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Sample records for carbon nanotube-doped tio2

  1. Carbon nanotube-doped tellurite glasses

    Science.gov (United States)

    Mazali, I. O.; Chillcce, E. F.; Ferreira, O. P.; Rodriguez, E.; Jacob, G. J.; Cesar, C. L.; Barbosa, L. C.

    2008-02-01

    In the past it was observed that buck ball doped glasses showed enhanced optical nonlinearities. However, carbon nanotubes are much more stable than buck ball and should be a better choice for that purpose. Therefore we decided to investigate the possibility to produce carbon nanotubes doped tellurite glasses and measured their optical nonlinearities. Tellurite glasses already have a larger nonlinearity compared to silica, and other, glasses. We produced TeO II-ZnO tellurite family glasses doped with multi wall Carbon Nanotube (CNT). The CNTs acquired from Carbolex were vigorously mechanically mixed with the tellurite glass precursors and melted in platinum crucible around 650°C in a controlled atmosphere inside an electrical induction furnace. We used the lowest temperature possible and controlled atmosphere to avoid the CNT oxidation. The glass melt was cast in a stainless steel and thermally treated at 300°C for 5 hours to relieve internal stresses. The samples were than cutted and polished to perform the optical characterization. We measured refractive index and thermo physical properties, such as vitreous transition T g, crystallization onset T x and melting T f temperatures. Raman spectroscopy showed the possible presence of CNTs.

  2. Synthesis and Characterization of Multi-walled Carbon Nanotube Doped Silica Aerogels

    Institute of Scientific and Technical Information of China (English)

    WANG Baomin; SONG Kai; HAN Yu; ZHANG Tingting

    2012-01-01

    Mulri-walled carbon nanotube doped silica aerogels(MWCNT-SAs) were synthesized from a wet gel of well-dispersed MWCNT by one-step solvent exchange/surface modification and ambient pressure drying(APD).Waterglass was employed as a precursor to prepare wet gel.The content of MWCNT varied from 0 to 15% volume by wet gel.The surface group,thermal stability and microstructure of pure silica aerogel and MWCNT-SAs were investigated by FTIR,DTA,and TEM.Experimental results show that MWCNT-SAs are hydrophobic when the temperature is below 400 ℃,MWCN T -SAs exhibit a mesoporous network structure,and they achieve the largest scale with least shrinkage and lowest density when doped with 5 vol% MWCNT.

  3. A Fumonisins Immunosensor Based on Polyanilino-Carbon Nanotubes Doped with Palladium Telluride Quantum Dots

    Directory of Open Access Journals (Sweden)

    Milua Masikini

    2014-12-01

    Full Text Available An impedimetric immunosensor for fumonisins was developed based on poly(2,5-dimethoxyaniline-multi-wall carbon nanotubes doped with palladium telluride quantum dots onto a glassy carbon surface. The composite was assembled by a layer-by-layer method to form a multilayer film of quantum dots (QDs and poly(2,5-dimethoxyaniline-multi-wall carbon nanotubes (PDMA-MWCNT. Preparation of the electrochemical immunosensor for fumonisins involved drop-coating of fumonisins antibody onto the composite modified glassy carbon electrode. The electrochemical impedance spectroscopy response of the FB1 immunosensor (GCE/PT-PDMA-MWCNT/anti-Fms-BSA gave a linear range of 7 to 49 ng L−1 and the corresponding sensitivity and detection limits were 0.0162 kΩ L ng−1 and 0.46 pg L−1, respectively, hence the limit of detection of the GCE/PT-PDMA-MWCNT immunosensor for fumonisins in corn certified material was calculated to be 0.014 and 0.011 ppm for FB1, and FB2 and FB3, respectively. These results are lower than those obtained by ELISA, a provisional maximum tolerable daily intake (PMTDI for fumonisins (the sum of FB1, FB2, and FB3 established by the Joint FAO/WHO expert committee on food additives and contaminants of 2 μg kg−1 and the maximum level recommended by the U.S. Food and Drug Administration (FDA for protection of human consumption (2–4 mg L−1.

  4. Photocatalytic Characterization of TiO2 Supported on Active Carbon

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    he Photocatalytic characterization of TiO2 supported on active carbon was investigated for photocatalytic decomposition of dichloroacetic acid. It was found that TiO2 / AC exhibited a higher photocatalytic activity than pure TiO2. The reason is that active carbon acting as powerful adsorbent supports makes high concentration environments of organic pollutant molecules around TiO2 particles.

  5. Interposition fixing structure of TiO2 film deposited on activated carbon fibers

    Institute of Scientific and Technical Information of China (English)

    FU Ping-feng; LUAN Yong; DAI Xue-gang

    2006-01-01

    The immobilized photocatalyst, TiO2 film supported on activated carbon fibers (TiO2/ACFs) prepared with molecular adsorption-deposition (MAD), exhibits high stability in cyclic photodegradation runs. The interposition fixing structure between TiO2 film and carbon fiber was investigated by means of SEM-EDX, XRD, XPS and FTIR, and a model was proposed to explain this structure. With SEM examination of carbon fiber surface after removing the deposited TiO2 film, a residual TiO2 super-thin film was found to exist still. By determining surface groups on ACFs, titanium sulfate (Ti2(SO4)3) in burnt remainders of the TiO2/ACFs was thought to be formed with an interfacial reaction between TiO2 film and carbon fibers. These provide some evidence of firm attachment of TiO2 film to carbon fiber surface. In the consideration of characteristics of the MAD, the deposition mechanism of TiO2 film on ACFs was proposed, and the interposition fixing structure was inferred to intercrossedly form between TiO2 film and ACFs' surface. This structure leaded to firm attachment and high stability of the TiO2 film.

  6. Photocatalytic properties of TiO2 bonded active carbon composites prepared by SOL-GEL

    Institute of Scientific and Technical Information of China (English)

    李佑稷; 李效东; 李君文; 尹静

    2004-01-01

    Photocatalyst of TiO2 bonded active carbon (TiO2/AC), was prepared via sol-gel method from a mixture of TiO2 sol with active carbon. Post heat treatment was performed at 250 ℃ for 2 h in air and then kept at 400 ℃ to 600 ℃ under a flow of nitrogen for 2 h. The TiO2/AC composites obtained were characterized by SEM, XRD, UV-vis and BET. The photocatalytic activities of the TiO2/AC composites were studied in comparison with TiO2, AC,P-25 and a mixture of TiO2 and AC, respectively. The Ramnant rate of Rhodamine B absorbed by the active carbon is found to be almost 70% and the remnant rates of the Rhodamine B decolorized by TiO2 and the mixture of TiO2 and the active carbon are 30% and 25%, respectively. However, nearly complete removal of Rhodamine B is observed for a TiO2/AC composite after 200 min under UV irradiation, which will take the P-25 commercial product 5 h. Therefore, the TiO2/AC composite is much more effective in decolorization of aqueous Rhodamine B. In addition, the composite can be easily separated from solutions.

  7. Achieving enhanced DSSC performance by microwave plasma incorporation of carbon into TiO2 photoelectrodes

    OpenAIRE

    Dang, Binh H.Q.; MacElroy, J. M. Don; Dowling, Denis P.

    2013-01-01

    The photoactivity of carbon-incorporated titanium dioxide (TiO2) has been widely reported. This study involves a novel approach to the incorporation of carbon into TiO2 through the use of microwave plasma processing. The process involved thermally treating printed TiO2 nanoparticle coatings in a microwave-induced argon-oxygen plasma containing low concentrations of methane. The resulting deposited carbon layer was characterized using XRD, XPS, Raman, UV–vis, ellipsometry, and optical profilom...

  8. Surface Properties and Catalytic Performance of Activated Carbon Fibers Supported TiO2 Photocatalyst

    Science.gov (United States)

    Yang, Huifen; Fu, Pingfeng

    Activated carbon fibers supported TiO2 photocatalyst (TiO2/ACF) in felt-form was successfully prepared with a dip-coating process using organic silicon modified acrylate copolymer as a binder followed by calcination at 500°C in a stream of Ar gas. The photocatalyst was characterized by SEM, XRD, XPS, FTIR, and BET surface area. Most of carbon fibers were coated with uniformly distributed TiO2 clusters of nearly 100 nm. The loaded TiO2 layer was particulate for the organic binder in the compact film was carbonized. According to XPS and FTIR analysis, amorphous silica in carbon grains was synthesized after carbonizing organic silicon groups, and the Ti-O-Si bond was formed between the interface of loaded TiO2 and silica. Additionally, the space between adjacent carbon fibers still remained unfilled after TiO2 coating, into which both UV light and polluted solutions could penetrate to form a three-dimensional environment for photocatalytic reactions. While loaded TiO2 amount increased to 456 mg TiO2/1 g ACF, the TiO2/ACF catalyst showed its highest photocatalytic activity, and this activity only dropped about 10% after 12 successive runs, exhibiting its high fixing stability of coated TiO2.

  9. A facile hydrothermal approach for construction of carbon coating on TiO2 nanoparticles

    OpenAIRE

    Olurode, Kehinde; Neelgund, Gururaj M.; Oki, Aderemi; Luo, Zhiphing

    2011-01-01

    Herein a facile hydrothermal approach is used to construct carbon coated TiO2 nanoparticles employing dextrose as the source of carbon. The procedure is operated at a low temperature of 200 °C. Fourier infrared spectroscopy demonstrated the successful coating of carbon on TiO2 nanoparticles. The phase composition of TiO2 and carbon coated TiO2 nanoparticles were studied using X-ray diffraction and the surface morphology was analyzed by scanning and transmission electron microscopy. The existe...

  10. SURFACE PROPERTIES AND CATALYTIC PERFORMANCE OF ACTIVATED CARBON FIBERS SUPPORTED TiO2 PHOTOCATALYST

    OpenAIRE

    HUIFEN YANG; PINGFENG FU

    2008-01-01

    Activated carbon fibers supported TiO2 photocatalyst (TiO2/ACF) in felt-form was successfully prepared with a dip-coating process using organic silicon modified acrylate copolymer as a binder followed by calcination at 500°C in a stream of Ar gas. The photocatalyst was characterized by SEM, XRD, XPS, FTIR, and BET surface area. Most of carbon fibers were coated with uniformly distributed TiO2 clusters of nearly 100 nm. The loaded TiO2 layer was particulate for the organic binder in the compac...

  11. TiO2@Carbon Photocatalysts: The Effect of Carbon Thickness on Catalysis.

    Science.gov (United States)

    Zhang, Jianming; Vasei, Mitra; Sang, Yuanhua; Liu, Hong; Claverie, Jerome P

    2016-01-27

    Nanocomposites composed of TiO2 and carbon materials (C) are widely popular photocatalysts because they combine the advantages of TiO2 (good UV photocatalytic activity, low cost, and stability) to the enhanced charge carrier separation and lower charge transfer resistance brought by carbon. However, the presence of carbon can also be detrimental to the photocatalytic performance as it can block the passage of light and prevent the reactant from accessing the TiO2 surface. Here using a novel interfacial in situ polymer encapsulation-graphitization method, where a glucose-containing polymer was grown directly on the surface of the TiO2, we have prepared uniform TiO2@C core-shell structures. The thickness of the carbon shell can be precisely and easily tuned between 0.5 and 8 nm by simply programming the polymer growth on TiO2. The resulting core@shell TiO2@C nanostructures are not black and they possess the highest activity for the photodegradation of organic compounds when the carbon shell thickness is 1-2 nm, corresponding to ∼3-5 graphene layers. Photoluminescence and photocurrent generation tests further confirm the crucial contribution of the carbon shell on charge carrier separation and transport. This in situ polymeric encapsulation approach allows for the careful tuning of the thickness of graphite-like carbon, and it potentially constitutes a general and efficient route to prepare other oxide@C catalysts, which can therefore largely expand the applications of nanomaterials in catalysis.

  12. Enhancement of Photocatalytic Activity on TiO2-Nitrogen-Doped Carbon Nanotubes Nanocomposites

    OpenAIRE

    Lingling Wang; Long Shen; Yihuai Li; Luping Zhu; Jiaowen Shen; Lijun Wang

    2013-01-01

    TiO2-nitrogen-doped carbon nanotubes (TiO2-CNx) nanocomposites are successfully synthesized via a facile hydrothermal method. The prepared photocatalysts were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric and differential scanning calorimetry analyses (TGA-DSC). The results show that the TiO2 nanoparticles with a narrow size of 7 nm are uniformly deposited on CNx. The photocatalytic ac...

  13. Photocatalytic degradation of indigo carmine dye using TiO2 impregnated activated carbon

    Indian Academy of Sciences (India)

    A K Subramani; K Byrappa; S Ananda; K M Lokanatha Rai; C Ranganathaiah; M Yoshimura

    2007-02-01

    The photocatalytic degradation of indigo carmine dye was studied using hydrothermally prepared TiO2 impregnated activated carbon (TiO2 : AC). A comparison between the degradation of the indigo carmine dye using commercial TiO2 and TiO2 : AC revealed the efficiency of the title compound. The degradation reaction was optimized with respect to the dye concentration and catalyst amount. The reduction in the chemical oxygen demand (COD) revealed the mineralization of dye along with colour removal. The active compound like TiO2 was impregnated onto the activated carbon surface under mild hydrothermal conditions (< 250°C, P ∼ 40 bars). The impregnated activated carbon samples were characterized using powder X-ray diffraction (XRD) and scanning electron microscope (SEM).

  14. A facile method for fabricating TiO2@mesoporous carbon and three-layered nanocomposites.

    Science.gov (United States)

    Liu, Yong; Jin, Haibao; Zhu, Shenmin; Liu, Yunchun; Long, Mingce; Zhou, Yongfeng; Yan, Deyue

    2012-08-17

    Herein, we report a new and facile method for fabricating TiO(2)@mesoporous carbon hybrid materials. Uniform polydopamine (PDA) layers were coated onto the surface of titanate nanotubes (TNTs) and TiO(2) nanorods (TNDs) through the spontaneous adhesion and self-polymerization of dopamine during the dipping process. Core-shell mesoporous carbon nanotubes with TiO(2) nanorods or nanoparticles encapsulated inside (TiO(2)@MC) were then obtained by transforming PDA layers into carbonaceous ones through calcination in nitrogen at 800 °C. The thickness of the mesoporous carbon layers is tens of nanometers and can be controlled by adjusting the coated PDA layers through the self-polymerization reaction time. In addition, three-layered nanocomposites of TiO(2)@MC@MO (MO, metal oxide) can be readily prepared by utilizing PDA layers in TNTs@PDA or TNDs@PDA to adsorb the metal ions, followed by the calcination process.

  15. Facile synthesis of tunable carbon modified mesoporous TiO2 for visible light photocatalytic application

    Science.gov (United States)

    Wei, Xiao-Na; Wang, Hui-Long; Wang, Xin-Kui; Jiang, Wen-Feng

    2017-08-01

    In this paper, we describe a simple and novel approach for preparing tunable carbon-modified mesoporous TiO2 photocatalysts by combining the in-situ carbonization of PAA-Ti/TiO2, hydrothermal reaction process and post-calcination treatment. The synthesized carbon-modified mesoporous TiO2 powders were of high crystallinity, large specific surface area and good visible light response. The carbon species were formed by the carbonization of polyacrylate (PAA). The presence of carbonates was subsequently confirmed by the XPS spectra, which significantly narrow down the band gap of TiO2. The organic group in polyacrylate served as the carbon source and carbon resulted from in-situ carbonization treatment could help to inhibit the excessive growth of TiO2 grain and enlarge the pore structure of TiO2. The amount of carbon species could be feasibly modulated by adjusting the post-calcination temperature and the surface area of the photocatalyst was enlarged further after the partial removal of carbon species. The carbon-modified mesoporous TiO2 powders exhibit excellent reproducibility and photocatalytic performance under visible light irradiation.

  16. Effective photocatalysis of functional nanocomposites based on carbon and TiO2 nanoparticles.

    Science.gov (United States)

    Lin, Chan; Song, Yang; Cao, Lixin; Chen, Shaowei

    2013-06-07

    A unique nanocomposite C-TiO2 was prepared by the growth of TiO2 on carbon nanoparticles using a simple hydrothermal procedure. Transmission electron microscopic (TEM) measurements showed that the nanocomposites exhibited an average core diameter of approximately 5 nm with a rather well-defined lattice space (0.4 nm) that was somewhat larger than that (0.38 nm) of the (100) crystalline planes of anatase TiO2. This lattice expansion was accounted for by the formation of surface defect dipoles of the nanosized TiO2 particles. X-ray photoelectron spectroscopic (XPS) measurements suggested that partial charge transfer occurred from carbon nanoparticles to TiO2 by the interfacial Ti-O-C linkages, which led to effective diminishment of the C-TiO2 photoluminescence as compared to that of pure TiO2 or carbon nanoparticles, suggesting intimate electronic interactions between the carbon and TiO2 components in the nanocomposites. Such unique characteristics were then exploited for the effective photocatalytic degradation of organic pollutants, as exemplified by methylene blue, by C-TiO2 under UV photoirradiation. Experimental measurements showed that the photocatalytic activity of C-TiO2 nanocomposites was about twice that of TiO2 alone, whereas little activity was observed with carbon nanoparticles. This was attributed to the electron-accepting sites on the carbon nanoparticles that facilitated interfacial charge separation.

  17. Formation of TiO2 Modified Film on Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    Laizhou SONG; Shizhe SONG; Zhiming GAO

    2004-01-01

    A new technique for preparing TiO2 modified film on carbon steel was accomplished by electroless plating and sol-gel composite process. The artificial neural network was applied to optimize the preparing condition of TiO2 modified film. The optimized condition for forming TiO2 modified film on carbon steel was that NiP plating for 50 min,dip-coating times as 4, heat treatment time for 2 h, and the molar ratio of complexing agent and Ti(OC4HZ9)4 kept 1.5:1. The results showed that TiO2 modified film have good corrosion resistance. The result conformed that it is feasible to design the preparing conditions of TiO2 modified film by artificial neural network.

  18. Nanohybrid TiO2/carbon black sensor for NO2 gas

    Institute of Scientific and Technical Information of China (English)

    Wei-Jen Liou; Hong-Ming Lin

    2007-01-01

    A nanohybrid sensor of nanosized TiO2-coated carbon black particles, prepared by sol-gel technology for the detection of NO2 gas, has been developed. The response of the electric resistance of the hybrid sensor to NO2 concentration is investigated, showing that the sensitivity of the hybrid sensor is raised as certain ratio of the TiO2 content in the sensor. Easy and cheap to fabricate, the hybrid TiO2/carbon black promises to be a practical sensor for detecting NO2 gas.

  19. Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Xie Yi

    2009-01-01

    Full Text Available Abstract A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs is presented. Anatase TiO2 nanoparticles (NPs with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV–visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

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

    Science.gov (United States)

    Yao, Shuhua; Song, Shuangping; Shi, Zhongliang

    2014-06-01

    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.

  1. On the mechanism of enhanced photocatalytic activity of composite TiO2/carbon nanofilms

    Science.gov (United States)

    Chakarov, Dinko; Sellappan, Raja

    2012-02-01

    We fabricated and analyzed well-defined model samples consisting of anatase and graphitic carbon films with and without modifying the interface between them by a thin SiO2 space layer. The study was performed in the search for the origin of the enhanced photocatalytic activity of composite TiO2--carbon systems observed previously by us, but also reported in number of publications. We found that the films with a TiO2/C interface show noticeably lower photoluminescence intensity and shorter carrier life times compared to single TiO2 films with the same thickness and composition. The stronger non-radiative recombination was mainly assigned to charge carrier leakage (transfer) at the interface between TiO2 nanocrystallites and the carbon film.

  2. Effective photocatalysis of functional nanocomposites based on carbon and TiO2 nanoparticles

    Science.gov (United States)

    Lin, Chan; Song, Yang; Cao, Lixin; Chen, Shaowei

    2013-05-01

    A unique nanocomposite C-TiO2 was prepared by the growth of TiO2 on carbon nanoparticles using a simple hydrothermal procedure. Transmission electron microscopic (TEM) measurements showed that the nanocomposites exhibited an average core diameter of approximately 5 nm with a rather well-defined lattice space (0.4 nm) that was somewhat larger than that (0.38 nm) of the (100) crystalline planes of anatase TiO2. This lattice expansion was accounted for by the formation of surface defect dipoles of the nanosized TiO2 particles. X-ray photoelectron spectroscopic (XPS) measurements suggested that partial charge transfer occurred from carbon nanoparticles to TiO2 by the interfacial Ti-O-C linkages, which led to effective diminishment of the C-TiO2 photoluminescence as compared to that of pure TiO2 or carbon nanoparticles, suggesting intimate electronic interactions between the carbon and TiO2 components in the nanocomposites. Such unique characteristics were then exploited for the effective photocatalytic degradation of organic pollutants, as exemplified by methylene blue, by C-TiO2 under UV photoirradiation. Experimental measurements showed that the photocatalytic activity of C-TiO2 nanocomposites was about twice that of TiO2 alone, whereas little activity was observed with carbon nanoparticles. This was attributed to the electron-accepting sites on the carbon nanoparticles that facilitated interfacial charge separation.A unique nanocomposite C-TiO2 was prepared by the growth of TiO2 on carbon nanoparticles using a simple hydrothermal procedure. Transmission electron microscopic (TEM) measurements showed that the nanocomposites exhibited an average core diameter of approximately 5 nm with a rather well-defined lattice space (0.4 nm) that was somewhat larger than that (0.38 nm) of the (100) crystalline planes of anatase TiO2. This lattice expansion was accounted for by the formation of surface defect dipoles of the nanosized TiO2 particles. X-ray photoelectron

  3. VLSI-compatible carbon nanotube doping technique with low work-function metal oxides.

    Science.gov (United States)

    Suriyasena Liyanage, Luckshitha; Xu, Xiaoqing; Pitner, Greg; Bao, Zhenan; Wong, H-S Philip

    2014-01-01

    Single-wall carbon nanotubes (SWCNTs) have great potential to become the channel material for future high-speed transistor technology. However, as-made carbon nanotube field effect transistors (CNFETs) are p-type in ambient, and a consistent and reproducible n-type carbon nanotube (CNT) doping technique has yet to be realized. In addition, for very large scale integration (VLSI) of CNT transistors, it is imperative to use a solid-state method that can be applied on the wafer scale. Herein we present a novel, VLSI-compatible doping technique to fabricate n-type CNT transistors using low work-function metal oxides as gate dielectrics. Using this technique we demonstrate wafer-scale, aligned CNT transistors with yttrium oxide (Y2Ox) gate dielectrics that exhibit n-type behavior with Ion/Ioff of 10(6) and inverse subthreshold slope of 95 mV/dec. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) analyses confirm that slow (∼1 Å/s) evaporation of yttrium on the CNTs can form a smooth surface that provides excellent wetting to CNTs. Further analysis of the yttrium oxide gate dielectric using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques revealed that partially oxidized elemental yttrium content increases underneath the surface where it acts as a reducing agent on nanotubes by donating electrons that gives rise to n-type doping in CNTs. We further confirm the mechanism for this technique with other low work-function metals such as lanthanum (La), erbium (Er), and scandium (Sc) which also provide similar CNT NFET behavior after transistor fabrication. This study paves the way to exploiting a wide range of materials for an effective n-type carbon nanotube transistor for a complementary (p- and n-type) transistor technology.

  4. Multi-Walled Carbon Nanotube-Doped Tungsten Oxide Thin Films for Hydrogen Gas Sensing

    OpenAIRE

    2010-01-01

    In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT)-doped tungsten oxide (WO3) thin films by means of the powder mixing and electron beam (E-beam) evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO3 thin film exhibits high sensitivity and selectivity ...

  5. Nitrite Oxidation with Copper-Cobalt Nanoparticles on Carbon Nanotubes Doped Conducting Polymer PEDOT Composite.

    Science.gov (United States)

    Wang, Junjie; Xu, Guiyun; Wang, Wei; Xu, Shenghao; Luo, Xiliang

    2015-09-01

    Copper-cobalt bimetal nanoparticles (Cu-Co) have been electrochemically prepared on glassy carbon electrodes (GCEs), which were electrodeposited with conducting polymer nanocomposites of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with carbon nanotubes (CNTs). Owing to their good conductivity, high mechanical strength, and large surface area, the PEDOT/CNTs composites offered excellent substrates for the electrochemical deposition of Cu-Co nanoparticles. As a result of their nanostructure and the synergic effect between Cu and Co, the Cu-Co/PEDOT/CNTs composites exhibited significantly enhanced catalytic activity towards the electrochemical oxidation of nitrite. Under optimized conditions, the nanocomposite-modified electrodes had a fast response time within 2 s and a linear range from 0.5 to 430 μm for the detection of nitrite, with a detection limit of 60 nm. Moreover, the Cu-Co/PEDOT/CNTs composites were highly stable, and the prepared nitrite sensors could retain more than 96 % of their initial response after 30 days.

  6. Photocatalytic Oxidation of Volatile Organic Compounds Over Electrospun Activated TIO2/CARBON Nanofiber Composite

    Science.gov (United States)

    Gholamvand, Zahra; Aboutalebi, Seyed Hamed; Keyanpour-Rad, Mansoor

    In this study, TiO2/PAN-based fibers were prepared by electrospinning a composite solution containing both the desirable contents of TiO2 and a 10 wt. % PAN polymer solution dissolved in N, N-dimethylformamide. The TiO2 loaded electrospun PAN nanofibers were then carbonized at 1000 °C in N2 atmosphere furnace after stabilization at 230 °C in air. Then CNF/TiO2 nanofibers were oxidized at 450 °C in air. The morphology and structure of the TiO2-embeded carbon nanofibers were investigated by SEM and Raman spectroscopy. Specific surface area was determined using BET equation from N2 adsorption analysis. Photocatalytic tests were conducted in a UV illuminated set-up specialized for the filters using ethanol vapor. The results have shown that ethanol vapor was efficiently degraded on TiO2/CNF composite nanofiber mat under UV illumination. The aim of this study was to further investigate the feasibility of TiO2/ACF for practical indoor air purification.

  7. Carbon nanotubes doped with trivalent elements by using back - scattering Raman spectroscopy

    Directory of Open Access Journals (Sweden)

    S. A. Babanejad

    2008-12-01

    Full Text Available  In this paper by using DC arc discharge method and acetylene gas, as the carbon source, and nitrogen, as the carrier gas, canrbon nanotubes, CNTs, doped with trivalent element boron, B, have been produced. The deposited CNTs on the cathod electrod, which have structural doped properties to boron element, have been collected and after purification have been investigated by back-scattering Raman spectroscopy. The results reveal that the high frequency G mode component in CNTs doped with electron acceptor element, B, shift to higher wavenumbers. The low frequency G mode component which can appear at approximately 1540–1570 cm-1 wavenumber region, called BWF mode, is a sign of metallic CNT. In the synthesized doped CNTs due to the presence of boron dopant, D mode has sharp peaks and has relatively high intensity in the Raman spectra .

  8. Multi-Walled Carbon Nanotube-Doped Tungsten Oxide Thin Films for Hydrogen Gas Sensing

    Directory of Open Access Journals (Sweden)

    Adisorn Tuantranont

    2010-08-01

    Full Text Available In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT-doped tungsten oxide (WO3 thin films by means of the powder mixing and electron beam (E-beam evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO3 thin film exhibits high sensitivity and selectivity to hydrogen. Thus, MWCNT doping based on E-beam co-evaporation was shown to be an effective means of preparing hydrogen gas sensors with enhanced sensing and reduced operating temperatures. Creation of nanochannels and formation of p-n heterojunctions were proposed as the sensing mechanism underlying the enhanced hydrogen sensitivity of this hybridized gas sensor. To our best knowledge, this is the first report on a MWCNT-doped WO3 hydrogen sensor prepared by the E-beam method.

  9. Multi-walled carbon nanotube-doped tungsten oxide thin films for hydrogen gas sensing.

    Science.gov (United States)

    Wongchoosuk, Chatchawal; Wisitsoraat, Anurat; Phokharatkul, Ditsayut; Tuantranont, Adisorn; Kerdcharoen, Teerakiat

    2010-01-01

    In this work we have fabricated hydrogen gas sensors based on undoped and 1 wt% multi-walled carbon nanotube (MWCNT)-doped tungsten oxide (WO(3)) thin films by means of the powder mixing and electron beam (E-beam) evaporation technique. Hydrogen sensing properties of the thin films have been investigated at different operating temperatures and gas concentrations ranging from 100 ppm to 50,000 ppm. The results indicate that the MWCNT-doped WO(3) thin film exhibits high sensitivity and selectivity to hydrogen. Thus, MWCNT doping based on E-beam co-evaporation was shown to be an effective means of preparing hydrogen gas sensors with enhanced sensing and reduced operating temperatures. Creation of nanochannels and formation of p-n heterojunctions were proposed as the sensing mechanism underlying the enhanced hydrogen sensitivity of this hybridized gas sensor. To our best knowledge, this is the first report on a MWCNT-doped WO(3) hydrogen sensor prepared by the E-beam method.

  10. Carbon Nanotube Coating on Titanium Substrate Modified with TiO2 Nanotubes

    Institute of Scientific and Technical Information of China (English)

    BAI Yu; PARK Ilsong; BAE Taesung; KLM Kyounga; WATARI Fumio; UO Motohiro; LEE Minho

    2011-01-01

    A combination of carbon nanotubes (CNTs) and titanium (Ti) modified with TiO2 nanotubes (TiO2 NTs) was fulfilled with the aim of improving bioactivity of Ti implant.First,well-ordered TiO2 NTs were prepared by the electrochemical anodization of Ti in an ethylene glycol electrolyte containing 1 wt% NH4F and 10 wt% H2O at 20 V for 50 min,followed by annealing.Then,the carboxylated CNTs were coated onto the TiO2NTs using electrophoretic deposition (EPD) technique.The growth of hydroxyapatite (HA) on the samples was investigated by soaking them in simulated body fiuid (SBF).The result showed the CNTs-coated Ti with the modification of TiO2 NTs (CNTs-TiO2 NTs) was more efficient to induce HA formation than the CNTs-coated smooth Ti (CNTs-Ti).The vitro cell response was evaluated using osteoblast cells (MC3T3-El).The good cell proliferation and strong cell adhesion could be obtained on the CNTs-TiO2 NTs.These results indicated that CNT coating on the Ti modified with TiO2 NTs could be potentially useful for the periodontal ligament combination on dental implants.

  11. A facile method for fabricating TiO2@mesoporous carbon and three-layered nanocomposites

    Science.gov (United States)

    Liu, Yong; Jin, Haibao; Zhu, Shenmin; Liu, Yunchun; Long, Mingce; Zhou, Yongfeng; Yan, Deyue

    2012-08-01

    Herein, we report a new and facile method for fabricating TiO2@mesoporous carbon hybrid materials. Uniform polydopamine (PDA) layers were coated onto the surface of titanate nanotubes (TNTs) and TiO2 nanorods (TNDs) through the spontaneous adhesion and self-polymerization of dopamine during the dipping process. Core-shell mesoporous carbon nanotubes with TiO2 nanorods or nanoparticles encapsulated inside (TiO2@MC) were then obtained by transforming PDA layers into carbonaceous ones through calcination in nitrogen at 800 °C. The thickness of the mesoporous carbon layers is tens of nanometers and can be controlled by adjusting the coated PDA layers through the self-polymerization reaction time. In addition, three-layered nanocomposites of TiO2@MC@MO (MO, metal oxide) can be readily prepared by utilizing PDA layers in TNTs@PDA or TNDs@PDA to adsorb the metal ions, followed by the calcination process.

  12. Photocatalytic degradation of L-acid by TiO2 supported on the activated carbon

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-ping; WANG Lian-jun; PENG Pan-ying

    2006-01-01

    TiO2 sol was prepared by sol-gel technique with tetrabutyl titanate as precursor. Supported TiO2 catalysts on activated carbon were prepared by soak and sintering method. The aggregation of nano-TiO2 particles can be effectively suppressed by added polyethylene glycol (PEG) as a surface modifier. The average particle diameter of TiO2, specific surface area and absorbability of catalyst can be modified. Based on characteristics of the TiO2 photocatalyst with XRD, specific surface area, adsorption valves of methylene blue and the amount of TiO2 supported on the activated carbon, the photocatalytic degradation of L-acid was studied. The effect of the factors, such as pH of the solution, the initial concentration of L-acid on the photocatalytic degradation of L-acid, were studied also. It was found that when the pH of the solution is 1.95, the amount ofphotocatalyst is 0.5 g, the concentration of the L-acid solution is 1.34 × 10-3 mol/L and the illumination time is 7 h, the photocatalytic degradation efficiency of L-acid can reach 89.88%.The catalyst was reused 6 times and its degradation efficiency hardly changed.

  13. Desulphurization performance of TiO2-modified activated carbon by a one-step carbonization-activation method.

    Science.gov (United States)

    Zhang, Chuanjun; Yang, Danni; Jiang, Xia; Jiang, Wenju

    2016-08-01

    In this study, TiO2 powder was used as the additive to directly blend with raw bituminous coal and coking coal for preparing modified activated carbon (Ti/AC) by one-step carbonization-activation method. The Ti/AC samples were prepared through blending with different ratios of TiO2 (0-12 wt%) and their desulphurization performance was evaluated. The results show that the desulphurization activity of all Ti/AC samples was higher than that of the blank one, and the highest breakthrough sulphur capacity was obtained at 200.55 mg/g C when the blending ratio of TiO2 was 6 wt%. The Brunauer-Emmett-Temer results show that the micropores were dominant in the Ti/AC samples, and their textual properties did not change evidently compared with the blank one. The X-ray photoelectron spectroscopy results show that the loaded TiO2 could influence the relative content of surface functional groups, with slightly higher content of π-π* transitions groups on the Ti/AC samples, and the relative contents of C=O and π-π* transitions groups decreased evidently after the desulphurization process. The X-ray diffraction results show that the anatase TiO2 and rutile TiO2 co-existed on the surface of the Ti/AC samples. After the desulphurization process, TiO2 phases did not change and Ti(SO4)2 was not observed on the Ti/AC samples, while sulphate was the main desulphurization product. It can be assumed that SO2 could be catalytically oxidized into SO3 by TiO2 indirectly, rather than TiO2 directly reacted with SO2 to Ti(SO4)2.

  14. USE OF BATTERY CARBON AS ELECTRODES IN ARC DISCHARGE METHOD FOR FABRICATION OF CARBON-MODIFIED TIO2

    Directory of Open Access Journals (Sweden)

    Isya Fitria Andhika

    2016-09-01

    Full Text Available Fabrication with carbon-modified TiO2 by arc discharge method in liquid medium has been studied. This research was performed in two steps including fabrication and characterization. This fabrication was done by arcdischarge method with graphite electrodes from dry cell batteries and liquid medium suspension of TiO2 in ethanol 30, 50 and 70 %. A strong current was applied to electrode as 10 -50 A (20-40 V. Nanocomposites formed on the liquid medium surface were collected and characterized using X-ray diffraction (XRD,scanning electron microscope (SEM dan energy dispersive spectroscopy (EDS to determine crystallinity, surface morphology and the constituent elements, respectively. XRD data shows that the most effective fabrication TiO2/Karbon by liquid medium in ethanol 50 % indicated from the formation of a new peak with high intensity of TiC on 2Ɵ= 36.02 °. SEM data shows that the morphology of each aggregated TiO2/Karbon compared to the morphology of TiO2. In addition, EDS data shows the presence of the element carbon, titanium and oxygen in the same area indicating that the successful formation of composite material between TiO2 dan carbon.

  15. TiO2/activated carbon fibers photocatalyst: effects of coating procedures on the microstructure, adhesion property, and photocatalytic ability.

