst has been now well recognized from massive experimental evidences, which demonstrates that the photocatalytic disinfection process could be technically feasible. However, the understanding on the photochemical mechanism of the biocidal action largely remains unclear. In particular, the identity of main acting photooxidants and their roles in the mechanism of killing microorganisms is under

Min Cho; Hyenmi Chung; Wonyong Choi; Jeyong Yoon

2004-01-01

335

Green synthesis of ?-aminophosphonate derivatives on a solid supported TiO2 -SiO2 catalyst and their anticancer activity.  

PubMed

Syntheses of a new series of biologically potent ?-aminophosphonates were accomplished by one-pot Kabachnik-Fields reaction using TiO2-SiO2 as solid supported catalyst under microwave irradiation conditions. The chemical structures of all the newly synthesized compounds were confirmed by analytical and spectral (IR, 1H, 13C, 31P NMR, and mass) data. Their anticancer nature was evaluated by screening the in vitro activity on two human cancer cell lines, HeLa and SK-BR-3. Compounds 4i and 4o showed the best activity on these cancer cells even though the majority of the compounds, and particularly 4l and 4p, have good cytotoxic activity against them. PMID:23959690

Chinthaparthi, Radha Rani; Bhatnagar, Ira; Gangireddy, Chandra Sekhar Reddy; Syama, Sundar Chereddy; Cirandur, Suresh Reddy

2013-09-01

336

Electronic Transport of TiO2 Nanowire Devices  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) is a wide band-gap semiconductor with applications in photovoltaics and sensing. Large scale integration of nanowires onto functional devices requires new techniques to manipulate them at the nanoscale. Currently engineering strategies for efficient assembly of nanoscale objects is very limited. Here we report the use of dielectrophoresis to assemble TiO2 nanowires onto devices. We use a sol-gel template based synthesis of TiO2 nanowires. The nanowires have typical diameters of 100-150 nm and range in length from 3-10 ?m. Devices for two probe and four probe measurements were fabricated by standard lithography. AC dielectrophoresis was used to assemble the TiO2 nanowires on devices. A dielectrophoretic translational force and a torque aligns the nanowires onto the devices. FIB assisted platinum deposition on the aligned TiO2 nanowires ensures ohmic contacts. Two probe room temperature I-V measurements show a resistivity of 0.22 ?-cm, which is comparable to 0.26 ?-cm for a thin film^1. Temperature dependent transport measurements are being pursued. We have demonstrated an efficient method of assembling and fabricating nanowire device structures. T. Miyata et. al. Thin Solid Films, 496, 136 (2006).

Dholakia, Geetha; Kuo, Steven; Allen, Emily

2008-03-01

337

Doping mode, band structure and photocatalytic mechanism of B-N-codoped TiO 2  

NASA Astrophysics Data System (ADS)

The photocatalyst B and N codoped TiO 2 (B-N-TiO 2) was prepared via the sol-gel method by using boric acid and ammonia as B and N precursors. The doping mode, band structure and photocatalytic mechanism of B-N-TiO 2 were investigated well and elucidated in detail. B-N-TiO 2 showed the narrowed band gap and thus extended the optical absorption due to interstitial N and [NOB] species in the TiO 2 crystal lattice. The coexistence of interstitial N and [NOB] species in the TiO 2 crystal lattice and surface NO x species allowed the more efficient utilization of visible light. Simultaneously, interstitial [NOB] and N species and surface B 2O 3 and NO x species facilitated the separation of photo generated electrons and holes and suppress their recombination effectively. Hence, B-N-TiO 2 showed a higher photocatalytic activity than pure TiO 2, N-doped TiO 2 (N-TiO 2) and B-doped TiO 2 (B-TiO 2) under both UV and visible light irradiation.

Yuan, Jixiang; Wang, Enjun; Chen, Yongmei; Yang, Wensheng; Yao, Jianghong; Cao, Yaan

2011-06-01

338

Photocatalytic process of simultaneous desulfurization and denitrification of flue gas by TiO2-polyacrylonitrile nanofibers.  

PubMed

TiO2 nanoparticles were successfully fabricated on electrospun polyacrylonitrile (PAN) nanofibers via the coupling of electrospinning and hydrothermal pathway. A straightforward photocatalysis oxidation process has been developed for simultaneous desulfurization and denitrification of flue gas using the TiO2-PAN photocatalyst. Also, the influences of some important operating parameters, such as titanium loading content of catalyst, flue gas humidity, flue gas flow, and inlet flue gas temperature on removal efficiencies of SO2 and NO were investigated. The results demonstrated that removal efficiencies of 99.3% for SO2 and 71.2% for NO were attained under the following optimal experiment conditions: titanium loading content, 6.78 At %; gas flow rate, 200 mL/min; flue gas humidity, 5%; inlet flue gas temperature, 40 °C. Furthermore, the presumed reaction mechanism of SO2 and NO removal using TiO2-PAN photocatalyst under UV light was proposed. PMID:24024677

Su, Chunyan; Ran, Xu; Hu, Jianglei; Shao, Changlu

2013-10-15

339

Enhanced photoactivity with nanocluster-grafted titanium dioxide photocatalysts.  

PubMed

Titanium dioxide (TiO2), as an excellent photocatalyst, has been intensively investigated and widely used in environmental purification. However, the wide band gap of TiO2 and rapid recombination of photogenerated charge carriers significantly limit its overall photocatalytic efficiency. Here, efficient visible-light-active photocatalysts were developed on the basis of TiO2 modified with two ubiquitous nanoclusters. In this photocatalytic system, amorphous Ti(IV) oxide nanoclusters were demonstrated to act as hole-trapping centers on the surface of TiO2 to efficiently oxidize organic contaminants, while amorphous Fe(III) or Cu(II) oxide nanoclusters mediate the reduction of oxygen molecules. Ti(IV) and Fe(III) nanoclusters-modified TiO2 exhibited the highest quantum efficiency (QE = 92.2%) and reaction rate (0.69 ?mol/h) for 2-propanol decomposition among previously reported photocatalysts, even under visible-light irradiation (420-530 nm). The desirable properties of efficient photocatalytic performance with high stability under visible light with safe and ubiquitous elements composition enable these catalysts feasible for large-scale practical applications. PMID:24883952

Liu, Min; Inde, Ryota; Nishikawa, Masami; Qiu, Xiaoqing; Atarashi, Daiki; Sakai, Etsuo; Nosaka, Yoshio; Hashimoto, Kazuhito; Miyauchi, Masahiro

2014-07-22

340

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts.  

PubMed

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol-gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate. PMID:24647187

Chen, C; Xie, Q; Hu, B Q; Zhao, X L

2014-01-01

341

Solar light induced and TiO 2 assisted degradation of textile dye reactive blue 4  

Microsoft Academic Search

Aqueous solutions of reactive blue 4 textile dye are totally mineralised when irradiated with TiO2 photocatalyst. A solution containing 4×10?4 M dye was completely degraded in 24 h irradiation time. The intensity of the solar light was measured using Lux meter. The results showed that the dye molecules were completely degraded to CO2, SO42?, NO3?, NH4+ and H2O under solar

B. Neppolian; H. C. Choi; S. Sakthivel; B. Arabindoo; V. Murugesan

2002-01-01

342

Photocatalytic Degradation of Diethyl Phthalate (DEP) in Water Using TiO 2  

Microsoft Academic Search

The degradation of diethyl phthalate (DEP) in aqueous solution by titanium dioxide (TiO2) photocatalysis has been investigated in our research. DEP was completely removed in the solution by 50-min irradiation.\\u000a Results show that DEP degradation rate was affected by initial DEP concentration, photocatalyst amount, light intensity, and\\u000a pH. Photocatalytic degradation intermediates were identified by gas chromatography-mass spectrometry intermediates were identified

Wen-Bin Huang; Chih-Yu Chen

2010-01-01

343

A quantitative evalution of the photocatalytic performance of TiO 2 slurries  

Microsoft Academic Search

This paper reports the results of a comparison between two TiO2 photocatalysts that differ for particle size and absorption\\/scattering optical properties. The catalyst with larger particles and lower surface area performed better in the degradation of phenol than the specimen with smaller particles and larger surface area. Following carefully designed experiments, it is possible to assess the relative role of

Claudio Minero; Davide Vione

2006-01-01

344

TiO2 promoted by two different non-noble metal cocatalysts for enhanced photocatalytic H2 evolution  

NASA Astrophysics Data System (ADS)

TiO2 photocatalysts modified by cobalt and nickel cocatalysts were prepared via polymerized complex method (PCM) and evaluated by photocatalytic hydrogen evolution. Hydrogen generation in 6 h for the TiO2 promoted by cobalt and nickel (0.1%Co + 0.2%Ni/TiO2) is about two times (2456 ?mol H2) compared to that of TiO2 promoted only by cobalt (1180 ?mol H2 for 0.1%Co/TiO2) or nickel (1127 ?mol H2 for 0.2%Ni/TiO2), and mechanically mixed TiO2 promoted by cobalt and TiO2 promoted by nickel (0.1%Co/TiO2:0.2%Ni/TiO2 = 1:1 (m/m), 1282 ?mol H2). The high photocatalytic H2 evolution activity over TiO2 promoted by cobalt and nickel is ascribed to enhanced photo response due to the presence of cobalt and nickel impurity level, and effective separation of photogenerated electrons and holes due to the synergistic effect of cobalt and nickel, which serve as active sites for H2 evolution reaction (HER) and oxidation reaction (OR) respectively. This study demonstrates a viable strategy to design more active photocatalysts for photocatalytic H2 evolution by substituting noble metals with more abundant elements using as HER and OR cocatalysts, respectively.

Lin, Jing-Dong; Yan, Shi; Huang, Qin-Dong; Fan, Mei-Ting; Yuan, You-Zhu; Tan, Timothy Thatt-Yang; Liao, Dai-Wei

2014-08-01

345

Synthesis of nanostructured magnetic photocatalyst by colloidal approach and spray-drying technique.  

PubMed

Nanostructured particles with a magnetic core and a photocatalytic shell are very interesting systems for their properties to be magnetically separable (and so reusable) in photocatalytic water depuration implant. Here, a robust, low time-consuming, easily scale up method to produce Fe(3)O(4)/SiO(2)/TiO(2) hierarchical nanostructures starting from commercial precursors (i.e. Fe(3)O(4), SiO(2)) by employing a colloidal approach (i.e. heterocoagulation) coupled with the spray-drying technique is presented. In particular, a self-assembled layer-by-layer methodology based on the coagulation of dissimilar colloidal particles was applied. First, a passive layer of silica (SiO(2), amorphous) was created on magnetite in order to avoid detrimental phenomena arising from the direct contact between magnetite and titania, then the deposition of titania onto silica-coated-magnetite was promoted. TiO(2), SiO(2) and Fe(3)O(4) nanosols were characterized in terms of zeta potential, optimized and a self-assembled layer-by-layer approach was followed in order to promote the heterocoagulation of silica onto magnetite surface and of titania onto silica coated magnetite. Once optimized the colloidal route, the mixture was then spray-dried to obtain a granulated powder with nano-scale reactivity, easier to handle and re-disperse in comparison to starting nanopowders with the same surface properties. The nanostructured particles have been characterized by different techniques such as SEM, TEM, XDR and their magnetic properties have been investigated. Moreover, preliminary photocatalytic texts have been performed. PMID:23010319

Costa, A L; Ballarin, B; Spegni, A; Casoli, F; Gardini, D

2012-12-15

346

Improvement of solar energy conversion with Nb-incorporated TiO2 hierarchical microspheres.  

PubMed

Niobium-modified TiO2 hierarchical spherical micrometer-size particles, which consist of many nanowires, are synthesized by solvothermal synthesis and studied as photoelectrodes for water photo-oxidation and dye-sensitized solar cell (DSSC) applications. Incorporation of Nb leads to a rutile-to-anatase TiO2 phase transition in the TiO2 hierarchical spheres (HSs), with the anatase percentage increasing from 0% for the pristine TiO2 HSs to 47.6% for the 1.82 at.% Nb-incorporated TiO2 sample. Incorporation of Nb leads to significant improvements in water photo-oxidation with the photocurrents reaching 70.5 ?A cm(-2) at 1.23 V versus the reversible hydrogen electrode, compared with 28.3 ?A cm(-2) for the pristine TiO2 sample. The photoconversion efficiency of Nb:TiO2 HS-based DSSCs reaches 6.09±0.15% at 0.25 at.% Nb, significantly higher than that for the pristine TiO2 HS cells (3.99±0.02%). In addition, the incident-photon-to-current efficiency spectra for DSSCs show that employing TiO2 and Nb:TiO2 HSs provides better light harvesting, especially of long-wavelength photons, than anatase TiO2 nanoparticle-based DSSCs. PMID:23512241

Hoang, Son; Ngo, Thong Q; Berglund, Sean P; Fullon, Raymond R; Ekerdt, John G; Mullins, C Buddie

2013-07-22

347

Plasma CVD treatment for titanium dioxides to approach the high performance of photocatalysts by visible light irradiation  

Microsoft Academic Search

TiO2 particles or casted thin films are treated with plasma CVD using the mixture of tantalum alkoxide and nitrogen gas or copper(II) acetylacetonate to improve the photocatalyst activities of TiO2 irradiated by visible light. The layer formed on the surface of the TiO2 after plasma treatment is composed of some species characterized by XPS measurement. The visible-light activity are shown

Kazuya Yamamoto; Yuki Matsuura; Ayako Nakamura; Tatsuhiko Sonoda; Shigenori Matsushima; Kenji Yamada

2010-01-01

348

TiO2-graphene nanocomposites. UV-assisted photocatalytic reduction of graphene oxide.  

PubMed

Graphene oxide suspended in ethanol undergoes reduction as it accepts electrons from UV-irradiated TiO(2) suspensions. The reduction is accompanied by changes in the absorption of the graphene oxide, as the color of the suspension shifts from brown to black. The direct interaction between TiO(2) particles and graphene sheets hinders the collapse of exfoliated sheets of graphene. Solid films cast on a borosilicate glass gap separated by gold-sputtered terminations show an order of magnitude decrease in lateral resistance following reduction with the TiO(2) photocatalyst. The photocatalytic methodology not only provides an on-demand UV-assisted reduction technique but also opens up new ways to obtain photoactive graphene-semiconductor composites. PMID:19206319

Williams, Graeme; Seger, Brian; Kamat, Prashant V

2008-07-01

349

Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts  

NASA Astrophysics Data System (ADS)

The photocatalytic activity and the promoting effect of titania (TiO2) by commercial activated carbon (CAC) for removing the pollutant in wastewater were investigated. The TiO2/CAC composite photocatalysts with various ratios of CAC to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of TiO2/CAC was investigated for the degradation of Sunset Yellow (SY) in aqueous solution using UV-A light. The TiO2/CAC is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The synergism between TiO2 and CAC may increase the catalytic activity. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable.

Rajamanickam, D.; Shanthi, M.

2014-07-01

350

Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts.  