    Science.gov (United States)

    Shi, Jian-Wen; Cui, Hao-Jie; Chen, Jian-Wei; Fu, Ming-Lai; Xu, Bin; Luo, Hong-Yuan; Ye, Zhi-Long

    2012-12-15

    In order to more easily separate TiO(2) photocatalyst from the treated wastewater, TiO(2) film was immobilized on the surface of activated carbon fibers (ACFs) by employing two kinds of coating procedures, dip-coating, and hydrothermal treatment. The effects of coating procedures on microstructure of TiO(2)-coated ACFs (TiO(2)/ACFs), such as morphology, porous property, crystal structure, and light absorption characteristics were investigated in detail. The adhesion property between TiO(2) film and ACFs was evaluated by ultrasonic vibration, and the photocatalytic activity of TiO(2)/ACFs was tested by the photocatalytic decoloration of methylene blue solution. The results show that hydrothermal treatment presented many advantages to obtain high-performance TiO(2)/ACFs photocatalyst in comparison with dip-coating. Hydrothermal treatment could improve the binding property between TiO(2) films and ACFs, which endowed the as-obtained TiO(2)/ACFs photocatalyst with improved reusable performance, and TiO(2)/ACFs synthesized by hydrothermal treatment presented higher photocatalytic activity.

  16. Anatase TiO2 Nanospindle/Activated Carbon (AC) Composite Photocatalysts with Enhanced Activity in Removal of Organic Contaminant

    OpenAIRE

    Wuyi Zhou; Peng Zhang; Weian Liu

    2012-01-01

    This paper embarks upon the three levels of analysis ranging from nanoscale materials synthesis to combination and functionality. Firstly, we have prepared anatase TiO2 nanospindles with an even length of about 200 nm and a central width of about 25 nm by hydrothermal synthesis method at 100°C for 6 h. Secondly, we have dispersed TiO2 nanospindles on the surface of activated carbon (AC) and fabricated TiO2/AC composite via a dip-coating method. Thirdly, the TiO2/AC composite has been studied ...

  17. Synthesis, Characterization, and Photocatalytic Properties of Sulfur- and Carbon-Codoped TiO2 Nanoparticles

    Science.gov (United States)

    Ivanov, S.; Barylyak, A.; Besaha, K.; Bund, A.; Bobitski, Y.; Wojnarowska-Nowak, R.; Yaremchuk, I.; Kus-Liśkiewicz, M.

    2016-03-01

    One-step TiO2 nanoparticle synthesis based on the interaction between thiourea and metatitanic acid is applied for sulfur and carbon anatase codoping. The synthesis of the doped TiO2 has been monitored by means of differential thermal analysis and thermogravimetric analysis (DTA-TG), which allows determining the optimal thermal conditions for the process. Electron microscopy showed micrometer-sized (5-15 μm) randomly distributed crystal aggregates, consisting of many 15-40-nm TiO2 nanoparticles. The obtained phase composition and chemical states of the doping elements are analyzed by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared (IR) and Raman spectroscopies, and electron paramagnetic resonance (EPR). XRD displays in both samples (doped and pristine) the existence of only one crystalline phase—the tetragonal modification of TiO2—anatase. Further data assessment by means of Rietveld refinement allowed detection of a slight c lattice parameter and volume increase related to incorporation of the doping elements. XPS demonstrated the presence of carbon and sulfur as doping elements in the material. It was confirmed that carbon is in elemental form and also present in oxygen-containing compounds, which are adsorbed on the particle surface. The binding energy for sulfur electron core shell corresponds to the established data for sulfate compounds, where sulfur is in 6+ oxidation state. The synthesized S- and C-codoped TiO2 showed excellent photocatalytic performance during the degradation of organic dyes (rhodamine B, methylene blue), gas-phase oxidation of ethanol under visible light, and photocatalytic hydrogen generation from ethanol under ultraviolet light.

  18. Thin carbon layer coated Ti(3+)-TiO2 nanocrystallites for visible-light driven photocatalysis.

    Science.gov (United States)

    Jiang, Baojiang; Tang, Yunqi; Qu, Yang; Wang, Jian-Qiang; Xie, Ying; Tian, Chungui; Zhou, Wei; Fu, Honggang

    2015-03-21

    Black TiO2 containing Ti(3+) attracts enormous attention due to its excellent visible-light driven photocatalytic activity. Herein, an in situ thermal decomposition approach to synthesize uniform thin carbon coated Ti(3+)-TiO2 nanocrystals is presented. During the oleic acid-assisted solvothermal process, the crystal size and morphology of TiO2 were controlled through oleic acid with carboxylic acid groups. Then the residual small quantities of oleic acid anchored on TiO2 were used as a carbon source, which could be in situ pyrolyzed into a carbon layer on TiO2 at high temperature and under an inert atmosphere. Meanwhile, Ti(4+) species were partly reduced into Ti(3+) states/oxygen vacancies on the surface of TiO2 due to the carbothermal reduction reaction for the carbon-encapsulated Ti(3+)-TiO2 structure. A series of characterizations indicated that the 20-25 nm TiO2 nanocrystals obtained were wrapped evenly by 1-2 nm carbon layers, which had an important effect on the energy band structure change of TiO2. The presence of the carbon layer also improves the Ti(3+) stability and the conduction behavior of the composites. The Ti(3+) states/oxygen vacancies created on the surface of TiO2 were responsible for the remarkable photogenerated charge separation and extended visible-light absorption range. Furthermore, Ti(3+) states/oxygen vacancies and the carbon layer together could enhance the adsorption ability of O2 so as to promote the photogenerated electrons captured by the adsorbed O2, leading to a great increase in the charge separation. As a result, the composites exhibit high photocatalytic performance for organic pollutants under visible light irradiation. This simple and new method may pave the way to practical applications for efficient photocatalytic degradation under visible light.

  19. Flexible symmetric supercapacitors based on vertical TiO2 and carbon nanotubes

    Science.gov (United States)

    Chien, C. J.; Chang, Pai-Chun; Lu, Jia G.

    2010-03-01

    Highly conducting and porous carbon nanotubes are widely used as electrodes in double-layer-effect supercapacitors. In this presentation, vertical TiO2 nanotube array is fabricated by anodization process and used as supercapacitor electrode utilizing its compact density, high surface area and porous structure. By spin coating carbon nanotube networks on vertical TiO2 nanotube array as electrodes with 1M H2SO4 electrolyte in between, the specific capacitance can be enhanced by 30% compared to using pure carbon nanotube network alone because of the combination of double layer effect and redox reaction from metal oxide materials. Based on cyclic voltammetry and galvanostatic charge-discharge measurements, this type of hybrid electrode has proven to be suitable for high performance supercapacitor application and maintain desirable cycling stability. The electrochemical impedance spectroscopy technique shows that the electrode has good electrical conductivity. Furthermore, we will discuss the prospect of extending this energy storage approach in flexible electronics.

  20. Preparation of TiO2-activated carbon complex membranes and their photoelectrocatalytic activity

    Institute of Scientific and Technical Information of China (English)

    尤宏; 姚杰; 孙丽欣; 王强

    2003-01-01

    The experimental process of preparing TiO2-activated carbon complex membranes with activated carbon powder as main carrier, PTFE as binder and wire netting as matrix is described in detail, and both photo-catalysis and photo-electro-catalysis are measured to study the properties of complex membranes. Experimental results show that the photo-catalytic activity of the membranes is high and stable in the process of treating Rhodamine-B; the application of an electric field accelerates the speed of photo-catalysis, and the efficiency of photo-catalysis is increased 2.5 times when the applied voltage is 0.8 V; and the degradation of Rhodamine-B follows the dynamics of first order reaction. It is concluded from the discussion of experimental results that the preparation process of TiO2-activated carbon complex membranes is a simple low-cost process suitable for large scale application.

  1. Carbon/nitrogen-doped TiO2: New synthesis route, characterization and application for phenol degradation

    Directory of Open Access Journals (Sweden)

    Aboubakr M. Abdullah

    2016-03-01

    Full Text Available Porous nanocrystalline carbon and nitrogen (CN-doped TiO2 photocatalyst was prepared using carbon tetrachloride and polyaniline as precursors. The obtained powders were characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, scanning electron microscopy (SEM, Raman spectroscopy, Fourier transform infrared (FT-IR spectroscopy, and gravimetric analysis. The purpose of this work was to explore the state and location of nitrogen and carbon atoms introduced inside the TiO2 lattice and to study the exploitation of the photocatalytic activity of the CN-doped TiO2 for application in phenol degradation under UV illumination. After 30 min from the illumination onset, 64% and 57% of the phenol were degraded when the CN-doped TiO2 and TiO2 catalysts were used respectively.

  2. Towards efficient photoinduced charge separation in carbon nanodots and TiO2 composites in the visible region

    NARCIS (Netherlands)

    Sun, M.; Qu, S.; Ji, W.; Jing, P.; Li, D.; Qin, L.; Cao, J.; Zhang, H.; Zhao, J.; Shen, D.

    2015-01-01

    In this work, photoinduced charge separation behaviors in non-long-chain-molecule-functionalized carbon nanodots (CDs) with visible intrinsic absorption (CDs-V) and TiO2 composites were investigated. Efficient photoinduced electron injection from CDs-V to TiO2 with a rate of 8.8 x 10(8) s(-1) and

  3. Towards efficient photoinduced charge separation in carbon nanodots and TiO2 composites in the visible region

    NARCIS (Netherlands)

    Sun, M.; Qu, S.; Ji, W.; Jing, P.; Li, D.; Qin, L.; Cao, J.; Zhang, H.; Zhao, J.; Shen, D.

    2015-01-01

    In this work, photoinduced charge separation behaviors in non-long-chain-molecule-functionalized carbon nanodots (CDs) with visible intrinsic absorption (CDs-V) and TiO2 composites were investigated. Efficient photoinduced electron injection from CDs-V to TiO2 with a rate of 8.8 x 10(8) s(-1) and ef

  4. Photocatalytic degradation of an azo-dye on TiO2/activated carbon composite material.

    Science.gov (United States)

    Andriantsiferana, C; Mohamed, E F; Delmas, H

    2014-01-01

    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.

  5. Photoreactive TiO2/carbon nanotube composites: synthesis and reactivity.

    Science.gov (United States)

    Yao, Yuan; Li, Gonghu; Ciston, Shannon; Lueptow, Richard M; Gray, Kimberly A

    2008-07-01

    Electron-hole recombination limits the efficiency of TiO2 photocatalysis. We have investigated the efficacy with which anatase/carbon nanotube (CNT) composite materials reduce charge recombination and enhance reactivity. We synthesized nanostructured assemblies composed of different proportions of anatase (5 or 100 nm) and either single-or multi-walled CNTs. The composites were prepared using a simple low temperature process in which CNTs and anatase nanoparticles were dispersed in water, dehydrated at 80 degrees C, and dried at 104 degrees C. The structures of the various TiO2/CNT composites were characterized by scanning electron microscopy (SEM) and their function was tested by phenol oxidation. Charge recombination was compared by measuring the photoluminescence spectra of select composites. We found that a nanostructured composite assembled from the 100 nm anatase and single-walled CNTs (SWCNTs) exhibited enhanced and selective photocatalytic oxidation of phenol in comparison to both pure anatase and Degussa P25. A mechanism for the enhanced reactivity is proposed in which electrons are shuttled from TiO2 particles to the SWCNTs as a result of an optimal TiO2/ CNT arrangement that stabilizes charge separation and reduces charge recombination. In addition, the SWCNT assembly provides better catalyst-support (dispersal and connection) than multi-walled CNTs.

  6. Photocatalytic Improvement under Visible Light in TiO2 Nanoparticles by Carbon Nanotube Incorporation

    Directory of Open Access Journals (Sweden)

    Mathana Wongaree

    2015-01-01

    Full Text Available Photocatalytic activity of TiO2 nanoparticles was successfully enhanced by addition of multiwall carbon nanotubes (MWCNT to make CNT/TiO2 nanocomposites by sol-gel method at ambient temperature. CNT treated by HNO3 : H2SO4 treatment (1 : 3 v/v was mixed with TiO2 nanoparticles at various molar ratios and calcination temperatures. The optimal molar ratio of CNT : TiO2 was found at 0.05 : 1 by weight. The optimal calcination condition was 400°C for 3 h. From the results, the photocatalytic activities of CNT/TiO2 nanocomposites were determined by the decolorization of 1 × 10−5 M methylene blue (MB under visible light. CNT/TiO2 nanocomposites could enhance the photocatalytic activity and showed faster for the degradation of MB with only 90 min. The degradation efficiency of the MB solution with CNT/TiO2 nanocomposite achieved 70% which was higher than that with pristine TiO2 (22%. This could be explained that CNT prevents TiO2 from its agglomeration which could further enhance electron transfer in the composites. In addition, CNT/TiO2 nanocomposites had high specific surface area (202 m2/g which is very promising for utilization as a photocatalyst for environmental applications.

  7. Preparation and performance of photocatalytic regenerationable activated carbon prepared via sol-gel TiO2

    Institute of Scientific and Technical Information of China (English)

    LIU Shou-xin; SUN Cheng-lin

    2006-01-01

    Preparation ofphotocatalytic regenerationable activated carbon (AC) is the key step for the practical application of in situ regeneration of exhausted AC. A novel photocatalytic regenerationable AC was prepared by sol-gel TiO2 in this work. The adsorption and regeneration performance of TiO2/AC were evaluated using phenol as model compound. Scanning electron microscope (SEM)and nitrogen (77 K) adsorption isotherm were used to determine the surface area, pore structure and the distribution of TiO2. The results showed that with the increase of TiO2 loading, adsorption capacity of TiO2/AC decreased and the regeneration efficiency increased. The photocatalytic regenerationable AC with suitable TiO2 loading (2 wt%) exhibited suitable adsorption capacity and regeneration efficiency. TiO2 located mainly in the entrance of macro-pore of carbon. The prepared TiO2/AC exhibited similar surface structure and pore structure with material carbon.

  8. Photocatalytic degradation of methylene blue by a combination of TiO2 and activated carbon fibers.

    Science.gov (United States)

    Yuan, Rusheng; Guan, Rongbo; Shen, Wenzhong; Zheng, Jingtang

    2005-02-01

    Photocatalytic degradation of methylene blue (MB) in aqueous solution was investigated using TiO2 immobilized on activated carbon fibers (ACFs). The TiO2 and ACF combination (TiO2/ACF) was prepared by using epoxy as the precursor of the link between TiO2 and ACFs, followed by calcination at 460 degrees C in a N2 atmosphere. The TiO2/ACF composite prepared was easier to handle than the original TiO2 powder in suspension. More significantly, the TiO2/ACF composite can be used repeatedly without a decline in photodegradation ability. After six cycles, the amount of MB removal for the TiO2/ACF composite was still slightly higher than that for fresh P25 TiO2 in suspension. Through measurement of chemical oxygen demand in the solution and the concentration of ammonium generated during degradation of MB, it was confirmed that MB molecules are mineralized instead of adsorbed by ACFs.

  9. Foam-structured Activated Carbon-ceramic as TiO2 Supports for Photocatalytic Degradation of Phenol

    Institute of Scientific and Technical Information of China (English)

    LIU Wei-min

    2013-01-01

    An activated foam-structured carbon-ceramic(AFCC) was prepared and investigated as TiO2 support for the photocatalytic degradation of phenol.AFCC and TiO2/AFCC catalysts were characterized by N2 adsorptiondesorption and X-ray diffraction(XRD).The effects of AFCC on the photocatalytic activity and the crystallinity of TiO2 were studied.The results show that the crystallinity and anatase/rutile ratio of TiO2 loaded on AFCC could be significantly influenced by the calcination temperature.The degradation rate of phenol benefited from the synergistic effects of the adsorption of activated carbon(AC) and the photocatalysis of TiO2,which suggests that a high surface area of AC is essential to achieve high degradation rates and efficiencies.It was found that the larger mean cell size of AFCC increased the light transmission within the foam.

  10. Inactivated properties of activated carbon-supported TiO2 nanoparticles for bacteria and kinetic study.

    Science.gov (United States)

    Li, Youji; Ma, Mingyuan; Wang, Xiaohu; Wang, Xiaohua

    2008-01-01

    The activated carbon-supported TiO2 nanoparticles (TiO2/AC) were prepared by a properly controlled sol-gel method. The effects of activated carbons (AC) support on inactivated properties of TiO2 nanoparticles were evaluated by photocatalytic inactivation experiments of Escherichia coli. The key factors affecting the inactivation efficiency were investigated, including electric power of lamp, temperature, and pH values. The results show that the TiO2/AC composites have high inactivation properties of E. coli in comparison with pure TiO2 powder. The kinetics of photocatalytic inactivation of E. coli was found to follow a pseudo-first order rate law for TiO2/AC composites, and kinetic behavior could be described in terms of a modified Langmuir-Hinshelwood model. The values of the adsorption equilibrium constants for the bacteria, K(c), and for the rate constants, k(r), were certainly depended on TiO2 content. At 47 wt.% TiO2 coatings with the highest rate constant, the K(c) and k(r) were 1.17 x 10(-8) L/cfu and 1.43 x 10(6) cfu/(L x min), respectively. The variety of parameters shows significant effects on inactivation rate. The outer layer of bacteria decomposed first resulting in inactivation of cell, and with further illumination, the cells nearly decomposed.

  11. Application of TiO2 nanoparticles coated multi-wall carbon nanotube to dye-sensitized solar cells.

    Science.gov (United States)

    Chang, Ho; Kao, Mu-Jung; Huang, Kuohsiu-David; Hsieh, Tung-Jung; Chien, Shu-Hua

    2010-11-01

    This study uses the sol-gel method to prepare TiO2 nanoparticle, and further applies TiO2 nanoparticle coating on the surface of the multi-wall carbon nanotube (MWCNT). As a result, TiO2-CNT composite nanoparticles are prepared to serve as photoelectrode material in dye-sensitized solar cell (DSSC). First, after acid treatment of MWCNT is used to remove impurities. Then, the sol-gel method is employed to prepare TiO2-CNT composite nanopowder. X-ray diffraction (XRD) pattern shows that after the TiO2 in TiO2-CNT composite nanopowder has been thermally treated at 450 degrees C, it can be completely changed to anatase phase. Furthermore, as shown from the SEM image, TiO2 has been successfully coated on CNT. The photoelectrode of DSSC is prepared using the electrophoretic deposition method (EPD) to mix the Degassa P25 TiO2 nanoparticles with TiO2-CNT powder for deposition on the indium tin oxide (ITO) conductive glass. After secondary EPD, a thin film of TiO2/CNTs with thickness 17 microm can be acquired. For the prepared TiO2-CNT composite nanoparticles, since MWCNT can increase the short-circuit current density of DSSC, the light-to-electricity conversion efficiency of DSSC can be effectively increased. Experimental results show that the photoelectric conversion efficiency of DSSC using CNT/TiO2 photoelectrode and N719 dye is increased by 41% from the original 3.45% to 4.87%.

  12. Anatase TiO2 Nanospindle/Activated Carbon (AC Composite Photocatalysts with Enhanced Activity in Removal of Organic Contaminant

    Directory of Open Access Journals (Sweden)

    Wuyi Zhou

    2012-01-01

    Full Text Available This paper embarks upon the three levels of analysis ranging from nanoscale materials synthesis to combination and functionality. Firstly, we have prepared anatase TiO2 nanospindles with an even length of about 200 nm and a central width of about 25 nm by hydrothermal synthesis method at 100°C for 6 h. Secondly, we have dispersed TiO2 nanospindles on the surface of activated carbon (AC and fabricated TiO2/AC composite via a dip-coating method. Thirdly, the TiO2/AC composite has been studied as the photocatalyst to remove the organic contaminants in the waste water and exhibits excellent degradation rate in comparison with pure anatase TiO2 nanospindles.

  13. Adsorption isotherms and kinetics for dibenzothiophene on activated carbon and carbon nanotube doped with nickel oxide nanoparticles

    Indian Academy of Sciences (India)

    MAZEN K NAZAL; GHASSAN A OWEIMREEN; MAZEN KHALED; MUATAZ A ATIEH; ISAM H ALJUNDI; ABDALLA M ABULKIBASH

    2016-04-01

    Activated carbon (AC) and multiwall carbon nanotubes (CNT) doped with 1, 5 and 10% Ni in the form of nickel oxide nanoparticles were prepared using the wetness impregnation method. These percentages were denoted by the endings NI1, NI5 and NI10 in the notations ACNI1, ACNI5, ACNI10 and CNTNI1, CNTNI5, CNTNIL10, respectively. The physicochemical properties for these adsorbents were characterized using N$_2$ adsorption–desorption surface area analyzer, thermal gravimetric analysis (TGA), scanning electron microscopy, energy-dispersive X-ray spectroscopy, field-emission transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectrometre. Adsorption isotherms were obtained and desulphurization kinetics were carried out on solutions of dibenzothiophene (DBT) and thiophene in a model fuel. The efficiencies of DBT and thiophene removal were reported. The adsorption isotherms fitted the Langmuir and Freundlich models. The highest adsorption capacity for DBT was $74\\pm 5$ mg g$^{−1}$ on ACNI5; the maximum adsorption capacities of the other adsorbents followed the trend ${\\rm ACNI1 > ACNI10 > AC > CNTNI5 > CNTNI1 > CNTNI10 > CNT}$. The adsorption rates for DBT and thiophene followed pseudo-second-order kinetics. The selective removal by these adsorbents of DBT relative to thiophene and naphthalene was evaluated. The adsorbents’ reusability and the effect of the percentage of aromaticcompounds on their adsorption capacity were also reported.

  14. Characterization of TiO2 Loaded on Activated Carbon Fibers and Its Photocatalytic Reactivity

    Institute of Scientific and Technical Information of China (English)

    JIA,Bing-Yu; DUAN,Li-Yan; MA,Chuan-Li; WANG,Chun-Ming

    2007-01-01

    In this paper,TiO2 loaded on activated carbon fibers(ACF)was prepared by a coating treatment,followed by calcination at different temperatures in air atmosphere.The photocatalyst developed was characterized by SEM,XRD,XPS and UV-Vis adsorption spectroscopy.It was observed from SEM images that TiO2 loaded on ACF was in the form of small clusters with nanometer size.As confirmed by XRD and XPS determinations,the crystalline pattern of immobilized TiO2 was still anatase-form after calcination,and the micrographic structure and surface properties of ACF have not been damaged by the deposition process and calcination at different temperatures.Photocatalytic degradation of methylene blue(MB)in aqueous solution was investigated using TiO2/ACF as photocatalyst.The comparison of photolysis,absorption and photocatalysis was carried out.The results indicated that the photocatalysis process of combined photocatalyst showed much higher degradation rate than that of photolysis and absorption processes.In addition,the possibility of cyclic usage of the photocatalyst was also confirmed.

  15. Inactivated properties of activated carbon-supported TiO2 nanoparticles for bacteria and kinetic study

    Institute of Scientific and Technical Information of China (English)

    LI Youji; MA Mingyuan; WANG Xiaohu; WANG Xiaohua

    2008-01-01

    The activated carbon-supported TiO2 nanoparticles (TiO2/AC) were prepared by a properly controlled sol-gel method. The effects of activated carbons (AC) support on inactivated properties of TiO2 nanoparticles were evaluated by photocatalytic inactivation experiments ofEscherichia coli. The key factors affecting the inactivation efficiency were investigated, including electric power of lamp, temperature, and pH values. The results show that the TiO2/AC composites have high inactivation properties of E. coli in comparison with pure TiO2 powder. The kinetics of photocatalytic inactivation of E. coli was found to follow a pseudo-first order rate law for TiO2/AC composites, and kinetic behavior could be described in terms of a modified Langmuir-Hinshelwood model. The values of the adsorption equilibrium constants for the bacteria, Kc, and for the rate constants, kr, were certainly depended on TiO2 content. At 47 variety of parameters shows significant effects on inactivation rate. The outer layer of bacteria decomposed first resulting in inactivation of cell, and with further illumination, the cells nearly decomposed.

  16. Preparation of TiO2/Activated Carbon Composites for Photocatalytic Degradation of RhB under UV Light Irradiation

    Directory of Open Access Journals (Sweden)

    Baolin Xing

    2016-01-01

    Full Text Available Photocatalysts comprising nanosized TiO2 particles on activated carbon (AC were prepared by a sol-gel method. The TiO2/AC composites were characterized by X-ray diffraction (XRD, thermogravimetric (TG analysis, nitrogen adsorption, scanning electron microscope (SEM, transmission electron microscope (TEM, and energy dispersive X-ray (EDX. Their photocatalytic activities were studied through the degradation of Rhodamine B (RhB in photocatalytic reactor at room temperature under ultraviolet (UV light irradiation and the effect of loading cycles of TiO2 on the structural properties and photocatalytic activity of TiO2/AC composites was also investigated. The results indicate that the anatase TiO2 particles with a crystal size of 10–20 nm can be deposited homogeneously on the AC surface under calcination at 500°C. The loading cycle plays an important role in controlling the loading amount of TiO2 and morphological structure and photocatalytic activity of TiO2/AC composites. The porosity parameters of these composite photocatalysts such as specific surface area and total pore volume decrease whereas the loading amount of TiO2 increases. The TiO2/AC composite synthesized at 2 loading cycles exhibits a high photocatalytic activity in terms of the loading amount of TiO2 and as high as 93.2% removal rate for RhB from the 400 mL solution at initial concentration of 2 × 10−5 mol/L under UV light irradiation.

  17. PREPARATION OF TiO2 PHOTOCATALYST ANCHORED ON ACTIVATED CARBON FIBERS AND ITS PHOTODEGRADATION OF METHYLENE BLUE

    Institute of Scientific and Technical Information of China (English)

    Pingfeng Fu; Yong Luan; Xuegang Dai

    2004-01-01

    TiO2 particulate photocatalyst anchored on activated carbon fibers (ACFs) was prepared by a molecular adsorption-deposition method. The TiO2 particles deposited on the carbon fibers formed a coating of about 100 nm in thickness. The photocatalyst prepared was characterized by means of SEM, EDS, XRD and UV-vis adsorption spectroscopy. Anatase-type TiO2 was uniquely developed, and the micrographic structure of ACFs was not damaged during preparation. The roomy space between adjacent carbon fibers could allow UV-light to penetrate into the felt-form photocatalyst to a certain depth, so that a three dimensional environment was formed for the photocatalytic reaction.Such TiO2/ACFs photocatalyst exhibited its photocatalytic reactivity in photodegradation of concentrated methylene blue(MB) solutions. The MB molecules in the bulk solutions was supposed to be condensed around TiO2 particles by adsorption by ACFs. Therefore, the photocatalyst possesses the combined effect of adsorption by activated carbon fibers and photocatalytic reactivity of anatase-type TiO2 on MB photodegradation.

  18. Carbon coating stabilized Ti(3+)-doped TiO2 for photocatalytic hydrogen generation under visible light irradiation.

    Science.gov (United States)

    Fu, Gao; Zhou, Peng; Zhao, Meiming; Zhu, Weidong; Yan, Shicheng; Yu, Tao; Zou, Zhigang

    2015-07-28

    Self-doping by Ti(3+) is a useful method to expand the light response of TiO2 into the visible light region. However, to obtain a stable Ti(3+)-doped TiO2 seems to be a challenge due to the easy oxidation of Ti(3+) during the heterogeneous reaction. Here, we propose a simple carbon coating route to stabilize the Ti(3+)-doped TiO2, in which both the Ti(3+) and precursor of the carbon coating layer were in situ formed from the hydrothermal hydrolysis of titanium isopropoxide. The carbon coated Ti(3+)-doped TiO2 exhibited excellent stability for photocatalytic hydrogen production. Based on electron paramagnetic resonance (EPR) analysis, the proposed stabilizing mechanism is that the conductive carbon coating layer as a barrier layer prevents the H2O and O2 from diffusing into the surface of the photocatalyst, which can oxidize the surface O vacancies and Ti(3+) in TiO2. Our findings offer a simple route to prepare a highly stable TiO2-based photocatalyst with visible light response.

  19. A Designed TiO2 /Carbon Nanocomposite as a High-Efficiency Lithium-Ion Battery Anode and Photocatalyst.

    Science.gov (United States)

    Peng, Liang; Zhang, Huijuan; Bai, Yuanjuan; Feng, Yangyang; Wang, Yu

    2015-10-12

    Herein, a peapod-like TiO2 /carbon nanocomposite has successfully been synthesized by a rational method for the first time. The novel nanostructure exhibits a distinct feature of TiO2 nanoparticles encapsulated inside and the carbon fiber coating outside. In the synthetic process, H2 Ti3 O7 nanotubes serve as precursors and templates, and glucose molecules act as the green carbon source. With the alliciency of hydrogen bonding between H2 Ti3 O7 and glucose, a thin polymer layer is hydrothermally assembled and subsequently converted into carbon fibers through calcinations under an inert atmosphere. Meanwhile, the precursors of H2 Ti3 O7 nanotubes are transformed into the TiO2 nanoparticles encapsulated in carbon fibers. The achieved unique nanocomposites can be used as excellent anode materials in lithium-ion batteries (LIBs) and photocatalytic reagents in the degradation of rhodamine B. Due to the synergistic effect derived from TiO2 nanoparticles and carbon fibers, the obtained peapod-like TiO2 /carbon cannot only deliver a high specific capacity of 160 mAh g(-1) over 500 cycles in LIBs, but also perform a much faster photodegradation rate than bare TiO2 and P25. Furthermore, owing to the low cost, environmental friendliness as well as abundant source, this novel TiO2 /carbon nanocomposite will have a great potential to be extended to other application fields, such as specific catalysis, gas sensing, and photovoltaics. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. PHOTOCATALYTIC DECOMPOSITION OF GASEOUS TOLUENE BY TIO2 NANOPARTICLES COATED ON ACTIVATED CARBON

    Directory of Open Access Journals (Sweden)

    A. Rezaee ، Gh. H. Pourtaghi ، A. Khavanin ، R. Sarraf Mamoory ، M. T. Ghaneian ، H. Godini

    2008-10-01

    Full Text Available Volatile organic compounds are considered as a group of major environmental pollutants and toluene is recognized as one of the representatives. In this research, the photocatalytic activity for toluene removal was studied over TiO2 nanoparticles embeded on activated carbon. Laboratory-scale experiments were conducted in a fixed-bed reactor equipped with 4 w and 8 w UV lamps (peak wavelength at 365 nm to determine the oxidation rates of toluene. The photocatalyst was extensively characterized by means of X- ray diffraction and scan electronmicroscopy. Experiments were conducted under general laboratory temperature (25ºC±2 while the irradiation was provided by the UV lamps. The dependence of the reaction rate on light intensity as well as the deactivation of the catalyst were determined. The results indicated that the rate of the photocatalytic process increased with increasing the intensity of UV irradiation. Using the UV-A lamps, the decomposition rate of toluene was 98%. The stabilized photocatalyst presented remarkable stability (no deactivation and excellent repeatability. The catalyst could be regenerated by UV irradiation in the absence of gas phase. The control experiments confirmed that the photocatalytic effects of toluene onto the TiO2/activated carbon catalysts in the dark conditions were negligible. Reproducibility tests proved that the photocatalytic activity of the photocatalyst remains intact even after several experiments of new added toluene quantities. The study demonstrated that the TiO2/activated carbon catalyst may be a practical and promising way to degrade the toluene under ultraviolet irradiation.

  1. Glycol Derived Carbon- TiO2 as Low Cost and High Performance Anode Material for Sodium-Ion Batteries

    Science.gov (United States)

    Tao, Hongwei; Zhou, Min; Wang, Kangli; Cheng, Shijie; Jiang, Kai

    2017-01-01

    Carbon coated TiO2 (TiO2@C) is fabricated by a convenient and green one-pot solvothermal method, in which ethylene glycol serve as both the reaction medium and carbon source without the addition of any other carbon additives. During the solvothermal process, ethylene glycol polymerize and coordinate with Ti4+ to form the polymeric ligand precursor, then the polymer brushes carbonize and convert to homogeneous carbon layer firmly anchored on the TiO2 nanoparticles (~1 nm thickness). The polymerization and carbonization process of the ethylene glycol is confirmed by FT-IR, Raman, TG and TEM characterizations. Benefiting from the well-dispersed nanoparticles and uniform carbon coating, the as-prepared TiO2@C demonstrate a high reversible capacity of 317 mAh g−1 (94.6% of theoretical value), remarkable rate capability of 125 mAh g−1 at 3.2 A g−1 and superior cycling stability over 500 cycles, possibly being one of the highest capacities reported for TiO2. PMID:28256630

  2. Nitrogen-doped carbon-embedded TiO2 nanofibers as promising oxygen reduction reaction electrocatalysts

    Science.gov (United States)

    Hassen, D.; Shenashen, M. A.; El-Safty, S. A.; Selim, M. M.; Isago, H.; Elmarakbi, A.; El-Safty, A.; Yamaguchi, H.

    2016-10-01

    The development of inexpensive and effective electrocatalysts for oxygen reduction reaction (ORR) as a substitute for commercial Pt/C catalyst is an important issue in fuel cells. In this paper, we report on novel fabrication of self-supported nitrogen-doped carbon-supported titanium nanofibers (Nsbnd TiO2@C) and carbon-supported titanium (TiO2@C) electrocatalysts via a facile electrospinning route. The nitrogen atom integrates physically and homogenously into the entire carbon-titanium structure. We demonstrate the catalytic performance of Nsbnd TiO2@C and TiO2@C for ORR under alkaline conditions in comparison with Pt/C catalyst. The Nsbnd TiO2@C catalyst shows excellent ORR reactivity and durability. Interestingly, among all the catalysts used in this ORR, Nsbnd TiO2@C-0.75 exhibits remarkable competitive oxygen reduction activity in terms of current density and onset potential, as well as superior methanol tolerance. Such tolerance attributes to maximizing the diffusion of trigger pulse electrons during catalytic reactions because of enhanced electronic features. Results indicate that our fabrication strategy can provide an opportunity to produce a simple, efficient, cost-effective, and promising ORR electrocatalyst for practical applications in energy conversion and storage technologies.

  3. Rectangular bunched rutile TiO2 nanorod arrays grown on carbon fiber for dye-sensitized solar cells.

    Science.gov (United States)

    Guo, Wenxi; Xu, Chen; Wang, Xue; Wang, Sihong; Pan, Caofeng; Lin, Changjian; Wang, Zhong Lin

    2012-03-07

    Because of their special application in photovoltaics, the growth of one-dimensional single-crystalline TiO(2) nanostructures on a flexible substrate is receiving intensive attention. Here we present a study of rectangular bunched TiO(2) nanorod (NR) arrays grown on carbon fibers (CFs) from titanium by a "dissolve and grow" method. After a corrosion process in a strong acid solution, every single nanorod is etched into a number of small nanowires. Tube-shaped dye-sensitized solar cells are fabricated by using etched TiO(2) NRs-coated CFs as the photoanode. An absolute energy conversion efficiency of 1.28% has been demonstrated under 100 mW cm(-2) AM 1.5 illumination. This work demonstrates an innovative method for growing bunched TiO(2) NRs on flexible substrates that can be applied in flexible devices for energy harvesting and storage.

  4. PHOTOCATALYTIC DEGRADATION OF INDIGO CARMINE BY TiO2/ACTIVATED CARBON DERIVED FROM WASTE COFFEE GROUNDS

    Directory of Open Access Journals (Sweden)

    Irwan Irwan

    2016-03-01

    Full Text Available TiO2/activated carbon derived from waste coffee grounds (TiO2/WCGAC has been prepared by a sol gel method . Waste coffee ground was chemically activated using hydrochloric acid 0.1 M solution and modified with titanium tetraisopropoxide as TiO2 precursor. The structural features of the photocatalyst was investigated by X-ray diffraction (XRD, scanning electron microscope energy dispersive X-ray spectroscopy (SEM EDX,  Fourier transform infrared spectroscopy (FT-IR and nitrogen adsorption-desorption. The XRD results showed that TiO2 is anatase and rutile phase, while FTIR spectra confirmed the presence of  Ti-O groups. The specifics surface area of TiO2/WCGAC was higher than that of activated carbon derived from waste coffee grounds. The photocatalytic activity of TiO2/WGCAC has been evaluated for degradation of indigo carmine solution under UV and solar light irradiation. It was found that degradation percentage of indigo carmine under solar light was higher than that of under UV light.

  5. A kinetic model for describing effect of the external surface concentration of TiO2 on the reactivity of egg-shell activated carbon supported TiO2 photocatalyst

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The porous support supported TiO2 is considered to be the promising photocatalyst due to the fact that it is easily recovered from water and has high capacity to mineralize pollutants. Obviously, the expected structure of this kind of photocatalyst is egg-shell, that is, TiO2 is mainly on the external surface of the porous support. The reactivity of the supported photocatalyst strongly depends on the concentration of TiO2 on the external surface of the porous support. In this study, a kinetic model was developed to describe the effect of the external surface concentration of TiO2 (CESC) on the reactivity of egg-shell activated carbon (AC) supported TiO2 photocatalysts. It was found that the obtained model precisely described the effect of CESC, on the reactivity of TiO2/AC photocatalysts. This study can be used to deeply understand the performance of TiO2/AC catalysts and to provide valuable information on designing efficient supported TiO2 photocatalysts.