PubMed

The photocatalytic activity and the promoting effect of titania (TiO2) by commercial activated carbon (CAC) for removing the pollutant in wastewater were investigated. The TiO2/CAC composite photocatalysts with various ratios of CAC to TiO2 were prepared by sol-gel method. The catalyst was characterized by X-ray diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive spectra (EDS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) surface area measurement methods. The photocatalytic activity of TiO2/CAC was investigated for the degradation of Sunset Yellow (SY) in aqueous solution using UV-A light. The TiO2/CAC is found to be more efficient than prepared TiO2 and TiO2-P25 at pH 7 for the mineralization of SY. The synergism between TiO2 and CAC may increase the catalytic activity. The effects of operational parameters such as the amount of photocatalyst, dye concentration and initial pH on photo mineralization of SY have been analyzed. The mineralization of SY has been confirmed by COD measurements. The catalyst is found to be reusable. PMID:24662758

Rajamanickam, D; Shanthi, M

2014-07-15

351

A bio-inspired inner-motile photocatalyst film: a magnetically actuated artificial cilia photocatalyst.  

PubMed

A new type of inner-motile photocatalyst film is explored to enhance photocatalytic performance using magnetically actuated artificial cilia. The inner-motile photocatalyst film is capable of generating flow and mixing on the microscale because it produces a motion similar to that of natural cilia when it is subjected to a rotational magnetic field. Compared with traditional photocatalyst films, the inner-motile photocatalyst film exhibits the unique ability of microfluidic manipulation. It uses an impactful and self-contained design to accelerate interior mass transfer and desorption of degradation species. Moreover, the special cilia-like structures increase the surface area and light absorption. Consequently, the photocatalytic activity of the inner-motile photocatalyst film is dramatically improved to approximately 3.0 times that of the traditional planar film. The inner-motile photocatalyst film also exhibits high photocatalytic durability and can be reused several times with ease. Furthermore, this feasible yet versatile platform can be extended to other photocatalyst systems, such as TiO2, P25, ZnO, and Co3O4 systems, to improve their photocatalytic performance. PMID:24728199

Zhang, Dunpu; Wang, Wei; Peng, Fengping; Kou, Jiahui; Ni, Yaru; Lu, Chunhua; Xu, Zhongzi

2014-05-21

352

Synthesis, characterization and excellent photocatalytic activity of Ag/AgBr/MoO3 composite photocatalyst  

NASA Astrophysics Data System (ADS)

A novel composite photocatalyst Ag/AgBr/MoO3 was successfully synthesized via a simple precipitation method at room temperature. The obtained products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy and UV-vis diffuse reflectance spectroscopy in detail. The photocatalytic activity of the samples was evaluated by monitoring the degradation of rhodamine B (RhB) solution under visible-light irradiation. The results showed that the photocatalytic activity of Ag/AgBr/MoO3 composite significantly enhanced and the degradation ratio of RhB reached 97.7 % after 15 min only. The excellent photocatalytic activity might be closely related to the large surface area, porosity structure and efficient separation of photoinduced electron-hole pairs. The possible reaction mechanism was also discussed.

Song, Jimei; Shi, Yali; Ren, Mingsong; Hu, Gang

2014-04-01

353

Synthesis and growth mechanism of thin-film TiO2 nanotube arrays on focused-ion-beam micropatterned 3D isolated regions of titanium on silicon.  

PubMed

In this paper, the fabrication and growth mechanism of net-shaped micropatterned self-organized thin-film TiO2 nanotube (TFTN) arrays on a silicon substrate are reported. Electrochemical anodization is used to grow the nanotubes from thin-film titanium sputtered on a silicon substrate with an average diameter of ~30 nm and a length of ~1.5 ?m using aqueous and organic-based types of electrolytes. The fabrication and growth mechanism of TFTN arrays from micropatterned three-dimensional isolated islands of sputtered titanium on a silicon substrate is demonstrated for the first time using focused-ion-beam (FIB) technique. This work demonstrates the use of the FIB technique as a simple, high-resolution, and maskless method for high-aspect-ratio etching for the creation of isolated islands and shows great promise toward the use of the proposed approach for the development of metal oxide nanostructured devices and their integration with micro- and nanosystems within silicon-based integrated-circuit devices. PMID:23957211

Hamedani, Hoda Amani; Lee, Simon W; Al-Sammarraie, Abdulkareem; Hesabi, Zohreh R; Bhatti, Asim; Alamgir, Faisal M; Garmestani, Hamid; Khaleel, Mohammad A

2013-09-25

354

SO2-4/TiO2-SiO2 Mixed Oxide Catalyst, I: Synthesis, Characterization, and Acidic Properties.  

PubMed

A series of sulfate-doped titania-silica mixed oxides have been prepared by immersing titania-silica gel in the required volume of sulfuric acid, followed by drying. The mixed oxide gel is obtained by hydrolyzing an equimolar mixture of tetraethylorthosilicate (TEOS) and tetrabutylorthotitanate (TBOT) at pH 3. The materials, after calcining at 723 K for 4 h, are characterized by XRD, FT-IR, the BET method, and surface acid strength by the Hammett indicator method. The catalytic activity tests are carried in a fixed bed catalytic reactor (i.d. = 10 mm) for alcohol conversion, whereas cumene cracking/dehydrogenation reactions are carried out in a micropulse reactor. XRD results shows that the titania-silica mixture is amorphous and the crystallization starts with sulfation. The surface of the mixed oxide contains both bridged and normal hydroxyl groups, as observed from FT-IR data. The surface area of the material is not much altered by sulfation and lies within 50 m2/g. The acid strength of 4 wt% SO2-4/TiO2-SiO2 is found to be stronger than that of 100% concentrated H2SO4. In the case of 2-propanol conversion, low acetone selectivity indicates the presence of weak basic sites, whereas methanol conversion over all solids shows that dehydration follows a parallel and consecutive pathway. A good correlation is found between the cumene cracking and the acidity of the catalysts. Copyright 1999 Academic Press. PMID:10395770

Parida; Samantaray; Mishra

1999-08-01

355

Synthesis of raspberry-like SiO2-TiO2 nanoparticles toward antireflective and self-cleaning coatings.  

PubMed

Silica-titania core-shell nanoparticles of 30, 40, 50, 55, 75, and 110 nm were prepared from tetraethyl orthosilicate (TEOS) and tetraisopropyl titanate (TIPT). After calcination, the amorphous titania shell transformed into anatase nanoparticles, and the silica-titania core-shell nanoparticles became raspberry-like nanoparticles. These nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and UV-vis spectroscopy. Hierarchically structured antireflective and self-cleaning particulate coatings were fabricated on glass substrates via layer-by-layer (LbL) assembly using silica-titania core-shell nanoparticles and silica nanoparticles as building blocks followed by calcination. The maximum transmittance of coated glass substrates reached as high as ca. 97%, while that of the glass substrates is only ca. 91%. The morphologies of the coatings were observed by SEM and atom force microscopy (AFM). Such hierarchically structured raspberry-like SiO2-TiO2 nanoparticle coatings had superhydrophilic and antifogging properties. The coatings also showed photocatalytic activity toward organic pollutants and thus a self-cleaning property. PMID:23719319

Li, Xiaoyu; He, Junhui

2013-06-12

356

TiO 2 coating types influencing the role of water vapor on the photocatalytic oxidation of methyl ethyl ketone in the gas phase  

Microsoft Academic Search

Four TiO2-based materials, named A, B, C and D, are used to investigate the influence of water vapor on the gas–solid adsorption and heterogeneous photocatalytic oxidation of gaseous methyl ethyl ketone (MEK). Two of the photocatalysts (A and B) are constituted of powdered TiO2 deposited onto two different supports (ordinary glass and non-woven cellulose fibers). The other ones (C and

C. Raillard; V. Héquet; P. Le Cloirec; J. Legrand

2005-01-01

357

Visible light-degradation of azo dye methyl orange using TiO2/?-FeOOH as a heterogeneous photo-Fenton-like catalyst.  

PubMed

In this study, a novel TiO2/?-FeOOH composite photocatalyst was synthesized by a hydrothermal method. X-ray diffraction, Fourier transform infrared spectrum, UV-vis diffuse reflectance spectra and scanning electron microscopy (SEM) were used to characterize the composite photocatalyst. The photocatalytic activity of the prepared composite photocatalyst was evaluated in a heterogeneous photo-Fenton-like process using methyl orange (MO) as target pollutant. The TiO2/?-FeOOH composites exhibited higher photocatalytic activity than pure ?-FeOOH and TiO2 under visible-light irradiation. The enhanced photocatalytic activity can be ascribed to the formation of TiO2/?-FeOOH heterostructure, which plays an important role in expanding the photoactivity to the visible light region and in effectively prolonging the lifetime of photoinduced electrons and holes. Further investigation revealed that the 25TiO2/?-FeOOH composite synthesized with the TiO2/Fe(3+) in a mole ratio of 25:75 showed the highest catalytic activity. PMID:24292465

Xu, Zhihui; Zhang, Ming; Wu, Jingyu; Liang, Jianru; Zhou, Lixiang; L, Bo

2013-01-01

358

Production of hydrogen by glycerol photoreforming using binary nitrogen-metal-promoted N-M-TiO(2) photocatalysts.  

PubMed

The need for renewable energy focuses attention on hydrogen obtained by using sustainable and green methods. The sustainable compound glycerol can be used for hydrogen production by heterogeneous photocatalysis. A novel approach involves the promotion of the TiO2 photocatalyst with a binary combination of nitrogen and transition metal. We report the synthesis and spectroscopic characterization of the new N-M-TiO2 photocatalysts (M=none, Cr, Co, Ni, Cu), and the photocatalytic reforming of glycerol to hydrogen under ambient conditions and near-UV or visible light versus benchmark P25 TiO2 . In units of activity ?mol?m(-2) ?h(-1) , N-Ni-TiO2 is five-fold more active than P25, and N-Cu-TiO2 is 44-fold more active. The photocatalytic activity of N-M-TiO2 increases from Cr to Co and Ni, whereas the photoluminescence decreases; the change in activity is due to the modulation of charge recombination. PMID:24616032

Taylor, Sean; Mehta, Mihir; Samokhvalov, Alexander

2014-04-01

359

P-doped TiO 2 nanoparticles film coated on ground glass substrate and the repeated photodegradation of dye under solar light irradiation  

Microsoft Academic Search

The convenient reuse of photocatalysts is essential to the practical application in the degradation of organic pollutant. In this study, compact P-doped TiO2 film coated on ground glass substrate was easily achieved by layer-by-layer assembly technique. Thus such an elaborate complex system exhibited very convenient in recycling photocatalyst in the degradation of dye with high catalytic activity. The excellent performance

Yingying Lv; Leshu Yu; Xiaolan Zhang; Jinyan Yao; Ruyi Zou; Zheng Dai

2011-01-01

360

Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications  

PubMed Central

Summary A biomolecule-assisted pyrolysis method has been developed to synthesize sulfur-doped graphitic carbon nitride (CNS) nanosheets. During the synthesis, sulfur could be introduced as a dopant into the lattice of carbon nitride (CN). Sulfur doping changed the texture as well as relative band positions of CN. By growing CN on preformed sulfur-doped CN nanosheets, composite CN/CNS heterojunction nanosheets were constructed, which significantly enhanced the photoelectrochemical performance as compared with various control counterparts including CN, CNS and physically mixed CN and CNS (CN+CNS). The enhanced photoelectrochemical performance of CN/CNS heterojunction nanosheets could be ascribed to the efficient separation of photoexcited charge carriers across the heterojunction interface. The strategy of designing and preparing CN/CNS heterojunction photocatalysts in this work can open up new directions for the construction of all CN-based heterojunction photocatalysts.

Tao, Hua Bing; Chen, Jiazang; Miao, Jianwei

2014-01-01

361

Visible light photoelectrocatalysis with salicylic acid-modified TiO 2 nanotube array electrode for p-nitrophenol degradation  

Microsoft Academic Search

This research focused on immersion method synthesis of visible light active salicylic acid (SA)-modified TiO2 nanotube array electrode and its photoelectrocatalytic (PEC) activity. The SA-modified TiO2 nanotube array electrode was synthesized by immersing in SA solution with an anodized TiO2 nanotube array electrode. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), UV–vis diffuse reflectance

Xin Wang; Huimin Zhao; Xie Quan; Yazhi Zhao; Shuo Chen

2009-01-01

362

Investigation on a novel ZnO/TiO2-B photocatalyst with enhanced visible photocatalytic activity  

NASA Astrophysics Data System (ADS)

A new type of composite photocatalysts (ZnO/TiO2-B) with Zinc oxide nanoparticles dispersed on boron doped titanium dioxide was prepared via a sol-gel method. The as-prepared powders were characterized by HRTEM, XRD, XPS, UV-vis DRS, and PL techniques. The results reveal that B3+ ions are doped into the TiO2 lattice in interstitial mode, while ZnO nanoparticles are dispersed on the surface of TiO2. The absorption of photocatalysts was extended into visible light region and the photogenerated electrons and holes were separated efficiently. Hence, ZnO/TiO2-B composite photocatalyst exhibits much better photocatalytic activity than those of pure TiO2 and TiO2-B on photodegradation of 4-chlorophenol under visible light irradiation.

Li, Wei; Wu, Di; Yu, Yanlong; Zhang, Peng; Yuan, Jing; Cao, Yongqiang; Cao, Yaan; Xu, Jingjun

2014-04-01

363

Preparation and photocatalytical performance of TiO2:SiO2 nanocomposites produced by the polymeric precursors method.  

PubMed

Anatase TiO2 is a promising photocatalyst due to its chemical stability, non-toxic characteristics, notable UV light absorption as well as photo-corrosion resistance and oxidative properties. Surface area and TiO2 dispersion quality are important factors that affect photoactivity of TiO2:SiO2 nanocomposites. In order to improve these factors, TiO2 nanoparticles were immobilized on mesoporous silica substrate through the polymeric precursors method, obtaining the nanocomposites in a simple routine. The TiO2 resin was synthesized by the polymeric precursors method and different resin thickness (0.5; 1.0; 2.0; 3.5; 5.0 nm) on silica were synthesized by calcination during 4 hours at 450 degrees C in pH 1.5. The selected pH for immobilization ensured adhesion of TiO2 nanoparticles onto the silica substrate surface. X-Ray Diffraction patterns indicate that all samples were predominantly anatase phase and immobilization improved surface area. Ametryn kinetic evaluation presents better results for SAM 3.5 and SAM 0.5. The results show that difference in TiO2 loading, surface area and crystallinity of samples are factors that influence photocatalytic efficiency. PMID:23901540

Dawson, Margaret; Soares, Gabriela Byzynski; Ribeiro, Caue

2013-07-01

364

TiO2 nanofibre assisted photocatalytic degradation of reactive blue 19 dye from aqueous solution.  

PubMed

The photocatalytic degradation of Reactive Blue 19 (RB19) dye has been studied using TiO2 nanofibre as the photocatalyst in aqueous solution under UV irradiation. Titanium dioxide nanofibre was prepared using a templating method with tetraisopropylorthotitanate as a precursor. The experiments were carried out in the presence of the TiO2 nanofibre, and the effects of pH and electron acceptors on the degradation process were investigated. In order to observe the quality of the aqueous solution, chemical oxygen demand (COD) measurements were also carried out before and after the treatments. The photocatalytic decomposition of RB19 was most efficient in acidic solution. With the addition of hydrogen peroxide and potassium persulphate, as electron acceptors, into illuminated TiO2 nanofibre suspensions, a synergistic effect was observed leading to an enhancement of the decolorization. From experimental results, under the condition of 1 g TiO2 nanofibre l(-1), pH 3, and UVC light irradiation, decolorization would be complete in two hours. A significant decrease in the COD values was observed, which clearly indicates that the photocatalytic method offers good potential for the removal of RB19 from aqueous solution. The kinetic of photocatalytic removal of RB19 followed the Langmuir-Hinshelwood model. These results suggest that TiO2 nanofibres with UV photocatalysis can be envisaged as a method for the treatment of coloured wastewaters, in particular in textile industries. PMID:19438055

Rezaee, A; Ghaneian, M T; Taghavinia, N; Aminian, M K; Hashemian, S J

2009-03-01

365

Easy synthesis of bismuth iron oxide nanoparticles as photocatalyst for solar hydrogen generation from water  

NASA Astrophysics Data System (ADS)

In this study, high purity bismuth iron oxide (BiFeO3/BFO) nanoparticles of size 50-80 nm have been successfully synthesized by a simple sol-gel method using urea and polyvinyl alcohol at low temperature. X-ray diffraction (XRD) measurement is used to optimize the synthetic process to get highly crystalline and pure phase material. Diffuse reflectance ultraviolet-visible (DRUV-Vis) spectrum indicates that the absorption cut-off wavelength of the nanoparticles is about 620 nm, corresponding to an energy band gap of 2.1 eV. Compared to BaTiO3, BFO has a better degradation of methyl orange under light radiation. Also, photocatalytic tests prove this material to be efficient towards water splitting under simulated solar light to generate hydrogen. The simple synthetic methodology adopted in this paper will be useful in developing low-cost semiconductor materials as effective photocatalysts for hydrogen generation. Photocatalytic tests followed by gas chromatography (GC) analyses show that BiFeO3 generates three times more hydrogen than commercial titania P25 catalyst under the same experimental conditions.

Deng, Jinyi

366

Aggregation effects in visible-light flavin photocatalysts: synthesis, structure, and catalytic activity of 10-arylflavins.  

PubMed

A series of 10-arylflavins (10-phenyl-, 10-(2',6'-dimethylphenyl)-, 10-(2',6'-diethylphenyl)-, 10-(2',6'-diisopropylphenyl)-, 10-(2'-tert-butylphenyl)-, and 10-(2',6'-dimethylphenyl)-3-methylisoalloxazine (2?a-f)) was prepared as potentially nonaggregating flavin photocatalysts. The investigation of their structures in the crystalline phase combined with (1)H-DOSY NMR spectroscopic experiments in CD(3)CN, CD(3)CN/D(2)O (1:1), and D(2)O confirm the decreased ability of 10-arylflavins 2 to form aggregates relative to tetra-O-acetyl riboflavin (1). 10-Arylflavins 2?a-d do not interact by ?-? interactions, which are restricted by the 10-phenyl ring oriented perpendicularly to the isoalloxazine skeleton. On the other hand, N3-H???O hydrogen bonds were detected in their crystal structures. In the structure of 10-aryl-3-methylflavin (2?f) with a substituted N3 position, weak C-H???O bonds and weak ?-? interactions were found. 10-Arylflavins 2 were tested as photoredox catalysts for the aerial oxidation of 4-methoxybenzyl alcohol to the corresponding aldehyde (model reaction), thus showing higher efficiency relative to 1. The quantum yields of 4-methoxybenzyl alcohol oxidation reactions mediated by arylflavins 2 were higher by almost one order of magnitude relative to values in the presence of 1. PMID:23197435

Da?ová, Jitka; Kümmel, Susanne; Feldmeier, Christian; Cibulková, Jana; Pažout, Richard; Maixner, Jaroslav; Gschwind, Ruth M; König, Burkhard; Cibulka, Radek

2013-01-14

367

Solvothermal synthesis of Ce-doped tungsten oxide nanostructures as visible-light-driven photocatalysts.  

PubMed

Cerium (Ce)-doped tungsten oxide nanostructures have been generated by using a simple solvothermal method with cerium chloride salts and tungsten hexachloride as precursors. The as-synthesized samples were characterized by electron microscopy, x-ray diffraction and x-ray photoelectron spectrometry. The photocatalytic activities of the samples were evaluated by degradation of methyl orange in an aqueous solution under visible light irradiation. Results showed that the as-synthesized samples underwent morphological evolution with decreasing W/Ce molar ratio, from one-dimensional bundled nanowires through straighter, shorter and thicker bundled nanorods to two-dimensional bundled blocks, then to a mixture of bundled nanorods and agglomerated nanoparticles, and finally to particle agglomerates. The Ce-doped tungsten oxides exhibited better photocatalytic activities than that of the undoped tungsten oxide. The cerium-doped tungsten oxide bundled blocks synthesized with a W/Ce molar ratio of 15:1 possessed the most effective photocatalytic activity among the tested samples. These novel nanomaterials may find potential applications as visible-light-driven photocatalysts. PMID:21576793

Chang, Xueting; Sun, Shibin; Zhou, Yun; Dong, Lihua; Yin, Yansheng

2011-07-01

368

Solvothermal synthesis of Ce-doped tungsten oxide nanostructures as visible-light-driven photocatalysts  

NASA Astrophysics Data System (ADS)

Cerium (Ce)-doped tungsten oxide nanostructures have been generated by using a simple solvothermal method with cerium chloride salts and tungsten hexachloride as precursors. The as-synthesized samples were characterized by electron microscopy, x-ray diffraction and x-ray photoelectron spectrometry. The photocatalytic activities of the samples were evaluated by degradation of methyl orange in an aqueous solution under visible light irradiation. Results showed that the as-synthesized samples underwent morphological evolution with decreasing W/Ce molar ratio, from one-dimensional bundled nanowires through straighter, shorter and thicker bundled nanorods to two-dimensional bundled blocks, then to a mixture of bundled nanorods and agglomerated nanoparticles, and finally to particle agglomerates. The Ce-doped tungsten oxides exhibited better photocatalytic activities than that of the undoped tungsten oxide. The cerium-doped tungsten oxide bundled blocks synthesized with a W/Ce molar ratio of 15:1 possessed the most effective photocatalytic activity among the tested samples. These novel nanomaterials may find potential applications as visible-light-driven photocatalysts.

Chang, Xueting; Sun, Shibin; Zhou, Yun; Dong, Lihua; Yin, Yansheng

2011-07-01

369

Synthesis of ZnO/Zn nano photocatalyst using modified polysaccharides for photodegradation of dyes.  

PubMed

A complete set of experiments in two aspects of studies combining the various factors affecting both the preparation and photocatalytic activity of ZnO/Zn nanocomposite obtained using corn starch and cellulose (native and modified) as chelating agents for the photodegradation of methylene blue, and congo red was carried out and discussed. The resulting ZnO/Zn nanoparticles obtained using modified polysaccharides exhibited super catalytic capability. The ZnO/Zn nanoparticles possessed favored surface area (11.8443-15.7100m(2)/g) and pore size (12.3473-13.7453nm). The photocatalytic degradation of nano ZnO/Zn was directly proportional to the surface area of nano ZnO/Zn. Regardless of the dye pollutants, nano ZnO/Zn obtained using modified corn starch showed enhanced catalytic activity than that of cellulose and methylene blue had comparatively faster degradation rate. Our findings shed light on the optimization of both preparation conditions of photocatalysts and their photocatalytic experimental conditions. PMID:24708945

Lin, Shi-Tsung; Thirumavalavan, Munusamy; Jiang, Ting-Yan; Lee, Jiunn-Fwu

2014-05-25

370

Transformation of rutile to TiO2-II in a high pressure hydrothermal environment  

NASA Astrophysics Data System (ADS)

The high pressure transformation of rutile to TiO2-II with the ?-PbO2 structure is known to be kinetically hindered. In this study we show that a hydrothermal environment at 6 GPa and 650 °C provides appreciable rates for producing single phase bulk samples of TiO2-II. So obtained TiO2-II was characterized by scanning electron microscopy, powder X-ray diffraction, Raman and Far-IR spectroscopy. The structural properties are identical to TiO2-II from dry transitions. Transmission electron microscopy studies strongly indicate that Ostwald ripening processes play an important role in the hydrothermally assisted transformation and subsequent growth of TiO2-II crystals. TiO2-II is thermally stable to about 550 °C. At 600 °C the onset of the transformation to rutile is observed. The thermal expansion in the temperature range from room temperature to 500 °C is highly anisotropic, virtually affecting only the c unit cell parameter (?c=7.1(2)×10-6 °C-1). The pressure-temperature conditions for the hydrothermally assisted transformation of rutile are viable for industrial production settings, and in light of the large technological significance of TiO2, TiO2-II may present an interesting target for large-scale synthesis.

Spektor, Kristina; Tran, Dung Trung; Leinenweber, Kurt; Häussermann, Ulrich

2013-10-01

371

The synthesis of nitrogen/sulfur co-doped TiO2 nanocrystals with a high specific surface area and a high percentage of {001} facets and their enhanced visible-light photocatalytic performance  

PubMed Central

Nitrogen/sulfur co-doped anatase TiO2 nanocrystals with a high specific surface area and a high percentage of {001} facets were synthesized by a solvent-thermal process followed by the calcination with thiourea at an optimum heat treatment temperature. Under current experimental conditions, the optimum heat treatment temperature was found at 300°C, which successfully introduced nitrogen and sulfur dopants into the anatase lattice to replace a small portion of oxygen atoms while preserving the geometry of these anatase TiO2 nanocrystals to maintain a high percentage of {001} facets. These nitrogen/sulfur co-doped anatase TiO2 nanocrystals demonstrated a largely enhanced light absorption in the whole visible-light range and exhibited much higher photocatalytic performance than both P25 TiO2 nanoparticles and anatase TiO2 nanocrystals with a high percentage of {001} facets under visible-light illumination.

2012-01-01

372

Photocatalytic Decomposition of Water on Double-Layered Visible Light-Responsive TiO 2 Thin Films Prepared by a Magnetron Sputtering Deposition Method  

Microsoft Academic Search

\\u000a Abstract  A radio-frequency magnetron sputtering (RF-MS) deposition method was applied to prepare a unique double-layered visible light-responsive\\u000a TiO2 thin film photocatalyst on a Ti foil substrate (DL-TiO2\\/Ti). The DL-TiO2\\/Ti consists of a UV light-responsive TiO2 thin film (UV-TiO2) deposited as the inner block layer on a Ti foil substrate and a visible light-responsive TiO2 thin film (Vis-TiO2) deposited as the outer

Ryohei Tode; Afshin Ebrahimi; Shohei Fukumoto; Kazushi Iyatani; Masato Takeuchi; Masaya Matsuoka; Chia Hui Lee; Chi-Sheng Jiang; Masakazu Anpo

2010-01-01

373

Assembly of CeO2-TiO2 nanoparticles prepared in room temperature ionic liquid on graphene nanosheets for photocatalytic degradation of pollutants.  

PubMed

CeO(2)-TiO(2) nanoparticles were prepared by the sol-gel process using 2-hydroxylethylammonium formate as room-temperature ionic liquid and calcined at different temperatures (500-700°C). CeO(2)-TiO(2)-graphene nanocomposites were prepared by hydrothermal reaction of graphene oxide with CeO(2)-TiO(2) nanoparticles in aqueous solution of ethanol. The photocatalysts were characterized by X-ray diffraction, BET surface area, diffuse reflectance spectroscopy, scanning electron microscopy, and Fourier transformed infrared techniques. The results demonstrate that the room-temperature ionic liquid inhibits the anatase-rutile phase transformation. This effect was promoted by addition of CeO(2) to TiO(2). The addition of graphene to CeO(2)-TiO(2) nanoparticles enhances electron transport and therefore impedes the charge recombination of excited TiO(2). The photodegradation results of the pollutants in aqueous medium under UV irradiation revealed that CeO(2)-TiO(2)-graphene nanocomposites exhibit much higher photocatalytic activity than CeO(2)-TiO(2) and pure TiO(2). The photocatalytic activity of CeO(2)-TiO(2)-graphene nanocomposites decreases with additional increasing of the graphene content. Moreover, comparison of the photocatalytic activities of CeO(2)-TiO(2)-graphene with the other CeO(2)-TiO(2)-carbon demonstrates that CeO(2)-TiO(2)-graphene nanocomposites have the highest photocatalytic activity due to their unique structure and electronic properties. Chemical oxygen demand for solutions of the pollutants gave a good idea about mineralization of them. PMID:22104082

Ghasemi, S; Setayesh, S Rahman; Habibi-Yangjeh, A; Hormozi-Nezhad, M R; Gholami, M R

2012-01-15

374

Photocatalytic degradation of toluene vapour using fixed bed multichannel photoreactors equipped with TiO2-coated fabrics.  

PubMed

The feasibility of producing TiO2-coated fabric using nonwoven polyester as a photocatalyst support was examined through investigations on (i) changes in the fabric properties after coating with TiO2, (ii) the toluene removal capacity of a multichannel TiO2/fabric/UV reactor in removing the toluene vapour with and without O3 addition, and (iii) the photocatalytic effect of regenerated TiO2. The value and usefulness of a multichannel photoreactor as a main reactor or a supplementary device to improve the efficiency of VOC (volatile organic chemicals) removal in a photoreacting fabric filter, which was originally invented to simultaneously remove fine dust and VOCs, was manifested through investigations of the multichannel effect in the treatment of large volumes of air containing toluene as a sample VOC vapour. The parallel-flow photoreactor was manufactured by fixing TiO2-coated fabrics in parallel along the gas flow and installing UV sources for every channel. Photocatalytic degradation of toluene vapour was investigated with respect to various operational parameters such as reaction time, photocatalyst load, vapour load and number of channels. Toluene vapour was taken as a sample VOC because it is a non-biodegradable toxic organic substance, and the UV/TiO2 process was tested as an alternative process to biofiltration. As a result of this study, it was confirmed that nonwoven polyester can be used as a photocatalyst support, and the multichannel photoreactor, equipped with TiO2-coated fabrics, is a useful device that can economically and efficiently treat a larger vapour load by providing more channels with ozone addition and by arranging the reactor units in series. PMID:18844127

Park, O H; Na, H Y

2008-09-01

375

Template-free synthesis of a CdSnO3?3H2O hollow-nanocuboid photocatalyst via a facile microwave hydrothermal method  

NASA Astrophysics Data System (ADS)

A CdSnO3?3H2O hollow-nanocuboid photocatalyst was successfully synthesized via a facile template-free microwave hydrothermal method for the first time. The as-prepared samples were characterized by x-ray diffraction, UV-vis diffuse reflectance spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis and x-ray photoelectron spectroscopy. Moreover, samples prepared under different reaction times were analyzed by transmission electron microscopy to investigate the formation process of the CdSnO3?3H2O hollow-nanocuboids. Based on this result, a possible mechanism for the formation process was proposed. The sample prepared at 160?° C for 2 h at pH 11 exhibited the best photocatalytic activity and stability for the degradation of gaseous benzene under UV irradiation (? = 254 nm) as compared with the other samples. The conversion and mineralization rates of benzene were about 12.5% and 67%, respectively. The mineralization rate was twice as high as that of commercial TiO2 (Degussa Co.). Furthermore, the excellent stability for the benzene decomposition was attributed to the positive charge on the catalyst surface, which was analyzed both by electron spin resonance and Zeta-potentials.