  6. Sonochemical Degradation of Reactive Black 5 with a Composite Catalyst of TiO2/Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Cho, Eunju; Choi, Jongbok; Lee, Yonghyeon; Park, Jeong Min; Khim, Jeehyeong

    2013-07-01

    In the sonocatalytic process, composites of TiO2-carbon were used because carbon provides more adsorption sites and acts like an electron sink to prevent the recombination of an electron/hole. Therefore, in the present study, the characteristics of a TiO2/single-walled carbon nanotubes catalyst (TiO2/SWCNTs) have been investigated, and the optimal weight ratio of SWCNTs and the dose for degradation of reactive black 5 (RB5) were also evaluated. TiO2/SWCNT composite was characterized using Brunauer-Emmett-Teller analysis, scanning electron microscopy, energy-dispersive X-ray diffraction microanalysis and spectra, and X-ray diffraction patterns. The degradation rate constants of RB5 with the ratio of SWCNTs were found to depend on the adsorption phenomenon of a surface catalyst, light absorbance, and the recombination of electrons and holes. As a result, the optimal ratio of carbon in the sono-TiO2/SWCNTs process for degradation of RB5 was TiO2:SWCNTs= 200:1. Additionally, the optimal dose of the catalyst was 0.5 g/L.

  7. In situ formation of nanometer-scale TiO2/SiC functional compositional film on carbon fiber

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chunhua; YIN Yansheng; ZHANG Shuxiang; LIU Wei

    2005-01-01

    In the toluene solution of the precursor Polycarbosilane (PCS) containing low- molecular-mass additive Ti(OC4H9)4, TiO2/SiC nanometer-scale functional compositional film with the surface TiO2 layer on CF was formed in situ by means of polymer-derived precursors. The effects of Ti (OC4H9)4 concentrations and the maturating time were studied on the densification and TiO2 particle size of surface layer. The compositions of film were TiO2 and SiC crystal by XRD. According to the results of ESCA analysis, Ti(OC4H9)4 compound oozed gradiently from the pre-ceramic PCS to the surface layer after maturating time of 100 h. In the conditions of 45wt% Ti (OC4H9)4 and 100 h maturation, the nanometer-scale TiO2 particles on continuous surface layer were formed by SEM photographs. The nanometer-scale TiO2/SiC functional compositional film can modify the resistance to oxidation of carbon fiber.

  8. Photodegradation of Methylene Blue in a Batch Fixed Bed Photoreactor Using Activated Carbon Fibers Supported TiO2 Photocatalyst

    Institute of Scientific and Technical Information of China (English)

    傅平丰; 赵卓; 彭鹏; 戴学刚

    2008-01-01

    A batch fixed bed photoreactor, using felt-form activated carbon fibers (ACF) supported TiO2 photocatalyst(TiO2/ACF), was developed to carry out photocatalytic degradation of methylene blue (MB) solution. The effects of TiO2 particle size, loaded TiO2 amount, initial MB concentration, airflow rate and successive run on the decomposition rate were investigated. The results showed that photodegradation process followed a pseudo-first-order reaction kinetic law. The apparent first-order reaction constant kapp was larger than 0.047 min-1 with half reaction time t1/2 shorter than 15 min, which was comparable to reported data using suspended Degussa P-25 TiO2 particles. The high degradation rate was mainly attributed to adsorption of MB molecules onto the surface of TiO2/ACF. The photocatalytic efficiency still remained nearly 90% after 12 successive runs, showing that successive usage of the designed photoreactor was possible. The synergic enhancement effect in combination of adsorption with ACF and photodegradation with TiO2 was proved by comparing MB removal rates in the successive degradation and adsorption runs, respectively.

  9. Synthesis of TiO2 supported on activated carbon by MOCVD:operation parameters study

    Institute of Scientific and Technical Information of China (English)

    张兴旺; 周明华; 雷乐成; 徐甦

    2004-01-01

    A novel metallo-organic chemical vapor deposition (MOCVD) technique has been applied to the preparation of the photocatalytic titanium dioxide supported on activated carbon. The effects of various condition parameters such as carrier gas flow rate, source temperature and deposition temperature on the deposition rate were investigated. The maximum deposition rate of 8.2 mg/(g.h) was obtained under conditions of carrier gas flow rate of 400 ml/min, source temperature of 423 K and deposition temperature of 913 K. The deposition rate followed Arrhenius behavior at temperature of 753 K to 913 K, corresponding to activation energy Ea of 51.09 kJ/mol. TiO2 existed only in anatase phase when the deposition temperature was 773 K to 973 K. With increase of deposition temperature from 1073 K to 1273 K, the rutile content sharply increased from 7% to 70%. It was found that a deposition temperature of 773 K and a higher source temperature of 448 K resulted in finely dispersed TiO2 particles, which were mainly in the range of 10-20 nm.

  10. Synthesis of TiO2 supported on activated carbon by MOCVD: operation parameters study

    Institute of Scientific and Technical Information of China (English)

    张兴旺; 周明华; 雷乐成; 徐甦

    2004-01-01

    A novel metallo-organic chemical vapor deposition (MOCVD) technique has been applied to the preparation of the photocatalytic titanium dioxide supported on activated carbon. The effects of various condition parameters such as carrier gas flow rate, source temperature and deposition temperature on the deposition rate were investigated. The maximum deposition rate of 8.2 mg/(g.h) was obtained under conditions of carrier gas flow rate of 400 ml/min, source temperature of 423 K and deposition temperature of 913 K. The deposition rate followed Arrhenius behavior at temperature of 753 K to 913 K, corresponding to activation energy Ea of 51.09 kJ/mol. TiO2 existed only in anatase phase when the deposition temperature was 773 K to 973 K. With increase of deposition temperature from 1073 K to 1273 K, the rutile content sharply increased from 7% to 70%. It was found that a deposition temperature of 773 K and a higher source temperature of 448 K resulted in finely dispersed TiO2 particles, which were mainly in the range of 10-20 nm.

  11. Synergetic effect between adsorption and photodegradation on nanostructured TiO2/activated carbon fiber felt porous composites for toluene removal.

    Science.gov (United States)

    Li, Min; Lu, Bin; Ke, Qin-Fei; Guo, Ya-Jun; Guo, Ya-Ping

    2017-03-15

    The low quantum efficiency and limited adsorption efficiency of TiO2 makes it only fit for the removal of VOCs with low concentrations. Herein, we for the first time fabricated nanostructured TiO2/activated carbon fiber felt (TiO2/ACFF) porous composites by the in situ deposition of TiO2 microspheres on the carbon fibers in ACFF. Interestingly, the TiO2 microspheres exhibit hierarchical nanostructures constructed by nanocrystals as building blocks. The TiO2/ACFF porous composites possess excellent adsorption and photodegradation properties for toluene because of the synergetic effects between the nanostructured TiO2 and ACFF. The adsorption efficiencies of the TiO2/ACFF porous composites reach approximately 98% at the toluene concentration (TiO2/ACFF porous composites significantly enhances photocatalytic property for toluene by hindering the recombination of electron-hole pairs, reducing the TiO2 band gap energy (Eg) to 2.95eV and accelerating toluene adsorption. At the toluene concentrations of 230ppm and 460ppm, the photocatalytic oxidation efficiency of toluene into CO2 arrives at 100% and 81.5%, respectively. Therefore, the TiO2/ACFF porous composites with synergetic adsorption and photocatalytic activities have great potentials for toluene removal.

  12. Preparation and Characterization of Activated Carbon from Coconut Shell – Doped Tio2 in Water Solution

    Directory of Open Access Journals (Sweden)

    Maulidiyah

    2015-12-01

    Full Text Available The objective of the study was to prepare the activated carbon material doped TiO2-P25 (P25in order to determine the interaction occured in the water medium. The method was to prepare the activated carbon from coconut shell which had been cleaned, pyrolyzed, sievedthen followed by physical activation using a thermal process. Preparation of P25 was to form structures of anatase crystals in the furnace at temperature of 500°C for 3 hours. Both materials were mixed using distilled water until sol-gel was formed. Results of characterization using SEM showed that there is interaction between the activated carbon and P25inserted in the pores of the carbon, while SEM-EDX showed the composition of carbon, titanium and oxide are 46.9%; 27.5% and 25.6%, respectively. Data from XRD showed the formation of peaks from P25 anatase crystals and the carbon. It was supported by data of Flourier Transform Infra Red (FTIR which showed the bonds of –OH; C-H; C=C; COand the O-Ti-O.

  13. Effect of TiO2 deposition on the mechanical properties of a carbon-fiber-reinforced bismaleimide composite

    Science.gov (United States)

    Di, Jang; Chunhua, Cao; Jie, Wu

    2013-07-01

    In order to improve the mechanical properties of carbon-fiber-reinforced bismaleimide (CF/BMI) composites, TiO2 was deposited on the carbon fibers. The short-beam shear and mechanical properties of the composites were investigated. Both raw and TiO2-coated CFs were utilized for their fabrication. The tensile strength of the composites, both with raw and TiO2-coated fibers, grew with increasing filler content. The tensile strength of the CF/BMI composites with treated fibers, at all mixing ratios, was found to be by 18% higher than that of the composites with untreated ones. The surface morphologies of fracture surfaces of the composites were recorded using the scanning electron microscopy (SEM) to gain information about the interfacial fiber-matrix adhesion in the composites.

  14. Influence of Different Defects in Vertically Aligned Carbon Nanotubes on TiO2 Nanoparticle Formation through Atomic Layer Deposition.

    Science.gov (United States)

    Acauan, Luiz; Dias, Anna C; Pereira, Marcelo B; Horowitz, Flavio; Bergmann, Carlos P

    2016-06-29

    The chemical inertness of carbon nanotubes (CNT) requires some degree of "defect engineering" for controlled deposition of metal oxides through atomic layer deposition (ALD). The type, quantity, and distribution of such defects rules the deposition rate and defines the growth behavior. In this work, we employed ALD to grow titanium oxide (TiO2) on vertically aligned carbon nanotubes (VACNT). The effects of nitrogen doping and oxygen plasma pretreatment of the CNT on the morphology and total amount of TiO2 were systematically studied using transmission electron microscopy, Raman spectroscopy, and thermogravimetric analysis. The induced chemical changes for each functionalization route were identified by X-ray photoelectron and Raman spectroscopies. The TiO2 mass fraction deposited with the same number of cycles for the pristine CNT, nitrogen-doped CNT, and plasma-treated CNT were 8, 47, and 80%, respectively. We demonstrate that TiO2 nucleation is dependent mainly on surface incorporation of heteroatoms and their distribution rather than structural defects that govern the growth behavior. Therefore, selecting the best way to functionalize CNT will allow us to tailor TiO2 distribution and hence fabricate complex heterostructures.

  15. Carbon wrapped and doped TiO2 mesoporous nanostructure with efficient visible-light photocatalysis for NO removal

    Science.gov (United States)

    He, Di; Li, Yongli; Wang, inshu; Wu, Junshu; Yang, Yilong; An, Qier

    2017-01-01

    Carbon wrapped and doped mesoporous anatase TiO2 nanocrystals were prepared by a hydrothermal approach in acetic acid aqueous containing chitosan. A designed post-thermal treatment was employed to enhance the incorporation between carbon and TiO2. After hydrothermal process, mesoporous anatase TiO2 formed with wrapped by a few layers of carbon shell. Here chitosan was used as not only the template for the formation of mesopores, but also the carbon source toward the carbon layers coating. Furthermore, chitosan provided doping element into TiO2 lattice and induced to form Tisbnd C bond which caused Ti(III) with oxygen vacancies. The Ti(III)-oxygen vacancy are partly responsible for visible-light response and high photocatalytic activity, which can accelerate electron transfer thus inhibit photogenerated charge recombination. The photocatalytic activity was evaluated using photo-oxidation of gaseous NO under visible light irradiation as the probe reaction. In the optimum result, 71% of NO with starting concentration at ppb level was photo-degraded. Our results also showed that the photogenerated electrons played a key role in photodegradation of NO, as a result, the environmental humidity level had a negligible effect on the photocatalysis.

  16. Photocatalytic Reduction of Carbon Dioxide with Modify Pd, Ru on TiO2 Surface

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Photocatalytic reduction of CO2 to organic compounds was reduction in semiconductor suspension system under simulated solar in laboratory. TiO2 load catalysts were prepared in different ways, and they were used in photocatalytic reduction of CO2 . Experimental results show that the photocatalytic activity can be improve by dressing Pd, Ru on TiO2 Surface and is obvious different when catalysts were prepared in different ways. The photocatalytic mechanism of dressing Pd on TiO2 Surface; dressing Pd and Ru on TiO2 Surface were also discussed in this paper.

  17. TiO2-coated mesoporous carbon: conventional vs. microwave-annealing process.

    Science.gov (United States)

    Coromelci-Pastravanu, Cristina; Ignat, Maria; Popovici, Evelini; Harabagiu, Valeria

    2014-08-15

    The study of coating mesoporous carbon materials with titanium oxide nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon materials in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of mesoporous carbon materials and titanium oxide is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. But, their synthesis is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors, which takes time and money. The thermal heating based techniques are time consuming and often lack control of particle size and morphology. Hence, since there is a growing interest in microwave technology, an alternative way of power input into chemical reactions through dielectric heating is the use of microwaves. This work is focused on the advantages of microwave-assisted synthesis of TiO2-coated mesoporous carbon over conventional thermal heating method. The reviewed studies showed that the microwave-assisted synthesis of such composites allows processes to be completed within a shorter reaction time allowing the nanoparticles formation with superior properties than that obtained by conventional method.

  18. TiO2 Processed by pressurized hot solvents as a novel photocatalyst for photocatalytic reduction of carbon dioxide

    Science.gov (United States)

    Reli, Martin; Kobielusz, Marcin; -->Matějová, Lenka; Daniš, Stanislav; Macyk, Wojciech; Obalová, Lucie; Kuśtrowski, Piotr; Rokicińska, Anna; Kočí, Kamila

    2017-01-01

    Anatase-brookite TiO2 photocatalysts were prepared by the sol-gel process controlled within reverse micelles and processing by pressurized hot solvents-water/methanol/water (TiO2(M)) and water/ethanol/water (TiO2(E)), as an unconventional alternative to common calcination. The main goal of this work was to prepare anatase-brookite mixtures by processing by two different alcohols (methanol and ethanol) and evaluate the influence of the alcohol on the photocatalytic activity. Prepared photocatalysts were characterized by organic elemental analysis, nitrogen physisorption, XRD, UV-vis, photoelectrochemical and spectroelectrochemical measurements and XPS. The prepared photocatalysts efficiency was tested on the photocatalytic reduction of carbon dioxide and compared with commercial TiO2 Evonik P25. Both prepared nanocomposites were more efficient towards methane production but Evonik P25 was the most efficient towards hydrogen generated through water splitting. The higher performance of anatase-brookite mixture towards methane production can be explained by (i) a higher photocatalytic activity of brookite than rutile; (ii) a large surface area of anatase-brookite composites enabling better carbon dioxide adsorption; (iii) the photoinduced electron transfer from the brookite conduction band to the anatase conduction band. On the other hand, a higher production of hydrogen in the presence of Evonik P25 is caused by a better charge separation in anatase-rutile than anatase-brookite phase compositions. TiO2(M) appeared more active than TiO2(E) in the photocatalytic reduction of carbon dioxide due to a lower density of defects created in the crystal lattice.

  19. Performance enhancement of TiO2-based dye-sensitized solar cells by carbon nanospheres in photoanode

    CERN Document Server

    Bayatloo, Elham; Polkoo, Sajad Saghaye

    2013-01-01

    The conversion efficiency of dye-sensitized solar cells (DSSCs) is optimized by modifying the optical design and improving absorbance within the cell. These objectives are obtained by creating different sized cavities in TiO2 photoanode. For this purpose, carbon nanospheres with diameters 100-600 nm are synthesized by hydrothermal method. A paste of TiO2 is mixed with various amounts of carbon nanospheres. During TiO2 photoanode sintering processes at 500C temperature, the carbon nanospheres are removed. This leads to random creation of cavities in the DSSCs photoanode. These cavities enhance light scattering and porosity which improve light absorbance by dye N719 and provide a larger surface area for dye loading. These consequences enhance performance of DSSCs. By mixing 3% Wt. carbon nanospheres in the TiO2 pastes, we were able to increase the short circuit current density and efficiency by 40% (from 12.59 to 17.73 mA/cm2) and 33% (from 5.72% to 7.59%), respectively.

  20. Removal of Trichloroethylene by Activated Carbon in the Presence and Absence of TiO2 Nanoparticles

    Science.gov (United States)

    Nanoparticles (NPs) are emerging as a new type of contaminant in water and wastewater. The fate of titanium dioxide nanoparticles (TiO2NPs) in a granular activated carbon (GAC) adsorber and their impact on the removal of trichloroethylene (TCE) by GAC was investigated...

  1. Heterogeneous TiO2/V2O5/Carbon Nanotube Electrodes for Lithium-Ion Batteries.

    Science.gov (United States)

    Kurttepeli, Mert; Deng, Shaoren; Mattelaer, Felix; Cott, Daire J; Vereecken, Philippe; Dendooven, Jolien; Detavernier, Christophe; Bals, Sara

    2017-03-08

    Vanadium pentoxide (V2O5) is proposed and investigated as a cathode material for lithium-ion (Li-ion) batteries. However, the dissolution of V2O5 during the charge/discharge remains as an issue at the V2O5-electrolyte interface. In this work, we present a heterogeneous nanostructure with carbon nanotubes supported V2O5/titanium dioxide (TiO2) multilayers as electrodes for thin-film Li-ion batteries. Atomic layer deposition of V2O5 on carbon nanotubes provides enhanced Li storage capacity and high rate performance. An additional TiO2 layer leads to increased morphological stability and in return higher electrochemical cycling performance of V2O5/carbon nanotubes. The physical and chemical properties of TiO2/V2O5/carbon nanotubes are characterized by cyclic voltammetry and charge/discharge measurements as well as electron microscopy. The detailed mechanism of the protective TiO2 layer to improve the electrochemical cycling stability of the V2O5 is unveiled.

  2. Light-Driven Preparation, Microstructure, and Visible-Light Photocatalytic Property of Porous Carbon-Doped TiO2

    OpenAIRE

    Xiao-Xin Zou; Guo-Dong Li; Jun Zhao; Juan Su; Xiao Wei; Kai-Xue Wang; Yu-Ning Wang; Jie-Sheng Chen

    2012-01-01

    Highly porous carbon-doped TiO2 (C-TiO2) has been prepared, for the first time, through a light-driven approach using crystalline titanium glycolate (TG) as the single-source precursor. Although the nonthermally prepared porous C-TiO2 is amorphous, it shows a remarkable visible-light photocatalytic activity higher than that of nitrogen-doped TiO2 (N-TiO2) due to its significant surface area (530 m2/g) and pore-rich structure. X-ray photoelectron, electron paramagnetic resonance, and UV-Vis di...

  3. Dye-sensitized solar cells based on anatase TiO 2 hollow spheres/carbon nanotube composite films

    Science.gov (United States)

    Yu, Jiaguo; Fan, Jiajie; Cheng, Bei

    Dye-sensitized solar cells (DSSCs) based on anatase TiO 2 hollow spheres (TiO2HS)/multi-walled carbon nanotubes (CNT) nanocomposite films are prepared by a directly mechanical mixing and doctor blade method. The prepared samples are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV-vis absorption spectroscopy and N 2 adsorption-desorption isotherms. The photoelectric conversion performances of the DSSCs based on TiO2HS/CNT composite film electrodes are also compared with commercial-grade Degussa P25 TiO 2 nanoparticles (P25)/CNT composite solar cells at the same film thickness. The results indicate that the photoelectric conversion efficiencies (η) of the TiO2HS/CNT composite DSSCs are dependent on CNT loading in the electrodes. A small amount of CNT clearly enhances DSSC efficiency, while excessive CNT loading significantly lowers their performance. The former is because CNT enhance the transport of electrons from the films to FTO substrates. The latter is due to high CNT loading shielding the visible light from being adsorbed by dyes.

  4. Direct formation of anatase TiO2 nanoparticles on carbon nanotubes by atomic layer deposition and their photocatalytic properties

    Science.gov (United States)

    Huang, Sheng-Hsin; Liao, Shih-Yun; Wang, Chih-Chieh; Kei, Chi-Chung; Gan, Jon-Yiew; Perng, Tsong-Pyng

    2016-10-01

    TiO2 with different morphology was deposited on acid-treated multi-walled carbon nanotubes (CNTs) by atomic layer deposition at 100 °C-300 °C to form a TiO2@CNT structure. The TiO2 fabricated at 100 °C was an amorphous film, but became crystalline anatase nanoparticles when fabricated at 200 °C and 300 °C. The saturation growth rates of TiO2 nanoparticles at 300 °C were about 1.5 and 0.4 Å/cycle for substrate-enhanced growth and linear growth processes, respectively. It was found that the rate constants for methylene blue degradation by the TiO2@CNT structure formed at 300 °C were more suitable to fit with second-order reaction. The size of 9 nm exhibited the best degradation efficiency, because of the high specific area and appropriate diffusion length for the electrons and holes.

  5. Endothelialization of TiO2 Nanorods Coated with Ultrathin Amorphous Carbon Films

    Science.gov (United States)

    Chen, Hongpeng; Tang, Nan; Chen, Min; Chen, Dihu

    2016-03-01

    Carbon plasma nanocoatings with controlled fraction of sp3-C bonding were deposited on TiO2 nanorod arrays (TNAs) by DC magnetic-filtered cathodic vacuum arc deposition (FCVAD). The cytocompatibility of TNA/carbon nanocomposites was systematically investigated. Human umbilical vein endothelial cells (HUVECs) were cultured on the nanocomposites for 4, 24, and 72 h in vitro. It was found that plasma-treated TNAs exhibited excellent cell viability as compared to the untreated. Importantly, our results show that cellular responses positively correlate with the sp3-C content. The cells cultured on high sp3-C-contented substrates exhibit better attachment, shape configuration, and proliferation. These findings indicate that the nanocomposites with high sp3-C content possessed superior cytocompatibility. Notably, the nanocomposites drastically reduced platelet adhesion and activation in our previous studies. Taken together, these findings suggest the TNA/carbon scaffold may serve as a guide for the design of multi-functionality devices that promotes endothelialization and improves hemocompatibility.

  6. Efficiency enhancement of solution-processed inverted organic solar cells with a carbon-nanotube-doped active layer

    Science.gov (United States)

    Lin, Wen-Kai; Su, Shui-Hsiang; Yeh, Meng-Cheng; Huang, Yang-Chan; Yokoyama, Meiso

    2016-01-01

    Solution-processed titanium-doped ZnO (TZO) is synthesized by the sol-gel method to be the electron-transporting layer (ETL) in an inverted organic solar cell (IOSC). Carbon nanotubes (CNTs) are doped into an active layer of poly(3-hexylthiophene):[6,6]-phenyl C 61 butyric acid methyl ester (P3HT:PCBM). The addition of CNTs in the P3HT:PCBM composite increases the conjugation length of P3HT:PCBM:CNTs, which simultaneously enhances the capacity of the composite to absorb solar energy radiation. Vanadium oxide (V2O5) was spin-coated onto the active layer to be a hole-transporting layer (HTL). The power conversion efficiency (PCE) results indicate that the V2O5 nanobelt structure possesses better phase separation and provides a more efficient surface area for the P3HT:PCBM:CNT active layer to increase photocurrent. The optimized IOSCs exhibited an open circuit voltage (Voc), a short-circuit current density (Jsc), a fill factor (FF), and a PCE of 0.55 V, 6.50 mA/cm2, 58.34%, and 2.20%, respectively, under simulated AM1.5G illumination of 100 mW/cm2.

  7. Theoretical Investigation on Single-Wall Carbon Nanotubes Doped with Nitrogen, Pyridine-Like Nitrogen Defects, and Transition Metal Atoms

    Directory of Open Access Journals (Sweden)

    Michael Mananghaya

    2012-01-01

    Full Text Available This study addresses the inherent difficulty in synthesizing single-walled carbon nanotubes (SWCNTs with uniform chirality and well-defined electronic properties through the introduction of dopants, topological defects, and intercalation of metals. Depending on the desired application, one can modify the electronic and magnetic properties of SWCNTs through an appropriate introduction of imperfections. This scheme broadens the application areas of SWCNTs. Under this motivation, we present our ongoing investigations of the following models: (i (10, 0 and (5, 5 SWCNT doped with nitrogen (CNxNT, (ii (10, 0 and (5, 5 SWCNT with pyridine-like defects (3NV-CNxNT, (iii (10, 0 SWCNT with porphyrine-like defects (4ND-CNxNT. Models (ii and (iii were chemically functionalized with 14 transition metals (TMs: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pd, Ag, Pt and Au. Using the spin-unrestricted density functional theory (DFT, stable configurations, deformations, formation and binding energies, the effects of the doping concentration of nitrogen, pyridine-like and porphyrine-like defects on the electronic properties were all examined. Results reveal that the electronic properties of SWCNTs show strong dependence on the concentration and configuration of nitrogen impurities, its defects, and the TMs adsorbed.

  8. Functionalized carbon nanotube doping of P3HT:PCBM photovoltaic devices for enhancing short circuit current and efficiency

    Directory of Open Access Journals (Sweden)

    Rohit Bhatia

    2017-03-01

    Full Text Available We have successfully functionalized multiwalled carbon nanotubes (MWCNTs using nitrene approach employing the two aryl azides as a precursor for nitrene generation. The dispersion of functionalized MWCNTs has been enhanced in various organic solvents. These functionalized MWCNTs have been successfully doped in various concentrations in the bulk heterojunction (BHJ organic photovoltaic (OPV cells with a poly (3-hexyl thiophene (P3HT and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM photoactive blended layer. The incorporation of MWCNTs with aryl functional groups, in active the layer, results in enhanced performance with respect to a reference cell. The maximum power conversion efficiency of 1.86% is achieved with adduct I while in the case of adduct II it gets double to 2.0% in comparison with a reference cell. This improvement in the device performance is attributed to enhanced exciton dissociation and improved charge transport properties due to the formation of a nanotube percolation network in the photoactive composite layer.

  9. Pt–Ru decorated self-assembled TiO2–carbon hybrid nanostructure for enhanced methanol electrooxidation

    Indian Academy of Sciences (India)

    K G Nishanth; P Sridhar; S Pitchumani; A K Shukla

    2013-06-01

    Porous titanium oxide–carbon hybrid nanostructure (TiO2–C) with a specific surface area of 350 m2/g and an average pore-radius of 21.8 Å is synthesized via supramolecular self-assembly with an in situ crystallization process. Subsequently, TiO2–C supported Pt–Ru electro-catalyst (Pt–Ru/TiO2–C) is obtained and investigated as an anode catalyst for direct methanol fuel cells (DMFCs). X-ray diffraction, Raman spectroscopy and transmission electron microscopy (TEM) have been employed to evaluate the crystalline nature and the structural properties of TiO2–C. TEM images reveal uniform distribution of Pt–Ru nanoparticles (Pt−Ru = 1.5–3.5 nm) on TiO2–C. Methanol oxidation and accelerated durability studies on Pt–Ru/TiO2–C exhibit enhanced catalytic activity and durability compared to carbon-supported Pt–Ru. DMFC employing Pt–Ru/TiO2–C as an anode catalyst delivers a peak-power density of 91 mW/cm2 at 65 °C as compared to the peak-power density of 60 mW/cm2 obtained for the DMFC with carbon-supported Pt–Ru anode catalyst operating under similar conditions.

  10. Combined sonochemical/CVD method for preparation of nanostructured carbon-doped TiO2 thin film

    Science.gov (United States)

    Rasoulnezhad, Hossein; Kavei, Ghassem; Ahmadi, Kamran; Rahimipour, Mohammad Reza

    2017-06-01

    The present work reports the successful synthesis of the nanostructured carbon-doped TiO2 thin films on glass substrate by combination of chemical vapor deposition (CVD) and ultrasonic methods, for the first time. In this method the ultrasound waves act as nebulizer for converting of sonochemically prepared TiO2 sol to the mist particles. These mist particles were thermally decomposed in subsequent CVD chamber at 320 °C to produce the carbon-doped TiO2 thin films. The obtained thin films were characterized by means of X-ray Diffraction (XRD), Raman spectroscopy, diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. The results show that the prepared thin films have anatase crystal structure and nanorod morphology, which calcination of them at 800 °C results in the conversion of nanorods to nanoparticles. In addition, the prepared samples have high transparency, monodispersity and homogeneity. The presence of the carbon element in the structure of the thin films causes the narrowing of the band-gap energy of TiO2 to about 2.8 eV, which results in the improvement of visible light absorption capabilities of the thin film.

  11. Super-fast switching of twisted nematic liquid crystals with a single-wall-carbon-nanotube-doped alignment layer

    Science.gov (United States)

    Liu, Yang; Lim, Young Jin; Kundu, Sudarshan; Lee, Seung Hee; Lee, Gi-Dong

    2015-03-01

    The application of a single-wall carbon-nanotube (SWCNT) and polyimide (PI) composite thin film on an indium tin-oxide (ITO) glass substrate, working as the command surface in a twisted nematic liquid crystal display (LCD), is described. SWCNTs were chopped and oxidized in a strong acid medium to make them more miscible in a polyimide solution. A film of this newly-developed PISWCNT composite was rubbed to determine the director direction for the LC molecules. The newlyfabricated command surface was examined using a laser beam profiler and atomic force microscopy. Sizes of shortened SWCNTs were characterized by using field-emission scanning electron microscopy (FE-SEM). Finally, small-sized test panels were fabricated from this composite-coated ITO glass, and their electro-optic performances were measured. Although the operating voltage to switch a cell was increased by around 41%, the switching speed was improved remarkably. The rise time of the test cells was found to be improved by around 10.12% and the decay time by around 29.77%. Thus, an overall improvement of around 16.12% in the total switching time was achieved. The change in the surface morphology of the newly-developed composite materials was found to be one of the factors responsible for the faster switching of the device. Detailed discussions are given in this report to explain the faster switching of the newly-developed twisted nematic liquid crystal display (TN-LCD). The device can be useful for practical applications.

  12. Fabrication of TiO2/Carbon Photocatalyst using Submerged DC Arc Discharged in Ethanol/Acetic Acid Medium

    Science.gov (United States)

    Saraswati, T. E.; Nandika, A. O.; Andhika, I. F.; Patiha; Purnawan, C.; Wahyuningsih, S.; Rahardjo, S. B.

    2017-05-01

    This study aimed to fabricate a modified photocatalyst of TiO2/C to enhance its performance. The fabrication was achieved using the submerged direct current (DC) arc-discharge method employing two graphite electrodes, one of which was filled with a mixture of carbon powder, TiO2, and binder, in ethanol with acetic acid added in various concentrations. The arc-discharge method was conducted by flowing a current of 10-20 A (~20 V). X-ray diffraction (XRD) patterns showed significant placements of the main peak characteristics of TiO2, C graphite, and titanium carbide. The surface analysis using Fourier transform infrared spectroscopy (FTIR) revealed that fabricated TiO2/C nanoparticles had stretching vibrations of Ti-O, C-H, C═O, C-O, O-H and C═C in the regions of 450-550 cm-1, 2900-2880 cm-1, 1690-1760 cm-1, 1050-1300 cm-1, 3400-3700 cm-1 and ~1600 cm-1, respectively. In addition, the study investigated the photocatalysts of unmodified and modified TiO2/C for photodegradation of methylene blue (MB) dye solution under mercury lamp irradiation. The effectiveness of the degradation was defined by the decrease in 60-minute absorbance under a UV-Vis spectrophotometer. Modified TiO2/C proved to be significantly more efficient in reducing dye concentrations, reaching ~70%. It indicated that the oxygen-containing functional groups have been successfully attached to the surface of the nanoparticles and played a role in enhancing photocatalytic activity.

  13. Enhanced lithium ion storage in TiO2 nanoparticles, induced by sulphur and carbon co-doping

    Science.gov (United States)

    Ivanov, Svetlozar; Barylyak, Adriana; Besaha, Khrystyna; Dimitrova, Anna; Krischok, Stefan; Bund, Andreas; Bobitski, Jaroslav

    2016-09-01

    Sulphur and carbon codoped anatase nanoparticles are synthesized by one-step approach based on interaction between thiourea and metatitanic acid. Electron microscopy shows micrometer-sized randomly distributed crystal aggregates, consisting of many 25-40 nm TiO2 nanoparticles. The obtained phase composition and chemical states of the elements in the structure are analyzed by means of X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD shows that after doping the tetragonal anatase structure is preserved. Further data assessment by Rietveld refinement allows detection of a slight increase of the c lattice parameter and volume related to incorporation of the doping elements. XPS confirms the coexistence of both elemental and oxide carbon forms, which are predominantly located on the TiO2 particle surface. According to XPS analysis sulphur occupies titanium sites and the element is present in S6+ sulfate environment. Analysis based on cyclic voltammetry and galvanostatic intermittent titration (GITT) suggests an accelerated Li+ transport in the doped TiO2 structure. The synthesized S and C co-doped anatase has an excellent electrochemical performance in terms of capacity and very fast lithiation kinetics, superior to the non-doped TiO2. The material displays 83% capacity retention for 500 galvanostatic cycles and nearly 100% current efficiency.

  14. Microwave photocatalytic degradation of Rhodamine B using TiO2 supported on activated carbon: mechanism implication

    Institute of Scientific and Technical Information of China (English)

    HE Zhong; YANG Shaogui; JU Yongming; SUN Cheng

    2009-01-01

    The photocatalytic degradation of rhodamine B (RhB) was carried out using TiO2 supported on activated carbon (TiO2-AC) under microwave irradiation. Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). In the process of microwave-enhanced photocatalysis (MPC), RhB (30 mg/L) was almost completely decoloured in 10 min, and the mineralization efficiency was 96.0% in 20 min. The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25. Additionally, according to Gas Chromatography/Mass Spectrometry (GC/MS) and Liquid Chromatography/Mass Spectrometry (LC/MS) identification, the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates (N,N-diethyl-N'-ethyl-rhodamine (DER)), oxalic acid, malonic acid, succinic acid, and phthalic acid, maleic acid, 3-nitrobenzoic acid, et al. The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure, and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide.

  15. Pipe-Wire TiO2-Sn@Carbon Nanofibers Paper Anodes for Lithium and Sodium Ion Batteries.

    Science.gov (United States)

    Mao, Minglei; Yan, Feilong; Cui, Chunyu; Ma, Jianmin; Zhang, Ming; Wang, Taihong; Wang, Chunsheng

    2017-06-14

    Metallic tin has been considered as one of the most promising anode materials both for lithium (LIBs) and sodium ion battery (NIBs) because of a high theoretical capacity and an appropriate low discharge potential. However, Sn anodes suffer from a rapid capacity fading during cycling due to pulverization induced by severe volume changes. Here we innovatively synthesized pipe-wire TiO2-Sn@carbon nanofibers (TiO2-Sn@CNFs) via electrospinning and atomic layer deposition to suppress pulverization-induced capacity decay. In pipe-wire TiO2-Sn@CNFs paper, nano-Sn is uniformly dispersed in carbon nanofibers, which not only act as a buffer material to prevent pulverization, but also serve as a conductive matrix. In addition, TiO2 pipe as the protection shell outside of Sn@carbon nanofibers can restrain the volume variation to prevent Sn from aggregation and pulverization during cycling, thus increasing the Coulombic efficiency. The pipe-wire TiO2-Sn@CNFs show excellent electrochemical performance as anodes for both LIBs and NIBs. It exhibits a high and stable capacity of 643 mA h/g at 200 mA/g after 1100 cycles in LIBs and 413 mA h/g at 100 mA/g after 400 cycles in NIBs. These results would shed light on the practical application of Sn-based materials as a high capacity electrode with good cycling stability for next-generation LIBs and NIBs.