Liu, Guodong; Liang, Shijing; Wu, Weiming; Lin, Rui; Qing, Na; Liang, Ruowen; Wu, Ling

2013-06-01

376

Preparation and photocatalytic properties of nanometer-sized magnetic TiO2/SiO2/CoFe2O4 composites.  

PubMed

Magnetic TiO2/SiO2/CoFe2O4 nanoparticles (TiO2/SCFs) were prepared by a sol-gel process in a reverse microemulsion combined with solvent-thermal technique. TiO2/SCFs were characterized by Fourier transform infrared spectrometry, thermogravimetric analysis-differential scanning calorimetry, X-ray diffraction, Raman spectrometry, TEM, BET specific surface area measurement, and magnetic analysis. Structure analyses indicated that TiO2/SCFs presented a core-shell structure with TiO2 uniformly coating on SiO2/CoFe2O4 nanomagnets (SCFs) and typical ferromagnetic hysteresis. TiO2/SCFs showed larger specific surface area and better photocatalytic activities than TiO2 and TiO2/CoFe2O4 photocatalysts prepared by the same method. The doping interaction between TiO2 and CoFe2O4 reduced thanks to the inert SiO2 mesosphere. PMID:22413361

Li, Hansheng; Zhang, Yaping; Wu, Qin; Wang, Xitao; Liu, Changhao

2011-11-01

377

Enhanced photoelectrochemical and photocatalytic performance of single-crystalline anatase TiO2 (1 0 1) nanobelts arrays originating from nanotubes arrays  

NASA Astrophysics Data System (ADS)

TiO2 photocatalysts with high photocatalytic activity are potentially applied to degrade pollutants, split water and transform solar energy. Herein, TiO2 nanobelts (TiO2 NB) arrays originating from nanotubes arrays were successfully prepared via simple anodization. The surface morphology, structure, elemental composition, photoluminescence spectra (PL), photoelectrochemical (PEC) properties and photocatalytic activity of the resulting samples were investigated. The results show that as-prepared TiO2 NB arrays exhibited significant enhancement in separation efficiency of photogenerated electrons (e-) and holes (h+) pairs and then in photocatalytic activity under simulative solar irradiation compared with TiO2 nanotubes (TiO2 NT) arrays, which could be attributed to the following aspects: (i) specific belt-like morphology leads to higher accessibility of TiO2 NB arrays for reactants and more active sites on the surface of TiO2 NB; (ii) single-crystalline anatase phase structure gives rise to faster electron mobility and less electron-trapping sites in the bulk; and (iii) exposed crystal face (1 0 1) yields an enhanced reactivity with molecular O2, facilitating the trapping of photogenerated electrons and generation of superoxide radical. Otherwise, this TiO2 NB arrays overcome the deficiency of filtering separation from water and exhibit excellent photocatalytic stability, thus it is promising to be applied in pollutants elimination and photocatalytic decomposition of water.

Chen, Qinghua; Liu, Huiling; Xin, Yanjun; Cheng, Xiuwen; Li, Junjing

2013-01-01

378

Weak polyion multilayer-assisted in situ synthesis as a route toward a plasmonic Ag/TiO2 photocatalyst.  

PubMed

Nanocrystalline Ag/TiO(2) composite thin films were synthesized using a two-step synthesis methodology: the in situ precipitation of Ag nanoparticles followed by an in situ sol-gel reaction of titanium iso-propoxide in a weak polyion multilayer (PEM) template formed by the layer-by-layer (LbL) self-assembly of poly(acrylic acid) (PAA) and polyallylamine (PAH). Because the PEM template is assembled from weak polyions, it contains nonionized carboxylic groups that are able to react with the inorganics, resulting in the formation of a homogeneous Ag(x)/TiO(2)-PEM precursor film, where the content of Ag is controlled by repeating the Ag loading cycle. The subsequent annealing of the precursor yields nanostructured Ag(x)/TiO(2) films with thicknesses controlled by the PEM template on the nanometer scale. Transmission electron, field-emission scanning electron, and atomic force microscopy methods were employed to evaluate the morphology and growth characteristics of the metallic and semiconductor nanocrystallites in the Ag(x)/TiO(2) composite thin films. The as-formed Ag(x)/TiO(2) composite thin films exhibited UV-visible photoactivity monitored by the decomposition of methylene blue (MB). In the near-UV range, the expected photocatalytic behavior of TiO(2) is greatly enhanced because it is assisted by the near-field amplitudes of the localized surface plasmon resonance (LSPR) of the Ag nanoparticles in the Ag(x)/TiO(2) films. PMID:20557056

Logar, Manca; Jancar, Bostjan; Sturm, Saso; Suvorov, Danilo

2010-07-20

379

Enhanced TiO2 Photocatalytic Processing of Organic Wastes for Green Space Exploration  

NASA Technical Reports Server (NTRS)

The effect of transition metal co-catalysts on the photocatalytic properties of TiO2 was investigated. Ruthenium (Ru), palladium, platinum, copper, silver, and gold, were loaded onto TiO2 powders (anatase and mixed-phase P25) and screened for the decomposition of rhodamine B (RhB) under broad-band irradiation. The morphology and estimated chemical composition of photocatalysts were determined by scanning electron microscopy and energy dispersive spectroscopy, respectively. Brunhauer, Emmett and Teller (BET) analysis measured mass-specific surface area(s). X-ray diffraction analysis was performed to confirm the identity of titania phase(s) present. The BET surface area of anatase TiO2/Ru 1% (9.2 sq m/gm) was one of the highest measured of all photocatalysts prepared in our laboratory. Photolyses conducted under air-saturated and nitrogen-saturated conditions revealed photodegradation efficiencies of 85 and 2 percent, respectively, after 60 min compared to 58 percent with no catalyst. The cause of low photocatalytic activity under an inert atmosphere is discussed. TiO2/Ru 1% showed a superior photocatalytic activity relative to P25-TiO2 under broad-band irradiation. A potential deployment of photocatalytic technologies on a mission could be a reactor with modest enhancement in solar intensity brought about by a trough-style reactor, with reactants and catalyst flowing along the axis of the trough and therefore being illuminated for a controlled duration based on the flow rate.

Udom, I.; Goswami, D. Y.; Ram, M. K.; Stefanakos, E. K.; Heep, A. F.; Kulis, M. J.; McNatt, J. S.; Jaworske, D. A.; Jones, C. A.

2013-01-01

380

Photocatalytic degradation of an azo-dye on TiO2/activated carbon composite material.  

PubMed

A sequential adsorption/photocatalytic regeneration process to remove tartrazine, an azo-dye in aqueous solution, has been investigated. The aim ofthis work was to compare the effectiveness of an adsorbent/photocatalyst composite-TiO2 deposited onto activated carbon (AC) - and a simple mixture of powders of TiO2 and AC in same proportion. The composite was an innovative material as the photocatalyst, TiO2, was deposited on the porous surface ofa microporous-AC using metal-organic chemical vapour deposition in fluidized bed. The sequential process was composed of two-batch step cycles: every cycle alternated a step of adsorption and a step of photocatalytic oxidation under ultra-violet (365 nm), at 25 degreeC and atmospheric pressure. Both steps, adsorption and photocatalytic oxidation, have been investigated during four cycles. For both materials, the cumulated amounts adsorbed during four cycles corresponded to nearly twice the maximum adsorption capacities qmax proving the photocatalytic oxidation to regenerate the adsorbent. Concerning photocatalytic oxidation, the degree of mineralization was higher with the TiO2/AC composite: for each cycle, the value of the total organic carbon removal was 25% higher than that obtained with the mixture powder. These better photocatalytic performances involved better regeneration than higher adsorbed amounts for cycles 2, 3 and 4. Better performances with this promising material - TiO2 deposited onto AC - compared with TiO2 powder could be explained by the vicinity of photocatalytic and AC adsorption sites. PMID:24600875

Andriantsiferana, C; Mohamed, E F; Delmas, H

2014-01-01

381

Influence of rare earth co-dopant on the photocatalytic property of TiO 2 nano-particles  

Microsoft Academic Search

A series of nanometer TiO2 photocatalysts co-doped respectively with rare earth Er3+-Ce3+ and La3+-Fe3+ were prepared by sol-gel method, and the photocatalytic activity under ultra-violet light was evaluated by photocatalytic\\u000a degradation of methyl blue. The crystallographic forms, particles size, and morphology were characterized by XRD and TEM.\\u000a The results showed that the optimum heat temperature of co-doped TiO2 was 550

Xiaohong Xu; Binzheng Fang; Fengyi Zhang; Yue Tian; Jianfeng Wu

2010-01-01

382

Preparation and characterization of Fe 3+-doped TiO 2 on fly ash cenospheres for photocatalytic application  

Microsoft Academic Search

Fe3+-doped TiO2 film deposited on fly ash cenosphere (Fe–TiO2\\/FAC) was successfully synthesized by the sol–gel method. These fresh photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analyses (TGA). The XRD results showed that Fe element can maintain metastable anatase phase of TiO2, and effect of temperature showed rutile phase appears in 650°C for 0.01% Fe–TiO2\\/FAC.

Bing Wang; Qin Li; Wei Wang; Ying Li; Jianping Zhai

2011-01-01

383

CdS nanorod arrays with TiO2 nano-coating for improved photostability and photocatalytic activity.  

PubMed

CdS nanorod arrays were grown on fluorine-doped tin oxide glass substrates via a hydrothermal process and subsequently coated with a TiO2 nanolayer via a vacuum dip-coating process to fabricate a one-dimensional array structured photocatalyst. The TiO2 nanolayer improved the photocatalytic efficiency of CdS nanorod arrays for the degradation of methylene blue due to the effective separation of the electron-hole pairs, and the photocorrosion of CdS nanorod arrays was successfully inhibited. PMID:24942928

Wu, Liangpeng; Zhang, Yulan; Li, Xinjun; Cen, Chaoping

2014-07-01

384

Nanostructured N-doped TiO2 marigold flowers for an efficient solar hydrogen production from H2S  

NASA Astrophysics Data System (ADS)

Nitrogen-doped TiO2 nanostructures in the form of marigold flowers have been synthesized for the first time using a facile solvothermal method. The structural analysis has shown that such an N-doped TiO2 system crystallizes in the anatase structure. The optical absorption spectra have clearly shown the shift in the absorption edge towards the visible-light range, which indicates successful nitrogen doping. The nitrogen doping has been further confirmed by photoluminescence and photoemission spectroscopy. Microscopy studies have shown the thin nanosheets (petals) of N-TiO2 with a thickness of ~2-3 nm, assembled in the form of the marigold flower with a high surface area (224 m2 g-1). The N-TiO2 nanostructure with marigold flowers is an efficient photocatalyst for the decomposition of H2S and production of hydrogen under solar light. The maximum hydrogen evolution obtained is higher than other known N-TiO2 systems. It is noteworthy that photohydrogen production using the unique marigold flowers of N-TiO2 from abundant H2S under solar light is hitherto unattempted. The proposed synthesis method can also be utilized to design other hierarchical nanostructured N-doped metal oxides.Nitrogen-doped TiO2 nanostructures in the form of marigold flowers have been synthesized for the first time using a facile solvothermal method. The structural analysis has shown that such an N-doped TiO2 system crystallizes in the anatase structure. The optical absorption spectra have clearly shown the shift in the absorption edge towards the visible-light range, which indicates successful nitrogen doping. The nitrogen doping has been further confirmed by photoluminescence and photoemission spectroscopy. Microscopy studies have shown the thin nanosheets (petals) of N-TiO2 with a thickness of ~2-3 nm, assembled in the form of the marigold flower with a high surface area (224 m2 g-1). The N-TiO2 nanostructure with marigold flowers is an efficient photocatalyst for the decomposition of H2S and production of hydrogen under solar light. The maximum hydrogen evolution obtained is higher than other known N-TiO2 systems. It is noteworthy that photohydrogen production using the unique marigold flowers of N-TiO2 from abundant H2S under solar light is hitherto unattempted. The proposed synthesis method can also be utilized to design other hierarchical nanostructured N-doped metal oxides. Electronic supplementary information (ESI) available: GC-MS graph of the filtrate obtained in solvothermal reaction after 16 h and FESEM images without guanidine carbonate for 16 h. See DOI: 10.1039/c3nr02975a

Chaudhari, Nilima S.; Warule, Sambhaji S.; Dhanmane, Sushil A.; Kulkarni, Milind V.; Valant, Matjaz; Kale, Bharat B.

2013-09-01

385

Ultrathin (0 0 1) and (1 0 0) TiO2(B) sheets: Surface reactivity and structural properties  

NASA Astrophysics Data System (ADS)

B polymorph of titanium dioxide (TiO2(B)) appears as a metastable phase during thermal annealing of low content sodium layered titanate nanostructures obtained via the widely used hydrothermal synthesis. In addition, the computed formation energy for the TiO2(B) (0 0 1) slabs in the order of the one calculated for anatase (1 0 1) which represents one of the most stable TiO2 surfaces. This encourages the study of this polymorph which could gain prominence in TiO2 applications at the nanoscale.

Fernández-Werner, Luciana; Faccio, Ricardo; Juan, Alfredo; Pardo, Helena; Montenegro, Benjamín; Mombrú, Álvaro W.

2014-01-01

386

Noble-metal-free plasmonic photocatalyst: hydrogen doped semiconductors  

PubMed Central

The unique capacity of localized surface plasmon resonance (LSPR) offers a new opportunity to overcome the limited efficiency of semiconductor photocatalyst. Here we unravel that LSPR, which usually occurs in noble metal nanoparticles, can be realized by hydrogen doping in noble-metal-free semiconductor using TiO2 as a model photocatalyst. Moreover, its LSPR is located in infrared region, which supplements that of noble metal whose LSPR is generally in the visible region, making it possible to extend the light response of photocatalyst to infrared region. The near field enhancement is shown to be comparable with that of noble-metal nanoparticles, indicating that highly enhanced light absorption rate can be expected. The present work can provide a key guideline for the creation of highly efficient noble-metal-free plasmonic photocatalysts and have a much wider impact in infrared bioimaging and spectroscopy where infrared LSPR is essential.

Ma, Xiangchao; Dai, Ying; Yu, Lin; Huang, Baibiao

2014-01-01

387

Nanoporous TiO2 nanoparticle assemblies with mesoscale morphologies: nano-cabbage versus sea-anemone.  

PubMed

We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation. PMID:24760418

Darbandi, Masih; Gebre, Tesfaye; Mitchell, Lucas; Erwin, William; Bardhan, Rizia; Levan, M Douglas; Mochena, Mogus D; Dickerson, James H

2014-06-01

388

Fabrication of bidirectionally doped ?-Bi2O3/TiO2-NTs with enhanced photocatalysis under visible light irradiation.  

PubMed

Stable ?-Bi2O3/TiO2-NTs photocatalyst with excellent visible-light-activity is successfully prepared by bidirectional doping. Stake structure of the TiO2-NTs provides a larger specific surface area and makes the contact area between the TiO2-NTs and ?-Bi2O3 much larger; The stake structure of TiO2-NTs not only leads to a firmer combination of TiO2-NTs and ?-Bi2O3, but also makes them dope one another deeply. The modification of Bi species into TiO2-NTs can form Bi-O-Ti chemical absorption bonds, then a localized impurity level is generated within the band gap. Electrons can be excited and transferred from the Bi(3+) impurity level to the conduction band (CB) of TiO2, similar to narrowing the band-gap of TiO2-NTs, resulting in a red shift of the absorption edge and an enhancement in visible-light activity. During annealing, Bi atoms are partially replaced by Ti atoms. The lattice of ?-Bi2O3 is compressed around the Ti impurity, making the lattice dislocate and distort. This dislocation and distortion leads to an increase in the ?-Bi2O3 valance band (VB), from 2.02 to 2.28 eV. Accordingly, the weak oxidability of ?-Bi2O3 is improved, and its photocatalytic ability is further enhanced. Moreover, this lattice dislocation and distortion changes the Bi-O distances, thus remarkably improving the stability of the ?-Bi2O3/TiO2-NTs. PMID:23692682

Li, Deyi; Zhang, Yonggang; Zhang, Yalei; Zhou, Xuefei; Guo, Sujin

2013-08-15

389

Enhanced photocatalytic activity of TiO2-C hybrid aerogels for methylene blue degradation  

PubMed Central

Carbon-based TiO2 composites have many advantages as photocatalysts. However, they suffer from low light efficiency due to the low contrast of TiO2 with carbon. We synthesized a novel type of anatase-type TiO2-C hybrid aerogel by a one-pot sol-gel method, which shows a photocatalytic activity for methylene degradation up to 4.23 times that of P25, a commercial photocatalyst from Degussa Inc. The hybrid aerogels are prepared from TiCl4 and resorcinol–furfural, and have a tunable macropore size from 167 to 996 nm. They are formed of submicrometer particles that consist of interwoven anatase and carbon nanoparticles. The anatase nanoparticles have a size of 8–9?nm and a tunable oxygen vacancy from 7.2 to 18.0%. The extremely high activity is ascribed to the large light absorption caused by macropore scattering and oxygen vacancies in the anatase. These findings may open up a new avenue and stimulate further research to improve photocatalytic performance.

Shao, Xia; Lu, Wencong; Zhang, Rui; Pan, Feng

2013-01-01

390

Enhanced photocatalytic activity of TiO2-C hybrid aerogels for methylene blue degradation  

NASA Astrophysics Data System (ADS)

Carbon-based TiO2 composites have many advantages as photocatalysts. However, they suffer from low light efficiency due to the low contrast of TiO2 with carbon. We synthesized a novel type of anatase-type TiO2-C hybrid aerogel by a one-pot sol-gel method, which shows a photocatalytic activity for methylene degradation up to 4.23 times that of P25, a commercial photocatalyst from Degussa Inc. The hybrid aerogels are prepared from TiCl4 and resorcinol-furfural, and have a tunable macropore size from 167 to 996 nm. They are formed of submicrometer particles that consist of interwoven anatase and carbon nanoparticles. The anatase nanoparticles have a size of 8-9 nm and a tunable oxygen vacancy from 7.2 to 18.0%. The extremely high activity is ascribed to the large light absorption caused by macropore scattering and oxygen vacancies in the anatase. These findings may open up a new avenue and stimulate further research to improve photocatalytic performance.

Shao, Xia; Lu, Wencong; Zhang, Rui; Pan, Feng

2013-10-01

391

Light-storing photocatalyst  

SciTech Connect

Light-storing photocatalyst was prepared by coating light-storing phosphor and TiO{sub 2} photocatalyst in sequence on ceramic. The light-storing photocatalyst can store light irradiation and emit slowly. Consequently, the photocatalyst remains active when the irradiation source is cut off. Rhodamine B (RhB) can be decomposed efficiently by this photocatalyst in the dark after it absorbs light irradiation. This photocatalyst is photoreactive in an outdoor environment or can save energy by supplying irradiation intermittently for the photocatalyst.

Zhang Junying; Pan Feng; Hao Weichang; Ge Qi; Wang Tianmian [Center of Materials Physics and Chemistry, School of Science, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China)

2004-12-06

392

Photocatalytically active titanium dioxide nanopowders: Synthesis, photoactivity and magnetic separation  

NASA Astrophysics Data System (ADS)

Two approaches were used to obtain nanocrystalline titanium dioxide (TiO2) photocatalyst powders. Firstly, low-temperature synthesis method and secondly liquid flame spraying. The structural properties of the produced powders were determined with X-ray diffraction, transmission electron microscopy and nitrogen adsorption tests. The photocatalytic properties of the powders were studied with methylene blue (MB) discoloration tests. After discolorations tests, TiO2 was coagulated with magnetite particles using FeCl3·6 H2O at a fixed pH value. Magnetic separation of coagulated TiO2 and magnetite was carried out by a permanent magnet. The obtained results showed that the particle size of the powders synthesized at low-temperature was very small and the specific surface area high. The phase content of the powder was also shown to depend greatly on the acidity of the synthesis solution. Powder synthesized by liquid flame spraying was mixture of anatase and rutile phases with essentially larger particle size and lower specific surface area than those of low-temperature synthesized powders. The MB discoloration test showed that photocatalytic activity depends on the phase structure as well as the specific surface area of the synthesized TiO2 powder. The magnetic separation of TiO2-magnetite coagulate from solution proved to be efficient around pH:8.

Nikkanen, J.-P.; Heinonen, S.; Huttunen Saarivirta, E.; Honkanen, M.; Levänen, E.

2013-12-01

393

LC/MS/MS structure elucidation of reaction intermediates formed during the TiO2 photocatalysis of microcystin-LR  

EPA Science Inventory

Microcystin-LR (MC-LR), a cyanotoxin and emerging drinking water contaminant, was treated with TiO(2) photocatalysts immobilized on stainless steel plates as an alternative to nanoparticles in slurry. The reaction intermediates of MC-LR were identified with mass spectrometry (MS)...

394

Preparation of nano-sized mixed crystal TiO2-coated Er3+:YAlO3 by sol-gel method for photocatalytic degradation of organic dyes under visible light irradiation.  

PubMed

In this work, an upconversion luminescence agent, crystallized Er(3 + ):YAlO(3), was synthesized and then coated by the nano-sized TiO(2) film through sol-gel technique. A novel TiO(2) photocatalyst, Er(3 + ):YAlO(3)/TiO(2), with high activity in visible light was subsequently prepared. The Er(3 + ):YAlO(3) and Er(3 + ):YAlO(3)/TiO(2) were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The photocatalytic activity of Er(3 + ):YAlO(3)/TiO(2) photocatalyst was tested by the degradation of acid red B in aqueous solution as the primary model compound under visible light irradiation. The experimental results proved that the prepared TiO(2)-coated crystallized Er(3 + ):YAlO(3) was able to decompose the acid red B efficiently, and it is promising to use the idea to develop new TiO(2) photocatalyst with high activity for photocatalytic degradation under visible light. PMID:19700830

Wang, Jun; Li, Jia; Liu, Bin; Xie, Yingpeng; Han, Guangxi; Li, Ying; Zhang, Liqun; Zhang, Xiangdong

2009-01-01

395

Room temperature one-step synthesis of microarrays of N-doped flower-like anatase TiO2 composed of well-defined multilayer nanoflakes by Ti anodization  

Microsoft Academic Search

Microarrays of N-doped flower-like TiO2 composed of well-defined multilayer nanoflakes were synthesized at room temperature by electrochemical anodization of Ti in NH4F aqueous solution. The TiO2 flowers were of good anatase crystallinity. The effects of anodizing time, applied voltage and NH4F concentration on the flower-like morphology were systematically examined. It was found that the morphologies of the anodized Ti were

Chenglin Wang; Mengye Wang; Kunpeng Xie; Qi Wu; Lan Sun; Zhiqun Lin; Changjian Lin

2011-01-01

396

Pulsed supercritical synthesis of anatase TiO2 nanoparticles in a water-isopropanol mixture studied by in situ powder X-ray diffraction  

NASA Astrophysics Data System (ADS)

A new step in supercritical nanoparticle synthesis, the pulsed supercritical synthesis reactor, is investigated in situ using synchrotron powder X-ray diffraction (PXRD) to understand the formation of nanoparticles in real time. This eliminates the common problem of transferring information gained during in situ studies to subsequent laboratory reactor conditions. As a proof of principle, anatase titania nanoparticles were synthesized in a 50/50 mixture of water and isopropanol near and above the critical point of water (P = 250 bar, T = 300, 350, 400, 450, 500 and 550 °C). The evolution of the reaction product was followed by sequentially recording PXRD patterns with a time resolution of less than two seconds. The crystallite size of titania is found to depend on both temperature and residence time, and increasing either parameter leads to larger crystallites. A simple adjustment of either temperature or residence time provides a direct method for gram scale production of anatase nanoparticles of average crystallite sizes between 7 and 35 nm, thus giving the option of synthesizing tailor-made nanoparticles. Modeling of the in situ growth curves using an Avrami growth model gave an activation energy of 66(19) kJ mol-1 for the initial crystallization. The in situ PXRD data also provide direct information about the size dependent macrostrain in the nanoparticles and with decreasing crystallite size the unit cell contracts, especially along the c-direction. This agrees well with previous ex situ results obtained for hydrothermal synthesis of titania nanoparticles.A new step in supercritical nanoparticle synthesis, the pulsed supercritical synthesis reactor, is investigated in situ using synchrotron powder X-ray diffraction (PXRD) to understand the formation of nanoparticles in real time. This eliminates the common problem of transferring information gained during in situ studies to subsequent laboratory reactor conditions. As a proof of principle, anatase titania nanoparticles were synthesized in a 50/50 mixture of water and isopropanol near and above the critical point of water (P = 250 bar, T = 300, 350, 400, 450, 500 and 550 °C). The evolution of the reaction product was followed by sequentially recording PXRD patterns with a time resolution of less than two seconds. The crystallite size of titania is found to depend on both temperature and residence time, and increasing either parameter leads to larger crystallites. A simple adjustment of either temperature or residence time provides a direct method for gram scale production of anatase nanoparticles of average crystallite sizes between 7 and 35 nm, thus giving the option of synthesizing tailor-made nanoparticles. Modeling of the in situ growth curves using an Avrami growth model gave an activation energy of 66(19) kJ mol-1 for the initial crystallization. The in situ PXRD data also provide direct information about the size dependent macrostrain in the nanoparticles and with decreasing crystallite size the unit cell contracts, especially along the c-direction. This agrees well with previous ex situ results obtained for hydrothermal synthesis of titania nanoparticles. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr33127j

Eltzholtz, Jakob Rostgaard; Tyrsted, Christoffer; Jensen, Kirsten Marie Ørnsbjerg; Bremholm, Martin; Christensen, Mogens; Becker-Christensen, Jacob; Iversen, Bo Brummerstedt

2013-02-01

397

Large scale electrochemical synthesis of high quality carbon nanodots and their photocatalytic property.  

PubMed

High quality carbon nanodots (C-dots) with high purity were synthesized through a mild, one-step electrochemical approach, without the assistance of any chemicals but only pure water. This high productivity method makes the synthetic process of C-dots synthesis both economical as well as environment-friendly. The as prepared C-dots are predominantly multi-layer graphene oxide, with luminescence and high up-conversion photoluminescence (emission of light at shorter wavelengths than the excitation wavelength). Meanwhile, C-dots showed peroxidise mimetic function and visible-light-sensitive photocatalytic activity for methyl orange degradation. In addition, a novel photocatalyst (TiO(2)/C-dots) was obtained by combining C-dots with TiO(2) through an easy hydrothermal method. Remarkably, TiO(2)/C-dots exhibited an excellent visible-light photocatalytic activity. PMID:22751568

Ming, Hai; Ma, Zheng; Liu, Yang; Pan, Keming; Yu, Hang; Wang, Fang; Kang, Zhenhui

2012-08-21

398

Water-dispersible TiO2 nanoparticles via a biphasic solvothermal reaction method  

NASA Astrophysics Data System (ADS)

A biphasic solvothermal reaction method has been used for the synthesis of TiO2 nanoparticles (NPs). In this method, hydrolysis and nucleation occur at the interface of organic phase (titanium (IV) n-propoxide and stearic acid dissolved in toluene) and water phase ( tert-butylamine dissolved in water) resulting in the nucleation of the stearic acid-capped TiO2 NPs. These NPs are hydrophilic due to hydrophobic stearic acid ligands and could be dispersed in toluene, but not in water. These stearic acid-capped TiO2 NPs were surface-modified with 2,3-dimercaptosuccinic acid (DMSA) in order to make them water soluble. The resultant TiO2 NPs were easily redispersed in water without any noticeable aggregation. The Rietveld profile fitting of X-ray diffraction (XRD) pattern of the TiO2 NPs revealed highly crystalline anatase structure. The average crystallite size of TiO2 NPs was calculated to be 6.89 nm, which agrees with TEM results. These results have important implications for the use of TiO2 in biomedical, environmental, and industrial applications.

Mohan, Rajneesh; Drbohlavova, Jana; Hubalek, Jaromir

2013-12-01

399

Preparation of mesoporous nanocrystalline anatase TiO2 for dye sensitized solar cell application  

NASA Astrophysics Data System (ADS)

Dye sensitized solar cell (DSSC) introduced by Prof.M.Gratzel is a low cost alternative to the existing silicon based solar cells. Solar light conversion efficiency of the current DSSC can be further improved by replacing the conventional anatase TiO2 having lesser surface area with mesoporous high surface area anatase TiO2. This paper describes the sol-gel synthesis of mesoporous high surface area nanocrystalline anatase TiO2 by the controlled hydrolysis and condensation of titanium isopropoxide followed by heat treatment. XRD reveals that xerogel heat treated at 500°C is phase pure anatase. Crystallite size of prepared anatase TiO2 calculated using Scherrer equation was found to be 15 nm. BET analysis of prepared anatase TiO2 exhibited relatively high specific surface area of 97 m2/g, which is found to be almost double to that of the anatase TiO2 generally used for DSSC photo anode fabrication. The pore size distribution (BJH plot) also revealed the mesoporous nature of prepared anatase TiO2 having an average pore size of 7.4 nm.

Jacob, K. Stanly; Abraham, P. A.; Panicker, N. Rani; Pramanik, N. C.

2014-01-01

400

Visible light driven photoelectrochemical water oxidation on nitrogen-modified TiO2 nanowires.  