  16. Defect-rich TiO2-δ nanocrystals confined in a mooncake-shaped porous carbon matrix as an advanced Na ion battery anode

    Science.gov (United States)

    He, Hanna; Zhang, Qi; Wang, Haiyan; Zhang, Hehe; Li, Jiadong; Peng, Zhiguang; Tang, Yougen; Shao, Minhua

    2017-06-01

    Inferior electronic conductivity and sluggish sodium ion diffusion are still two big challenges for TiO2 anode material for Na ion batteries (SIBs). Herein, we synthesize TiO2/C composites by the pyrolysis of MIL-125(Ti) precursor and successfully introduce defects to TiO2/C composite by a simple magnesium reduction. The as-prepared defect-rich TiO2-δ/C composite shows mooncake-shaped morphology consisting of TiO2-δ nanocrystals with an average particle size of 5 nm well dispersed in the carbon matrix. When used as a SIBs anode, the defect-rich TiO2-δ/C composite exhibits a high reversible capacity of 330.2 mAh g-1 at 50 mA g-1 at the voltage range of 0.001-3.0 V and long-term cycling stability with negligible decay after 5000 cycles. Compared with other four TiO2/C samples, the electrochemical performance of defect-rich TiO2-δ/C is highly improved, which may benefit from the enhanced electronic/ionic conductivities owing to the defect-rich features, high surface area rendering shortened electronic and ionic diffusion path, and the suppress of the TiO2 crystal aggregation during sodiation and desodiation process by the carbon matrix.

  17. Construction of solid-state Z-scheme carbon-modified TiO2/WO3 nanofibers with enhanced photocatalytic hydrogen production

    Science.gov (United States)

    Hu, Junhua; Wang, Lijie; Zhang, Peng; Liang, Changhao; Shao, Guosheng

    2016-10-01

    Carbon-layer-coated TiO2/WO3 nanofibers (WTC) were fabricated by combining the electrospinning technique (for TiO2/WO3 nanofibers) and hydrothermal method (for carbon shell). The structure characterization results showed that TiO2/WO3 nanofibers (WT) were encased within an uniform carbon shell about 10 nm in thickness. By adjusting the content of WO3, the graphitization degree of carbon layer could be controlled, and the WTC nanofibers had remarkable light absorption in the visible region. Furthermore, the photoelectrochemical performance and photocatalytic activity were investigated systematically. As expected, the H2-generation rate of the as-prepared composite materials was greatly enhanced compared with pure TiO2 nanofibers (TNFs), TiO2/WO3 nanofibers (WT) and TiO2@carbon core/shell nanofibers (TC). The enhanced activities were mainly attributed to the multichannel-improved charge-carrier photosynthetic heterojunction system with the carbon layer on the surface of TiO2 as an electron collector and WO3 as a hole collector, leading to effective charge separation on these components, which were evidenced by photoluminescence spectroscopy (PL), electrochemical impedance spectroscopy (EIS) and photocurrent analysis. Besides, the addition of WO3 promoted the graphitization of carbon layer, which in turn improved transport of electrons in the carbon layer and also contributed to the performance improvement.

  18. Nanostructured TiO2-coated activated carbon composite as an electrode material for asymmetric hybrid capacitors.

    Science.gov (United States)

    Kim, Sang-Ok; Lee, Joong Kee

    2012-02-01

    A nanostructured TiO2-coated activated carbon (TAC) composite was synthesized by a modified sol-gel reaction and employed it as a negative electrode active material for an asymmetric hybrid capacitor. The structural characterization showed that the TiO2 nano-layer was deposited on the surface of the activated carbon and the TAC composite has a highly mesoporous structure. The evaluation of electrochemical characteristics of the TAC electrode was carried out by galvanostatic charge/discharge cycling tests and electrochemical impedance spectroscopy. The obtained specific capacitance of the TAC composite was 42.87 F/g, which showed by 27.1% higher than that of the activated carbon (AC). The TAC composite also exhibited an excellent cycle performance and kept 95% of initial capacitance over 500 cycles.

  19. Facile synthesis of carbon-mediated porous nanocrystallite anatase TiO2 for improved sodium insertion capabilities as an anode for sodium-ion batteries

    Science.gov (United States)

    Wu, Feng; Luo, Rui; Xie, Man; Li, Li; Zhang, Xiaoxiao; Zhao, Luzi; Zhou, Jiahui; Wang, KangKang; Chen, Renjie

    2017-09-01

    Porous carbon-mediated nanocrystallite anatase TiO2 composites are synthesized successfully via a simple dilatory hydrolysis-calcination method. The structural and morphological characterizations reveal that carbon-mediated TiO2 with a carbon content of 9.9 wt % (C2-TiO2) shows a combination of mesoporous and macroporous structures with a pore volume of 0.20 cm3 g-1 and surface area of 40.3 m2 g-1. Notably, C2-TiO2 delivered enhanced electrochemical performances of a high charge capacity of 259 mA h g-1 at 0.1 C and a high rate performance of 110 mA h g-1 after 150 cycles, even at 1 C. A significant decrease is also observed in the electrochemical impedance of the carbon-mediated samples, which explains superior electrochemical performance. Compared with the bare anatase TiO2 (B-TiO2), improved sodium storage capabilities of carbon-mediated samples are attributed to the participation of carbon to form a symbiotic structure with TiO2, which not only increases pore volume of the samples but serves as highly conductive network to provide a Na+ diffusion path during the insertion/de-insertion of sodium ions. All of these encouraging results suggest that carbon-mediated TiO2 has a great potential for improving sodium insertion capabilities with a facile and low-cost synthesis process.

  20. Light-Driven Preparation, Microstructure, and Visible-Light Photocatalytic Property of Porous Carbon-Doped TiO2

    Directory of Open Access Journals (Sweden)

    Xiao-Xin Zou

    2012-01-01

    Full Text Available Highly porous carbon-doped TiO2 (C-TiO2 has been prepared, for the first time, through a light-driven approach using crystalline titanium glycolate (TG as the single-source precursor. Although the nonthermally prepared porous C-TiO2 is amorphous, it shows a remarkable visible-light photocatalytic activity higher than that of nitrogen-doped TiO2 (N-TiO2 due to its significant surface area (530 m2/g and pore-rich structure. X-ray photoelectron, electron paramagnetic resonance, and UV-Vis diffuse reflectance spectroscopy reveal that the as-prepared porous C-TiO2 photocatalyst contains Ti–O–C bonds which result in visible-light absorption of the material at wavelengths less than 550 nm. Furthermore, it is discovered that the Ti–O–C bonds in the as-prepared C-TiO2 is easily transformed to coke-type species under mild thermal treatment (200°C. The resulting coke-containing porous TiO2 is an even better visible-light photocatalyst, almost twice as effective as N-TiO2, because of its stronger visible-light absorption. The Ti–O–C and the coke-containing porous TiO2 materials follow two different mechanisms in the visible-light photocatalysis process for degradation of methylene blue.

  1. Influence of anatase and rutile phase in TiO2 upon the photocatalytic degradation of methylene blue under solar irradiation in presence of activated carbon.

    Science.gov (United States)

    Matos, J; Montaña, R; Rivero, E; Escudero, A; Uzcategui, D

    2014-01-01

    The influence of activated carbon (AC) on the photocatalytic activity of different crystalline TiO2 phases was verified in the photocatalytic degradation of methylene blue under UV and solar irradiation. The results showed a volcano trend with a maximum photoactivity for the crystalline phase ratio of anatase:rutile equal to 80:20 both under UV or solar irradiation. By contrast, in presence of AC the photocatalytic activity of the binary materials of TiO2/AC followed an exponential trend, increasing as a function of the increase in anatase proportion in the TiO2 framework. The increase in the photoactivity of the binary material TiO2/AC relative to neat TiO2 was up to 22 and about 17 times higher under UV and visible irradiation, respectively. The present results suggest that AC interacts more efficiently with anatase phase than with rutile phase.

  2. Nitrogen-doped carbon-embedded TiO2 nanofibers as promising oxygen reduction reaction electrocatalysts

    OpenAIRE

    Hassen, D.; M. A. Shenashen; El-Safty, S A; Selim, M. M.; Isago, H; Elmarakbi, Ahmed; El-Safty, A; Yamaguchi, H.(International Center for Elementary Particle Physics and Department of Physics, The University of Tokyo, Tokyo, Japan)

    2016-01-01

    The development of inexpensive and effective electrocatalysts for oxygen reduction reaction (ORR) as a substitute for commercial Pt/C catalyst is an important issue in fuel cells. In this paper, we report on novel fabrication of self-supported nitrogen-doped carbon-supported titanium nanofibers (N–TiO2@C) and carbon-supported titanium (TiO2@C) electrocatalysts via a facile electrospinning route. The nitrogen atom integrates physically and homogenously into the entire carbon–titanium structure...

  3. Synthesis, characterization, and performance evaluation of multilayered photoanodes by introducing mesoporous carbon and TiO2 for humic acid adsorption

    Directory of Open Access Journals (Sweden)

    Hosseini S

    2016-08-01

    Full Text Available Soraya Hosseini,1 Hossein Jahangirian,2 Thomas J Webster,2 Salman Masoudi Soltani,3 Mohamed Kheireddine Aroua1 1Department of Chemical Engineering, University of Malaya, Kuala Lumpur, Malaysia; 2Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 3Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK Abstract: Nanostructured photoanodes were prepared via a novel combination of titanium dioxide (TiO2 nanoparticles and mesoporous carbon (C. Four different photoanodes were synthesized by sol–gel spin coating onto a glassy substrate of fluorine-doped tin oxide. The photocatalytic activities of TiO2, TiO2/C/TiO2, TiO2/C/C/TiO2, and TiO2/C/TiO2/C/TiO2 photoanodes were evaluated by exposing the synthesized photoanodes to UV–visible light. The photocurrent density observed in these photoanodes confirmed that an additional layer of mesoporous carbon could successfully increase the photocurrent density. The highest photocurrent density of ~1.022 mA cm-2 at 1 V/saturated calomel electrode was achieved with TiO2/C/C/TiO2 under an illumination intensity of 100 mW cm-2 from a solar simulator. The highest value of surface roughness was measured for a TiO2/C/C/TiO2 combination owing to the presence of two continuous layers of mesoporous carbon. The resulting films had a thickness ranging from 1.605 µm to 5.165 µm after the calcination process. The presence of double-layer mesoporous carbon resulted in a 20% increase in the photocurrent density compared with the TiO2/C/TiO2 combination when only a single mesoporous carbon layer was employed. The improved performance of these photo­anodes can be attributed to the enhanced porosity and increased void space due to the presence of mesoporous carbon. For the first time, it has been demonstrated here that the photoelectrochemical performance of TiO2 can be improved by integrating several layers of mesoporous carbon. Comparison of the

  4. Electronic Structure of Semiconducting and Metallic Tubes in TiO2/Carbon Nanotube Heterojunctions: Density Functional Theory Calculations.

    Science.gov (United States)

    Long, Run

    2013-04-18

    The electronic structure of the TiO2(110) surface interfaced with both a semiconducting and metallic carbon nanotube (CNT) was investigated by density functional theory. Our simulations rationalized visible light photocatalytic activity of CNT/TiO2 hybrid materials higher than that under ultraviolent irradiation and showed that the photoactivity of a semiconducting CNT decorating TiO2 is better than that of the metallic CNT/TiO2 system due to efficient charge separation across the interface. This suggests that semiconducting CNT/TiO2 could be a potential photovoltaic material. In contrast, strong interaction between a metallic CNT and TiO2 leads to large charge transfer. Such charge transfer reduces the built-in potential, in turn resulting in inefficient charge separation. Functionalizing the metallic CNT with a small platinum cluster can increase the built-in potential and drive charge separation. These observations indicate that the CNT/TiO2 interface can be a potential photovoltaic material by a metal cluster decorating a CNT despite a real tube being composed of the mixture of metallic and semiconducting CNTs.

  5. Selective responses of human gingival fibroblasts and bacteria on carbon fiber reinforced polyetheretherketone with multilevel nanostructured TiO2.

    Science.gov (United States)

    Wang, Xiao; Lu, Tao; Wen, Jin; Xu, Lianyi; Zeng, Deliang; Wu, Qianju; Cao, Lingyan; Lin, Shuxian; Liu, Xuanyong; Jiang, Xinquan

    2016-03-01

    The long-term success of dental implants relies not only on stable osseointegration but also on the integration of implant surfaces with surrounding soft tissues. In our previous work, titanium plasma immersion ion implantation (PIII) technique was applied to modify the carbon-fiber-reinforced polyetheretherketone (CFRPEEK) surface, constructing a unique multilevel TiO2 nanostructure thus enhancing certain osteogenic properties. However, the interactions between the modified surface and soft-tissue cells are still not clear. Here, we fully investigate the biological behaviors of human gingival fibroblasts (HGFs) and oral pathogens on the structured surface, which determine the early peri-implant soft tissue integration. Scanning electron microscopy (SEM) shows the formation of nanopores with TiO2 nanoparticles embedded on both the sidewall and bottom. In vitro studies including cell adhesion, viability assay, wound healing assay, real-time PCR, western blot and enzyme-linked immunosorbent assay (ELISA) disclose improved adhesion, migration, proliferation, and collagen secretion ability of HGFs on the modified CFRPEEK. Moreover, the structured surface exhibits sustainable antibacterial properties towards Streptococcus mutans, Fusobacterium nucleatum and Porphyromonas gingivalis. Our results reveal that the multilevel TiO2 nanostructures can selectively enhance soft tissue integration and inhibit bacterial reproduction, which will further support and broaden the adoption of CFRPEEK materials in dental fields.

  6. Spectroscopic studies of porphyrin functionalized multiwalled carbon nanotubes and their interaction with TiO2 nanoparticles surface

    Science.gov (United States)

    Zannotti, Marco; Giovannetti, Rita; D'Amato, Chiara Anna; Rommozzi, Elena

    2016-01-01

    UV-vis and fluorescence investigations about the non-covalent interaction, in ethanolic solutions, of multi-wall carbon nanotube (MWCNT) with Coproporphyrin-I, and its Cu(II) and Zn(II) complexes (MCPIs) have been reported. Evidence of binding between MWCNTs and porphyrins was discovered from spectral adsorption decrease with respect to free porphyrins and by the exhibition of photoluminescence quenching with respect to free porphyrins demonstrating that MWCNT@MCPIs are potential donor-acceptor complexes. Equilibrium and kinetic aspects in the interactions with monolayer transparent TiO2 thin films with the obtained MWCNT@MCPIs are clarified showing their effective adsorption by porphyrin links on the TiO2 monolayer support, with respect to not only MWCNTs, according to the Langmuir model and with pseudo-first-order kinetics. Morphological description of the adsorption of MWCNT@MCPIs on TiO2 with scanning electron microscopy has been reported. The obtained experimental evidences describe therefore MWCNT@MCPIs as potential sensitizers in the DSSC (Dye-Sensitized Solar Cell) applications.

  7. Photodecolorization of Rhodamine B on tungsten-doped TiO2/activated carbon under visible-light irradiation.

    Science.gov (United States)

    Li, Youji; Zhou, Xiaoming; Chen, Wei; Li, Leiyong; Zen, Mengxiong; Qin, Shidong; Sun, Shuguo

    2012-08-15

    Tungsten-doped TiO(2)/activated carbon catalysts have been prepared by a supercritical-pretreatment-assisted sol-gel process. The structural features of the photocatalysts have been investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV/Vis diffuse-reflectance spectroscopy (DRS), electron dispersive X-ray (EDX), photoluminescence spectroscopy, and Brunauer-Emmett-Teller (BET) analysis. The results revealed that a W-TiO(2) layer was coated on the AC surface, and had higher surface area and smaller crystallite size than TiO(2)/AC obtained by a similar route. The W dopant was responsible for narrowing the band gap of TiO(2) and shifting its optical response from the ultraviolet (UV) to the visible-light region. The photocatalytic performances of the supported catalysts have been evaluated for the degradation of Rhodamine B (RhB) solution under visible-light irradiation. Compared with bulk W-TiO(2), the photoactivity was obviously enhanced when it was coated onto AC. In addition, it was found that the reactivity showed a significant relationship with the amount of W dopant, and the photoactivity order of the catalysts from weak to strong showed good agreement with their PL intensities. The effects of TiO(2) content, tungsten ion content, catalyst amount, pH, and initial RhB concentration have been examined as operational parameters. The photocatalytic reactions followed pseudo-first-order kinetics and are discussed in terms of the Langmuir-Hinshelwood model.

  8. In-situ preparation of hierarchical flower-like TiO2/carbon nanostructures as fillers for polymer composites with enhanced dielectric properties

    Science.gov (United States)

    Xu, Nuoxin; Zhang, Qilong; Yang, Hui; Xia, Yuting; Jiang, Yongchang

    2017-01-01

    Novel three-dimensional hierarchical flower-like TiO2/carbon (TiO2/C) nanostructures were in-situ synthesized via a solvothermal method involving calcination of organic precursor under inert atmosphere. The composite films comprised of P (VDF-HFP) and as-prepared hierarchical flower-like TiO2/C were fabricated by a solution casting and hot-pressing approach. The results reveal that loading the fillers with a small amount of carbon is an effective way to improve the dielectric constant and suppress the dielectric loss. In addition, TiO2/C particles with higher carbon contents exhibit superiority in promoting the dielectric constants of composites when compared with their noncarbon counterparts. For instance, the highest dielectric constant (330.6) of the TiO2/C composites is 10 times over that of noncarbon-TiO2-filled ones at the same filler volume fraction, and 32 times over that of pristine P (VDF-HFP). The enhancement in the dielectric constant can be attributed to the formation of a large network, which is composed of local micro-capacitors with carbon particles as electrodes and TiO2 as the dielectric in between. PMID:28262766

  9. In-situ preparation of hierarchical flower-like TiO2/carbon nanostructures as fillers for polymer composites with enhanced dielectric properties

    Science.gov (United States)

    Xu, Nuoxin; Zhang, Qilong; Yang, Hui; Xia, Yuting; Jiang, Yongchang

    2017-03-01

    Novel three-dimensional hierarchical flower-like TiO2/carbon (TiO2/C) nanostructures were in-situ synthesized via a solvothermal method involving calcination of organic precursor under inert atmosphere. The composite films comprised of P (VDF-HFP) and as-prepared hierarchical flower-like TiO2/C were fabricated by a solution casting and hot-pressing approach. The results reveal that loading the fillers with a small amount of carbon is an effective way to improve the dielectric constant and suppress the dielectric loss. In addition, TiO2/C particles with higher carbon contents exhibit superiority in promoting the dielectric constants of composites when compared with their noncarbon counterparts. For instance, the highest dielectric constant (330.6) of the TiO2/C composites is 10 times over that of noncarbon-TiO2-filled ones at the same filler volume fraction, and 32 times over that of pristine P (VDF-HFP). The enhancement in the dielectric constant can be attributed to the formation of a large network, which is composed of local micro-capacitors with carbon particles as electrodes and TiO2 as the dielectric in between.

  10. TiO2 nanorods grown on carbon fiber cloth as binder-free electrode for sodium-ion batteries and flexible sodium-ion capacitors

    Science.gov (United States)

    Liu, Sainan; Luo, Zhigao; Tian, Gengyu; Zhu, Mengnan; Cai, Zhenyang; Pan, Anqiang; Liang, Shuquan

    2017-09-01

    Na-ion batteries (NIBs) and Na-ion capacitors (NICs) have tremendous potential in many large-scale energy storage applications. Here, NIBs based on TiO2 nanorods/carbon fiber cloth (TiO2/CFC) flexible anode materials are introduced. The as-prepared flexible anode exhibited a notable rate performance and high specific capacity of 148.7 mAh g-1 after 2000 cycles at 1 A g-1. Furthermore, we demonstrate a highly flexible NIC system employing the TiO2/CFC anode and carbon fibers (CFs) as the cathode material. The flexible TiO2/CFC//CFs NIC device achieved a high energy density of 73.8 Wh kg-1 and high power density of 13,750 W kg-1, as well as long-term cycling stability over 4000 cycles with a capacity retention of ∼90%.

  11. Synthesis, characterization, and performance evaluation of multilayered photoanodes by introducing mesoporous carbon and TiO2 for humic acid adsorption

    Science.gov (United States)

    Hosseini, Soraya; Jahangirian, Hossein; Webster, Thomas J; Soltani, Salman Masoudi; Aroua, Mohamed Kheireddine

    2016-01-01

    Nanostructured photoanodes were prepared via a novel combination of titanium dioxide (TiO2) nanoparticles and mesoporous carbon (C). Four different photoanodes were synthesized by sol–gel spin coating onto a glassy substrate of fluorine-doped tin oxide. The photocatalytic activities of TiO2, TiO2/C/TiO2, TiO2/C/C/TiO2, and TiO2/C/TiO2/C/TiO2 photoanodes were evaluated by exposing the synthesized photoanodes to UV–visible light. The photocurrent density observed in these photoanodes confirmed that an additional layer of mesoporous carbon could successfully increase the photocurrent density. The highest photocurrent density of ~1.022 mA cm−2 at 1 V/saturated calomel electrode was achieved with TiO2/C/C/TiO2 under an illumination intensity of 100 mW cm−2 from a solar simulator. The highest value of surface roughness was measured for a TiO2/C/C/TiO2 combination owing to the presence of two continuous layers of mesoporous carbon. The resulting films had a thickness ranging from 1.605 µm to 5.165 µm after the calcination process. The presence of double-layer mesoporous carbon resulted in a 20% increase in the photocurrent density compared with the TiO2/C/TiO2 combination when only a single mesoporous carbon layer was employed. The improved performance of these photoanodes can be attributed to the enhanced porosity and increased void space due to the presence of mesoporous carbon. For the first time, it has been demonstrated here that the photoelectrochemical performance of TiO2 can be improved by integrating several layers of mesoporous carbon. Comparison of the rate of removal of humic acid by the prepared photoanodes showed that the highest performance from TiO2/C/C/TiO2 was due to the highest photocurrent density generated. Therefore, this study showed that optimizing the sequence of mesoporous carbon layers can be a viable and inexpensive method for enhanced humic acid removal. PMID:27574426

  12. Synthesis, characterization, and performance evaluation of multilayered photoanodes by introducing mesoporous carbon and TiO2 for humic acid adsorption.

    Science.gov (United States)

    Hosseini, Soraya; Jahangirian, Hossein; Webster, Thomas J; Soltani, Salman Masoudi; Aroua, Mohamed Kheireddine

    2016-01-01

    Nanostructured photoanodes were prepared via a novel combination of titanium dioxide (TiO2) nanoparticles and mesoporous carbon (C). Four different photoanodes were synthesized by sol-gel spin coating onto a glassy substrate of fluorine-doped tin oxide. The photocatalytic activities of TiO2, TiO2/C/TiO2, TiO2/C/C/TiO2, and TiO2/C/TiO2/C/TiO2 photoanodes were evaluated by exposing the synthesized photoanodes to UV-visible light. The photocurrent density observed in these photoanodes confirmed that an additional layer of mesoporous carbon could successfully increase the photocurrent density. The highest photocurrent density of ~1.022 mA cm(-2) at 1 V/saturated calomel electrode was achieved with TiO2/C/C/TiO2 under an illumination intensity of 100 mW cm(-2) from a solar simulator. The highest value of surface roughness was measured for a TiO2/C/C/TiO2 combination owing to the presence of two continuous layers of mesoporous carbon. The resulting films had a thickness ranging from 1.605 µm to 5.165 µm after the calcination process. The presence of double-layer mesoporous carbon resulted in a 20% increase in the photocurrent density compared with the TiO2/C/TiO2 combination when only a single mesoporous carbon layer was employed. The improved performance of these photoanodes can be attributed to the enhanced porosity and increased void space due to the presence of mesoporous carbon. For the first time, it has been demonstrated here that the photoelectrochemical performance of TiO2 can be improved by integrating several layers of mesoporous carbon. Comparison of the rate of removal of humic acid by the prepared photoanodes showed that the highest performance from TiO2/C/C/TiO2 was due to the highest photocurrent density generated. Therefore, this study showed that optimizing the sequence of mesoporous carbon layers can be a viable and inexpensive method for enhanced humic acid removal.

  13. Preparation and photocatalytic activity of TiO2-coated granular activated carbon composites by a molecular adsorption-deposition method

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    TiO2 nanoparticle-coated granular activated carbon (GAC) composite photocatalysts (CPs) were suc-cessfully prepared by a molecular adsorption-deposition (MAD) method. The CPs were detected by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), BET surface area and UV-Vis adsorption spectroscopy, and their photoactivity was evaluated by methyl orange (MO) photodegradation. The results show that small-sized TiO2 nanoparticles were dispersed well, deposited on the surface of GAC, and showed slight blue shift in comparison with pure TiO2. With the increase in TiO2 content, the CPs showed band gaps in lower energy, smaller surface areas and the higher content of Ti3+ ions. Compared with pure TiO2 and others CPs samples, CPs-382 sample showed the highest photoactivity due to the optimum TiO2 content and surface area besides the synergic effect of photocatalytic degradation of TiO2 and adsorptive property of GAC. In addition, the CPs could be very easily reclaimed, recycled and reused for methyl orange removal while high photoactivity is pre-served.

  14. Preparation and photocatalytic activity of TiO2-coated granular activated carbon composites by a molecular adsorption-deposition method

    Institute of Scientific and Technical Information of China (English)

    LI Youdi; LI Jing; MA MingYuan; OUYANG YuZhu; YAN WenBin

    2008-01-01

    TiO2 nanoparUcle-coated granular activated carbon (GAC) composite photocatalysts (CPs) were suc-cessfully prepared by a molecular adsorption-deposition (MAD) method. The CPs were detected by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), BET surface area and UV-Vis adsorption spectroscopy, and their photoactivity was evaluated by methyl orange (MO) photodegradation. The results show that small-sized TiO2 nanoparticles were dispersed well, deposited on the surface of GAC, and showed slight blue shift in comparison with pure TiO2. With the increase in TiO2 content, the CPs showed band gaps in lower energy, smaller surface areas and the higher content of Ti3+ ions. Compared with pure TiO2 and others CPs samples, CPs-382 sample showed the highest photoactivity due to the optimum TiO2 content and surface area besides the synergic effect of photocatslytic degradation of TiO2 and adsorptive property of GAC. In addition, the CPs could be very easily reclaimed, recycled and reused for methyl orange removal while high photoactivity is pre-served.

  15. Soft-Templated Self-Assembly of Mesoporous Anatase TiO2/Carbon Composite Nanospheres for High-Performance Lithium Ion Batteries.

    Science.gov (United States)

    Wu, Ruofei; Shen, Shuiyun; Xia, Guofeng; Zhu, Fengjuan; Lastoskie, Christian; Zhang, Junliang

    2016-08-10

    Mesoporous anatase TiO2/carbon composite nanospheres (designated as meso-ATCCNs) were successfully synthesized via a facile soft-templated self-assembly followed by thermal treatment. Structural and morphological analyses reveal that the as-synthesized meso-ATCCNs are composed of primary TiO2 nanoparticles (∼5 nm), combined with in situ deposited carbon either on the surface or between the primary TiO2 nanoparticles. When cycled in an extended voltage window from 0.01 to 3.0 V, meso-ATCCNs exhibit excellent rate capabilities (413.7, 289.7, and 206.8 mAh g(-1) at 200, 1000, and 3000 mA g(-1), respectively) as well as stable cyclability (90% capacity retention over 500 cycles at 1000 mA g(-1)). Compared with both mesoporous TiO2 nanospheres and bulk TiO2, the superior electrochemical performance of the meso-ATCCNs electrode could be ascribed to a synergetic effect induced by hierarchical structure that includes uniform TiO2 nanoparticles, the presence of hydrothermal carbon derived from phenolic resols, a high surface area, and open mesoporosity.

  16. Preparation and photovoltaic properties of layered TiO2/carbon nanotube/TiO2 photoanodes for dye-sensitized solar cells

    Science.gov (United States)

    Barberio, M.; Grosso, D. R.; Imbrogno, A.; Xu, F.

    2016-03-01

    In this paper, we report on the realization of photoanodes for dye sensitized solar cells based on composites of carbon nanotubes and titanium dioxide nanoparticles. Our results show the best photovoltaics performance for carbon nanotubes weight percentages between 0.2% and 0.4%. Photoanodes realized in three-layer configuration, TiO2/carbon nanotube/TiO2, show a cell efficiency of 10.5% and a fill factor of 70%, values 2.4 times greater with respect to that of classical TiO2 anode. The presence of carbon nanotubes enhances the charge transport, strongly reducing the electron/hole recombination in the anode bulk, while the double layer of TiO2 increases the dye adsorption limiting the reduction caused by the presence of carbon nanotubes.

  17. Photoelectrochemical Immunosensor for Detection of Carcinoembryonic Antigen Based on 2D TiO2 Nanosheets and Carboxylated Graphitic Carbon Nitride.

    Science.gov (United States)

    Wang, Huan; Wang, Yaoguang; Zhang, Yong; Wang, Qi; Ren, Xiang; Wu, Dan; Wei, Qin

    2016-06-06

    Carcinoembryonic antigen (CEA) was used as the model, an ultrasensitive label-free photoelectrochemical immunosensor was developed using 2D TiO2 nanosheets and carboxylated graphitic carbon nitride (g-C3N4) as photoactive materials and ascorbic acid as an efficient electron donor. 2D TiO2 nanosheets was sythsized by surfactant self-assembly method and proved to have higher photoelectrochemical signals than TiO2 nanoparticles. Firstly, carboxylated g-C3N4 could be attached to 2D TiO2 nanosheets through the bond formed between carboxyl group of carboxylated g-C3N4 and TiO2. And the photocurrent of g-C3N4/TiO2 drastically enhances compared to carboxylated g-C3N4 and TiO2. Then, antibody of CEA was bonded to TiO2 through the dentate bond formed between carboxyl group of anti-CEA and TiO2, leading to the decrease of the photocurrents. As proven by PEC experiments and electrochemical impedance spectroscopy (EIS) analysis, the fabrication process of the immunosensor is successful. Under the optimal conditions, the intensity decreased linearly with CEA concentration in the range of 0.01~10 ng/mL. The detection limit is 2.1 pg/mL. The work provides an effective method for the detection of tumor markers and can be extended for the application in food safety and environmental monitoring analysis.

  18. Hybrid Multi-Walled Carbon Nanotube TiO2 Electrode Material for Next Generation Energy Storage Devices

    CERN Document Server

    Marler, Sydney

    2016-01-01

    Current supercapacitors present several distinct limitations that severely inhibit the efficiency, power, and electrical capacitance of energy storage devices. Supercapacitors present an exciting prospect that has countless applications in renewable energy storage and modern day electronic devices. In recent years the exciting development of carbon nanotubes (CNTs) has presented an advantage in electrode development. CNTs, however beneficial for their increased electrode surface area, have severe limitations regarding conductivity and electrode density. Creating a nanocomposite hybrid out of a transition metal-oxide and carbon nanotube array would help the current limitations of the modern supercapacitor. TiO2 was chosen for its common occurrence in everyday materials and promising capacitance levels. A multi-walled carbon nanotube array was grown on a SiO2 precursor via CCVD. The transition metal oxide was then deposited via RF Sputtering methods to a MWCNT array. Recharge tests and characterization were con...

  19. Atomic layer deposition of amorphous oxygen-deficient TiO2-x on carbon nanotubes as cathode materials for lithium-air batteries

    Science.gov (United States)

    Yang, Jingbo; Ma, Dingtao; Li, Yongliang; Zhang, Peixin; Mi, Hongwei; Deng, Libo; Sun, Lingna; Ren, Xiangzhong

    2017-08-01

    The amorphous oxygen-deficient TiO2-x thin layer coated carbon nanotubes (CNTs) are synthesized by atomic layer deposition and employed as cathode materials for lithium-air battery. The cathode demonstrates high electrocatalytic activity toward electrode reactions, resulting from the introduction of oxygen-deficient TiO2-x into the nanocomposites. It is found that the intrinsically isotropic nature of amorphous TiO2 which a certain amount of Ti3.5+ and Ti3+ can improve the catalytic activity. Consequently, the battery with the corresponded CNT@TiO2-x cathode shows high discharge/charge capacities and good cycling performance, which the cyclic retention of more than 90 cycles are achieved, while with the pristine CNTs only 50 cycles are obtained. This study provides an approach to fabricate cathode materials for lithium-air battery and moreover clarifies the influence of oxygen vacancies of TiO2 on the electrochemical performance.

  20. Preparation of vertically oriented TiO2 nanosheets modified carbon paper electrode and its enhancement to the performance of MFCs.

    Science.gov (United States)

    Yin, Tao; Lin, Zhenya; Su, Lin; Yuan, Chunwei; Fu, Degang

    2015-01-14

    A unique vertically oriented TiO2 nanosheets (TiO2-NSs) layer was synthesized in situ on the surface of a carbon paper (CP) electrode via hydrothermal synthesis upon addition of a suitable amount of activated carbon powders in a reactor. Field emission scanning electron microscopy images showed that the nanosheets were about 2 μm in length, 200-600 nm in width and 15 nm in thickness. X-ray diffraction and Raman patterns verified TiO2-NSs crystallized in the anatase phase. The electrochemical activities of CP and TiO2-NSs/CP electrode have been investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The maximum power output density of a mixed consortia inoculated microbial fuel cell was increased by 63% upon using TiO2-NSs/CP as a bioanode compared with that using bare CP as a bioanode. The performance improvement could be ascribed to unique 3D open porous interface made of vertically oriented TiO2-NSs, which provides good biocompatibility, favorable mass transport process, large surface areas for adhension of bacteria and direct pathways for electron movement to the electrode.

  1. Carbon as amorphous shell and interstitial dopant in mesoporous rutile TiO2: Bio-template assisted sol-gel synthesis and photocatalytic activity

    Science.gov (United States)

    Mohamed, Mohamad Azuwa; Wan Salleh, Wan Norharyati; Jaafar, Juhana; Rosmi, Mohamad Saufi; Mohd. Hir, Zul Adlan; Abd Mutalib, Muhazri; Ismail, Ahmad Fauzi; Tanemura, Masaki

    2017-01-01

    Regenerated cellulose membrane was used as bio-template nanoreactor for the formation of rutile TiO2 mesoporous, as well as in-situ carbon dopant in acidified sol-gel system. The effects of calcination temperature on the physicochemical characteristic of core-shell nanostructured of bio-templated C-doped mesoporous TiO2 are highlighted in this study. By varying the calcination temperature, the thickness of the carbon shell coating on TiO2, crystallinity, surface area, and optical properties could be tuned as confirmed by HRTEM, nitrogen adsorption/desorption measurement, XRD and UV-vis-NIR spectroscopy. The results suggested that increment in the calcination temperature would lead to the band gap narrowing from 2.95 to 2.80 eV and the thickness of carbon shell increased from 0.40 to 1.20 nm. The x-ray photoelectron spectroscopy showed that the visible light absorption capability was mainly due to the incorporation of carbon dopant at interstitial position in the TiO2 to form Osbnd Tisbnd C or Tisbnd Osbnd C bond. In addition, the formation of the carbon core-shell nanostructured was due to carbonaceous layer grafted onto the surface of TiO2 via Tisbnd Osbnd C and Tisbnd OCO bonds. The result indicated that bio-templated C-doped core-shell mesoporous TiO2 prepared at 300 °C exhibited the highest photocatalytic activity. It is worthy to note that, the calcination temperature provided a huge impact towards improving the physicochemical and photocatalytic properties of the prepared bio-templated C-doped core-shell mesoporous TiO2.

  2. Removal of toluene from water by photocatalytic oxidation with activated carbon supported Fe(3+)-doped TiO2 nanotubes.

    Science.gov (United States)

    Yuan, Rongfang; Zhou, Beihai; Ma, Li

    2014-01-01

    In this work, activated carbon (AC)-supported TiO2 containing 1.0% (mass percent) of 1.0 at.% (atomic percent) Fe(3+)-doped TiO2 nanotubes (Fe-TNTs) were successfully synthesized. The catalyst was used to effectively decompose toluene in water under O3/UV conditions, and some properties including the morphology, X-ray photoelectron spectroscopy, X-ray diffraction patterns, specific surface area and UV-visible diffuse reflectance spectroscopy were analyzed. A removal efficiency of 90.7% was achieved in the presence of fresh AC-supported Fe-TNTs calcined at 550 °C, with a pseudo-first-order rate constant of 0.038/min. The removal efficiency of toluene was reduced when the catalysts were repeatedly used, since the amount of adsorption sites of the supporting substrates decreased. However, even after AC-supported catalyst was used four times, the removal efficiency of toluene was still sufficient in water treatment. The enhanced photocatalytic activity of AC-supported Fe-TNTs was related to the synergistic effect of AC adsorption and Fe-TNTs photocatalytic ozonation. The water from a petrochemical company in China was used to obtain the removal efficiency of the pollutants, and the toluene and total organic carbon removal efficiencies were 69.9% and 58.3%, respectively.

  3. Adsorption of carbon dioxide on amine-modified TiO2 nanotubes

    Institute of Scientific and Technical Information of China (English)

    Fujiao Song; Yunxia Zhao; Qin Zhong

    2013-01-01

    TiO2 nanotubes (TiNT) were prepared by a hydrothermal treatment and modified by three kinds of amines,namely ethylenediamine,polyetherimide and tetraethylenepentamine (TEPA),to study their CO2 adsorption properties from gas streams.The resultant samples were characterized by X-ray diffraction,transmission electron microscopy,and infrared spectroscopy,as well as low temperature N2adsorption.CO2 capture was investigated in a dynamic packed column at 30℃.TEPA-modified TiO2 nanotubes showed the highest adsorption capacity of 167.64 mg/g because it had the highest amino-group content among the three amines.CO2 fixation on TiNT impregnated by TEPA was investigated at 30,50,and 70℃C,and the adsorption capacity increased slightly with temperature.Following the adsorption step,the sorbents were regenerated by temperature programmed desorption,and the TiNT-TEPA sample,as CO2 sorbent,was found to be readily regenerated and energy-efficient.The cycle test also revealed that the TiNT-TEPA adsorbent is fairly stable,with only a 5% drop in the adsorption capacity after 10 adsorption/desorption cycles.In addition,the CO2 adsorption behavior was investigated with the deactivation model,and which showed an excellent prediction for the TiNT-TEPA breakthrough curves.

  4. EUV-induced oxidation of carbon on TiO2

    Science.gov (United States)

    Faradzhev, Nadir S.; Hill, Shannon B.

    2016-10-01

    Previously we reported estimates of the maximum etch rates of C on TiO2 by oxidizers including NO, O3 and H2O2 when irradiated by a spatially-non-uniform beam of extreme ultraviolet (EUV) radiation at 13.5 nm (Faradzhev et al., 2013 [6]). Here we extend that work by presenting temporally and spatially resolved measurements of the C etching by these oxidizers as a function of EUV intensity in the range (0.3 to 3) mW/mm2 [(0.2 to 2) × 10 [16] photons s- 1 cm- 2]. We find that the rates for NO scale linearly with intensity and are smaller than those for O3, which exhibit a weak, sub-linear intensity dependence in this range. We demonstrate that these behaviors are consistent with adsorption of the oxidizing precursor on the C surface followed by a photon-stimulated reaction resulting in volatile C-containing products. The kinetics of photon-induced C etching by hydrogen peroxide, however, appear to be more complex. The spatially resolved measurements reveal that C removal by H2O2 begins at the edges of the C spot, where the light intensity is the lowest, and proceeds toward the center of the spot. This localization of the reaction may occur because hydroxyl radicals are produced efficiently on the catalytically active TiO2 surface.

  5. Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared Carbonaceous TiO2

    OpenAIRE

    Zatil Amali Che Ramli; Nilofar Asim; Isahak, Wan N. R. W.; Zeynab Emdadi; Norasikin Ahmad-Ludin; M. Ambar Yarmo; K. Sopian

    2014-01-01

    This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC), TiO2/carbon (C), and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC) was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 45...

  6. Morphology and crystallinity control of ultrathin TiO2 layers deposited on carbon nanotubes by temperature-step atomic layer deposition

    Science.gov (United States)

    Guerra-Nuñez, Carlos; Zhang, Yucheng; Li, Meng; Chawla, Vipin; Erni, Rolf; Michler, Johann; Park, Hyung Gyu; Utke, Ivo

    2015-06-01

    Carbon nanotubes (CNTs) coated with titanium oxide (TiO2) have generated considerable interest over the last decade and become a promising nanomaterial for a wide range of energy applications. The efficient use of the outstanding electrical properties of this nanostructure relies heavily on the quality of the interface and the thickness and morphology of the TiO2 layer. However, complete surface coverage of the chemically inert CNTs and appropriate control of the morphology of the TiO2 layer have not been achieved so far. Here, we report a new strategy to obtain ultrathin TiO2 coatings deposited by ``Temperature-step'' Atomic Layer Deposition (TS-ALD) with complete surface coverage of non-functionalized multiwall carbon nanotubes (MWCNTs) and controlled morphology and crystallinity of the TiO2 film. This strategy consists of adjusting the temperature during the ALD deposition to obtain the desired morphology. Complete coverage of long non-functionalized MWCNTs with conformal anatase layers was obtained by using a low temperature of 60 °C during the nucleation stage followed by an increase to 220 °C during the growth stage. This resulted in a continuous and amorphous TiO2 layer, covered with a conformal anatase coating. Starting with the deposition at 220 °C and reducing to 60 °C resulted in sporadic crystal grains at the CNT/TiO2 interface covered with an amorphous TiO2 layer. The results were accomplished through an extensive study of nucleation and growth of titanium oxide films on MWCNTs, of which a detailed characterization is presented in this work.Carbon nanotubes (CNTs) coated with titanium oxide (TiO2) have generated considerable interest over the last decade and become a promising nanomaterial for a wide range of energy applications. The efficient use of the outstanding electrical properties of this nanostructure relies heavily on the quality of the interface and the thickness and morphology of the TiO2 layer. However, complete surface coverage of the

  7. Preparation and Characterization of Mn/N Co-Doped TiO2 Loaded on Wood-Based Activated Carbon Fiber and Its Visible Light Photodegradation

    Directory of Open Access Journals (Sweden)

    Xiaojun Ma

    2015-09-01

    Full Text Available Using MnSO4·H2O as manganese source and urea as nitrogen source, Mn/N co-doped TiO2 loaded on wood-based activated carbon fiber (Mn/Ti-N-WACF was prepared by sol–gel method. Mn/Ti-N-WACF with different Mn doping contents was characterized by scanning electron microscopy, X-ray diffraction (XRD and X-ray photoelectron spectroscopies (XPS, and ultraviolet-visible spectrophotometer. Results showed that the loading rate of TiO2 in Mn/Ti-N-WACF was improved by Mn/N co-doping. After calcination at 450 °C, the degree of crystallinity of TiO2 was reduced due to Mn/N co-doption in the resulting Mn/Ti-N-WACF samples, but the TiO2 crystal phase was not changed. XPS spectra revealed that some Ti4+ ions from the TiO2 lattice of Mn/Ti-N-WACF system were substituted by doped Mn. Moreover, new bonds formed within N–Ti–N and Ti–N–O because of the doped N that substituted some oxygen atoms in the TiO2 lattice. Notably, the degradation rate of methylene blue for Mn/Ti-N-WACF was improved because of the co-doped Mn/N under visible-light irradiation.

  8. Facile route to fabricate carbon-doped TiO2 nanoparticles and its mechanism of enhanced visible light photocatalytic activity

    Science.gov (United States)

    Zhang, Jing; Huang, Gui-Fang; Li, Dongfeng; Zhou, Bing-Xin; Chang, Shengli; Pan, Anlian; Huang, Wei-Qing

    2016-12-01

    High-efficiency photocatalysis requires wide photoresponse range and effective separation of photogenerated charges to fully utilize solar energy. Exploring the simple and cheap methods to synthesize efficient photocatalysts is still a challenging issue. Herein, we report a facile and simple room-temperature hydrolysis method using glucose as carbon source to prepare visible light-active C-doped TiO2 photocatalyst. This approach features low-cost, reliable, and easily upscalable. It is found that C atoms have been incorporated into the interstitial position of anatase TiO2 lattice and distributed homogeneously throughout the surface of TiO2 nanoparticles. The appropriate C doping can greatly improve the separation of photogenerated electron-hole pairs in C-doped TiO2. The C-doped TiO2 samples exhibit enhanced photocatalytic activity with the degradation efficiency under UV and visible light irradiation, which is much faster than that of pure TiO2. The mechanism of the enhanced photocatalytic activity is discussed in detail, which is confirmed by using different scavengers. The work provides a simple and useful way to prepare C-doped wide-gap semiconductors with enhanced photocatalytic activity.

  9. Preparation of TiO2/activated carbon with Fe ions doping photocatalyst and its application to photocatalytic degradation of reactive brilliant red K2G

    Institute of Scientific and Technical Information of China (English)

    LI YouJi; LI Jing; MA MingYuan; OUYANG YuZhu; YAN WenBin

    2009-01-01

    Titanium dioxide coated on activated carbon(AC)with Fe ions doping(Fe-TiO2/AC)composite was prepared by an improved sol-gel method.The photocatalytic activities were tested by photocatalytic degradation of reactive brilliant red K2G in solution.The results show that in comparison with the agglomeration of pure TiO2,the TiO2 nanoparticles are well dispersed in the AC matrix,of which sizes are decreased with Fe ions doping.Additionally,the iron species on TiO2 of composite are Fe2O3 and FeO,which do not affect the crystalline structures of TiO2 nanopanicles.The AC matrix and iron doping content influence the fluorescence intensity of composite due to their effects on recombination prob ability of hole-electron paire.Compared with TiO2,0.3%Fe-TiO2,TiO2/AC,0.5% Fe-TiO2/AC and 0.1% Fe-TiO2/AC,the 0.3%Fe-TiO2/AC shows the highest photoactivity with the complete mineralization of K2G for finite time due to the optimum Fe ions content and AC matrix.Furthermore,the kinetic constant(K=0.0229 min-1)of 0.3% Fe-TiO2/AC composite is more than the sum of both TiO2/AC(0.0154 min-1)and 0.3% Fe-TiO2(0.0057 min-1)because coexistence of the AC end Fe ions has an enlarging effect on improving the photoactivity of TiO2.

  10. Preparation of TiO2/activated carbon with Fe ions doping photocatalyst and its application to photocatalytic degradation of reactive brilliant red K2G

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Titanium dioxide coated on activated carbon(AC) with Fe ions doping(Fe-TiO2/AC) composite was prepared by an improved sol-gel method.The photocatalytic activities were tested by photocatalytic degradation of reactive brilliant red K2G in solution.The results show that in comparison with the agglomeration of pure TiO2,the TiO2 nanoparticles are well dispersed in the AC matrix,of which sizes are decreased with Fe ions doping.Additionally,the iron species on TiO2 of composite are Fe2O3 and FeO,which do not affect the crystalline structures of TiO2 nanoparticles.The AC matrix and iron doping content influence the fluorescence intensity of composite due to their effects on recombination probability of hole-electron pairs.Compared with TiO2,0.3% Fe-TiO2,TiO2/AC,0.5% Fe-TiO2/AC and 0.1% Fe-TiO2/AC,the 0.3% Fe-TiO2/AC shows the highest photoactivity with the complete mineralization of K2G for finite time due to the optimum Fe ions content and AC matrix.Furthermore,the kinetic constant(k=0.0229 min-1) of 0.3% Fe-TiO2/AC composite is more than the sum of both TiO2/AC(0.0154 min-1) and 0.3% Fe-TiO2(0.0057 min-1) because coexistence of the AC and Fe ions has an enlarging effect on improving the photoactivity of TiO2.

  11. Carbonate Doping in TiO2 Microsphere: The Key Parameter Influencing Others for Efficient Dye Sensitized Solar Cell

    Science.gov (United States)

    Seddigi, Zaki S.; Ahmed, Saleh A.; Sardar, Samim; Pal, Samir Kumar

    2016-03-01

    Four key parameters namely light trapping, density of light harvesting centre, photoinduced electron injection and electron transport without self-recombination are universally important across all kinds of solar cells. In the present study, we have considered the parameters in the context of a model Dye Sensitized Solar Cell (DSSC). Our experimental studies reveal that carbonate doping of TiO2 mesoporous microspheres (doped MS) makes positive influence to all the above mentioned key parameters responsible for the enhanced solar cell efficiency. A simple method has been employed to synthesize the doped MS for the photoanode of a N719 (ruthenium dye)-based DSSC. A detail electron microscopy has been used to characterize the change in morphology of the MS upon doping. The optical absorption spectrum of the doped MS reveals significant shift of TiO2 (compared to that of the MS without doping) towards maximum solar radiance (~500 nm) and the excellent scattering in the entire absorption band of the sensitizing dye (N719). Finally, and most importantly, for the first time we have demonstrated that the solar cells with doped MS offers better efficiency (7.6%) in light harvesting compared to MS without doping (5.2%) and also reveal minimum self recombination of photoelectrons in the redox chain.

  12. Dye-sensitized solar cells with vertically aligned TiO2 nanowire arrays grown on carbon fibers.

    Science.gov (United States)

    Cai, Xin; Wu, Hongwei; Hou, Shaocong; Peng, Ming; Yu, Xiao; Zou, Dechun

    2014-02-01

    One-dimensional semiconductor TiO2 nanowires (TNWs) have received widespread attention from solar cell and related optoelectronics scientists. The controllable synthesis of ordered TNW arrays on arbitrary substrates would benefit both fundamental research and practical applications. Herein, vertically aligned TNW arrays in situ grown on carbon fiber (CF) substrates through a facile, controllable, and seed-assisted thermal process is presented. Also, hierarchical TiO2 -nanoparticle/TNW arrays were prepared that favor both the dye loading and depressed charge recombination of the CF/TNW photoanode. An impressive conversion efficiency of 2.48 % (under air mass 1.5 global illumination) and an apparent efficiency of 4.18 % (with a diffuse board) due to the 3D light harvesting of the wire solar cell were achieved. Moreover, efficient and inexpensive wire solar cells made from all-CF electrodes and completely flexible CF-based wire solar cells were demonstrated, taking into account actual application requirements. This work may provide an intriguing avenue for the pursuit of lightweight, cost-effective, and high-performance flexible/wearable solar cells.

  13. Hole-Conductor-Free Mesoscopic TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on Anatase Nanosheets and Carbon Counter Electrodes.

    Science.gov (United States)

    Rong, Yaoguang; Ku, Zhiliang; Mei, Anyi; Liu, Tongfa; Xu, Mi; Ko, Songguk; Li, Xiong; Han, Hongwei

    2014-06-19

    A hole-conductor-free fully printable mesoscopic TiO2/CH3NH3PbI3 heterojunction solar cell was developed with TiO2 nanosheets containing high levels of exposed (001) facets. The solar cell embodiment employed a double layer of mesoporous TiO2 and ZrO2 as a scaffold infiltrated by perovskite as a light harvester. No hole conductor or Au reflector was employed. Instead, the back contact was simply a printable carbon layer. The perovskite was infiltrated from solution through the porous carbon layer. The high reactivity of (001) facets in TiO2 nanosheets improved the interfacial properties between the perovskite and the electron collector. As a result, photoelectric conversion efficiency of up to 10.64% was obtained with the hole-conductor-free fully printable mesoscopic TiO2/CH3NH3PbI3 heterojunction solar cell. The advantages of fully printable technology and the use of low-cost carbon-materials-based counter electrode and hole-conductor-free structure provide this design a promising prospect to approach low-cost photovoltaic devices.

  14. Multiscale anode materials in lithium ion batteries by combining micro- with nanoparticles: design of mesoporous TiO2 microfibers@nitrogen doped carbon composites.

    Science.gov (United States)

    Cheng, Wei; Rechberger, Felix; Primc, Darinka; Niederberger, Markus

    2015-09-07

    TiO2 has been considered as a promising anode material for lithium ion batteries. However, its poor rate capability originating from the intrinsically low lithium ion diffusivity and its poor electronic conductivity hampers putting such an application into practice. Both issues can be addressed by nanostructure engineering and conductive surface coating. Herein, we report a template-assisted synthesis of micron sized TiO2 fibers consisting of a mesoporous network of anatase nanoparticles of about 7.5 nm and coated by N doped carbon. In a first step, an amorphous layer of TiO2 was deposited on cobalt silicate nanobelts and subsequently transformed into crystalline anatase nanoparticles by hydrothermal treatment. The N doped carbon coating was realized by in situ polymerization of dopamine on the crystalline TiO2 followed by annealing under N2. After removal of the template, we obtained the final mesoporous TiO2 fibers@N doped carbon composite. Electrochemical tests revealed that the composite electrode exhibited excellent electrochemical properties in terms of specific capacity, rate performance and long term stability.

  15. Fibrinogen enhances the inflammatory response of alveolar macrophages to TiO2, SiO2 and carbon nanomaterials.

    Science.gov (United States)

    Marucco, Arianna; Gazzano, Elena; Ghigo, Dario; Enrico, Emanuele; Fenoglio, Ivana

    2016-01-01

    Many studies have shown that the composition of the protein corona dramatically affects the response of cells to nanomaterials (NMs). However, the role of each single protein is still largely unknown. Fibrinogen (FG), one of the most abundant plasma proteins, is believed to mediate foreign-body reactions. Since this protein is absent in cell media used in in vitro toxicological tests the possible FG-mediated effects have not yet been assessed. Here, the effect of FG on the toxicity of three different kinds of inorganic NMs (carbon, SiO2 and TiO2) on alveolar macrophages has been investigated. A set of integrated techniques (UV-vis spectroscopy, dynamic light scattering and sodium dodecyl sulphate-polyacrylamide gel electrophoresis) have been used to study the strength and the kinetics of interaction of FG with the NMs. The inflammatory response of alveolar macrophages (MH-S) exposed to the three NMs associated with FG has also been investigated. We found that FG significantly enhances the cytotoxicity (lactate dehydrogenase leakage) and the inflammatory response (increase in nitric oxide (NO) concentration and NO synthase activation) induced by SiO2, carbon and TiO2 NMs on alveolar macrophages. This effect appears related to the amount of FG interacting with the NMs. In the case of carbon NMs, the activation of fibrinolysis, likely related to the exposure of cryptic sites of FG, was also observed after 24 h. These findings underline the critical role played by FG in the toxic response to NMs.

  16. Solid-state NMR and EPR analysis of carbon-doped titanium dioxide photocatalysts (TiO(2-)(x)C(x)).

    Science.gov (United States)

    Reyes-Garcia, Enrique A; Sun, Yanping; Reyes-Gil, Karla R; Raftery, Daniel

    2009-04-01

    Carbon-doped TiO(2) have received attention recently because of their potential for environmental photocatalysis and solar hydrogen conversion applications. Three different carbon-doped TiO(2) nanoparticle materials were synthesized via sol-gel and hydrothermal procedures, and analyzed by (13)C solid-state nuclear magnetic resonance (SSNMR) and other methods to characterize the environment of the doping species. UV/vis spectra and powder X-ray diffraction (XRD) patterns showed that the synthesized materials absorbed visible light and their crystal structures corresponded to anatase. (13)C SSNMR analyses of TiO(2-)(x)C(x) displayed signals corresponding to carbonate-type or sp(2)-type carbon species. Variable contact CP-MAS and dipolar dephasing analyses gave evidence for the presence and proximity of H atoms near these carbonate species. Electron paramagnetic resonance (EPR) spectroscopy showed that the thermally oxidized TiO(2-)(x)C(x) displayed a complex mixture of point defects, electron and hole trapping centers, all attributable to the incorporation of carbon, while the XPS data ruled out the presence of carbide species.

  17. TiO2 quantum dots embedded in bamboo-like porous carbon nanotubes as ultra high power and long life anodes for lithium ion batteries

    Science.gov (United States)

    Tang, Yakun; Liu, Lang; Wang, Xingchao; Jia, Dianzeng; Xia, Wei; Zhao, Zongbin; Qiu, Jieshan

    2016-07-01

    TiO2 quantum dots embedded in bamboo-like porous carbon nanotubes have been constructed through the pyrolysis of sulfonated polymer nanotubes and TiO2 hybrids. The TiO2 quantum dots are formed during the pyrolysis, due to the space confinement within the highly cross-linked copolymer networks. The sulfonation degree of the polymer nanotubes is a critical factor to ensure the formation of the unique interpenetrating structure. The nanocomposites exhibit high reversible capacity of 523 mAh g-1 at 100 mA g-1 after 200 cycles, excellent rate capability and superior long-term cycling stability at high current density, which could attain a high discharge capacity of 189 mAh g-1 at 2000 mA g-1 for up to 2000 cycles. The enhanced electrochemical performance of the nanocomposites benefit from the uniform distribution of TiO2 quantum dots, high electronic conductivity of porous carbons and unique interpenetrating structure, which simultaneously solved the major problems of TiO2 anode facing the pulverization, loss of electrical contact and particle aggregation.

  18. Preparation of Carbon-Doped TiO2 and Its Application as a Photoelectrodes in Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Park, Su Kyung; Jeong, Jin Seong; Yun, Tae Kwan; Bae, Jae Young

    2015-02-01

    In this study, C-doped TiO2 particles were successfully synthesized by a hydrothermal method. Three binding energy peaks were observed at 284.6, 286.2, and 288.5 eV in the C is region of the XPS. The signals at 286.2 and 288.5 eV were attributed to chemically bound C-O and Ti-C-O linkages within the crystalline TiO2 lattice, respectively. The introduction of carbon did not affect the crystallite structure or BET surface area of TiO2. The JSC value of DSSCs based on a C-doped TiO2 electrode was increased by 20% compared to DSSCs using a pure TiO2 electrode, and the energy conversion efficiency was increased by 23%. This was due to the enhancement of dye adsorption and high electrical conductivity of the carbon. High energy conversion efficiency was achieved with the DSSCs based on the C-doped TiC2 electrode.

  19. Carbon-Pt nanoparticles modified TiO2 nanotubes for simultaneous detection of dopamine and uric acid.

    Science.gov (United States)

    Mahshid, Sara; Luo, Shenglian; Yang, Lixia; Mahshid, Sahar Sadat; Askari, Masoud; Dolati, Abolghasem; Cai, Qingyun

    2011-08-01

    The present work describes sensing application of modified TiO2 nanotubes having carbon-Pt nanoparticles for simultaneous detection of dopamine and uric acid. The TiO2 nanotubes electrode was prepared using anodizing method, followed by electrodeposition of Pt nanoparticles onto the tubes. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. The C-Pt-TiO2 nanotubes modified electrode was characterized by cyclic voltammetry and differential pulse voltammetry methods. The modified electrode displayed high sensitivity towards the oxidation of dopamine and uric acid in a phosphate buffer solution (pH 7.00). The electro-oxidation currents of dopamine and uric acid were linearly related to the concentration over a wide range of 3.5 x 10(-8) M to 1 x 10(-5) M and 1 x 10(-7) M to 3 x 10(-5) M respectively. The limit of detection was determined as 2 x 10(-10) M for dopamine at signal-to-noise ratio of 3. The interference of uric acid was also investigated. Electro-oxidation currents of dopamine in the presence of fix amount of uric acid represented a linear behaviour towards successive addition of dopamine in range of 1 x 10(-7) M to 1 x 10(-5) M. Furthermore, in a solution containing dopamine, uric acid and ascorbic acid the overlapped oxidation peaks of dopamine and ascorbic acid could be easily separated by using C-Pt-TiO2 nanotubes modified electrode.

  20. Capture of carbon dioxide by amine-loaded as-synthesized TiO2 nanotubes.

    Science.gov (United States)

    Song, Fujiao; Zhao, Yunxia; Ding, Huiling; Cao, Yan; Ding, Jie; Bu, Yunfei; Zhong, Qin

    2013-01-01

    Titanium-based adsorbents for CO2 capture were prepared through impregnating the as-synthesized TiO2 nanotubes (TiNT) with four kinds of amines, namely monoethanolamine (MEA), ethylenediamine (EDA), triethylenetetramine (TETA) and tetraethylenepentamine (TEPA). The resultant samples were characterized by X-ray diffraction, low-temperature N2 adsorption as well as transmission electron microscopy. The absorption of CO2 was carried out in a dynamic packed column. The sample impregnated with TEPA showed a better adsorption capacity due to its higher amino groups content. In addition, CO2 adsorption capacity increases as the amount of amine loaded increases. Therefore, TiNT-TEPA-69 showed the highest CO2 adsorption capacity among the three samples impregnated with TETA; approximately 4.10 mmol/g at 30 degrees C. In addition, the dynamic adsorption/desorption performance was investigated. The adsorption capacity of TiNT-TEPA-69 dropped slightly (about 2%) during a total of five cycles. The TiNT-TEPA-69 adsorbent exhibited excellent CO2 adsorption/desorption performance.

  1. Fabrication of TiO2@Yeast-Carbon Hybrid Composites with the Raspberry-Like Structure and Their Synergistic Adsorption-Photocatalysis Performance

    Directory of Open Access Journals (Sweden)

    Dang Yu

    2013-01-01

    Full Text Available In the present work, we report the preparation and photocatalytic properties of TiO2@yeast-carbon with raspberry-like structure using a pyrolysis method. The products are characterized by field emission scanning electron microscopy (FE-SEM, energy dispersive spectrometry (EDS, X-ray diffraction (XRD, thermal gravimetric and differential thermal analysis (TGA-DTA, Fourier transformed infrared spectroscopy (FT-IR, and ultraviolet visible spectroscopy (UV-VIS, respectively. The results show that the hybrid TiO2@yeast-carbon microspheres have ordered elliptic shapes of uniform size (length = 3.5±0.3 μm; width = 2.5±0.5 μm. UV-VIS ascertains that the as-prepared microspheres possess an obvious light response in a wide range of 250–400 nm. In the decomposition of typical model pollutants including methylene blue and congo red, the hybrid composites exhibited excellent photocatalytic activity for the methylene blue due to the enhanced adsorption ability. Further investigation reveals that the combined effect of adsorption from the yeast-carbon core and photocatalytic degradation from the attached TiO2 nanoparticles were responsible for the improvement of the photocatalytic activities. Hereby, the raspberry-like TiO2@yeast-carbon has promising applications in water purification.

  2. Effect of Carbon Modification on the Electrical, Structural, and Optical Properties of TiO2 Electrodes and Their Performance in Labscale Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    R. Taziwa

    2012-01-01

    Full Text Available Carbon-modified titanium dioxide nanoparticles (C:TiO2 NPs have been synthesized by ultrasonic nebulizer spray pyrolysis (USP and pneumatic spray pyrolysis (PSP techniques. HRTEM on the NPs shows difference in lattice spacing in the NP structures prepared by the two methods—2.02 Å for the USP NPs and an average of 3.74 Å for the PSP NPs. The most probable particle sizes are 3.11 nm and 5.5 nm, respectively. Raman spectroscopy supported by FTIR confirms the TiO2 polymorph to be anatase with the intense phonon frequency at 153 cm−1 blue-shifted from 141 cm−1 ascribed to both carbon doping and particle size. A modified phonon confinement model for nanoparticles has been used to extract phonon dispersion and other parameters for anatase for the first time. Electronic measurements show “negative conductance” at some critical bias voltage, which is characteristic of n-type conductivity in the carbon-doped TiO2 NPs as confirmed by the calculated areas under the I-V curves, a property suited for solar cell applications. Practical solar cells built from carbon-doped TiO2 electrodes show up to 1.5 times improvement in efficiency compared to pure TiO2 electrodes of similar construction.

  3. Influence of environmental temperature and relative humidity on photocatalytic oxidation of toluene on activated carbon fibers coated TiO2

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    TiO2 supported on active carbon fiber (TiO2/ACF),an absorbable photocatalyst,is a new kind of material applied in air purification.In this paper,the influence of environmental temperature (T) and relative humidity (RH)on the gas-solid adsorption of toluene and the photocatalyric oxidation (PCO) efficiency of adsorbed toluene on TiO2/ACF were studied,and then,the purification capabil ity of TiO2/ACF was estimated.PCO results showed that although the PCO efficiency increased under high RH and T levels,the amount of adsorption of toluene decreased.Moreover,quantitative analysis results of intermediates indicated that more environmental risk emerged when PCO of toluene was carried out at higher environmental T and RH levels because more toxic intermediates would be accumulated on the TiO2/ACF.So,it is significant to control the environmental T and RH conditions in the application of the PCO technique.T = 25℃ and RH = 30% is the optimal condition for purifying toluene in our experimental system.

  4. Photocatalysis-assisted water filtration: using TiO2-coated vertically aligned multi-walled carbon nanotube array for removal of Escherichia coli O157:H7.

    Science.gov (United States)

    Oza, Goldie; Pandey, Sunil; Gupta, Arvind; Shinde, Sachin; Mewada, Ashmi; Jagadale, Pravin; Sharon, Maheshwar; Sharon, Madhuri

    2013-10-01

    A porous ceramic was coated with vertically aligned multi-walled carbon nanotubes (MWCNTs) by spray pyrolysis. Titanium dioxide (TiO2) nanoparticles were then coated onto this densely aligned MWCNT. The presence of TiO2/MWCNT interfacial arrays was confirmed by X-ray diffraction (XRD), scanning electron microscope-energy dispersive analysis of X-ray (SEM-EDAX) and transmission electron microscope (TEM). This is a novel report in which water loaded with a most dreadful enterohemorrhagic pathogenic strain of Escherichia coli O157:H7 was filtered through TiO2/MWCNT coated porous ceramic filter and then analysed. Bacterial removal performance was found to be significantly lower in control i.e. plain porous ceramic (PTiO2/MWCNT coated ceramic. The photocatalytic killing rate constant for TiO2-ceramic and MWCNT/TiO2-ceramic under fluorescent light was found be 1.45×10(-2) min(-1) and 2.23×10(-2) min(-1) respectively. Further, when I-V characteristics were performed for TiO2/MWCNT composite, it was corroborated that the current under light irradiation is comparatively higher than that in dark, thus proving it to be photocatalytically efficient system. The enhanced photocatalysis may be a contribution of increased surface area and charge transfer rate as a consequence of aligned MWCNT network.

  5. Ultra-long Pt nanolawns supported on TiO2-coated carbon fibers as 3D hybrid catalyst for methanol oxidation.

    Science.gov (United States)

    Shen, Yu-Lin; Chen, Shih-Yun; Song, Jenn-Ming; Chen, In-Gann

    2012-06-26

    In this study, TiO2 thin film photocatalyst on carbon fibers was used to synthesize ultra-long single crystalline Pt nanowires via a simple photoreduction route (thermally activated photoreduction). It also acted as a co-catalytic material with Pt. Taking advantage of the high-aspect ratio of the Pt nanostructure as well as the excellent catalytic activity of TiO2, this hybrid structure has the great potential as the active anode in direct methanol fuel cells. The electrochemical results indicate that TiO2 is capable of transforming CO-like poisoning species on the Pt surface during methanol oxidation and contributes to a high CO tolerance of this Pt nanowire/TiO2 hybrid structure.

  6. Síntese, caracterização e atividade fotocatalítica de catalisadores nanoestruturados de TiO2 dopados com metais Synthesis, characterization and photocatalytic activity of nanostructured TiO2 catalysts doped with metals

    Directory of Open Access Journals (Sweden)

    William Leonardo da Silva

    2013-01-01

    Full Text Available Titanium dioxide nanostructured catalysts (nanotubes doped with different metals (silver, gold, copper, palladium and zinc were synthesized by the hydrothermal method in order to promote an increase in their photocatalytic activity under visible light. The catalysts were characterized by X-ray diffraction, diffuse reflectance spectroscopy, transmission electron microscopy and specific area and pore volume determination. The materials' photocatalytic activity was evaluated by rhodamine B decomposition in a glass batch reactor. Under UV radiation, only nanotubes doped with palladium were more active than the TiO2 P25, but the samples doped with silver, palladium and gold exhibited better results than the undoped samples under visible light.

  7. TiO2-NT electrodes modified with Ag and diamond like carbon (DLC) for hydrogen production by alkaline water electrolysis

    Science.gov (United States)

    Baran, Evrim; Baz, Zeynep; Esen, Ramazan; Yazici Devrim, Birgül

    2017-10-01

    In present work, the two-step anodization technique was applied for synthesis of TiO2 nanotube (NT). Silver and diamond like carbon (DLC) were coated on the surface of as prepared TiO2-NT using chemical reduction method and MW ECR plasma system. The morphology, composition and structure of the electrodes were examined by field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). The results showed that Ag nanoparticles, having size in the range of 48-115 nm, are evenly distributed on the top, inside and outside surface of TiO2-NT and when DLC was coated on the surface of TiO2-NT and TiO2-NT-Ag, the top of nanotubes were partially open and the pore diameter of hexagonal structure decreased from 165 nm to of 38-80 nm. On the other hand, the microhardness test and contact angle measurements revealed that additions of Ag and diamond like carbon have a positive effect on the mechanical properties of TiO2-NT film. The electrocatalytic properties of the electrodes towards the hydrogen evolution reaction (HER) were investigated by the electrochemical measurements recorded in 1 M KOH solution. In addition, long-term durability of electrodes towards HER and the energy consumption of alkaline electrolysis were investigated. The energy requirement showed that while the deposition of silver provides approximately 14.95% savings of the energy consumption, the DLC coating causes increase in energy consumption.

  8. TiO2 embedded in carbon submicron-tablets: synthesis from a metal-organic framework precursor and application as a superior anode in lithium-ion batteries.

    Science.gov (United States)

    Wang, Peiyu; Lang, Junwei; Liu, Dongxia; Yan, Xingbin

    2015-07-21

    Rutile TiO2 embedded in carbon submicron-tablets (TiO2/C) with a "blueberry muffin" morphology was fabricated via a two-step pyrolysis from a metal-organic framework precursor. Such a unique structure of the TiO2/C submicron-tablets provides the ideal anode characteristics (high reversible capacity, superior rate capability and excellent long-term cycling stability) for fast rechargeable lithium ion batteries.

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

    Science.gov (United States)

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

    2012-01-15

    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.

  10. Methanol Oxidation over TiO2-modified Multi-walled Carbon Nanotubes Supported Pt-Mo Electrocatalyst

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-yu; JIANG Yuan-sheng; ZHU Hong; ZHANG Jing-chang

    2011-01-01

    In order to develop a novel and high-performance catalytic material for direct methanol fuel cells(DMFC),molybdenum oxide as a co-catalyst with Pt on multi-walled carbon nanotubes which were modified by titanium dioxide(denoted as CNTs@TiO2) was investigated. The physicochemical characterizations of the catalysts were carried out via X-ray diffraction(XRD), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS).Cyclic voltammetry(CV) showed that the CO-tolerance performance increased in the sequence of Pt/CNTs<Pt/CNTs@TiO2<Pt-Mo/CNTs@TiO2. The improved CO-tolerance performance of the Pt-Mo/CNTs@TiO2 catalyst can be attributed to the combined beneficial effects of highly dispersed Pt nanoparticles on the CNTs, the existence of oxygen holes in the MoO3 layer structure and the oxidation capability of TiO2.

  11. Synthesis and Characterization of Photoreactive TiO2/Carbon Nanosheet Composites

    OpenAIRE

    Kurttepeli, Mert; Deng, Shaoren; Verbruggen, Sammy W.; Guzzinati, Giulio; Cott, Daire J.; Lenaerts, Silvia; Verbeeck, Jo; Van Tendeloo, Gustaaf; Detavernier, Christophe; Bals, Sara

    2015-01-01

    We report the atomic layer deposition of titanium dioxide on carbon nanosheet templates and investigate the effects of post-deposition annealing in a helium environment using different characterization techniques. The crystallization of the titanium dioxide coating upon annealing is observed using in-situ X-ray diffraction. The (micro)-structural characterization of the films is carried out by scanning electron microscopy and advanced transmission electron microscopy techniques. Our study sho...