PubMed

We report hydrothermal synthesis of single crystalline TiO(2) nanowire arrays with unprecedented small feature sizes of ~5 nm and lengths up to 4.4 ?m on fluorine-doped tin oxide substrates. A substantial amount of nitrogen (up to 1.08 atomic %) can be incorporated into the TiO(2) lattice via nitridation in NH(3) flow at a relatively low temperature (500 °C) because of the small cross-section of the nanowires. The low-energy threshold of the incident photon to current efficiency (IPCE) spectra of N-modified TiO(2) samples is at ~520 nm, corresponding to 2.4 eV. We also report a simple cobalt treatment for improving the photoelectrochemical (PEC) performance of our N-modified TiO(2) nanowire arrays. With the cobalt treatment, the IPCE of N-modified TiO(2) samples in the ultraviolet region is restored to equal or higher values than those of the unmodified TiO(2) samples, and it remains as high as ~18% at 450 nm. We propose that the cobalt treatment enhances PEC performance via two mechanisms: passivating surface states on the N-modified TiO(2) surface and acting as a water oxidation cocatalyst. PMID:22112010

Hoang, Son; Guo, Siwei; Hahn, Nathan T; Bard, Allen J; Mullins, C Buddie

2012-01-11

401

Water-dispersible TiO2 nanoparticles via a biphasic solvothermal reaction method.  

PubMed

A biphasic solvothermal reaction method has been used for the synthesis of TiO2 nanoparticles (NPs). In this method, hydrolysis and nucleation occur at the interface of organic phase (titanium (IV) n-propoxide and stearic acid dissolved in toluene) and water phase (tert-butylamine dissolved in water) resulting in the nucleation of the stearic acid-capped TiO2 NPs. These NPs are hydrophilic due to hydrophobic stearic acid ligands and could be dispersed in toluene, but not in water. These stearic acid-capped TiO2 NPs were surface-modified with 2,3-dimercaptosuccinic acid (DMSA) in order to make them water soluble. The resultant TiO2 NPs were easily redispersed in water without any noticeable aggregation. The Rietveld profile fitting of X-ray diffraction (XRD) pattern of the TiO2 NPs revealed highly crystalline anatase structure. The average crystallite size of TiO2 NPs was calculated to be 6.89 nm, which agrees with TEM results. These results have important implications for the use of TiO2 in biomedical, environmental, and industrial applications. PMID:24289214

Mohan, Rajneesh; Drbohlavova, Jana; Hubalek, Jaromir

2013-01-01

402

Structure and photocatalytic performance of magnetically separable titania photocatalysts for the degradation of propachlor  

Microsoft Academic Search

A magnetic photocatalyst was prepared by modification of TiO2 nanoparticles (Degussa P25) with nanocrystalline ?-Fe2O3 nanoparticles through a protective lining made up of two oppositely charged polyelectrolytes. As-prepared magnetically separable photocatalysts differing in ?-Fe2O3 loading (3, 8, 13, 20 and 30wt.%) were characterized by XRD, TEM, thermal analysis, Mössbauer and magnetic measurements. The photocatalytic efficiency of the nanocomposite catalysts was

V. Belessi; D. Lambropoulou; I. Konstantinou; R. Zboril; J. Tucek; D. Jancik; T. Albanis; D. Petridis

2009-01-01

403

TiO2 nanoparticles versus TiO2-SiO2 nanocomposites: A comparative study of photo catalysis on acid red 88  

NASA Astrophysics Data System (ADS)

A novel, simple, less time-consuming and cost-effective wet chemical technique was used to synthesis TiO2 nanoparticles and TiO2-SiO2 nanocomposites using Titanium tetra isopropoxide (TTIP) as a precursor relatively at low temperature in acidic pH. Titania sol was prepared by hydrolysis of TTIP and was mixed with silicic acid and tetrahydrofuran mixture. The reaction was carried out under vigorous stirring for 6 h and dried at room temperature. The resulting powders were characterized by UV-Visible spectroscopy, Fourier transform infrared (FT-IR), X-ray diffraction, scanning electron microscope (SEM) and transmission electron microscope (TEM). The grain size of the particles was calculated by X-ray diffraction, surface morphology and chemical composition was determined from scanning electron microscopy-energy dispersive spectroscopy, metal oxide stretching was confirmed from FT-IR spectroscopy, band gap was calculated using UV-Visible spectroscopy. Surface area of the composite as calculated by BET analyzer and it was found to be 65 and 75 m2/g for TiO2 and TiO2-SiO2 respectively. The photocatalytic experiments were performed with aqueous solution of acid red 88 with TiO2 and TiO2-SiO2 batch studies for 4 h irradiation, direct photolysis of TiO2 and TiO2-SiO2 contributed 94.2% and 96.5% decomposition in solar radiation for the optimized concentration of acid red 88.

Balachandran, K.; Venckatesh, Rajendran; Sivaraj, Rajeshwari; Rajiv, P.

2014-07-01

404

Visible-light-induced photocatalytic degradation of methylene blue with polyaniline-sensitized TiO composite photocatalysts  

NASA Astrophysics Data System (ADS)

A series of polyaniline (PANI)-sensitized TiO 2 composite photocatalysts (PANI/TiO 2) with different mass ratio of polyaniline to nano- TiO 2 (P25) (1:200-1:700) were facilely prepared by mixing a tetrahydrofuran (THF) solution of camphorsulfonic acid (CSA)-doped polyaniline (PANI-CSA) and TiO 2 nanoparticle suspension in ethanol. Transmission electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (DRS) measurements were used to characterize the resulting composite photocatalysts, and their photocatalytic activities were investigated by degrading methylene blue (MB) under visible-light irradiation ( ?>400 nm). The results showed that the surface polyaniline sensitization had no effect on the crystalline structure but aggravated the agglomeration of TiO 2 nanoparticles by forming multi-particles. After being sensitized by PANI, the light response of TiO 2 was extended to visible-light regions and the photocatalytic activity of the composite photocatalysts was enhanced. MB could be degraded more efficiently on PANI/TiO 2 than on the bare TiO 2 when the mass ratio of polyaniline to TiO 2 was in the range 1:400-1:700, and the optimum sensitized effect was found at a mass ratio of 1:500. The determined rate constant of MB degradation over PANI/TiO 2 (1:500) was 0.01515 min -1, which is 1.57 times higher than that of bare TiO 2 (0.00963 min -1). Furthermore, PANI/TiO 2 composite photocatalysts showed good photocatalytic stability after five runs under visible light. The enhancement of photocatalytic activity of the composite photocatalysts could be attributed to the sensitizing effect of PANI. A possible mechanism for the photocatalytic degradation of methylene blue is also proposed.

Wang, Fang; Min, Shixiong; Han, Yuqi; Feng, Lei

2010-08-01

405

Synthesis, photovoltaic performances and TD-DFT modeling of push-pull diacetylide platinum complexes in TiO2 based dye-sensitized solar cells.  

PubMed

In this joint experimental-theoretical work, we present the synthesis and optical and electrochemical characterization of five new bis-acetylide platinum complex dyes end capped with diphenylpyranylidene moieties, as well as their performances in dye-sensitized solar cells (DSCs). Theoretical calculations relying on Time-Dependent Density Functional Theory (TD-DFT) and a range-separated hybrid show a very good match with experimental data and allow us to quantify the charge-transfer character of each compound. The photoconversion efficiency obtained reaches 4.7% for 8e (see TOC Graphic) with the tri-thiophene segment, which is among the highest efficiencies reported for platinum complexes in DSCs. PMID:24837848

Gauthier, Sébastien; Caro, Bertrand; Robin-Le Guen, Françoise; Bhuvanesh, Nattamai; Gladysz, John A; Wojcik, Laurianne; Le Poul, Nicolas; Planchat, Aurélien; Pellegrin, Yann; Blart, Errol; Jacquemin, Denis; Odobel, Fabrice

2014-08-01

406

Preparation and characterization of Fe 3+-doped TiO 2 on fly ash cenospheres for photocatalytic application  

NASA Astrophysics Data System (ADS)

Fe 3+-doped TiO 2 film deposited on fly ash cenosphere (Fe-TiO 2/FAC) was successfully synthesized by the sol-gel method. These fresh photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analyses (TGA). The XRD results showed that Fe element can maintain metastable anatase phase of TiO 2, and effect of temperature showed rutile phase appears in 650 °C for 0.01% Fe-TiO 2/FAC. The SEM analysis revealed the Fe-TiO 2 films on the surface of a fly ash cenosphere with a thickness of 2 ?m. The absorption threshold of Fe-TiO 2/FACs shifted to a longer wavelength compared to the photocatalyst without Fe 3+-doping in the UV-vis absorption spectra. The photocatalytic activity and kinetics of Fe-TiO 2/FAC with varying the iron content and the calcination temperatures were investigated by measuring the photodegradation of methyl blue (MB) during visible light irradiation. Compared with TiO 2/FAC and Fe 3+-doped TiO 2 powder (Fe-TiO 2), the degradation ratio using Fe-TiO 2/FAC increased by 33% and 30%, respectively, and the best calcined temperature was 450 °C and the optimum doping of Fe/Ti molar ratio was 0.01%. The Fe-TiO 2/FAC particles can float in water due to the low density of FAC in favor of phase separation to recover these photocatalyst after the reaction, and the recovery test shows that calcination contributes to regaining photocatalytic activity of Fe-TiO 2/FAC photocatalyst.

Wang, Bing; Li, Qin; Wang, Wei; Li, Ying; Zhai, Jianping

2011-02-01

407

Photocatalytic removal of C.I. Basic Red 46 on immobilized TiO2 nanoparticles: Artificial neural network modelling  

Microsoft Academic Search

C.I. Basic Red 46, commonly used as a textile dye, was photocatalytically removed using supported TiO2 nanoparticles irradiated by a 30 W UV?C lamp in a batch reactor. The investigated photocatalyst was industrial Degussa P25 (crystallite mean size 21 nm) immobilized on glass beads by a heat attachment method. The catalyst was characterized by XRD, SEM, TEM and BET techniques.

A. R. Khataee

2009-01-01

408

Photo-electro catalytic oxidation of aromatic alcohols on visible light-absorbing nitrogen-doped TiO2  

Microsoft Academic Search

Visible light illumination of nitrogen-doped TiO2 brings about the selective oxidation of benzyl and cinnamyl alcohol to the corresponding aldehydes. The photocatalyst was prepared by a sol–gel method and characterised mainly by XRD, UV–vis diffuse reflectance and Raman spectroscopy. The conditions limiting the observation of visible light photoactivity are the use of dry nitriles as nonaqueous solvents and aromatic alcohols

L. Samiolo; M. Valigi; D. Gazzoli; R. Amadelli

2010-01-01

409

Application of nano TiO 2 towards polluted water treatment combined with electro-photochemical method  

Microsoft Academic Search

A novel composite reactor was prepared and studied towards the degradation of organic pollutants in this work. In the reactor, a UV lamp was installed to provide energy to excite nano TiO2, which served as photocatalyst, leading to the production of hole–electron pairs, and a three-electrode electrolysis system was used to accumulate H2O2 which played an important role in the

Junshui Chen; Meichuan Liu; Li Zhang; Jidong Zhang; Litong Jin

2003-01-01

410

Photocatalytic property of Fe 2O 3 nanograin chains coated by TiO 2 nanolayer in visible light irradiation  

Microsoft Academic Search

The visible light photocatalytic activity of ?-Fe2O3 nanograin chains coated by anatase TiO2 nanolayer, as a photocatalyst thin film for inactivation of Escherichia coli bacteria, was investigated for the solutions containing 106 colony forming units per milliliter of the bacteria, without and with H2O2 (60?M). Thin films of the ?-Fe2O3 nanograins with the grain size of 40–280nm were grown on

O. Akhavan; R. Azimirad

2009-01-01

411

Removal of VOCs by photocatalysis process using adsorption enhanced TiO 2–SiO 2 catalyst  

Microsoft Academic Search

Volatile organic compounds (VOCs) exist widely in both the indoor and outdoor environment. The main contributing sources of VOCs are motor vehicle exhaust and solvent utilization. Some VOCs are toxic and carcinogenic to human health, such as benzene. In this study, TiO2–SiO2 based photocatalysts were synthesized using the sol–gel method, with high surface areas of 274.1–421.1m2\\/g obtained. Two types of

Linda Zou; Yonggang Luo; Martin Hooper; Eric Hu

2006-01-01

412

Visible light active TiO 2 films prepared by electron beam deposition of noble metals  

NASA Astrophysics Data System (ADS)

TiO 2 films prepared by sol-gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV-Vis spectroscopy techniques. Photocatalytic activity of modified TiO 2 films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO 2 is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV-Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO 2 films by this method is affected by the concentration of impregnating solution.

Hou, Xing-Gang; Ma, Jun; Liu, An-Dong; Li, De-Jun; Huang, Mei-Dong; Deng, Xiang-Yun

2010-03-01

413

Photoassisted and photocatalytic degradation of sulfur mustard using TiO2 nanoparticles and polyoxometalates.  

PubMed

The decomposition of highly toxic chemical warfare agent, sulfur mustard (bis(2-chloroethyl) sulfide or HD), has been studied by homogeneous photolysis and heterogeneous photocatalytic degradation on titania nanoparticles. Direct photolysis degradation of HD with irradiation system was investigated. The photocatalytic degradation of HD was investigated in the presence of TiO(2) nanoparticles and polyoxometalates embedded in titania nanoparticles in liquid phase at room temperature (33 ± 2 °C). Degradation products during the treatment were identified by gas chromatography-mass spectrometry. Whereas apparent first-order kinetics of ultraviolet (UV) photolysis were slow (0.0091 min(-1)), the highest degradation rate is obtained in the presence of TiO(2) nanoparticles as nanophotocatalyst. Simultaneous photolysis and photocatalysis under the full UV radiation leads to HD complete destruction in 3 h. No degradation products observed in the presence of nanophotocatalyst without irradiation in 3 h. It was found that up to 90 % of agent was decomposed under of UV irradiation without TiO(2), in 6 h. The decontamination mechanisms are often quite complex and multiple mechanisms can be operable such as hydrolysis, oxidation, and elimination. By simultaneously carrying out photolysis and photocatalysis in hexane, we have succeeded in achieving faster HD decontamination after 90 min with low catalyst loading. TiO(2) nanoparticles proved to be a superior photocatalyst under UV irradiation for HD decontamination. PMID:22707206

Naseri, Mohammad Taghi; Sarabadani, Mansour; Ashrafi, Davood; Saeidian, Hamdollah; Babri, Mehran

2013-02-01

414

Photocatalysis with chromium-doped TiO2: bulk and surface doping.  

PubMed

The photocatalytic properties of TiO2 modified by chromium are usually found to depend strongly on the preparation method. To clarify this problem, two series of chromium-doped titania with a chromium content of up to 1.56?wt?% have been prepared under hydrothermal conditions: the first series (Cr:TiO2) is intended to dope the bulk of TiO2, whereas the second series (Cr/TiO2) is intended to load the surface of TiO2 with Cr. The catalytic properties have been compared in the photocatalytic oxidation of formic acid. Characterization data provides evidence that in the Cr/TiO2 catalysts chromium is located on the surface of TiO2 as amorphous CrOOH clusters. In contrast, in the Cr:TiO2 series, chromium is mostly dissolved in the titania lattice, although a minor part is still present on the surface. Photocatalytic tests show that both series of chromium-doped titania demonstrate visible-light-driven photo-oxidation activity. Surface-doped Cr/TiO2 solids appear to be more efficient photocatalysts than the bulk-doped Cr:TiO2 counterparts. PMID:24737636

Ould-Chikh, Samy; Proux, Olivier; Afanasiev, Pavel; Khrouz, Lhoussain; Hedhili, Mohamed N; Anjum, Dalaver H; Harb, Moussab; Geantet, Christophe; Basset, Jean-Marie; Puzenat, Eric

2014-05-01

415

Bactericidal activity of photocatalytic TiO(2) reaction: toward an understanding of its killing mechanism.  