  12. Synthesis of TiO2 nanoparticles containing Fe, Si, and V using multiple diffusion flames and catalytic oxidation capability of carbon-coated nanoparticles

    KAUST Repository

    Ismail, Mohamed

    2016-01-19

    Titanium dioxide (TiO2) nanoparticles containing iron, silicon, and vanadium are synthesized using multiple diffusion flames. The growth of carbon-coated (C–TiO2), carbon-coated with iron oxide (Fe/C–TiO2), silica-coated (Si–TiO2), and vanadium-doped (V–TiO2) TiO2 nanoparticles is demonstrated using a single-step process. Hydrogen, oxygen, and argon are utilized to establish the flame, with titanium tetraisopropoxide (TTIP) as the precursor for TiO2. For the growth of Fe/C–TiO2 nanoparticles, TTIP is mixed with xylene and ferrocene. While for the growth of Si–TiO2 and V–TiO2, TTIP is mixed with hexamethyldisiloxane (HMDSO) and vanadium (V) oxytriisopropoxide, respectively. The synthesized nanoparticles are characterized using high-resolution transmission electron microscopy (HRTEM) with energy-filtered TEM for elemental mapping (of Si, C, O, and Ti), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nitrogen adsorption BET surface area analysis, and thermogravimetric analysis. Anatase is the dominant phase for the C–TiO2, Fe/C–TiO2, and Si–TiO2 nanoparticles, whereas rutile is the dominant phase for the V–TiO2 nanoparticles. For C–TiO2 and Fe/C–TiO2, the nanoparticles are coated with about 3-5-nm thickness of carbon. The iron-based TiO2 nanoparticles significantly improve the catalytic oxidation of carbon, where complete oxidation of carbon occurs at a temperature of 470 °C (with iron) compared to 610 °C (without iron). Enhanced catalytic oxidation properties are also observed for model soot particles, Printex-U, when mixed with Fe/C-TiO2. With regards to Si–TiO2 nanoparticles, a uniform coating of 3 to 8 nm of silicon dioxide is observed around the TiO2 particles. This coating mainly occurs due to variance in the chemical reaction rates of the precursors. Finally, with regards to V–TiO2, vanadium is doped within the TiO2 nanoparticles as visualized by HRTEM and XPS further confirms the formation of

  13. Fibrous TiO2 prepared by chemical vapor deposition using activated carbon fibers as template via adsorption, hydrolysis and calcinations

    Institute of Scientific and Technical Information of China (English)

    Hui-na YANG; Li-fen LIU; Feng-lin YANG; Jimmy C. YU

    2008-01-01

    TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by Ne to an APCVD (chemical vapor deposition under atmospheric pressure) reactor at <200 ℃. Activated carbon fibers (ACFs) were used as templates for deposition and later removed by calcinations. The obtained catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brtmauer, Emmett and Teller (BET) and X-ray diffraction (XRD) analysisThe pores within TiO2 fibers included micro-range and meso-range, e.g., 7 nm, and the specific surface areas for TiO2 fibers were 141 m2/g and 148 m2/g for samples deposited at 100 ℃ and 200 ℃ (using ACF1700 as template), respectively. The deposition temperature significantly influenced TiO2 morphology. The special advantages of this technique for preparing porous nano-material include no consumption of organic solvent in the process and easy control of deposition conditions and speeds.

  14. W-doped TiO2 mesoporous electron transport layer for efficient hole transport material free perovskite solar cells employing carbon counter electrodes

    Science.gov (United States)

    Xiao, Yuqing; Cheng, Nian; Kondamareddy, Kiran Kumar; Wang, Changlei; Liu, Pei; Guo, Shishang; Zhao, Xing-Zhong

    2017-02-01

    Doping of TiO2 by metal elements for the scaffold layer of the perovskite solar cells has been proved to be one of the effective methods to improve the power conversion efficiency. In the present work, we report the impact of doping of TiO2 nanoparticles with different amounts of tungsten (W) on the photovoltaic properties of hole transport material free perovskite solar cells (PSCs) that employ carbon counter electrode. Light doping with W (less than 1000 ppm) improves the power conversion efficiencies (PCEs) of solar cells by promoting the electron conductivity in the TiO2 layer which facilitates electron transfer and collection. With the incorporation of W, average efficiency of PSCs is increased from 9.1% for the un-doped samples to 10.53% for the 1000 ppm W-doped samples, mainly originates from the increase of short circuit current density and fill factor. Our champion cell exhibits an impressive PCE of 12.06% when using the 1000 ppm W-doped TiO2 films.

  15. Facile synthesis of carbon doped TiO2 nanowires without an external carbon source and their opto-electronic properties

    Science.gov (United States)

    Kiran, Vankayala; Sampath, Srinivasan

    2013-10-01

    The present study demonstrates a simple protocol for the preparation of one dimensional (1D) oxidized titanium carbide nanowires and their opto-electronic properties. The oxidized titanium carbide nanowires (Ox-TiC-NW) are prepared from TiC nanowires (TiC-NW) that are in turn synthesized from micron sized TiC particles using the solvothermal technique. The Ox-TiC-NW is characterized by X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. Thermal oxidation of TiC-NW yields carbon doped TiO2-NW (C-TiO2-NW), a simple methodology to obtain 1D C-TiO2-NW. Temperature dependent Raman spectra reveal characteristic bands for TiO2-NW. Electrical characterization of individual C-TiO2-NW is performed by fabricating a device structure using the focused ion beam deposition technique. The opto-electronic properties of individual C-TiO2-NW demonstrate visible light activity and the parameters obtained from photoconductivity measurements reveal very good sensitivity. This methodology opens up the possibility of using C-TiO2-NW in electronic and opto-electronic device applications.The present study demonstrates a simple protocol for the preparation of one dimensional (1D) oxidized titanium carbide nanowires and their opto-electronic properties. The oxidized titanium carbide nanowires (Ox-TiC-NW) are prepared from TiC nanowires (TiC-NW) that are in turn synthesized from micron sized TiC particles using the solvothermal technique. The Ox-TiC-NW is characterized by X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. Thermal oxidation of TiC-NW yields carbon doped TiO2-NW (C-TiO2-NW), a simple methodology to obtain 1D C-TiO2-NW. Temperature dependent Raman spectra reveal characteristic bands for TiO2-NW. Electrical characterization of individual C-TiO2-NW is performed by fabricating a device structure using the

  16. Synergistic effects of the aspect ratio of TiO2 nanowires and multi-walled carbon nanotube embedment for enhancing photovoltaic performance of dye-sensitized solar cells.

    Science.gov (United States)

    Ahn, Ji Young; Kim, Ji Hoon; Moon, Kook Joo; Park, So Dam; Kim, Soo Hyung

    2013-08-07

    The existence of numerous interfacial boundaries among TiO2 nanoparticles (NPs) accumulated in the photoelectrode layer of dye-sensitized solar cells (DSSCs) hinders the effective transport of photogenerated electrons to an electrode. Therefore, as a replacement for TiO2 NPs, one-dimensional TiO2 nanowires (NWs) can be suggested to provide pathways for fast electron transport by significantly reducing the number of interfacial boundaries. In order to provide direct evidence for the better performance of such longer TiO2 NWs than shorter TiO2 NWs, we examine the effect of the controlled aspect ratio of the TiO2 NWs randomly accumulated in the photoelectrode layer on the photovoltaic performance of DSSCs. It is clearly found that longer TiO2 NWs significantly improve the electron transport by reducing the TiO2/dye/electrolyte interfacial contact resistance. Furthermore, the embedment of multi-walled carbon nanotubes (MWCNTs) as an effective charge transfer medium in longer TiO2 NWs is proposed in this study to promote more synergistic effects, which lead to significant improvements in the photovoltaic properties of DSSCs.

  17. Synthesis and Characterization of Carbon Nanotubes Catalyzed by TiO2 Supported Ni, Co and Ni-Co Nanoparticles via CCVD

    Directory of Open Access Journals (Sweden)

    A. A. Hosseini

    2013-09-01

    Full Text Available Monometallic and bimetallic Ni and Co catalytic nanoparticles supported on Titanium dioxide (rutile phase substrate were prepared by wet impregnation method. These nanoparicles were used as catalysts for synthesis of multiwalled carbon nanotubes (MWCNTs from acetylene decomposition at 700°C by the catalytic chemical vapor deposition (CCVD technique. The nanomaterials (catalyst and CNTs were characterized by X-ray diffraction (XRD, Scanning electron microscopy (SEM and Raman spectroscopy. In this paper, the usage of TiO2 powder as catalyst support was examined and the effect of applied catalyst type on characteristics of grown CNTs was investigated. The results showed that the rutile phase of TiO2 powder can be applied as a suitable catalyst support in CNT growth process. Furthermore, it was observed that the CNTs synthesized on Ni-Co bimetallic catalyst possess smaller average diameters, better quality and less amorphous carbon compared to Ni and Co monometallic catalyst types.

  18. TiO2/Halloysite Composites Codoped with Carbon and Nitrogen from Melamine and Their Enhanced Solar-Light-Driven Photocatalytic Performance

    Directory of Open Access Journals (Sweden)

    Pengcheng Yao

    2015-01-01

    Full Text Available Carbon (C and nitrogen (N codoped anatase TiO2/amorphous halloysite nanotubes (C+N-TiO2/HNTs were fabricated using melamine as C and N source. The samples prepared by different weight ratios of melamine and TiO2 were investigated by X-ray diffraction (XRD and UV-vis diffuse reflectance spectrometer. It is shown that the doping amounts of C and N could influence the photocatalytic performance of as-prepared composites. When the weight ratio of melamine/TiO2 is 4.5, the C+N-TiO2/HNTs exhibited the best photocatalytic degradation efficiency of methyl blue (MB under solar light irradiation. The obtained C+N-TiO2/HNTs were characterized by transmission electron microscopy (TEM, N2 adsorption-desorption isotherm (BET, X-ray photoelectron spectroscopy (XPS, and Fourier transform infrared spectrum (FT-IR. The results showed that the aggregation was effectively reduced, and TiO2 nanoparticles could be uniformly deposited on the surface of HNTs. This leads to an increase of their specific surface area. XPS and FT-IR analyses indicated TiO2 particles were doped successfully with C and N via the linkage of the Ti–O–N, O–Ti–N, and Ti–O–C. Photocatalytic experiments showed that C+N-TiO2/HNTs had higher degradation efficiency of MB than TiO2/HNTs. This makes the composite a potential candidate for the photocatalytic wastewater treatment.

  19. Microwave-Assisted Synthesis of Carbon-Based (N, Fe)-Codoped TiO2 for the Photocatalytic Degradation of Formaldehyde

    Science.gov (United States)

    Tian, Fei; Wu, Zhansheng; Tong, Yanbin; Wu, Zhilin; Cravotto, Giancarlo

    2015-09-01

    A microwave-assisted sol-gel method was used to synthesize (N, Fe)-codoped activated carbon (AC)/TiO2 photocatalyst for enhanced optical absorption in the visible light region. The prepared samples were characterized via X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, ultraviolet-visible light spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The results showed no significant difference in the surface area of AC/TiO2 (approximately 500 m2/g) after doping. TiO2 was uniformly distributed on the surface of AC, which exhibited coexisting anatase and rutile structures with a mean crystallite diameter of approximately 20 nm. N and Fe monodoping on AC/TiO2 reduced the energy band gap of TiO2 to 2.81 and 2.79 eV, respectively, which mainly attributed to the impurity energy formed in the energy gap of TiO2. In (N, Fe)-codoped AC/TiO2, N and Fe are incorporated into the TiO2 framework and narrow the band gap of TiO2 to 2.58 eV, thereby causing a large redshift. Codoping of N and Fe enhanced the production of hydroxyl radicals (ṡOH) and improved the photocatalytic activity of the resultant AC/TiO2 compared with those of undoped and N- or Fe-monodoped AC/TiO2. N-Fe-AC/TiO2 degraded 93 % of the formaldehyde under Xe-lamp irradiation. Moreover, the photocatalyst was easily recyclable. In summary, a novel and efficient method to mineralize low concentrations of HCHO in wastewater was discovered.

  20. TiO2 Immobilized on Manihot Carbon: Optimal Preparation and Evaluation of Its Activity in the Decomposition of Indigo Carmine

    Directory of Open Access Journals (Sweden)

    Cynthia M. Antonio-Cisneros

    2015-01-01

    Full Text Available Applications of carbon-TiO2 materials have attracted attention in nanotechnology due to their synergic effects. We report the immobilization of TiO2 on carbon prepared from residues of the plant Manihot, commercial TiO2 and glycerol. The objective was to obtain a moderate loading of the anatase phase by preserving the carbonaceous external surface and micropores of the composite. Two preparation methods were compared, including mixing dry precursors and immobilization using a glycerol slurry. The evaluation of the micropore blocking was performed using nitrogen adsorption isotherms. The results indicated that it was possible to use Manihot residues and glycerol to prepare an anatase-containing material with a basic surface and a significant SBET value. The activities of the prepared materials were tested in a decomposition assay of indigo carmine. The TiO2/carbon eliminated nearly 100% of the dye under UV irradiation using the optimal conditions found by a Taguchi L4 orthogonal array considering the specific surface, temperature and initial concentration. The reaction was monitored by UV-Vis spectrophotometry and LC-ESI-(Qq-TOF-MS, enabling the identification of some intermediates. No isatin-5-sulfonic acid was detected after a 60 min photocatalytic reaction, and three sulfonated aromatic amines, including 4-amino-3-hydroxybenzenesulfonic acid, 2-(2-amino-5-sulfophenyl-2-oxoacetic acid and 2-amino-5-sulfobenzoic acid, were present in the reaction mixture.

  1. TiO2 immobilized on Manihot carbon: optimal preparation and evaluation of its activity in the decomposition of indigo carmine.

    Science.gov (United States)

    Antonio-Cisneros, Cynthia M; Dávila-Jiménez, Martín M; Elizalde-González, María P; García-Díaz, Esmeralda

    2015-01-12

    Applications of carbon-TiO2 materials have attracted attention in nanotechnology due to their synergic effects. We report the immobilization of TiO2 on carbon prepared from residues of the plant Manihot, commercial TiO2 and glycerol. The objective was to obtain a moderate loading of the anatase phase by preserving the carbonaceous external surface and micropores of the composite. Two preparation methods were compared, including mixing dry precursors and immobilization using a glycerol slurry. The evaluation of the micropore blocking was performed using nitrogen adsorption isotherms. The results indicated that it was possible to use Manihot residues and glycerol to prepare an anatase-containing material with a basic surface and a significant SBET value. The activities of the prepared materials were tested in a decomposition assay of indigo carmine. The TiO2/carbon eliminated nearly 100% of the dye under UV irradiation using the optimal conditions found by a Taguchi L4 orthogonal array considering the specific surface, temperature and initial concentration. The reaction was monitored by UV-Vis spectrophotometry and LC-ESI-(Qq)-TOF-MS, enabling the identification of some intermediates. No isatin-5-sulfonic acid was detected after a 60 min photocatalytic reaction, and three sulfonated aromatic amines, including 4-amino-3-hydroxybenzenesulfonic acid, 2-(2-amino-5-sulfophenyl)-2-oxoacetic acid and 2-amino-5-sulfobenzoic acid, were present in the reaction mixture.

  2. One-step preparation of carbon nanotubes doped mesoporous birnessite K2Mn4O9 achieving 77% of theoretical capacitance by a facile redox reaction

    Science.gov (United States)

    Kang, Litao; Li, Peiyang; Tao, Keyu; Wang, Xiaomin; Liang, Wei; Gao, Yanfeng

    2016-01-01

    A facile, scalable and cost-efficient redox reaction is developed to prepare micro-powders of a quasi-crystallised, mesoporous birnessite-type manganese oxide, K2Mn4O9. In 1 M KOH electrolyte, the K2Mn4O9 powder shows a high specific capacitance of 754 F g-1 at 1 A g-1 (calculated with the net weight of K2Mn4O9 micro-powder only). Meanwhile, the electrode retains 91% of its initial capacitance after 5000 cycles at a high current density of 5 A g-1. By simply adding carbon nanotubes (CNTs) into the reaction system, the specific capacitances of as-prepared K2Mn4O9/CNTs composites are further increased to 929 and 1055 F g-1 at 1 A g-1 in 1 and 6 M KOH electrolyte (corresponding to 69 and 77% of the theoretical capacitance of MnO2), or 600 and 674 F g-1 at 5 A g-1, respectively. Significantly, a maximum energy density of 62 Wh kg-1 at a power density of 852 W kg-1 could be achieved based on a K2Mn4O9/CNTs//activated carbon asymmetric supercapacitor (ASC). At the same time, the ASC device exhibits a decent long cycle life with 85% specific capacitance retained after 1000 cycles, suggesting its wide application potential in low-cost high energy density storage systems.

  3. Mesoporous and Nanostructured TiO2 layer with Ultra-High Loading on Nitrogen-Doped Carbon Foams as Flexible and Free-Standing Electrodes for Lithium-Ion Batteries.

    Science.gov (United States)

    Chu, Shiyong; Zhong, Yijun; Cai, Rui; Zhang, Zhaobao; Wei, Shenying; Shao, Zongping

    2016-12-01

    A simple and green method is developed for the preparation of nanostructured TiO2 supported on nitrogen-doped carbon foams (NCFs) as a free-standing and flexible electrode for lithium-ion batteries (LIBs), in which the TiO2 with 2.5-4 times higher loading than the conventional TiO2 -based flexible electrodes acts as the active material. In addition, the NCFs act as a flexible substrate and efficient conductive networks. The nanocrystalline TiO2 with a uniform size of ≈10 nm form a mesoporous layer covering the wall of the carbon foam. When used directly as a flexible electrode in a LIB, a capacity of 188 mA h g(-1) is achieved at a current density of 200 mA g(-1) for a potential window of 1.0-3.0 V, and a specific capacity of 149 mA h g(-1) after 100 cycles at a current density of 1000 mA g(-1) is maintained. The highly conductive NCF and flexible network, the mesoporous structure and nanocrystalline size of the TiO2 phase, the firm adhesion of TiO2 over the wall of the NCFs, the small volume change in the TiO2 during the charge/discharge processes, and the high cut-off potential contribute to the excellent capacity, rate capability, and cycling stability of the TiO2 /NCFs flexible electrode.

  4. Facile synthesis of carbon doped TiO2 nanowires without an external carbon source and their opto-electronic properties.

    Science.gov (United States)

    Kiran, Vankayala; Sampath, Srinivasan

    2013-11-07

    The present study demonstrates a simple protocol for the preparation of one dimensional (1D) oxidized titanium carbide nanowires and their opto-electronic properties. The oxidized titanium carbide nanowires (Ox-TiC-NW) are prepared from TiC nanowires (TiC-NW) that are in turn synthesized from micron sized TiC particles using the solvothermal technique. The Ox-TiC-NW is characterized by X-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Raman spectroscopy. Thermal oxidation of TiC-NW yields carbon doped TiO2-NW (C-TiO2-NW), a simple methodology to obtain 1D C-TiO2-NW. Temperature dependent Raman spectra reveal characteristic bands for TiO2-NW. Electrical characterization of individual C-TiO2-NW is performed by fabricating a device structure using the focused ion beam deposition technique. The opto-electronic properties of individual C-TiO2-NW demonstrate visible light activity and the parameters obtained from photoconductivity measurements reveal very good sensitivity. This methodology opens up the possibility of using C-TiO2-NW in electronic and opto-electronic device applications.

  5. Activated carbon-based magnetic TiO2 photocatalyst codoped with iodine and nitrogen for organic pollution degradation

    Science.gov (United States)

    Wang, Xuejiang; Song, Jingke; Huang, Jiayu; Zhang, Jing; Wang, Xin; Ma, RongRong; Wang, Jiayi; Zhao, Jianfu

    2016-12-01

    Magnetic photocatalyst - iodine and nitrogen codoped TiO2 based on chitosan decorated magnetic activated carbon (I-N-T/CMAC) was prepared via simple coprecipitation and sol-gel method. The characteristics of photocatalysts were investigated by X-ray diffraction (XRD), N2 adsorption-desorption isotherm, field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflection spectroscopy (UV-vis DRS), photoluminescence (PL) spectroscopy and vibrating sample magnetometer (VSM). It turned out that the prepared material had large surface area, enhanced absorption of visible light, and magnetically separable properties when mole ratio of I/Ti was 0.1. Iodine-nitrogen codoped magnetic photocatalyst was used for the removal of salicylic acid (SA), and the rate of adsorption reaction for SA by I0.1-N-T/CMAC followed the pseudo second-order kinetic. Under visible light irradiation, 89.71% SA with initial concentration = 30 mg/L could be removed by I0.1-N-T/CMAC, and photodegradation rate of SA on I0.1-N-T/CMAC composites was 0.0084 min-1 which is about 4 times higher than that of magnetic photocatalyst with nitrogen doped only. The effects of SA initial concentration, pH, coexisting anions and humic acid to the degradation of SA with the prepared material were also investigated. Main oxidative species in the photodegradation process are rad OH and h+.

  6. Operando atomic structure and active sites of TiO2(110)-supported gold nanoparticles during carbon monoxide oxidation.

    Science.gov (United States)

    Saint-Lager, Marie-Claire; Laoufi, Issam; Bailly, Aude

    2013-01-01

    It is well known that gold nanoparticles supported on TiO2 act as a catalyst for CO oxidation, even below room temperature. Despite extensive studies, the origin of this catalytic activity remains under debate. Indeed, when the particle size decreases, many changes may occur; thus modifying the nanoparticles' electronic properties and consequently their catalytic performances. Thanks to a state-of-the-art home-developed setup, model catalysts can be prepared in ultra-high vacuum and their morphology then studied in operando conditions by Grazing Incidence Small Angle X-ray Scattering, as well as their atomic structure by Grazing Incidence X-ray Diffraction as a function of their catalytic activity. We previously reported on the existence of a catalytic activity maximum observed for three-dimensional gold nanoparticles with a diameter of 2-3 nm and a height of 6-7 atomic planes. In the present work we correlate this size dependence of the catalytic activity to the nanoparticles' atomic structure. We show that even when their size decreases below the optimum diameter, the gold nanoparticles keep the face-centered cubic structure characteristic of bulk gold. Nevertheless, for these smallest nanoparticles, the lattice parameter presents anisotropic strains with a larger contraction in the direction perpendicular to the surface. Moreover a careful analysis of the atomic-scale morphology around the catalytic activity maximum tends to evidence the role of sites with a specific geometry at the interface between the nanoparticles and the substrate. This argues for models where atoms at the interface periphery act as catalytically active sites for carbon monoxide oxidation.

  7. Statistical analysis of thermal conductivity of nanofluid containing decorated multi-walled carbon nanotubes with TiO2 nanoparticles

    Indian Academy of Sciences (India)

    Sedigheh Abbasi; Seyed Mojtaba Zebarjad; Seyed Hossein Noie Baghban; Abbas Youssefi

    2014-10-01

    In this paper, we report for the first time the statistical analysis of thermal conductivity of nanofluids containing TiO2 nanoparticles, pristine MWCNTs and decorated MWCNTs with different amounts of TiO2 nanoparticles. The functionalized MWCNT and synthesized hybrid of MWCNT–TiO2 were characterized using transmission electron microscopy (TEM). TEM image confirmed that the ends of MWCNTs were opened during their oxidation of them in HNO3 and TiO2 nanoparticles successfully attach to the outer surface of oxidized MWCNTs. Thermal conductivity measurements of nanofluids were analysed via two-factor completely randomized design and comparison of data means is carried out with Duncan’s multiple-range test. Statistical analysis of experimental data show that temperature and weight fraction have a reasonable impact on the thermal conductivity of all tested nanofluids ( = 0.05). The results also show that increased temperature and weight fraction leads to the increased thermal conductivity.

  8. Highly selective and effective solid phase microextraction of benzoic acid esters using ionic liquid functionalized multiwalled carbon nanotubes-doped polyaniline coating.

    Science.gov (United States)

    Ai, Youhong; Wu, Mian; Li, Lulu; Zhao, Faqiong; Zeng, Baizhao

    2016-03-11

    The present work reports the electrochemical fabrication of an ionic liquid functionalized multiwalled carbon nanotubes-polyaniline (MWCNT@IL/PANI) nanocomposite coating and its application in the headspace-solid phase microextraction (HS-SPME) and gas chromatography (GC) determination of benzoic acid esters (i.e., methyl benzoate, ethyl benzoate, propyl benzoate and butyl benzoate). The MWCNTs was firstly functionalized with amine-terminated IL (MWCNT@IL) through chemical reduction, and then was doped in PANI during the electropolymerization of aniline. The resulting coating was characterized by infrared spectroscopy, field emission scanning electron microscopy and thermo gravimetry. It showed net-like structure and had high thermal stability (up to 330°C). Furthermore, it presented high selectivity for the four benzoic acid esters and thus suited for their HS-SPME-GC determination. Results showed that under optimized extraction conditions, the detection limits were less than 6.1ngL(-1) (S/N=3) and the linear detection ranges were 0.012-50μgL(-1) (R≥0.9957) for these analytes. The relative standard deviations (RSDs) were lower than 6.4% for five successive measurements with one fiber, and the RSDs for fiber-to-fiber were 4.4-9.6% (n=5). The developed method was successfully applied to the determination of these benzoic acid esters in perfume samples.

  9. Ionic liquid polymer functionalized carbon nanotubes-doped poly(3,4-ethylenedioxythiophene) for highly-efficient solid-phase microextraction of carbamate pesticides.

    Science.gov (United States)

    Wu, Mian; Wang, Liying; Zeng, Baizhao; Zhao, Faqiong

    2016-04-29

    A poly(3,4-ethylenedioxythiophene)-ionic liquid polymer functionalized multiwalled carbon nanotubes (PEDOT-PIL/MWCNTs) composite solid-phase microextraction (SPME) coating was fabricated by electrodeposition. After being dipped in Nafion solution, a Nafion-modified coating was obtained. The outer layer Nafion played a crucial role in enhancing the durability and stability of the coating, thus it was robust enough for replicated extraction for at least 150 times without decrease of extraction performance. The Nafion-modified coating exhibited much higher sensitivity than commercial coatings for the direct extraction of carbamate pesticides in aqueous solutions, due to its strong hydrophobic effect and π-π affinity based enrichment. When it was used for the determination of carbamate pesticides in combination with gas chromatography-flame ionization detection, good linearity (correlation coefficients higher than 0.9981), low limits of detection (15.2-27.2 ng/L) and satisfactory precision (relative standard deviation carbamate pesticides in apple and lettuce samples, and acceptable recoveries (i.e. 87.5-106.5%) were obtained for the standard addition. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Effect of beam expansion loss in a carbon nanotube-doped PVA film on passively mode-locked erbium-doped fiber lasers with different feedback ratios

    Science.gov (United States)

    Cheng, Kuang-Nan; Chi, Yu-Chieh; Cheng, Chih-Hsien; Lin, Yung-Hsiang; Lo, Jui-Yung; Lin, Gong-Ru

    2014-10-01

    The effect of beam expansion induced divergent loss in a single-wall carbon nanotube (SWCNT) doped polyvinyl alcohol (PVA) based ultrafast saturable absorber (SA) film thickness on the passive mode-locking (PML) performances of erbium-doped fiber lasers are demonstrated. The variation on the PML pulsewidth of the EDFL is discussed by changing the SWCNT-PVA SA film thicknesses, together with adjusting the pumping power and the intra-cavity feedback ratio. An almost 6 dB increment of divergent loss when enlarging the SWCNT-PVA based SA film thickness from 30-130 µm is observed. When shrinking the SA thickness to 30 µm at the largest pumping power of 52.5 mW, the optical spectrum red-shifts to 1558.8 nm with its 3 dB spectral linewidth broadening up to 2.7 nm, while the pulse has already entered the soliton regime with multi-order Kelly sidebands aside the spectral shoulder. The soliton pulsewidth is as short as 790 fs, which is much shorter than those obtained with other thicker SWCNT doped PVA polymer film based SAs; therefore, the peak power from the output of the PML-EDFL is significantly enlarged accompanied by a completely suppressed residual continuous-wave level to achieve the largest on/off extinction ratio. The main mechanism of pulse shortening with reducing thickness of SWCNT doped PVA polymer film based SA is attributed to the limited beam expansion as well as the enlarged modulation depth, which results in shortened soliton pulsewidth with a clean dc background, and broadened spectrum with enriched Kelly sidebands. The increase of total SWCNT amount in the thicker SA inevitably causes a higher linear absorption; hence, the mode-locking threshold also rises accordingly. By enlarging pumping power from 38.5-52.5 mW, the highest ascent on pulse extinction of up to 32 dB is observed among all kinds of feedback conditions. Nevertheless, the enlargement on the extinction slightly decays with increasing the feedback ratio from 30-90%, as

  11. Síntese, caracterização e atividade fotocatalítica de catalisadores nanoestruturados de TiO2 dopados com metais

    Directory of Open Access Journals (Sweden)

    William Leonardo da Silva

    2013-01-01

    Full Text Available Titanium dioxide nanostructured catalysts (nanotubes doped with different metals (silver, gold, copper, palladium and zinc were synthesized by the hydrothermal method in order to promote an increase in their photocatalytic activity under visible light. The catalysts were characterized by X-ray diffraction, diffuse reflectance spectroscopy, transmission electron microscopy and specific area and pore volume determination. The materials' photocatalytic activity was evaluated by rhodamine B decomposition in a glass batch reactor. Under UV radiation, only nanotubes doped with palladium were more active than the TiO2 P25, but the samples doped with silver, palladium and gold exhibited better results than the undoped samples under visible light.

  12. Effect of photocatalytic reduction of carbon dioxide by N-Zr co-doped nano TiO2.

    Science.gov (United States)

    Zhang, Ru; Wang, Li; Kang, Zhuo; Li, Qiang; Pan, Huixian

    2017-01-04

    Modified sol-gel method was adopted to prepare TiO2, Zr-TiO2 and N/Zr-TiO2 composite catalyst. The as-synthesized photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Brunner- Emmet- Teller measurement and UV-Vis diffuse reflectance spectroscopy. And the photocatalytic performance toward CO2 reduction was evaluated under ultraviolet light. The catalyst particles were demonstrated in the nanometer level size. When N and Zr are co-doped, on the one hand, Ti(4+) can be replaced by Zr4 +, which leads to lattice distortion and inhibits electron-hole recombination. On the other hand, N enters into TiO2 lattice gap to form O-Ti-N bond structure, and partial Ti(4+) are reduced to Ti(3+). Compared with pristine TiO2, the specific surface area and the band gap of N/Zr-TiO2 were improved and reduced, respectively. The N and Zr synergistically contribute to the obviously strengthened absorption intensity in visible region, as well as significantly improved photocatalytic activity. In the gas phase reactor, when the calcination temperature was 550°C, 0.125N/0.25Zr-TiO2 composite performed the highest photocatalytic activity UV irradiation for 8 h, and the corresponding CH4 yield was 11.837 µmol/g, which was 87.8% higher than that of pristine TiO2. For the visible light, the CH4 yield was 9.003 µmol/g after 8 h irradiation, which was 83.9% higher than that of pristine TiO2.

  13. Voltammetric Sensor Based on Fe-doped ZnO and TiO2 Nanostructures-modified Carbon-paste Electrode for Determination of Levodopa

    Science.gov (United States)

    Anaraki Firooz, Azam; Hosseini Nia, Bahram; Beheshtian, Javad; Ghalkhani, Masoumeh

    2017-10-01

    In this study, undoped and 1 wt.% Fe-doped with ZnO, and TiO2 nanostructures were synthesized by a simple hydrothermal method without using templates. The influence of the Fe dopant on structural, optical and electrochemical response was studied by x-ray diffraction, scanning electron microscopy, UV-Vis spectra, photoluminescence spectra and electrochemical characterization system. The electrochemical response of the carbon paste electrode modified with synthesized nanostructures (undoped ZnO and TiO2 as well as doped with Fe ions) toward levodopa (L-Dopa) was studied. Cyclic voltammetry using provided modified electrodes showed electro-catalytic properties for electro-oxidation of L-Dopa and a significant reduction was observed in the anodic overvoltage compared to the bare electrode. The results indicated the presence of the sufficient dopants. The best response was obtained in terms of the current enhancement, overvoltage reduction, and reversibility improvement of the L-Dopa oxidation reaction under experimental conditions by the modified electrode with TiO2 nanoparticles doped with Fe ions.

  14. Highly sensitive chemiluminescence immunoassay on chitosan membrane modified paper platform using TiO2 nanoparticles/multiwalled carbon nanotubes as label.

    Science.gov (United States)

    Li, Weiping; Ge, Shenguang; Wang, Shoumei; Yan, Mei; Ge, Lei; Yu, Jinghua

    2013-01-01

    A highly sensitive chemiluminescence (CL) immunoassay was incorporated into a low-cost microfluidic paper-based analytical device (μ-PAD) to fabricate a facile paper-based CL immunodevice (denoted as μ-PCLI). This μ-PCLI was constructed by covalently immobilizing capture antibody on a chitosan membrane modified μ-PADs, which was developed by simple wax printing methodology. TiO2 nanoparticles coated multiwalled carbon nanotubes (TiO2/MWCNTs) were synthesized as an amplification catalyst tag to label signal antibody (Ab2). After sandwich-type immunoreactions, the TiO2/MWCNTs were captured on the surface of μ-PADs to catalyze the luminol-p-iodophenol-H2O2 CL system, which produced an enhanced CL emission. Using prostate-specific antigen as a model analyte, the approach provided a good linear response range from 0.001 to 20 ng/mL with a low detection limit of 0.8 pg/mL under optimal conditions. This μ-PCLI showed good reproducibility, selectivity and stability. The assay results of prostate-specific antigen in clinical serum samples were in good agreement with that obtained by commercially used electrochemiluminescence methods at the Cancer Research Center of Shandong Tumor Hospital (Jinan, Shandong Province, China). This μ-PCLI could be very useful to realize highly sensitive, qualitative point-of-care testing in developing or developed countries.

  15. Enhanced clustering tendency of Cu-impurities with a number of oxygen vacancies in heavy carbon-loaded TiO2 - the bulk and surface morphologies

    Science.gov (United States)

    Zatsepin, D. A.; Boukhvalov, D. W.; Kurmaev, E. Z.; Zatsepin, A. F.; Kim, S. S.; Gavrilov, N. V.; Zhidkov, I. S.

    2017-09-01

    The over threshold carbon-loadings (∼50 at.%) of initial TiO2-hosts and posterior Cu-sensitization (∼7 at.%) was made using pulsed ion-implantation technique in sequential mode with 1 h vacuum-idle cycle between sequential stages of embedding. The final Cx-TiO2:Cu samples were qualified using XPS wide-scan elemental analysis, core-levels and valence band mappings. The results obtained were discussed on the theoretic background employing DFT-calculations. The combined XPS-and-DFT analysis allows to establish and prove the final formula of the synthesized samples as Cx-TiO2:[Cu+][Cu2+] for the bulk and Cx-TiO2:[Cu+][Cu0] for thin-films. It was demonstrated the in the mode of heavy carbon-loadings the remaining majority of neutral C-C bonds (sp3-type) is dominating and only a lack of embedded carbon is fabricating the O-Cdbnd O clusters. No valence base-band width altering was established after sequential carbon-copper modification of the atomic structure of initial TiO2-hosts except the dominating majority of Cu 3s states after Cu-sensitization. The crucial role of neutral carbon low-dimensional impurities as the precursors for the new phases growth was shown for Cu-sensitized Cx-TiO2 intermediate-state hosts.

  16. Electrospinning preparation of oxygen-deficient nano TiO2-x/carbon fibre membrane as a self-standing high performance anode for Li-ion batteries

    Science.gov (United States)

    Jing, Mao-xiang; Li, Jing-quan; Han, Chong; Yao, Shan-shan; Zhang, Ji; Zhai, Hong-ai; Chen, Li-li; Shen, Xiang-qian; Xiao, Ke-song

    2017-07-01

    Improving the specific capacity and electronic conductivity of TiO2 can boost its practical application as a promising anode material for lithium ion batteries. In this work, a three-dimensional networking oxygen-deficient nano TiO2-x/carbon fibre membrane was achieved by combining the electrospinning process with a hot-press sintering method and directly used as a self-standing anode. With the synergistic effects of three-dimensional conductive networks, surface oxygen deficiency, high specific surface area and high porosity, binder-free and self-standing structure, etc., the nano TiO2-x/carbon fibre membrane electrode displays a high electrochemical reaction kinetics and a high specific capacity. The reversible capacity could be jointly generated from porous carbon, full-lithiation of TiO2 and interfacial lithium storage. At a current density of 100 mA g-1, the reversible discharge capacity can reach 464 mA h g-1. Even at 500 mA g-1, the discharge capacity still remains at 312 mA h g-1. Compared with pure carbon fibre and TiO2 powder, the TiO2-x/C fibre membrane electrode also exhibits an excellent cycle performance with a discharge capacity of 209 mA h g-1 after 700 cycles at the current density of 300 mA g-1, and the coulombic efficiency always remains at approximately 100%.

  17. TiO2 nanoparticles immobilized on carbon nanotubes for enhanced visible-light photo-induced activity

    Directory of Open Access Journals (Sweden)

    Ali Akbar Ashkarran

    2015-04-01

    Full Text Available CNT–TiO2 nanocomposites were prepared through (i simple mixing of as prepared CNTs and TiO2 nanoparticles (NPs, (ii simple mixing of as prepared CNTs and TiO2 NPs followed by heat treatment and (iii simple mixing of as prepared CNTs and TiO2 NPs followed by UV illumination. The synthesis of CNTs and TiO2 NPs were performed individually by arc discharge in water and sol–gel methods, respectively and characterized by X-ray diffraction (XRD, ultra violet and visible spectroscopy (UV–vis, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The visible-light photocatalytic performance of CNT–TiO2 nanocomposites was successfully demonstrated for the degradation of Rhodamine B (Rh. B as a model dye at room temperature. It is found that CNT–TiO2 nanocomposites extended the light absorption spectrum toward the visible region and considerably improved the photocatalytic efficiency under visible-light irradiation. The visible-light photocatalytic activities of CNT–TiO2 nanocomposites in which CNTs are produced by arc discharge in deionized (DI water at 40, 60 and 80 A arc currents and combined through three different protocols are also investigated. It was found that samples prepared at 80 A arc current and 5 s arc duration followed by UV illumination revealed best photocatalytic activity compared with the same samples prepared under simple mixing and simple mixing followed by heat treatment. The enhancement in the photocatalytic property of CNT–TiO2 nanocomposites prepared at 80 A arc current followed by UV illumination may be ascribed to the quality of CNTs produced at this current, as was reported before.

  18. Effect of Carbon Modification on the Electrical, Structural, and Optical Properties of TiO2 Electrodes and Their Performance in Labscale Dye-Sensitized Solar Cells

    OpenAIRE

    Taziwa, R.; Meyer, E. L.; Sideras-Haddad, E.; R. M. Erasmus; E. MANIKANDAN; Mwakikunga, B. W.

    2012-01-01

    Carbon-modified titanium dioxide nanoparticles (C:TiO2 NPs) have been synthesized by ultrasonic nebulizer spray pyrolysis (USP) and pneumatic spray pyrolysis (PSP) techniques. HRTEM on the NPs shows difference in lattice spacing in the NP structures prepared by the two methods—2.02 Å for the USP NPs and an average of 3.74 Å for the PSP NPs. The most probable particle sizes are 3.11 nm and 5.5 nm, respectively. Raman spectroscopy supported by FTIR confirms the TiO2 polymorph to be anatase with...

  19. Enhanced Photocatalytic Activity of CdS-Decorated TiO2/Carbon Core-Shell Microspheres Derived from Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2016-03-01

    Full Text Available The fabrication of reusable and biodegradation materials from renewable resources such as cellulose is essential for a sustainable world. The core-shell structured CdS-decorated TiO2/Carbon microspheres (CdS/TiO2/Carbon MS photocatalyst was synthesized with controlled hydrolysis and a novel sonochemical method. It was prepared by using crosslinked microcrystalline cellulose as the core, tetrabutyl titanate as the titania source and CdS as the photosensitizer. The morphology, chemical structure and properties of the obtained material were characterized by many means. Additionally, the photocatalytic activity of the CdS/TiO2/Carbon MS was evaluated by the photodegradation efficiency of Rhodamine B solution, which reached 95.24% under visible light irradiation. This study demonstrated the excellent photocatalytic performance of CdS/TiO2/Carbon MS, which might have promising applications in environmental treatments.

  20. Direct Synthesis of Carbon-Doped TiO2-Bronze Nanowires as Anode Materials for High Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Goriparti, Subrahmanyam; Miele, Ermanno; Prato, Mirko; Scarpellini, Alice; Marras, Sergio; Monaco, Simone; Toma, Andrea; Messina, Gabriele C; Alabastri, Alessandro; De Angelis, Francesco; Manna, Liberato; Capiglia, Claudio; Zaccaria, Remo Proietti

    2015-11-18

    Carbon-doped TiO2-bronze nanowires were synthesized via a facile doping mechanism and were exploited as active material for Li-ion batteries. We demonstrate that both the wire geometry and the presence of carbon doping contribute to the high electrochemical performance of these materials. Direct carbon doping for example reduces the Li-ion diffusion length and improves the electrical conductivity of the wires, as demonstrated by cycling experiments, which evidenced remarkably higher capacities and superior rate capability over the undoped nanowires. The as-prepared carbon-doped nanowires, evaluated in lithium half-cells, exhibited lithium storage capacity of ∼306 mA h g(-1) (91% of the theoretical capacity) at the current rate of 0.1C as well as excellent discharge capacity of ∼160 mAh g(-1) even at the current rate of 10 C after 1000 charge/discharge cycles.

  1. Size-Tunable Olive-Like Anatase TiO2 Coated with Carbon as Superior Anode for Sodium-Ion Batteries.

    Science.gov (United States)

    Chen, Jun; Zhang, Yan; Zou, Guoqiang; Huang, Zhaodong; Li, Simin; Liao, Hanxiao; Wang, Jufeng; Hou, Hongshuai; Ji, Xiaobo

    2016-10-01

    Olive-shaped anatase TiO2 with tunable sizes in nanoscale are designed employing polyvinyl alcohol (PVA) as structure directing agents to exert dramatic impacts on structure shaping and size manipulation. Notably, the introduced PVA simultaneously serves as carbon sources, bringing about a homogenous carbon layer with intimate coupling interfaces for boosted electronic conductivity. Constructed from tiny crystalline grains, the uniformly dispersed carbon-coated TiO2 nano-olives (TOC) possess subtle loose structure internally for prompt Na(+) transportations. When utilized for sodium-ion storage, the size effects are increasingly significant at high charge-discharge rates, leading to the much superior rate performances of TOC with the smallest size. Bestowed by the improved Na(+) adsorption and diffusion kinetics together with the promoted electron transfer, it delivers a high specific capacity of 267 mAh g(-1) at 0.1 C (33.6 mA g(-1) ) and sustains 110 mAh g(-1) at a rather high rate of 20 C. Even after cycled at 10 C over 1000 cycles, a considerable capacity of 125 mAh g(-1) with a retention of 94.6% is still obtained, highlighting its marvelous long-term cyclability and high-rate capabilities. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Effective Carbon Dioxide Photoreduction over Metals (Fe-, Co-, Ni-, and Cu- Incorporated TiO2/Basalt Fiber Films

    Directory of Open Access Journals (Sweden)

    Jeong Yeon Do

    2016-01-01

    Full Text Available Mineralogical basalt fibers as a complementary adsorbent were introduced to improve the adsorption of CO2 over the surfaces of photocatalysts. TiO2 photocatalysts (M-TiO2 incorporated with 5.0 mol.% 3d-transition metals (Fe, Co, Ni, and Cu were prepared using a solvothermal method and mixed with basalt fibers for applications to CO2 photoreduction. The resulting 5.0 mol.% M-TiO2 powders were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible spectroscopy, photoluminescence, Brunauer, Emmett, and Teller surface area, and CO2-temperature-programmed desorption. A paste composed of two materials was coated and fixed on a Pyrex plate by a thermal treatment. The 5.0 mol.% M-TiO2/basalt fiber films increased the adsorption of CO2 significantly, indicating superior photocatalytic behavior compared to pure TiO2 and basalt fiber films, and produced 158~360 μmol gcat-1 L−1 CH4 gases after an 8 h reaction. In particular, the best performance was observed over the 5.0 mol.% Co-TiO2/basalt fiber film. These results were attributed to the effective CO2 gas adsorption and inhibition of photogenerated electron-hole pair recombination.

  3. Homogeneous and nanomolar detection of hydrazine by indigocarmine as a mediator at the surface of TiO2 nanoparticles modified carbon paste electrode

    Institute of Scientific and Technical Information of China (English)

    Mohammad Mazloum-Ardakani; Hossein Rajabi; Hadi Beitollahi

    2012-01-01

    The homogeneous electrocatalytic oxidation of hydrazine (HZ) has been studied by indigocarmine (IND) as a mediator at the surface of TiO2 nanoparticles modified carbon paste electrode (TNMCPE).Cyclic voltammetry was used to study the electrochemical behavior of IND at different scan rates.The voltammetric response of the modified electrode was linear against the concentration of HZ in the ranges of 3.0 × 10-8-7.0 × 10 -6 mol/L with differential pulse voltammetry method.The detection limit (3σ) was determined as 27.3 nmoL/L.To evaluate the applicability of the proposed method to real samples,the modified CPE was applied to the determination of HZ in water samples.

  4. Self-assembled mesoporous TiO2/carbon nanotube composite with a three-dimensional conducting nanonetwork as a high-rate anode material for lithium-ion battery

    Science.gov (United States)

    Wang, Jie; Ran, Ran; Tade, Moses O.; Shao, Zongping

    2014-05-01

    Mesoporous three-dimensional (3D) TiO2/carbon nanotube conductive hybrid nanostructures can be successfully developed using polyethylene oxide (PEO) to modify the surfaces of carbon nanotubes (CNTs). During the synthesis process, PEO acts as not only "bridges" to connect the TiO2 nanoparticles to the CNT surfaces but also as "hosts" to accommodate and stabilize the in situ generated TiO2 particles. As the electrodes for lithium-ion batteries, such mesoporous 3D TiO2/CNT hybrids, demonstrate high Li storage capacity, superior rate performance and excellent long-term cycling stability. They exhibit a reversible specific capacity of 203 mA h g-1 at 100 mA g-1 and a stable capacity retention of 91 mA h g-1 at 8000 mA g-1 (47.6 C) over 100 cycles; they also retain approximately 90% (71 mA h g-1) of their initial discharge capacity after 900 cycles at an extremely high rate of 15,000 mA g-1 (89 C). This facile synthetic strategy to construct mesoporous 3D TiO2/CNT conductive hybrids provides a convenient route that efficiently assembles various inorganic oxide components on the CNTs' surfaces and enables the formation of heterogeneous nanostructures with novel functionalities. In particular, utilizing a conductive 3D CNT network can serve as a promising strategy for developing high-performance electrodes for Li secondary batteries and supercapacitors.

  5. Photocatalytic Degradation of Methylene Blue under UV Light Irradiation on Prepared Carbonaceous TiO2

    Directory of Open Access Journals (Sweden)

    Zatil Amali Che Ramli

    2014-01-01

    Full Text Available This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC, TiO2/carbon (C, and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, thermogravimetric analysis (TG-DTA, Brunauer-Emmet-Teller (BET, and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m2 g−1. The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.

  6. Photocatalytic degradation of methylene blue under UV light irradiation on prepared carbonaceous TiO2.

    Science.gov (United States)

    Ramli, Zatil Amali Che; Asim, Nilofar; Isahak, Wan N R W; Emdadi, Zeynab; Ahmad-Ludin, Norasikin; Yarmo, M Ambar; Sopian, K

    2014-01-01

    This study involves the investigation of altering the photocatalytic activity of TiO2 using composite materials. Three different forms of modified TiO2, namely, TiO2/activated carbon (AC), TiO2/carbon (C), and TiO2/PANi, were compared. The TiO2/carbon composite was obtained by pyrolysis of TiO2/PANi prepared by in situ polymerization method, while the TiO2/activated carbon (TiO2/AC) was obtained after treating TiO2/carbon with 1.0 M KOH solution, followed by calcination at a temperature of 450°C. X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermogravimetric analysis (TG-DTA), Brunauer-Emmet-Teller (BET), and UV-Vis spectroscopy were used to characterize and evaluate the prepared samples. The specific surface area was determined to be in the following order: TiO2/AC > TiO2/C > TiO2/PANi > TiO2 (179 > 134 > 54 > 9 m(2) g(-1)). The evaluation of photocatalytic performance for the degradation of methylene blue under UV light irradiation was also of the same order, with 98 > 84.7 > 69% conversion rate, which is likely to be attributed to the porosity and synergistic effect in the prepared samples.

  7. The Implications of Fe2O3 and TiO2 Nanoparticles on the Removal of Trichloroethylene by Activated Carbon in the Presence and Absence of Humic Acid

    Science.gov (United States)

    The implications of Fe2O3 and TiO2 nanoparticles (NPs) on a granular activated carbon (GAC) adsorber and their impact on the removal of Trichloroethylene (TCE) were investigated in the presence of humic acid (HA). The surface charge of the GAC and NPs was obtained in the presence...

  8. ALD TiO2-Coated Flower-like MoS2 Nanosheets on Carbon Cloth as Sodium Ion Battery Anode with Enhanced Cycling Stability and Rate Capability.

    Science.gov (United States)

    Ren, Weina; Zhou, Weiwei; Zhang, Haifeng; Cheng, Chuanwei

    2017-01-11

    We report the fabrication of 3D flower-like MoS2 nanosheets arrays on carbon cloth as a binder-free anode for sodium ion battery. Ultrathin and conformal TiO2 layers are used to modify the surface of MoS2 by atomic layer deposition. The electrochemical performance measurements demonstrate that the ALD TiO2 layer can improve the cycling stability and rate capability of MoS2. The MoS2 nanosheets with 0.5-nm TiO2 coating electrode show the highest initial discharge capacity of 1392 mA h g(-1) at 200 mA g(-1), which is increased by 53% compared with that of bare MoS2. After 150 cycles, the capacity retention rate of the TiO2-coated MoS2 achieves 75.8% of its second cycle's capacity at 200 mA h g(-1) in contrast to that of 59% of pure MoS2. Furthermore, the mechanism behind the experimental results is revealed by ex situ scanning electron microscope (SEM), X-ray powder diffraction (XRD), and electrochemical impedance spectroscopy (EIS) characterizations, which confirms that the ultrathin TiO2 modifications can prevent the structural degradation and the formation of SEI film of MoS2 electrode.

  9. Photocatalytic degradation of carbofuran by TiO2-coated activated carbon: Model for kinetic, electrical energy per order and economic analysis.

    Science.gov (United States)

    Vishnuganth, M A; Remya, Neelancherry; Kumar, Mathava; Selvaraju, N

    2016-10-01

    The photocatalytic removal of carbofuran (CBF) from aqueous solution in the presence of granular activated carbon supported TiO2 (GAC-TiO2) catalyst was investigated under batch-mode experiments. The presence of GAC enhanced the photocatalytic efficiency of the TiO2 catalyst. Experiments were conducted at different concentrations of CBF to clarify the dependence of apparent rate constant (kapp) in the pseudo first-order kinetics on CBF photodegradation. The general relationship between the adsorption equilibrium constant (K) and reaction rate constant (kr) were explained by using the modified Langmuir-Hinshelwood (L-H) model. From the observed kinetics, it was observed that the surface reaction was the rate limiting step in the GAC-TiO2 catalyzed photodegradation of CBF. The values of K and kr for this pseudo first-order reaction were found to be 0.1942 L  mg(-1) and 1.51 mg L(-1) min(-1), respectively. In addition, the dependence of kapp on the half-life time was determined by calculating the electrical energy per order experimentally (EEO experimental) and also by modeling (EEO model). The batch-mode experimental outcomes revealed the possibility of 100% CBF removal (under optimized conditions and at an initial concentration of 50 mg L(-1) and 100 mg L(-1)) at a contact time of 90 min and 120 min, respectively. Both L-H kinetic model and EEO model fitted well with the batch-mode experimental data and also elucidated successfully the phenomena of photocatalytic degradation in the presence of GAC-TiO2 catalyst. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Effects of boron doping in TiO2 nanotubes and the performance of dye-sensitized solar cells

    Science.gov (United States)

    Subramanian, Alagesan; Wang, Hong-Wen

    2012-06-01

    Titanium nanotubes doped with boron used as the photoelectrode for dye-sensitized solar cells were investigated. The materials were characterized by SEM, XRD, and UV-vis spectroscopy and their photoconversion efficiencies were evaluated. The chemical compositions of TiO2 nanotubes (TNA) and boron doped TNA (B-TNA) were identified by the energy dispersive X-ray spectroscopy (EDS). XRD evidenced the presence of anatase as the main phase and presented the existence of boron elements at interstitial sites between the TiO2 lattices. The UV-vis spectra indicated the narrowing of band gap upon doping boron into titanium nanotubes. The photovoltaic properties were measured by a current-voltage meter under AM1.5 simulated light radiation. The boron-doped TiO2 nanotube arrays showed an enhanced performance with a photocurrent density of 7.85 ± 0.20 mA/cm2 and an overall conversion efficiency (η) of 3.44 ± 0.10%. The enhanced performance was attributed to the enhanced electron injection rate and retardation of the charge recombination, which could be due to perfect matching between the LUMO of dye molecules and the conduction band of TiO2. Electrochemical impedance spectroscopy (EIS) measurement indicated the longer electron lifetime and reduced TiO2/dye/electrolyte interface resistance for boron doped TiO2 nanotubes than that of undoped TiO2 nanotubes.

  11. Electrochemical Performance of a Carbon Nanotube/La-Doped TiO2 Nanocomposite and its Use for Preparation of an Electrochemical Nicotinic Acid Sensor

    Directory of Open Access Journals (Sweden)

    Hanxing Liu

    2008-11-01

    Full Text Available A carbon nanotube/La-doped TiO2 (La-TiO2 nanocomposite (CLTN was prepared by a procedure similar to a complex/adsorption process. Scanning electron microscopy (SEM images show that the La-TiO2 distributes on the carbon nanotube walls. The CLTN was mixed with paraffin to form a CLTN paste for the CLTN paste electrode (CLTNPE. The electrochemical characteristics of CLTNPE were compared with that of conventional carbon electrodes such as the carbon paste electrode (CPE and glass carbon electrode (GC. The CLTNPE exhibits electrochemical activity and was used to investigate the electrochemistry of nicotinic acid (NA. The modified electrode has a strong electrocatalytic effect on the redox of NA. The cyclic voltammetry (CV redox potential of NA at the CLTNPE is 320 mV. The oxidation process of NA on the CLTNPE is pH dependent. A sensitive chronoamperometric response for NA was obtained covering a linear range from 1.0×10-6 mol·L-1 to 1.2×10-4 mol·L-1, with a detection limit of 2.7×10-7 mol·L-1. The NA sensor displays a remarkable sensitivity and stability. The mean recovery of NA in the human urine is 101.8%, with a mean variation coefficient (RSD of 2.6%.

  12. Sugarapple-like N-doped TiO2@carbon core-shell spheres as high-rate and long-life anode materials for lithium-ion batteries

    Science.gov (United States)

    Ren, Manman; Xu, Hong; Li, Fang; Liu, Weiliang; Gao, Cuiling; Su, Liwei; Li, Guangda; Hei, Jinpei

    2017-06-01

    In this work, sugarapple-like N-doped TiO2@N-doped carbon (NTiO2@NC) core-shell spheres have been synthesized with a facile and effective preparation process using polypyrrole (PPy) as carbon and nitrogen sources. Conductive N-doped carbon with slit pores uniformly coated on the TiO2 spheres surface. Benefiting from the N-doping and carbon shell, NTiO2@NC demonstrates superior long-term cycling stability and high-rate performance as anode materials for lithium ion batteries. Even tested at a current density of 5000 mA g-1, the NTiO2@NC composites can deliver a reversible capacity of 232.7 mAh g-1 after 2000 cycles. This new strategy may shed light on preparing metal oxides@NC core-shell composites for Li-ion batteries and other energy storage applications.

  13. Carbon-dot-decorated TiO2 nanotube arrays used for photo/voltage-induced organic pollutant degradation and the inactivation of bacteria

    Science.gov (United States)

    Feng, Lingyan; Sun, Hanjun; Ren, Jinsong; Qu, Xiaogang

    2016-03-01

    Photoluminescent carbon dots (c-dots) have recently attracted growing interest as a new member of the carbon-nanomaterial family. Here, we report for the first time that c-dot-decorated TiO2 nanotube arrays (c-dot/TiNTs) exhibit highly enhanced abilities regarding photo/voltage-induced organic pollutant degradation and bacterial inactivation. By applying UV irradiation (365 nm) or an electrochemical potential over 3 V (versus Ag/AgCl), an organic dye and a herbicide were efficiently degraded. Moreover, the inactivation of Gram-positive S. aureus and Gram-negative E. coli bacteria was realized on a c-dot/TiNT film. The c-dots were able to absorb light efficiently resulting in multiple exciton generation and also a reduction in the recombination of the e-/h+ pair produced in c-dot/TiNT film during photo/voltage-induced degradation. It was also possible to readily regenerate the surface using ultraviolet light irradiation, leaving the whole film structure undamaged and with high reproducibility and stability.

  14. Preparation, characterization, and photocatalytic activity of La-doped TiO2 supported on activated carbon at the decomposition of methylene orange

    Science.gov (United States)

    Xing, Jun; Sun, Xiaogang; Qiu, Jingping

    2015-06-01

    A composite photocatalyst (La/TiO2/AC) has been prepared by supporting photoactive La-doped TiO2 (La/TiO2) on activated carbon (AC) via hydrolysis of tetrabutyl titanate (Ti(OC4H9)4) with La(NO3)3 · 6H2O and Ti(OC4H9)4 as precursors in the presence of activated carbon. The prepared photocatalysts were characterized by BET surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-vis absorption spectroscopy. The photocatalytic activities of the obtained photocatalysts under UV light are estimated by measuring the degradation rate of methylene orange in aqueous solution. The effect of La-doped content on the photocatalytic activity was studied and the result revealed that 0.2 mol % La/TiO2/AC exhibited highest photoactivity. In addition, the recyclability of the prepared photocatalyst was also confirmed, the photocatalytic activity of La/TiO2/AC remains about 86.5% of its activity as-prepared after being used four times. The photocatalyst therefore may be used as effective catalyst in photooxidation reactions and potentially applied for the treatment of water contaminated by organic pollutants.

  15. Improving the Power Conversion Efficiency of Carbon Quantum Dot-Sensitized Solar Cells by Growing the Dots on a TiO2 Photoanode In Situ

    Directory of Open Access Journals (Sweden)

    Quanxin Zhang

    2017-05-01

    Full Text Available Dye-sensitized solar cells (DSSCs are highly promising since they can potentially solve global energy issues. The development of new photosensitizers is the key to fully realizing perspectives proposed to DSSCs. Being cheap and nontoxic, carbon quantum dots (CQDs have emerged as attractive candidates for this purpose. However, current methodologies to build up CQD-sensitized solar cells (CQDSCs result in an imperfect apparatus with extremely low power conversion efficiencies (PCEs. Herein, we present a simple strategy of growing carbon quantum dots (CQDs onto TiO2 surfaces in situ. The CQDs/TiO2 hybridized photoanode was then used to construct solar cell with an improved PCE of 0.87%, which is higher than all of the reported CQDSCs adopting the simple post-adsorption method. This result indicates that an in situ growing strategy has great advantages in terms of optimizing the performance of CQDSCs. In addition, we have also found that the mechanisms dominating the performance of CQDSCs are different from those behind the solar cells using inorganic semiconductor quantum dots (ISQDs as the photosensitizers, which re-confirms the conclusion that the characteristics of CQDs differ from those of ISQDs.

  16. TiO2 Nanocatalysts Supported on a Hybrid Carbon-Covered Alumina Support: Comparison between Visible Light and UV Light Degradation of Rhodamine B

    Directory of Open Access Journals (Sweden)

    Mphilisi M. Mahlambi

    2015-01-01

    Full Text Available Titania nanoparticles were successfully supported on carbon-covered alumina (CCA supports via the impregnation method to form carbon-covered alumna titania (CCA/TiO2. The CCA supports were synthesised through an equilibrium adsorption of toluene 2,4-diisocyante where the N=C=O irreversibly adsorbs on the alumina and pyrolysis at 700°C affords CCA supports. These CCA/TiO2 nanocatalysts were tested for their photocatalytic activity both under UV and visible light using Rhodamine B as a model pollutant. The reaction rate constant of the CCA/TiO2 was found to be higher than that of unsupported titania and the reaction kinetics were found to follow an apparent first-order rate law. The CCA/TiO2 nanocatalysts had a much larger surface area than the unsupported titania and they exhibited overall higher photodegradation efficiency under both UV and visible light than unsupported TiO2.

  17. Laser oxidative pyrolysis synthesis and annealing of TiO2 nanoparticles embedded in carbon-silica shells/matrix

    Science.gov (United States)

    Fleaca, C. T.; Scarisoreanu, M.; Morjan, I.; Luculescu, C.; Niculescu, A.-M.; Badoi, A.; Vasile, E.; Kovacs, G.

    2015-05-01

    Titania nanoparticles containing a mixture of anatase and rutile phases (with mean crystalline sizes up to 24 nm) covered with/embedded in carbon/silica thin layers or matrix were obtained in a single step using laser oxidative pyrolysis. Titanium tetrachloride and hexamethyldisiloxane (HMDSO) vapors were separately introduced into the reaction zone - both together with the laser-absorbing agent (sensitizer) ethylene - which acts also as carbon source - and the oxidant (air) - through the inner and the concentric nozzle, respectively. By increasing the air flow through the annular nozzle, while keeping constant the TiC4, inner air, HMDSO and C2H4 flows, the atomic carbon concentration as well as the rutile to anatase ratio in the resulted nanopowders decrease. A much brighter and extended flame was observed for the experiment involving the greatest air flow. The Ti/Si atomic ratio in the resulted nanocomposites was higher than that from the introduced precursors (1.8), indicating a partial siloxane conversion to silica. The annealed powders (at 450 °C to further carbon content reducing) exhibit a lower bandgap energy than those of the reference sample without silica (and also lower than the commercial Degussa P25 nano-TiO2).

  18. Efficient electrochemical remediation of microcystin-LR in tap water using designer TiO2@carbon electrodes

    Science.gov (United States)

    Sanz Lobón, Germán; Yepez, Alfonso; Garcia, Luane Ferreira; Morais, Ruiter Lima; Vaz, Boniek Gontijo; Carvalho, Veronica Vale; de Oliveira, Gisele Augusto Rodrigues; Luque, Rafael; Gil, Eric de Souza

    2017-01-01

    Microcystin-leucine arginine (MC-LR) is the most abundant and toxic secondary metabolite produced by freshwater cyanobacteria. This toxin has a high potential hazard health due to potential interactions with liver, kidney and the nervous system. The aim of this work was the design of a simple and environmentally friendly electrochemical system based on highly efficient nanostructured electrodes for the removal of MC-LR in tap water. Titania nanoparticles were deposited on carbon (graphite) under a simple and efficient microwave assisted approach for the design of the electrode, further utilized in the electrochemical remediation assays. Parameters including the applied voltage, time of removal and pH (natural tap water or alkaline condition) were investigated in the process, with results pointing to a high removal efficiency for MC-LR (60% in tap water and 90% in alkaline media experiments, under optimized conditions). PMID:28145477

  19. Efficient electrochemical remediation of microcystin-LR in tap water using designer TiO2@carbon electrodes

    Science.gov (United States)

    Sanz Lobón, Germán; Yepez, Alfonso; Garcia, Luane Ferreira; Morais, Ruiter Lima; Vaz, Boniek Gontijo; Carvalho, Veronica Vale; de Oliveira, Gisele Augusto Rodrigues; Luque, Rafael; Gil, Eric De Souza

    2017-02-01

    Microcystin-leucine arginine (MC-LR) is the most abundant and toxic secondary metabolite produced by freshwater cyanobacteria. This toxin has a high potential hazard health due to potential interactions with liver, kidney and the nervous system. The aim of this work was the design of a simple and environmentally friendly electrochemical system based on highly efficient nanostructured electrodes for the removal of MC-LR in tap water. Titania nanoparticles were deposited on carbon (graphite) under a simple and efficient microwave assisted approach for the design of the electrode, further utilized in the electrochemical remediation assays. Parameters including the applied voltage, time of removal and pH (natural tap water or alkaline condition) were investigated in the process, with results pointing to a high removal efficiency for MC-LR (60% in tap water and 90% in alkaline media experiments, under optimized conditions).

  20. Photocatalytic enhancement of floating photocatalyst: Layer-by-layer hybrid carbonized chitosan and Fe-N- codoped TiO2 on fly ash cenospheres

    Science.gov (United States)

    Song, Jingke; Wang, Xuejiang; Bu, Yunjie; Wang, Xin; Zhang, Jing; Huang, Jiayu; Ma, RongRong; Zhao, Jianfu

    2017-01-01

    Due to the advantage of floating on water surface, floating photocatalysts show higher rates of radical formation and collection efficiencies. And they were expected to be used for solar remediation of non-stirred and non-oxygenated reservoirs. In this research, floating fly ash cenospheres (FAC) supported layer-by- layer hybrid carbonized chitosan and Fe-N-codoped TiO2 was prepared by a simple sol-gel method. The catalysts were characterized by X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy(DRS), nitrogen adsorption analyses for Brunauer-Emmett-Teller (BET) specific surface area. It is indicated that Fe-N codoped narrowed the material's band gap, and the layer of carbonized chitosan (Cts) increased the catalyst's adsorption capacity and the absorption ability of visible light. Comparing with Fe-N-TiO2/FAC and N-TiO2/FAC, the composite photocatalyst show excellent performance on the degradation of RhB. Photodegradation rate of RhB by Fe-N-TiO2/FAC-Cts was 0.01018 min-1, which is about 1.5 and 2.09 times higher than Fe-N-TiO2/FAC and N-TiO2/FAC under visible light irradiation in 240 min, respectively. The dye photosentization, capture of holes and electrons by Fe3+ ion, and synergistic effect of adsorption and photodegradation were attributed to the results for the improvement of photocatalytic performance. The floating photocatalyst can be reused for at least three consecutive times without any significant decrease on the degradation of Rhodamin B after each reuse.

  1. Preparation and performance of Pr3+:Y2SiO5/TiO2 composites deposited on activated carbon fiber%活性炭纤维负载Pr3+:Y2SiO5/TiO2复合材料的制备与性能

    Institute of Scientific and Technical Information of China (English)

    徐萌川; 王亚淼; 杨毅; 焦岩; 刘颖; 颜学武

    2016-01-01

    为了提高纳米 TiO2对太阳光的利用率和实现光催化剂的回收再利用,采用溶胶-凝胶法将上转换荧光材料与纳米TiO2复合,通过负载于活性炭纤维(ACF)表面制备了Pr3+:Y2SiO5/TiO2/ACF复合材料。运用XRD、FT-IR、SEM、FS、UV-vis DRS等对材料的结构及性能进行了综合表征,并以亚甲基蓝为模拟污染物评价复合材料的可见光催化活性,考察了材料制备过程中煅烧温度、负载次数等制备条件对复合材料可见光下催化性能的影响。结果表明,在浸渍2次、800℃煅烧的制备条件下,复合材料中TiO2为锐钛矿相(占34.1%)与金红石相(占65.9%)的混合相,亚甲基蓝(15 mg·L−1)12 h内去除率高达93.8%,反应符合拟一级动力学,反应速率常数为0.2471 h−1,回收再生利用4次后去除率仍保持在75%以上。%In order to improve sunlight utilization as well as to recycle and reuse photocatalyst of titanium dioxide, Pr3+:Y2SiO5/TiO2/ACF composites were prepared by sol-gel technique of anchoring upconversion fluorescent material and nano-titanium dioxide on activated carbon fiber (ACF). Structures and properties of the Pr3+:Y2SiO5/TiO2/ACF composites were characterized by XRD, FT-IR, SEM, FS, and UV-vis DRS. Photocatalytic activity of the composites in the visible light region was evaluated with methylene blue solution as model pollutant and studied the effect of fabrication conditions such as calcination temperature and number of coating layers. The experimental results showed that TiO2 in Pr3+:Y2SiO5/TiO2/ACF composite contained both anatase (34.1%) and rutile (65.9%) when prepared by double coating and 800℃ calcination. This composite had the highest visible-light photocatalytic activity which degraded methylene blue (15 mg·L−1) high as 93.8% in 12h. The photodegradation followed pseudo first order kinetics with reaction rate constant is 0.2471 h−1. Pr3+:Y2SiO5/TiO2/ACF composite

  2. Synthesis and Characterization of TiO2/Carbon Nanoparticle (C-Dot Composites and Their Application as Photocatalysts to Degrade of Persistent Organic Pollutant

    Directory of Open Access Journals (Sweden)

    Dedri Syafei

    2017-04-01

    Full Text Available TiO2/C-dot composites were synthesised by sol-gel method and  investigated as catalysts for photocatalytic degradation of persistent organic pollutants (perchloroethylene, PCE. The composites photoluminescence properties was shown by visual analysis and the synthesis product was characterized by XRD, FTIR, fluorescence spectrophotometer, and UV-Vis spectrophotometer. Degradation of PCE 0.1% (v/v in the aqueous phase was investigated under sunlight irradiation for 2 h. Photodegrade efficiency of PCE was determined by GC. Composites of TiO2/C-dot 2.5% (w/w was succesfully to degrade PCE under sunlight irradiation and its photodegrade efficiency was up to 89.45%.

  3. Extremely fast dark adsorption rate of carbon and nitrogen co-doped TiO2 prepared by a relatively fast, facile and low-cost microwave method

    Science.gov (United States)

    Du, Chun; Zhou, Jiangshan; Li, Fangzhou; Li, Wei; Wang, Yinzhen; He, Qinyu

    2016-07-01

    A facile and low-cost microwave method was used to prepare C and N co-doped TiO2 in just 8 min. The prepared samples were thoroughly characterized and were found to have favourable features such as surface adsorption of pollutants and photocatalysis. The rapid decomposition of CH5N3HCl under microwave irradiation led to mesopores and surface roughness in the as-prepared particles, resulting in large surface adsorption of pollutant and good photodegradation. The best sample is the one with the ratio of TiO2/CH2N3HCl at 3:1, which adsorbed 86.3 % of a methylene orange (MO) solution (20 mg L-1) in 10 min.

  4. Synthesis and characterization of silica nanotubes doped with carbon quantum dots%掺杂碳量子点的二氧化硅纳米管的合成与表征

    Institute of Scientific and Technical Information of China (English)

    孙靖; 刘晓; 王华; 韩金玉

    2016-01-01

    To obtain the carbon quantum dots doped silica nanotubes ,firstly organosilica nanotubes were formed through the hy‐drolysis and crystallization of the organosilane precursor using commercially available P123 as surfactant .Then the carbon doped silica nanotubes were fabricated after carbonization in N2 atmosphere .The nanotubes were investigated by the field emission transmission electronic microscope (TEM) ,nitrogen absorption/desorption isotherm (BET) ,thermogravimetry (TG) ,Raman spectrum and photoluminescense spectrum .The results show that carbon‐doped silica nanotubes with mesoporous tubular struc‐tures were successfully prepared .Finally ,HF was used to dissolve silica and the remaining carbon was characterized by high‐res‐olution TEM and photoluminescence spectrum (PL spectrum) .The clear crystalline fringes as well as favorable photolumines‐cense effect of the about 2‐4 nm carbon nanoparticles could be observed ,which is suitable for expressing the characteristics of the carbon quantum dots ,demonstrating that carbon quantum dots are doped in the nanotubes .%为了得到掺杂碳量子点的二氧化硅纳米管,首先将有机硅烷前驱体在软模板剂P123作用下通过水解、晶化过程合成形貌、结构清晰的有机氧化硅纳米管,再在高温下对其进行碳化,即可得到掺杂碳的二氧化硅纳米管。采用场发射透射电子显微镜(TEM)、氮气吸附脱附等温线(BET)、热重(TG)、拉曼光谱(Raman spectrum)和荧光光谱(photoluminescence spectrum)等表征手段对掺杂碳的二氧化硅纳米管的结构与特性进行表征、分析。结果表明,通过高温碳化,制备了具有介孔管状结构的掺杂碳的二氧化硅纳米管。最后用氢氟酸处理除去二氧化硅,发现剩余物为大小约2~4 nm的碳纳米颗粒,该颗粒具有清晰的晶格条纹和荧光发光性能,证明了合成的纳米管中的碳为碳量子点。

  5. Optimized dispersion of conductive agents for enhanced Li-storage performance of TiO2

    Science.gov (United States)

    Han, Moyan; Chen, Ge

    2016-12-01

    Novel TiO2/carbon (TiO2/C) composites have been synthesized by a layer-by-layer deposition method, with electrostatic interaction. The addition of carbon conductive agents enhances the electrochemical performance of TiO2. Carbon for these has been sourced 0D nitrogen-doped carbon, 1D carbon nanotubes and 2D graphene. The as-obtained TiO2/C composites show carbon nanotubes and titanium dioxide coaxial nanocables anchored on the graphene. The nitrogen-doped carbon is uniformly dispersed on the nanocables. As anode materials for Li-ion batteries, the TiO2/C composites exhibit excellent rate capability and cycling stability. A capacity of 150 mAh/g is retained at a current density of 4 A/g. The enhanced electrochemical performance may be attributed to the well-dispersed carbon conductive framework, which facilitates charge transfer during the lithium insertion/extraction process.