PubMed

When titanium dioxide (TiO(2)) is irradiated with near-UV light, this semiconductor exhibits strong bactericidal activity. In this paper, we present the first evidence that the lipid peroxidation reaction is the underlying mechanism of death of Escherichia coli K-12 cells that are irradiated in the presence of the TiO(2) photocatalyst. Using production of malondialdehyde (MDA) as an index to assess cell membrane damage by lipid peroxidation, we observed that there was an exponential increase in the production of MDA, whose concentration reached 1.1 to 2.4 nmol. mg (dry weight) of cells(-1) after 30 min of illumination, and that the kinetics of this process paralleled cell death. Under these conditions, concomitant losses of 77 to 93% of the cell respiratory activity were also detected, as measured by both oxygen uptake and reduction of 2,3,5-triphenyltetrazolium chloride from succinate as the electron donor. The occurrence of lipid peroxidation and the simultaneous losses of both membrane-dependent respiratory activity and cell viability depended strictly on the presence of both light and TiO(2). We concluded that TiO(2) photocatalysis promoted peroxidation of the polyunsaturated phospholipid component of the lipid membrane initially and induced major disorder in the E. coli cell membrane. Subsequently, essential functions that rely on intact cell membrane architecture, such as respiratory activity, were lost, and cell death was inevitable. PMID:10473421

Maness, P C; Smolinski, S; Blake, D M; Huang, Z; Wolfrum, E J; Jacoby, W A

1999-09-01

416

3D silk fibroin scaffold incorporating titanium dioxide (TiO2) nanoparticle (NPs) for tissue engineering.  

PubMed

The present study deals with fabrication of scaffolds composing of silk fibroin and TiO2 NPs fabricated using a salt-leaching process. At first instance, the TiO2 NPs were prepared by using sol-gel synthesis, affording to have average diameter of 77±21?m. Furthermore, the aqueous solutions of silk fibroin were mixed with 0.2%, 2.0% and 4.0% of TiO2 NPs and salt-leaching process was introduced which resulted in creation of porous scaffolds modified with TiO2 NPs. The presence of TiO2 NPs in scaffolds was confirmed by VP-FE-SEM-EDS, TGA and XRD. The presence of TiO2 NPs influenced in decrease in pore size and swelling behavior of composite scaffolds. The resultant mechanical property of scaffolds was improved upon the introduction of TiO2 NPs. Moreover, cell cytotoxicity results for 1, 3 and 7 days; revealed no toxic behavior to osteoblasts. However, a mild toxicity to NIH 3T3 fibroblasts was observed with the scaffolds containing 4.0% TiO2 NPs. The cell fixation results from 1 and 7 days of incubation indicated the attachment, spreading and subsequent proliferation of fibroblasts. However, these findings were independent to the amount of TiO2 NPs in scaffolds. PMID:24794196

Kim, Jung-Ho; Sheikh, Faheem A; Ju, Hyung Woo; Park, Hyun Jung; Moon, Bo Mi; Lee, Ok Joo; Park, Chan Hum

2014-07-01

417

Dispersed-Nanoparticle Loading Synthesis for Monodisperse Au-Titania Composite Particles and Their Crystallization for Highly Active UV and Visible Photocatalysts.  

PubMed

Submicrometer-sized amorphous titania spheres incorporating Au nanoparticles (NPs) were prepared in a one-pot synthesis consisting of a sol-gel reaction of titanium(IV) isopropoxide in the presence of chloroauric acid and a successive reduction with sodium borohydride in a mixed solvent of ethanol/acetonitrile. The synthesis was allowed to prepare monodisperse titania spheres that homogeneously incorporated Au NPs with sizes of ca. 7 nm. The Au NP-loaded titania spheres underwent different crystallization processes, including 500 °C calcination in air, high-temperature hydrothermal treatment (HHT), and/or low-temperature hydrothermal treatment (LHT). Photocatalytic experiments were conducted with the Au NP-loaded crystalline titania spheres under irradiation of UV and visible light. A combined process of LHT at 80 °C followed by calcination at 500 °C could effectively crystallize titania spheres maintaining the dispersion state of Au NPs, which led to photocatalytic activity higher than that of commercial P25 under UV irradiation. Under visible light irradiation, the Au NP-titania spheres prepared with a crystallization process of LHT at 80 °C for 6 h showed photocatalytic activity much higher than a commercial product of visible light photocatalyst. Structure analysis of the visible light photocatalysts indicates the importance of prevention of the Au NPs aggregation in the crystallization processes for enhancement of photocatalytic activity. PMID:24878432

Sakamoto, Takeshi; Nagao, Daisuke; Noba, Masahiro; Ishii, Haruyuki; Konno, Mikio

2014-06-24

418

Fabrication of TiO2 film with different morphologies on Ni anode and application in photoassisted water electrolysis  

NASA Astrophysics Data System (ADS)

The anode of an alkaline electrolytic cell for water electrolysis was modified by TiO2 photocatalysts with different morphologies. The water electrolysis was coupled with photocatalytic decomposition of water by irradiation of UV light on the modified anode. And a feasible process for the hydrogen production of water electrolysis assisted by photocatalysis (WEAP) was proposed and experimentally confirmed. The results show that the highly ordered, vertically oriented tubular arrays structure on Ni anode surface has better hydrogen production performance than random TiO2. In WEAP process, the maximum rate of hydrogen production is 2.77 ml/(h*cm2) when the anode modified by ordered TiO2 nanotube arrays, compared to traditional alkaline electrolytic cell for water electrolysis with Ni anode, H2-production rate increased by 139%.

He, Hongbo; Chen, Aiping; Lv, Hui; Dong, Haijun; Chang, Ming; Li, Chunzhong

2013-02-01

419

Synthesis, loading control and applications of 2,4,6-triphenylpyrilium as a solar photocatalyst  

NASA Astrophysics Data System (ADS)

The technologies or processes of oxidation outpost that uses like energy the solar radiation for the degradation of polluting agents, suppose a novel alternative with important economic and environmental advantages. A proof of it has been the spectacular development which they have been these applications at world-wide level in the last years old, as well as the interest that the subject in international the scientific community has provoked. 2,4,6-trifenilpirilio by its singularity in this field has been chosen for this thesis the cation. It has been left from a study about the fotocatalitica activity of this cation, from the salt of hidrogenosulfato 2,4,6-trifenilpirilio and of the salt of tetrafluorborato 2,4,6-trifenilpirilio, when they act in homogenous phase on polluting agents, derivatives of dissolved fenolicos compounds in residual coming from the industry. In the first stage of the study I confirm the degradativo power of this cation but nevertheless a series of disadvantages in homogena phase was detected, had to the chemical characteristics of this organic species: hidrolitica opening of the ring and impossibility of reusability. With the purpose of correcting these problems it has been investigated and developed different methods from synthesis, in which this cation is supported in inorganic materials, concretely: silica gel, zeolites and sepiolitas. It has been come to the study, of individual form, the parameters that influence of significant form in the yield of the different processes and also has been verified the fotocatalitica activity of the new synthesized materials. In the developed methods it has been managed to totally control the amount of cation supported in the chosen materials and of this form to be able to know the effectiveness his activity like fotocatalizador in heterogenous phase. It is possible to emphasize, that the proposed procedures of synthesis, are quite simple and fast in his execution. The made studies have been carried out on scale laboratory, trying to follow future investigations in plant pilot industrial level, like also, is tried to investigate the development of synthesis methods using the cation 2,4,6-trifeniltiopirilio for the obtaining of new heterogenous materials, with fotocataliticas properties.

Vercher Perez, Rosa

420

Electrophoretic deposition of uniformly distributed TiO2 nanoparticles using an anodic aluminum oxide template for efficient photolysis  

NASA Astrophysics Data System (ADS)

In this study, a novel method for fabricating a high efficiency titanium dioxide photocatalyst is presented. Radio frequency (RF) magnetron sputtering was employed to grow 3D nano-structured Au thin films using the barrier-layer side of anodic aluminum oxide (AAO) as the template. The template was prepared by immersing this side of an AAO film into a 30 wt% phosphoric acid solution to modify the surface of the barrier layer in such a manner that a contrasting surface was obtained. The electrophoretic deposition method was then implemented to uniformly deposit TiO2 nanoparticles on the 3D nano-structured Au electrode. The efficiency of the proposed photocatalyst, in terms of the photolysis efficiency, was measured using proton-motive-force driving chloroplastmimic photovoltaics. Experiments were carried out to demonstrate the photolysis efficiency of the proposed 3D nano-structured TiO2 photocatalyst, which showed a 10-fold increase over that of Degussa P25 plane TiO2. The photocurrent could be further enhanced by the deposition of a sensitized dye, such as N3, which extended the absorption spectrum from the UV range to the visible light range.

Wang, Gou-Jen; Chou, Shi-Wei

2010-03-01

421

New TiO2/MgAl-LDH nanocomposites for the photocatalytic degradation of dyes.  

PubMed

In this study we report the synthesis of a series of composite nanostructures comprising LDH and TiO2 phases. The materials characterization showed that the LDH crystallites are encapsulated inside the TiO2 matrix after the anatase seeds are deposited on MgxAl-LDHs. The structure in which LDH phase is embedded into anatase matrix is unique bringing important advantages to the photocatalytic performances of the nanocomposites. The photocatalytic activity of the prepared nanocomposites was tested on the degradation of the methylene blue (MB) in aqueous solution. The photocatalytic activities of the nanocomposites were compared with commercial TiO2 nanoparticles Degussa P25. The nanocomposites exhibited superior photocatalytic activity in basic environment because the negatively charged surface of TiO2 nanoparticles at high pH attracts the positively charged methylene blue species. PMID:21121320

Seftel, E M; Popovici, E; Beyers, E; Mertens, M; Zhu, H Y; Vansant, E F; Cool, P

2010-12-01

422

Experimental and molecular dynamics study of the growth of crystalline TiO2  

NASA Astrophysics Data System (ADS)

Thin films of crystalline TiO2 are of high interest due to their photoactivity and photoinduced hydrophilicity. Previously, preparation of TiO2 has been described in terms of extrinsic process parameters, such as total pressure, oxygen partial pressure, or substrate bias potential. We study the growth of TiO2 phases, rutile and anatase, by atom-by-atom molecular dynamics simulations. We focus on the effect of intrinsic process parameters including particle energy, growth temperature, and growth template. While experiments indicate that the deposition of rutile requires higher temperatures and/or energies compared to anatase, we show that the growth of previously nucleated rutile can take place in a wider range of temperatures and energies compared to anatase. In parallel, we show relationships between crystal growth and the lateral size of a crystal. The results facilitate defining new synthesis pathways for TiO2, and constitute phenomena which may be relevant for other ceramics.

Houska, J.; Mraz, S.; Schneider, J. M.

2012-10-01

423

Fabrication of In2S3 nanoparticle decorated TiO2 nanotube arrays by successive ionic layer adsorption and reaction technique and their photocatalytic application.  

PubMed

In2S3 nanoparticle (NP) decorated self-organized TiO2 nanotube array (In2S3/TiO2 NT) hybrids were fabricated via simple successive ionic layer adsorption and reaction (SILAR) technique. The In2S3 NPs in a size of about 15 nm were found to deposit on the top surface of the highly oriented TiO2 NT while without clogging the tube entrances. The loading amount of In2S3 NPs on the TiO2 NT was controlled by the cycle number of SILAR deposition. Compared with the bare TiO2 NT, the In2S3/TiO2 NT hybrids showed stronger absorption in the visible light region and significantly enhanced photocurrent density. The photocatalytic activity of the In2S3/TiO2 NT photocatalyst far exceeds that of bare TiO2 NT in the degradation of typical herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) under simulated solar light. After 160-min irradiation, almost 100% 2,4-D removal is obtained on the 7-In2S3/TiO2 NT prepared through seven SILAR deposition cycles, much higher than 26% on the bare TiO2 NT. After 10 successive cycles of photocatalytic process with total 1,600 min of irradiation, In2S3/TiO2 NT maintained as high 2,4-D removal efficiency as 95.1% with good stability and easy recovery, which justifies the potential of the photocatalytic system in application for the photocatalytic removal of organic pollutants such as herbicides or pesticides from water. PMID:24738366

Zhang, Zhenrong; Tang, Yanhong; Liu, Chengbin; Wan, Long

2014-06-01

424

Ionic liquid promoted synthesis of conjugated carbon nitride photocatalysts from urea.  

PubMed

To allow for simultaneous textural engineering and doping of carbon nitride materials with heteroatoms, urea has been polymerized with an ionic liquid. The role of urea is to create a delamination effect during carbon nitride synthesis, whereas ionic liquid functions as texture modifier as well as B/F dopant source. This will result in the rational fabrication of boron- and fluorine-containing 2D carbon nitride nanosheets with enhanced optical harvesting and charge separation capabilities for hydrogen evolution catalysis using visible light. We believe that the innovative modification strategy developed herein can be coupled with the already known modification tools of 2D carbon nitride, thus further developing a new family of light-harvesting 2D platforms for the efficient and sustained utilization of solar radiation for a variety of advanced applications, including CO2 photofixation, organic photosynthesis, and pollutant controls. PMID:24692300

Lin, Zhenzhen; Wang, Xinchen

2014-06-01

425

Photodegradation of aqueous reactive dye using TiO(2)/zeolite admixtures in a continuous flow reactor.  

PubMed

The photocatalytic degradation of an organic dye, i.e. reactive blue 19 (RB19), was studied by employing different TiO(2)/zeolite (TZ) photocatalysts, which have TiO(2)/(TiO(2) + zeolite) weight ratios ranging from 20 to 80%, in a continuous flow system. Three light sources including two UV lights (i.e. ?(max,254 nm) and ?(max,365 nm)) and natural sunlight were used. The results showed that the decoloring rate of RB19 increased as the amount of TiO(2) in the TZ catalyst increased. The photodegradation of RB19 exhibited pseudo-first-order kinetics with respect to the concentration of RB19. Almost 100% of initial RB19 was mineralized under the controlled conditions in this study. And the activities of the prepared photocatalysts were retained after long-term durability experiments. Compared with UV lights (i.e. ?(max,254 nm) and ?(max,365 nm)), the decoloring efficiency of RB19 was significantly increased under natural sunlight illumination, which is likely due to the long-wavelength incident light that photoexcited RB19 and accelerated the degradation rate of RB19 radicals by the UV fraction of sunlight. PMID:22592465

Kuo, Chao-Yin; Pai, Chueh-Ying; He, Cheng-Chun; Lin, Chin-Jung; Cheng, Chin-Min

2012-01-01

426

Novel photocatalyst-based colourimetric indicator for oxygen  

Microsoft Academic Search

The preparation and characterisation of a novel, UV-activated solvent-based, colourimetric indicator for O2 is described, comprising a redox dye (methylene blue, MB), semiconductor photocatalyst (TiO2), and a sacrificial electron donor (SED), all dispersed\\/dissolved in a polymer medium (sulfonated polystyrene, SPS). Upon exposure, the indicator is readily photobleached as the MB is converted into its oxygen-sensitive, leuco form, LMB. Unlike its

Andrew Mills; David Hazafy; Katherine Lawrie

2011-01-01

427

Synthesis and characterization of F-N-W-codoped TiO{sub 2} photocatalyst with enhanced visible light response  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? Anatase F-N-W-codoped TiO{sub 2} was prepared by a sol–gel-hydrothermal method. ? Under visible illumination, carbon removal rate of RB reached 94% using F-7NW-TiO{sub 2}. ? F, N and W dopants narrowed band gap and lowed charge pairs recombination rate. ? There were W{sub x}Ti{sub 1?x}O{sub 2}, O-Ti-N and valence variation of W ions existing. -- Abstract: Anatase F-N-W-codoped TiO{sub 2} photocatalyst was successfully prepared by a method combining sol–gel with hydrothermal treatment. Effects of F, N and W ion dosage concentration on the crystallinity, morphology, grain size and chemical status of the photocatalyst were investigated. The results showed that the F-7NW-TiO{sub 2} photocatalyst composed of uniform ellipsoidal particles around 20 nm in length and 10 nm in width, and the photocatalyst displayed enhanced visible-light absorption and photocatalytic activities. Using the photocatalyst and under visible irradiation for 1.5 h, the decoloration percent of RB and carbon removal rate were about 98% and 94% respectively, which were much higher than that of commercial P25, TiO{sub 2}, N-W-TiO{sub 2} and F-TiO{sub 2}. The high visible-light photocatalytic activity of F-7NW-TiO{sub 2} might result from narrowing the band gap and lowing charge pairs recombination rate for the W{sub x}Ti{sub 1?x}O{sub 2}, O-Ti-N and valence variation of W ions existing.

Shi, Xiaoliang, E-mail: sxl071932@126.com [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China) [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Qin, Haibo; Yang, Xingyong [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China)] [School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); Zhang, Qiaoxin [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China) [School of Mechanical and Electronic Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China); School of Materials Science and Engineering, Wuhan University of Technology, 122 Luoshi Road, Wuhan 430070 (China)

2012-12-15

428

Molecular-Level Insights into Photocatalysis from Scanning Probe Microscopy Studies on TiO2(110)  

SciTech Connect

The field of heterogeneous photocatalysis has grown considerably in the decades since Fujishima and Honda's ground-breaking publications of photoelectrochemistry on TiO2. Numerous review articles continue to point to both progress made in the use of heterogeneous materials (such as TiO2) to perform photoconversion processes, and the many opportunities and challenges in heterogeneous photocatalysis research such as solar energy conversion and environmental remediation. The past decade has also seen an increase in the use of molecular-level approaches applied to model single crystal surfaces in an effort to obtain new insights into photocatalytic phenomena. In particular, scanning probe techniques (SPM) have enabled researchers to take a ‘nanoscale’ approach to photocatalysis that includes interrogation of the reactivities of specific sites and adsorbates on a model photocatalyst surface. The rutile TiO2(110) surface has become the prototypical oxide single crystal surface for fundamental studies of many interfacial phenomena. In particular, TiO2(110) has become an excellent model surface for probing photochemical and photocatalytic reactions at the molecular level. A variety of experimental approaches have emerged as being ideally suited for studying photochemical reactions on TiO2(110), including desorption-oriented approaches and electronic spectroscopies, but perhaps the most promising techniques for evaluating site-specific properties are those of SPM. In this review, we highlight the growing use of SPM techniques in providing molecular-level insights into surface photochemistry on the model photocatalyst surface of rutile TiO2(110). Our objective is to both illustrate the unique knowledge that scanning probe techniques have already provided the field of photocatalysis, and also to motivate a new generation of effort into the use of such approaches to obtain new insights into the molecular level details of photochemical events occurring at interfaces. Discussion will start with an examination of how scanning probe techniques are being used to characterize the TiO2(110) surface in ways that are relevant to photocatalysis. We will then discuss specific classes of photochemical reaction on TiO2(110) for which SPM has proven indispensible in providing unique molecular-level insights, and conclude with discussion of future areas in which SPM studies may prove valuable to photocatalysis on TiO2. This work was supported by the US Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. I.L. was partially supported by a Pacific Northwest National Laboratory (PNNL) Chemical Imaging Initiative project. PNNL is a multiprogram national laboratory operated for DOE by Battelle.

Henderson, Michael A.; Lyubinetsky, Igor

2013-06-12

429

Template-free synthesis of cube-like Ag/AgCl nanostructures via a direct-precipitation protocol: highly efficient sunlight-driven plasmonic photocatalysts.  

PubMed

In this paper, we report that cube-like Ag/AgCl nanostructures could be facilely fabricated in a one-pot manner through a direct-precipitation protocol under ambient conditions, wherein no additional issues such as external energy (e.g., high temperature or high pressure), surfactants, or reducing agents are required. In terms of using sodium chloride (NaCl) as chlorine source and silver acetate (CH?COOAg) as silver source, it is disclosed that simply by adding an aqueous solution of NaCl into an aqueous solution of CH?COOAg, Ag/AgCl nanostructures with a cube-like geometry, could be successfully formulated. We show that thus-formulated cube-like Ag/AgCl nanospecies could be used as high-performance yet durable visible-light-driven or sunlight-driven plasmonic photocatalysts for the photodegradation of methyl orange (MO) and 4-chlorophenol (4-CP) pollutants. Compared with the commercially available P25-TiO?, and the Ag/AgCl nanospheres previously fabricated via a surfactant-assisted method, our current cube-like Ag/AgCl nanostructures could exhibit much higher photocatalytic performance. Our template free protocol might open up new and varied opportunities for an easy synthesis of cube-like Ag/AgCl-based high-performance sunlight-driven plasmonic photocatalysts for organic pollutant elimination. PMID:23138343

Zhu, Mingshan; Chen, Penglei; Ma, Wanhong; Lei, Bin; Liu, Minghua

2012-11-01

430

Improved binary and ternary nanostructured photocatalysts for gas phase detoxification of toluene  

NASA Astrophysics Data System (ADS)

Photocatalysis using nanocrystalline materials with enhanced catalytic properties under ultraviolet (UV) or visible light has the potential for becoming one of the leading processes for the abatement of environmental problems. This work is focused on the study of the synthesis, characterization, and photocatalytic application of nanocrystalline binary and ternary oxide catalysts. These nanostructured materials were synthesized by conventional sol-gel preparation methods, by inverse micelles, and by incipient wetness impregnation. The photocatalysts were characterized using XRD, FTIR, UV-Visible, and Raman spectroscopy, SEM, and TEM. The addition of silica to titania reduces anatase crystallite size, increases surface area, and modifies surface acidity. The photocatalytic results demonstrate that 7.5% sol-gel based catalysts are more active than the Degussa catalysts (P25 TiO2, and 8% SiO 2-TiO2) using UV or Visible light on a catalyst mass basis. The photocatalytic activity using UV light is four times higher than the photocatalytic activity using visible light. The photocatalytic activity of the WO3-TiO2 binary oxide catalysts was higher than P25 TiO2 and Degussa 8% SiO 2-TiO2 under UV or visible light, and depended strongly on the tungsten content. The addition of WO3 into the anatase crystal structure of titania may potentially affect the photocatalytic activity by several factors such as: increasing the absorption capacity in the visible region, presence of surface W sites enhancing oxygen activation, changing the surface acidity, increasing the surface area, and improving the surface trapping of electron and holes before recombination. The results for the photocatalytic oxidation of toluene demonstrate that the addition of a third metal oxide does not improve the photocatalytic activity significantly in comparison with the binary oxides. The addition of Fe 2O3 reduces the activity of the catalyst. All the samples prepared by the sol-gel method have less rutile than P25 TiO2. The intensity of the peaks associated to the anatase crystal phase decreased with an increase in the Si or W content. Loading the Degussa and sol-gel catalysts with 2.5% MoS2 improves the photocatalytic performance for the toluene oxidation. The MoS2 was synthesized using an inverse micelle method and loaded on to the catalysts by incipient wetness impregnation. Doping the Degussa catalysts with MoS 2 dobles the initial activity relative to the unloaded catalysts. The MoS2 impregnated Degussa catalysts enhance the applicability of the visible light for the photocatalytic oxidation of toluene. Loading the 12.4% WO3-TiO2 sol-gel sample with 2.5% MoS2 increases the activity for the toluene oxidation using UV or visible light for the photocatalytic process. When MoS2 is loaded on a sample of 31.9% WO3-TiO2 no significant improvement of the activity occurred. All the MoS2 impregnated catalysts deactivate slower than the unloaded catalysts.

Mendez Roman, Rafael

431

Nanoporous TiO2 nanoparticle assemblies with mesoscale morphologies: nano-cabbage versus sea-anemone  

NASA Astrophysics Data System (ADS)

We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation.We report the novel synthesis of nanoporous TiO2 nanoparticle ensembles with unique mesoscale morphologies. Constituent nanoparticles evolved into multifaceted assemblies, exhibiting excellent crystallinity and enhanced photocatalytic activity compared with commercial TiO2. Such materials could be exploited for applications, like organic pollutant degradation. Electronic supplementary information (ESI) available: Synthesis and characterization procedures, TEM/XRD of samples prepared at different temperature and water content, table of nitrogen adsorption-desorption values of different samples. See DOI: 10.1039/c3nr06154j

Darbandi, Masih; Gebre, Tesfaye; Mitchell, Lucas; Erwin, William; Bardhan, Rizia; Levan, M. Douglas; Mochena, Mogus D.; Dickerson, James H.

2014-05-01

432

TiO2\\/AC Composites for Synergistic Adsorption-Photocatalysis Processes: Present Challenges and Further Developments for Water Treatment and Reclamation  

Microsoft Academic Search

Titanium dioxide supported on activated carbon, or TiO2\\/AC composite, exhibits bifunctionality of adsorption and photocatalysis in synergism. The authors review the TiO2\\/AC synthesis techniques, characteristics, and performances in removing organic pollutants in water. Practical issues pertinent to applications of the TiO2\\/AC composite in water treatment and reclamation are discussed. These include dispersing the particles and recovering from the product water,

Teik-Thye Lim; Pow-Seng Yap; Madhavi Srinivasan; Anthony G. Fane

2011-01-01

433

Investigations of near infrared reflective behaviour of TiO2 nanopowders synthesized by arc discharge  

NASA Astrophysics Data System (ADS)

Titanium dioxide (TiO2) nanopowders with different polymorphic phases were successfully synthesized by an arc discharge method. Samples were characterized using synchrotron radiation X-ray diffraction, high resolution scanning electron microscopy, high resolution transmission electron microscope and near infrared diffuse reflectance spectroscopy. Spherical structures were obtained after arc discharge. A mixture of both anatase and rutile phases was discovered in TiO2 samples synthesized at an arc current of 50 A, showing a majority particle size of 34 nm with size distribution between 5 nm and 60 nm. Completed anatase to rutile phase transformation was observed when the arc current increased from 50 A to 74 A. The crystallite size of the TiO2 nanopowders was significant effected by the arc discharge current during synthesis. After the arc current increased from 74 A to 110 A, the majority particle size of the obtained TiO2 increased to 85 nm with a size distribution in the range between 50 nm and 1800 nm. Diffuse reflectance of the TiO2 nanopowders synthesized at different arc discharge currents was measured. Broadband near infrared reflection (800–950 nm) of up to 50% was observed for TiO2 nanopowders synthesized at an arc current of 74 A. It is considered that rutile phase together with an appropriate mean crystallite size of the TiO2 nanopowders synthesized at an arc current of 74 A contributes to the best near infrared reflectivity in this study. The developed TiO2 nanoppowders will be of immense use in NIR reflective pigment.

Fang, Fang; Kennedy, John; Carder, Damian; Futter, John; Rubanov, Sergey

2014-05-01

434

Significant enhancement in the photocatalytic activity of N, W co-doped TiO2 nanomaterials for promising environmental applications  

NASA Astrophysics Data System (ADS)

In this work, a mesoporous N, W co-doped TiO2 photocatalyst was synthesized via a one-step solution combustion method, which utilized urea as the nitrogen source and sodium tungstate as the tungsten source. The photocatalytic activity of the N, W co-doped TiO2 photocatalyst was significantly enhanced by a facile UV pretreatment approach and was evaluated by measuring the rate of photodegradation of Rhodamine B under both UV and visible (? > 420) light. Following the UV pretreatment, the UV photocatalytic activity of the N, W co-doped TiO2 was doubled. In terms of visible light activity, the UV pretreatment resulted in an extraordinary >12 fold improvement. In order to gain insight into this substantial enhancement, the N, W co-doped TiO2 photocatalysts were studied using x-ray diffraction, transmission electron microscopy, N2 physisorption, UV-vis absorbance spectroscopy and x-ray photoelectron spectroscopy prior to and following the UV pretreatment. Our experimental results have revealed that this significant augmentation of photocatalytic activity may be attributed to several synergetic factors, including increase of the specific surface area, reduction of the band gap energy and the removal of carbon impurities.

Thind, Sapanbir S.; Wu, Guosheng; Tian, Min; Chen, Aicheng

2012-11-01

435

Preparation of heteropolyacid/TiO2/fly-ash-cenosphere photocatalyst for the degradation of ciprofloxacin from aqueous solutions  

NASA Astrophysics Data System (ADS)

The TiO2/fly-ash cenosphere photocatalysts modified with heteropolyacid were synthesized by sol-gel followed solvothermal method at 40 °C. Their chemical composition and optical absorption were characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), Fourier Transform Infra Red spectroscopy (FTIR) and Scanning electron microscopy (SEM). It was found that heteropolyacid modification could facilitate the absorption edge of TiO2/fly-ash cenosphere photocatalyst to shift the visible light region. Heteropolyoxanion could be loaded on the titanium dioxide surface, by which could hinder the recombination rate of excited electron holes. The photocatalytic activity of TiO2/fly-ash cenospheres modified with heteropolyacid was observed for the degradation of ciprofloxacin (CPFX) under visible light irradiation. The result from degradation of CPFX suggested that the photocatalytic activity of TiO2/fly-ash cenospheres modified with silicotungstic acid was superior. The synergistic effects of heteropolyacid in modified TiO2/fly-ash cenospheres photocatalyst particles were responsible for improving visible light photocatalytic activity. Besides, the novel photocatalyst was easy to recycle during post treatment because the fly-ash cenosphere was adopted for carrier.

Wu, Di; Huo, Pengwei; Lu, Ziyang; Gao, Xun; Liu, Xiaolin; Shi, Weidong; Yan, Yongsheng

2012-07-01