  6. Photocatalytic Oxidation of Diethyl Sulfide Vapor over TiO2-Based Composite Photocatalysts

    Directory of Open Access Journals (Sweden)

    Dmitry Selishchev

    2014-12-01

    Full Text Available Composite TiO2/activated carbon (TiO2/AC and TiO2/SiO2 photocatalysts with TiO2 contents in the 10 to 80 wt. % range were synthesized by the TiOSO4 thermal hydrolysis method and characterized by AES, BET, X-ray diffraction and FT-IR ATR methods. All TiO2 samples were in the anatase form, with a primary crystallite size of about 11 nm. The photocatalytic activities of the TiO2/AC and TiO2/SiO2 samples were tested in the gas-phase photocatalytic oxidation (PCO reaction of diethyl sulfide (DES vapor in a static reactor by the FT-IR in situ method. Acetaldehyde, formic acid, ethylene and SO2 were registered as the intermediate products which finally were completely oxidized to the final oxidation products – H2O, CO2, CO and SO42− ions. The influence of the support on the kinetics of DES PCO and on the TiO2/AC and TiO2/SiO2 samples’ stability during three long-term DES PCO cycles was investigated. The highest PCO rate was observed for TiO2/SiO2 photocatalysts. To evaluate the activity of photocatalysts the turnover frequency values (TOF were calculated for three photocatalysts (TiO2, TiO2/AC and TiO2/SiO2 for the same amount of mineralized DES. It was demonstrated that the TOF value for composite TiO2/SiO2 photocatalysts was 3.5 times higher than for pure TiO2.

  7. Photocatalytic oxidation of diethyl sulfide vapor over TiO2-based composite photocatalysts.

    Science.gov (United States)

    Selishchev, Dmitry; Kozlov, Denis

    2014-12-19

    Composite TiO2/activated carbon (TiO2/AC) and TiO2/SiO2 photocatalysts with TiO2 contents in the 10 to 80 wt. % range were synthesized by the TiOSO4 thermal hydrolysis method and characterized by AES, BET, X-ray diffraction and FT-IR ATR methods. All TiO2 samples were in the anatase form, with a primary crystallite size of about 11 nm. The photocatalytic activities of the TiO2/AC and TiO2/SiO2 samples were tested in the gas-phase photocatalytic oxidation (PCO) reaction of diethyl sulfide (DES) vapor in a static reactor by the FT-IR in situ method. Acetaldehyde, formic acid, ethylene and SO2 were registered as the intermediate products which finally were completely oxidized to the final oxidation products - H2O, CO2, CO and SO42- ions. The influence of the support on the kinetics of DES PCO and on the TiO2/AC and TiO2/SiO2 samples' stability during three long-term DES PCO cycles was investigated. The highest PCO rate was observed for TiO2/SiO2 photocatalysts. To evaluate the activity of photocatalysts the turnover frequency values (TOF) were calculated for three photocatalysts (TiO2, TiO2/AC and TiO2/SiO2) for the same amount of mineralized DES. It was demonstrated that the TOF value for composite TiO2/SiO2 photocatalysts was 3.5 times higher than for pure TiO2.

  8. Direct hydrothermal synthesis and magnetic property of titanate nanotubes doped magnetic metal ions

    Institute of Scientific and Technical Information of China (English)

    Meili Wang; Gongbao Song; Jian Li; Landong Miao; Baoshu Zhang

    2008-01-01

    Pure titanate nanotubes and titanate nanotubes doped with Fe3+/Ni2+/Mn2+ ions were synthesized by the hydrothermal method. In this process, titanate nanotubes were first prepared synchronously with doping Fe3+/Ni2+/Mn2+ ions. The morphology,structure, thermal stability and magnetic property of titanate nanotubes were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), and magnetic measurement. The titanate nanotubes transformed into the anatase titania nanocrystals,and further the mixture of anatase and rutile titania along with increasing temperature. The results indicate that the titanate nanotubes doped with Fe3+/Ni2+/Mn2+ ions are paramagnetic behaviors.

  9. Hybrid TiO2-C composites for the photodegradation of methylene blue under visible light

    Directory of Open Access Journals (Sweden)

    J. Matos

    2013-01-01

    Full Text Available Photodegradation of methylene blue (MB on TiO2 in presence of activated carbons (AC was studied. Two different lamps were employed and results were compared against those obtained on a commercial TiO2. Apparent first order rate constant for the degradation of MB was higher in presence of any AC in comparison of TiO2 alone but much higher under visible light irradiation. It can be concluded that TiO2 enhances its photoactivity by a factor up to 8.7 in the degradation of MB in presence of AC and this increase was associated with the surface properties of AC.

  10. Hybrid TiO2-C composites for the photodegradation of methylene blue under visible light

    OpenAIRE

    Matos, Juan

    2013-01-01

    [EN] Photodegradation of methylene blue (MB) on TiO2 in presence of activated carbons (AC) was studied. Two different lamps were employed and results were compared against those obtained on a commercial TiO2. Apparent first order rate constant for the degradation of MB was higher in presence of any AC in comparison of TiO2 alone but much higher under visible light irradiation. It can be concluded that TiO2 enhances its photoactivity by a factor up to 8.7 in the degr...

  11. TiO2 Nanotube-Carbon (TNT-C) as Support for Pt-based Catalyst for High Methanol Oxidation Reaction in Direct Methanol Fuel Cell.

    Science.gov (United States)

    Abdullah, M; Kamarudin, S K; Shyuan, L K

    2016-12-01

    In this study, TiO2 nanotubes (TNTs) were synthesized via a hydrothermal method using highly concentrated NaOH solutions varying from 6 to 12 M at 180 °C for 48 h. The effects of the NaOH concentration and the TNT crystal structure on the performance for methanol oxidation were investigated to determine the best catalyst support for Pt-based catalysts. The results showed that TNTs produced with 10 M NaOH exhibited a length and a diameter of 550 and 70 nm, respectively; these TNTs showed the best nanotube structure and were further used as catalyst supports for a Pt-based catalyst in a direct methanol fuel cell. The synthesized TNT and Pt-based catalysts were analysed by FESEM, TEM, BET, EDX, XRD and FTIR. The electrochemical performance of the catalysts was investigated using cyclic voltammetry (CV) and chronoamperometric (CA) analysis to further understand the methanol oxidation in the direct methanol fuel cell (DMFC). Finally, the result proves that Pt-Ru/TNT-C catalyst shows high performance in methanol oxidation as the highest current density achieved at 3.3 mA/cm(2) (normalised by electrochemically active surface area) and high catalyst tolerance towards poisoning species was established.

  12. TiO2 Nanotube-Carbon (TNT-C) as Support for Pt-based Catalyst for High Methanol Oxidation Reaction in Direct Methanol Fuel Cell

    Science.gov (United States)

    Abdullah, M.; Kamarudin, S. K.; Shyuan, L. K.

    2016-12-01

    In this study, TiO2 nanotubes (TNTs) were synthesized via a hydrothermal method using highly concentrated NaOH solutions varying from 6 to 12 M at 180 °C for 48 h. The effects of the NaOH concentration and the TNT crystal structure on the performance for methanol oxidation were investigated to determine the best catalyst support for Pt-based catalysts. The results showed that TNTs produced with 10 M NaOH exhibited a length and a diameter of 550 and 70 nm, respectively; these TNTs showed the best nanotube structure and were further used as catalyst supports for a Pt-based catalyst in a direct methanol fuel cell. The synthesized TNT and Pt-based catalysts were analysed by FESEM, TEM, BET, EDX, XRD and FTIR. The electrochemical performance of the catalysts was investigated using cyclic voltammetry (CV) and chronoamperometric (CA) analysis to further understand the methanol oxidation in the direct methanol fuel cell (DMFC). Finally, the result proves that Pt-Ru/TNT-C catalyst shows high performance in methanol oxidation as the highest current density achieved at 3.3 mA/cm2 (normalised by electrochemically active surface area) and high catalyst tolerance towards poisoning species was established.

  13. Hole-Conductor-Free, Metal-Electrode-Free TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode.

    Science.gov (United States)

    Zhou, Huawei; Shi, Yantao; Dong, Qingshun; Zhang, Hong; Xing, Yujin; Wang, Kai; Du, Yi; Ma, Tingli

    2014-09-18

    Low cost, high efficiency, and stability are straightforward research challenges in the development of organic-inorganic perovskite solar cells. Organolead halide is unstable at high temperatures or in some solvents. The direct preparation of a carbon layer on top becomes difficult. In this study, we successfully prepared full solution-processed low-cost TiO2/CH3NH3PbI3 heterojunction (HJ) solar cells based on a low-temperature carbon electrode. Power conversion efficiency of mesoporous (M-)TiO2/CH3NH3PbI3/C HJ solar cells based on a low-temperature-processed carbon electrode achieved 9%. The devices of M-TiO2/CH3NH3PbI3/C HJ solar cells without encapsulation exhibited advantageous stability (over 2000 h) in air in the dark. The ability to process low-cost carbon electrodes at low temperature on top of the CH3NH3PbI3 layer without destroying its structure reduces the cost and simplifies the fabrication process of perovskite HJ solar cells. This ability also provides higher flexibility to choose and optimize the device, as well as investigate the underlying active layers.

  14. Detection of Catechol by TiO2-graphene-modified Glassy Carbon Electrode%TiO2-石墨烯修饰玻碳电极测定邻苯二酚

    Institute of Scientific and Technical Information of China (English)

    熊小琴; 王兰; 张丽媛

    2011-01-01

    制备了Ti02 -石墨烯修饰玻碳电极,利用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了邻苯二酚在该修饰电极的电化学行为.结果表明:在pH值为6.0的磷酸盐缓冲液(PBS)中,该修饰电校对邻苯二酚具有良好的电催化作用.邻苯二酚氧化峰电流与其浓度(1.0×10-6~ 1.0×10-5 mol/L)呈现良好的线性关系,线性相关系数为0.993,检出限为1×10-7 mol/L.该电极显著提高了检测的灵敏度,并表现出良好的选择性和重现性.%novel TiO2-graphene-modified glassy carbon electrode (TiO2-Gr/GCE) was fabricated. The electrochemical behaviors of catechol at the modified electrode were studied by cyclic voltammetry ( CV) and differential pulse voltammetry ( DPV). In pH 6.0 phosphate buffer solution ( PBS) , the composite film showed excellent electrocatalytic activity for the redox of catechol. The results of DPV indicated that the oxidation peak currents was linear with catechol concentrations in the range of 1.0 × 10 -6 mol/L to 1. 0 × 10 -5 mol/L. The detection limit of catechol is 1.0 × 10 -7 mol/L (S/iV = 3). This modified CCE showed good sensitivity and selectivity and reproducibility.

  15. Enhanced conversion efficiency of dye-sensitized solar cells using a CNT-incorporated TiO2 slurry-based photoanode

    OpenAIRE

    Jiaoping Cai; Zexiang Chen; Jun Li; Yan Wang; Dong Xiang; Jijun Zhang; Hai Li

    2015-01-01

    A new titanium dioxide (TiO2) slurry formulation is herein reported for the fabrication of TiO2 photoanode for use in dye-sensitized solar cells (DSSCs). The prepared TiO2 photoanode featured a highly uniform mesoporous structure with well-dispersed TiO2 nanoparticles. The energy conversion efficiency of the resulting TiO2 slurry-based DSSC was ∼63% higher than that achieved by a DSSC prepared using a commercial TiO2 slurry. Subsequently, the incorporation of acid-treated multi-walled carbon ...

  16. Control of TiO2 grain size and positioning in three-dimensionally ordered macroporous TiO2/C composite anodes for lithium ion batteries.

    Science.gov (United States)

    Petkovich, Nicholas D; Rudisill, Stephen G; Wilson, Benjamin E; Mukherjee, Anwesha; Stein, Andreas

    2014-01-21

    After several high-profile incidents that raised concerns about the hazards posed by lithium ion batteries, research has accelerated in the development of safer electrodes and electrolytes. One anode material, titanium dioxide (TiO2), offers a distinct safety advantage in comparison to commercialized graphite anodes, since TiO2 has a higher potential for lithium intercalation. In this article, we present two routes for the facile, robust synthesis of nanostructured TiO2/carbon composites for use as lithium ion battery anodes. These materials are made using a combination of colloidal crystal templating and surfactant templating, leading to the first report of a three-dimensionally ordered macroporous TiO2/C composite with mesoporous walls. Control over the size and location of the TiO2 crystallites in the composite (an often difficult task) has been achieved by changing the chelating agent in the precursor. Adjustment of the pyrolysis temperature has also allowed us to strike a balance between the size of the TiO2 crystallites and the degree of carbonization. Using these pathways to optimize electrochemical performance, the primarily macroporous TiO2/C composites can attain a capacity of 171 mAh/g at a rate of 1 C. Additionally, the carbon in these composites can function as a secondary template for high-surface-area, macroporous TiO2 with disordered mesoporous voids. Combining the advantages of a nanocrystalline framework and significant open porosity, the macroporous TiO2 delivers a stable capacity (>170 mAh/g at a rate of C/2) over 100 cycles.

  17. TiO2@C Core-Shell Nanoparticles Formed by Polymeric Nano-Encapsulation

    Directory of Open Access Journals (Sweden)

    Mitra eVasei

    2014-07-01

    Full Text Available 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 pyrolisis, 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.

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

    Science.gov (United States)

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

    2014-01-01

    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.

  19. Effect of MWCNT Inclusion in TiO2 Nanowire Array Film on the Photoelectrochemical Performance

    Institute of Scientific and Technical Information of China (English)

    Menglei Chang; Liangpeng Wu; Xinjun Li; Wei Xu

    2012-01-01

    Rutile TiO2 nanowire array films with multi-walled carbon nanotube (MWCNT) inclusion perpendicularly grown on fluorine-doped tin oxide (FTO) substrate were prepared by a facile hydrothermal method. The absorption edges of the TiO2 nanowire array films are blue-shifted with increasing MWCNT content. The resistance of the TiO2 nanowire array film is decreased by MWCNT inclusion. The optimum TiO2/MWCNT molar ratio in the feedstock is 1:0.1. For the TiO2 nanowire array film with MWCNT inclusion served as electrode in dye-sensitized solar cell (DSSC), an overall 194% increase of photoelectric conversion efficiency has been achieved.

  20. Hierarchically structured suspended TiO2 nanofibers for use in UV and pH sensor devices.

    Science.gov (United States)

    Lee, Won Seok; Park, Yang-Seok; Cho, Yoon-Kyoung

    2014-08-13

    Photoelectrochemical sensors based on hierarchically structured titanium dioxide (TiO2) nanofibers (NFs) were fabricated by combination of electrospinning, carbon microelectromechanical systems (MEMS), and hydrothermal reaction. During the electrospinning step, a rotating drum collector was used to align and position NFs of titanium tetraisopropoxide (TTIP) in polyvinylpyrrolidone (PVP) on top of a carbon-MEMS structure. Following calcination under vacuum, a stable ohmic contact was obtained between suspended TiO2-carbon NFs (TiO2/C NF) and the carbon electrodes. Subsequent to this, a hierarchical nanostructure of TiO2 nanowires (TiO2 NWs) was hydrothermally synthesized onto the TiO2/C NFs and successfully utilized as UV and pH sensors. This is the first demonstration of a semiconductor-based nanofiber sensor suspended on carbon electrodes that has been achieved by a relatively simple and cost-effective electrospinning method. Furthermore, these sensors demonstrate a high sensitivity, as well as a stable ohmic contact, due to the large surface area of the TiO2 NWs and the carbon-carbon contact between the suspended TiO2/C NFs and carbon electrodes.

  1. A versatile new method for synthesis and deposition of doped, visible light-activated TiO2 thin films

    DEFF Research Database (Denmark)

    In, Su-il; Kean, A.H.; Orlov, A.

    2009-01-01

    A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates.......A flexible and widely applicable method allows the deposition of carbon-doped visible light-activated photocatalytic TiO2 thin films on a variety of substrates....

  2. Enhanced photocatalytic activity towards degradation and H2 evolution over one dimensional TiO2@MWCNTs heterojunction

    Science.gov (United States)

    Zhang, Xiao; Cao, Shuang; Wu, Zhijiao; Zhao, Suling; Piao, Lingyu

    2017-04-01

    With the distinct electronic and optical properties, multiwall carbon nanotubes (MWCNTs) are identified as an outstanding catalyst support, which can effectively improve the performance of the TiO2 photocatalysts. Herein, the unique one dimensional TiO2@MWCNTs nanocomposites have been prepared by a facile hydrothermal method. The TiO2 coating layers are extremely uniform and the thickness is adjustable for different nanocomposites. XPS measurements confirm that intimate electronic interactions are existed between MWCNTs and TiO2 via interfacial Tisbnd Osbnd C bond and the photoluminescence intensity of the TiO2@MWCNTs nanocomposites are effectively quenched compared with pure TiO2, suggesting the fast electron transfer rates. The thickness of TiO2 coating layers of the TiO2@MWCNTs nanocomposites plays a significant role in the photocatalytic degradation of organic pollutants, such as methylene blue (MB) and Rhodamine B (RhB), and photocatalytic H2 evolution from water. Due to the formation of one dimensional heterojunction of TiO2@MWCNTs nanocomposites and the positive synergistic effect between TiO2 and carbon nanotubes, it is found that the photocatalytic activity of the system is significantly improved.

  3. Photoluminescence properties of TiO2 nanofibers

    Science.gov (United States)

    Chetibi, Loubna; Busko, Tetiana; Kulish, Nikolay Polikarpovich; Hamana, Djamel; Chaieb, Sahraoui; Achour, Slimane

    2017-04-01

    Multi-walled carbon nanotube (MWCNT)-TiO2 nanofiber (NF) composites forming a layered nanostructure (MWCNTs/TiO2 NFs/Ti) were prepared by impregnation at low temperature. Room temperature photoluminescence (PL) of these nanostructures shows a broad intense band in the visible light range (˜450-600 nm). The origin of the PL emission which, mainly, resulted from surface oxygen vacancies and other defects was investigated. We studied the effect of MWCNT deposition on the PL of TiO2 NFs where the MWCNTs can act as an electron reservoir of electrons emitted from TiO2 nanofibers when irradiated with UV light. The combination of MWCNTs and TiO2 results in quenching of TiO2 luminescence in the visible range. In addition, the prepared surface of MWCNTs-TiO2 was irradiated with Ti+ ions using irradiation energy of 140 keV and doses of 1013 ions/cm2. Also, this treatment induced the PL intensity quenching due to the generation of non-radiative additional levels inside the band gap.

  4. Combination of TiO2-Film Photocatalysis and Ultrafiltration to Treat Wastewater

    Directory of Open Access Journals (Sweden)

    Shu-Hai You

    2013-01-01

    Full Text Available In this study, a combination of TiO2-film photocatalysis reactor and ultrafiltration was used treat the secondary effluent from the manufacturing of thin film transistor-liquid crystal display (TFT-LCD. TiO2 particles, as a photocatalyst, were immobilized on silica glass to form TiO2-film by the sol-gel and dip coating methods. TiO2-film photocatalysis was done within three parameters, including number of coating times of TiO2-film, wavelengths of UV light source, and operating time. During ultrafiltration, the operating pressure and feed water temperature were controlled at 300 KN/m2 and 25°C, respectively. It was found that TiO2-film photocatalysis followed by ultrafiltration increased the removal of total organic carbon (TOC to 47.13% and 49.94% for 5 KDa and 10 KDa membranes, respectively. It was also found that the process increased the permeate flux rate (ca 23% for 10 KDa membrane after 6 hours of operation, since some larger organic matter had been broken into small organic matter and some small organic matter had been mineralized into CO2 following TiO2-film photocatalysis. Therefore, combining TiO2-film photocatalysis reactor and ultrafiltration can improve organic wastewater quality and increase the permeate flux of ultrafiltration membrane, which may enhance the recycling and reuse of wastewater.

  5. Mo + C codoped TiO(2) using thermal oxidation for enhancing photocatalytic activity.

    Science.gov (United States)

    Zhang, Jun; Pan, Chunxu; Fang, Pengfei; Wei, Jianhong; Xiong, Rui

    2010-04-01

    The photocatalytic activity of TiO(2) is enhanced mainly through heightening absorption of UV-vis light and improving the separation efficiency of photoinduced electrons and holes. The recent new theoretical research revealed that the TiO(2) codoped with Mo + C is considered to be an optimal doping system. On the basis of this theory, the Mo + C codoped TiO(2) powders were first experimentally synthesized by thermal oxidizing a mixture of TiC and MoO(3) powders in the air. The XRD patterns and the XPS survey spectrum showed that carbon (C) acted as a Ti-O-C band structure and molybdenum (Mo) existed as Mo(6+) in anatase TiO(2). The Mo+C codoped TiO(2) had a 32 nm red shift of the spectrum onset compared with pure anatase TiO(2), and its band gap was reduced from 3.20 to 2.97 eV. The photocurrent of the Mo + C codoped TiO(2) was about 4 times as high as that of pure anatase TiO(2), and its photocatalytic activity on decomposition of methylene blue was enhanced.

  6. A Bi-layer Composite Film Based on TiO2 Hollow Spheres, P25, and Multi-walled Carbon Nanotubes for Efficient Photoanode of Dye-sensitized Solar Cell

    Institute of Scientific and Technical Information of China (English)

    Putao Zhang; Zhiqiang Hu; Yan Wang; Yiying Qin; Wenqin Li; Jinmin Wang

    2016-01-01

    A bi-layer photoanode for dye-sensitized solar cell (DSSC) was fabricated, in which TiO2 hollow spheres (THSs) were designed as a scattering layer and P25/multi-walled carbon nanotubes (MWNTs) as an under-layer. The THSs were synthesized by a sacrifice template method and showed good light scattering ability as an over-layer of the pho-toanode. MWNTs were mixed with P25 to form an under-layer of the photoanode to improve the electron transmission ability of the photoanode. The power conversion efficiency of this kind of DSSC with bi-layer was enhanced to 5.13%, which is 14.25%higher than that of pure P25 DSSC. Graphical Abstract A bi-layer composite photoanode based on P25/MWNTs-THSs with improved light scattering and electron transmission, which will provide a new insight into fabrication and structure design of highly efficient dye-sensitized solar cells.

  7. Microwave-Assisted Synthesis of Carbon-Based (N, Fe)-Codoped TiO2 for the Photocatalytic Degradation of Formaldehyde

    OpenAIRE

    Tian, Fei; Wu, Zhansheng; Tong, Yanbin; Wu, Zhilin; Cravotto, Giancarlo

    2015-01-01

    A microwave-assisted sol–gel method was used to synthesize (N, Fe)-codoped activated carbon (AC)/TiO2 photocatalyst for enhanced optical absorption in the visible light region. The prepared samples were characterized via X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller analysis, ultraviolet–visible light spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy. The resul...

  8. Novel TiO2/C nanocomposites: synthesis, characterization, and application as a photocatalyst for the degradation of organic pollutants.

    Science.gov (United States)

    da Costa, Elias; Zamora, Patricio P; Zarbin, Aldo J G

    2012-02-15

    Novel TiO(2)/carbon nanocomposites were prepared through the pyrolysis of TiO(2)/poly(furfuryl alcohol) hybrid materials, which were obtained by the sol-gel method, starting from titanium tetraisopropoxide (TTIP) and furfuryl alcohol (FA) precursors. Six different TiO(2)/C samples were prepared based on different TiO(2) nanoparticle sizes and TiO(2)/FA ratios. All of the samples were characterized using X-ray diffraction, infrared, and Raman spectroscopy. The results indicated effective FA polymerization onto the TiO(2) (anatase) nanoparticles, polymer conversion to disordered carbon following the pyrolysis, and a simultaneous TiO(2) anatase-rutile phase transition. The resulting TiO(2)/carbon composites were used as photocatalysts in the advanced oxidative process (AOP) for the degradation of reactive organic dyes in aqueous solution. The results indicate excellent photocatalytic performance (degradation of 99% of the dye after 60 min) with several advantages over traditional TiO(2)-based photocatalysts. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Microbial inactivation kinetics and mechanisms of carbon-doped TiO2 (C-TiO2) under visible light.

    Science.gov (United States)

    Shim, Jaehong; Seo, Young-Seok; Oh, Byung-Taek; Cho, Min

    2016-04-05

    In this study, titanium dioxide nanoparticles doped with carbon (C-TiO2) were synthesized by means of sol-gel methods, and the synthesis was verified by means of X-ray photoelectron spectroscopy. The nanoparticles' photocatalytic disinfection activity of Listeria monocytogenes was tested under UV and visible light. The observed inactivation levels for 150min of visible light exposure with and without UV cutoff filters were 2.10 and 2.45 log, respectively. We also found that traditional reactive oxygen species had insignificant actions on C-TiO2 photocatalysts and that L. monocytogenes inactivation in the C-TiO2 system under visible light was induced in large part by the midgap states (hmid(+)) that was produced photochemically from the visible light response. C-TiO2 was found to accelerate bacterial inactivation (of L. monocytogenes) in the presence of visible light. Our data suggests that the C-TiO2 may be useful in the development of alternative disinfectants for environmental applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Comparison of Adsorption Capability of Activated Carbon and Metal Doped TiO2 for Geosmin and 2-MIB Removal from Water

    Directory of Open Access Journals (Sweden)

    Aisha Asghar

    2015-01-01

    Full Text Available This study stemmed from consumer complaints about earthy and musty off-flavours in treated water of Rawal Lake Filtration Plant. In recent years, several novel adsorbents have been developed from nanomaterials for enhancing the contaminant removal efficiency. This paper presents preparation and the use of new adsorbents Pt doped titania and Fe doped titania, for the adsorption capacity of Geosmin and 2-MIB from water under laboratory conditions and their comparison, with most widely used activated carbon, under batch and column experiments. Stock solutions were prepared by using Geosmin and 2-MIB standards, procured by Sigma Aldrich (England. Samples were analysed using SPME-GC-FID. The adsorption of Geosmin and 2-MIB on GAC conformed to the Freundlich isotherm, while that of adsorption on metal doped titania fit equally well to both Langmuir and Freundlich isotherms. Moreover, data, generated for the kinetic isotherm, confirmed that Geosmin and 2-MIB removal is a function of contact time. Breakthrough column tests using 125 mg/L Pt doped titania nanoparticles, coated on glass beads against 700 ng/L of off-flavours, attained later breakthrough and exhaustion points and removed 98% of Geosmin and 97% of 2-MIB at room temperature. All columns could be regenerated using 50 mL 0.1 molar sodium hydroxide.

  11. TiO2 thin film photocatalyst

    Institute of Scientific and Technical Information of China (English)

    YU Jiaguo

    2004-01-01

    It is well known that the photocatalytic activity of TiO2 thin films strongly depends on the preparing methods and post-treatment conditions, since they have a decisive influence on the chemical and physical properties of TiO2 thin films.Therefore, it is necessary to elucidate the influence of the preparation process and post-treatment conditions on the photocatalytic activity and surface microstructures of the films. This review deals with the preparation of TiO2 thin film photocatalysts by wet-chemical methods (such as sol-gel, reverse micellar and liquid phase deposition) and the comparison of various preparation methods as well as their advantage and disadvantage. Furthermore, it is discussed that the advancement of photocatalytic activity, super-hydrophilicity and bactericidal activity of TiO2 thin film photocatalyst in recent years.

  12. TiO2纳米管电极金属离子掺杂的表征%Characterization of Metal Ion Doped TiO2 Nanotubes Electrode

    Institute of Scientific and Technical Information of China (English)

    阮修莉; 邵冬海

    2011-01-01

    The Zn2+ , Fe3+ and Cu2+ are doped on TiO2 nanotubes electrode using dipping method in this study. The properties of doped TiO2 nanotubes electrode are characterized using some advanced analytic methods. It is found from the images of scanning electron microscope (SEM) and patterns of X-ray diffraction (XRD) that the doped TiO2 nanotubes electrode, whose nanotubes diameter are range from 60 to 100 nm, still remain the original morphology and anatase crystal structure with 101 crystal face. However, the results of UV-Vis diffusion reflectance spectroscopy (DRS) indicate that the initial absorption edges for the three doped TiO2 nanotubes electrodes shift at different degree. Energy band gaps of Zn2+, Fe3+ and Cu2+ doped TiO2 nanotubes are 3. 37 eV, 3. 14 eV and 2.86 eV, respectively. This indicates that the absorption edge of the TiO2 nanotubes doped with Cu2+ is red-shift.%采用浸渍法对TiO2纳米管电极进行Zn2+、Fe3+、Cu2+离子的掺杂改性,并进行了各种性能表征.扫描电镜(SEM)及X射线衍射光谱(XRD)结果表明,金属离子掺杂后的TiO2纳米管电极依然保持了良好的表面形态及锐钛矿晶型,纳米管的直径为60-100 nm,其晶面主要为101面;可见紫外漫反射光谱(DRS)分析表明,进行掺杂的TiO2纳米管电极的光学性质有不同程度的改变,Zn2+、Fe3+和Cu2+掺杂的TiO2纳米管电极的禁带宽度分别为3.37 eV、3.14 eV、2.86 eV.这表明掺Cu2+的TiO2纳米管电极的吸收边带发生了明显的红移.

  13. 具有高可见光催化活性的Ti3+和碳共掺杂改性的TiO2光催化剂%Ti3+and carbon co-doped TiO2 with improved visible light photocatalytic activity

    Institute of Scientific and Technical Information of China (English)

    刘允昌; 邢明阳; 张金龙

    2014-01-01

    以乙醇为碳源,采用操作简单的真空活化法一步实现对TiO2的Ti3+与C的共掺杂改性, TiO2用X衍线衍射、紫外-可见光谱、顺磁共振、X射线光电子能谱和红外光谱等手段表征了催化剂的结构、组成、光学性质。结果表明,经Ti3+与C共掺杂改性后的催化剂表现出高的可见光降解甲基橙活性。复合在催化剂表面的石墨可以增强催化剂对可见光的响应范围,而Ti3+与氧缺陷形成的掺杂能级则可以提高光生电子的迁移效率。实验表明,两者之间的协同作用促进了其可见光催化活性的提高。%Using ethanol as the carbon source, a series of Ti3+and carbon co-doped TiO2 samples were suc-cessfully synthesized by an innovative and simple vacuum activation method in a one-step process. The Ti3+self-doped TiO2 featured a high visible light photocatalytic activity that improved consid-erably following subsequent carbon doping modification of the catalyst surface. The samples were characterized by X-ray diffraction, UV-Vis diffuse reflectance spectroscopy, electron spin resonance, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The Ti3+ and C co-doped TiO2 catalyst showed a high methyl orange photo-degradation efficiency under visible light irradiation. The doping levels induced by Ti3+and oxygen vacancies were responsible for the improved visible light response of TiO2. Simultaneously, the surface coverage of graphite on the catalyst could improve the absorption of visible light and migration efficiency of photo-induced electrons. The synergistic effects of Ti3+self-doping and graphite coverage led to the improved visi-ble light photocatalytic activity of Ti3+and C co-doped TiO2.

  14. Determination of reaction rate constants for phenol oxidation using SnO2/Ti anodes coupled with activated carbon adsorption in the presence of TiO2 as catalyst.

    Science.gov (United States)

    Zhao, Yuemin; Ding, Yi; Wang, Lizhang; Wang, Xiao

    2011-01-01

    Series of experiments for phenol degradation with assistance of TiO2 catalyst at pH of 6.5 and temperature of 25 degrees C were conducted using a lab-scale electrochemical reactor constructed in our laboratory. According to the results, at the presence of the TiO2 catalyst the removal of phenol was increased and first-order kinetics could describe the evolution of phenol concentration. For inspecting the relationship between rate constants and dosage of TiO2, two possible kinetics were proposed in this study. Contrasted to the abundant experimental data, a reasonable kinetics was obtained for the estimation of phenol concentration effluent during continuous flow of raw wastewater, especially when the TiO2 dosage was less than 0.5g L(-1). The model obtained from these experiments could employed for the calculation of rate constants at different TiO2 dosage and the necessary dosage of catalyst when a discharge standard was designed.

  15. Improved photoanode structure based on anodic titania nanotube array covered by TiO2-NPs/nanographite composite layer for ETA-cells

    Science.gov (United States)

    Gavrilin, I. M.; Dronov, A. A.; Shilyaeva, Yu I.; Lebedev, E. A.; Kuzmicheva, M. S.; Savchuk, T. P.; Gavrilov, S. A.

    2016-08-01

    This work is devoted to the morphology and electrical properties optimization of flexible photoanodes based on anodic titanium oxide nanotubular arrays (TiO2-NTAs) for solar cells with extremely thin absorbing layer (ETA-cells) by TiO2-nanographite thin composite layer formation on the TiO2-NTAs surface. First, the carbon doped TiO2-NTAs were synthesized by annealing of the as-anodized TiO2-NTAs in argon without foreign carbonaceous precursor. The residual ethylene glycol absorbed on the nanotube wall during anodization serves as the carbon source and the C species are uniformly distributed along the entire nanotube to form the C-TiO2 NTAs. Further decorating of C-TiO2-NTAs surface by TiO2 nanoparticles to form the TiO2-nanographite (NG) composite layer with high conductivity and increased photoanode effective area showed improved ETA-cells performance.

  16. Synthesis, characterization and electrochemical study of Mn-doped TiO2 decorated polypyrrole nanotubes

    Science.gov (United States)

    Saidur, M. R.; Aziz, A. R. Abdul; Basirun, W. J.

    2017-06-01

    Nanostructured conductive polymers are the growing interest in the field of electrochemistry due to their superior conductivity and environmental friendliness. The existence of transition metal oxides could improve their nanostructure as well as conductive properties. In this study, polypyrrole nanotubes are synthesized in the presence of TiO2 and manganese (Mn)-doped TiO2 nanoparticles (NPs) to investigate their electrochemical properties. Details characterization of the synthesized composites were done by X-Ray diffraction (XRD) and TEM. The TEM analysis shows that doping of TiO2 with Mn decrease the grain size of the TiO2 nanoparticles and successively its effects on the synthesis of the PPy nanotubes (PPyNTs). TEM confirmed that PPyNTs synthesized in the presence of Mn-doped TiO2 are thinner in size compare to the PPyNTs synthesized in presence of pure TiO2. The electrochemical effectiveness of the synthesized PPy nanocomposite was investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV and EIS both on a modified glassy carbon electrode reveal the better electron transportability for the Mn-doped TiO2 PPyNTs due to the synergistic effect of doping and decreased the size of PPyNTs as well as increased surface area.

  17. Preparation and photocatalytic activity of Gd-doped TiO2 nanofibre

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yi; ZHANG Shi-ying; ZHU Zhi-ping; LI Yong-kun

    2005-01-01

    In order to realize the photocatalysis of TiO2 in the sunlight and directly apply it to waste water treatment, the Gd-doped TiO2 nanofibre was synthesized using two-step synthesis method as follows: Firstly, potassium carbonate, titanium dioxide and proper gadolinium oxide (dopant) were calcined in the muffle at high temperature and the doped gadolinium K2Ti4O9 fibres were obtained; secondly, the fibre was heated using glycerol as solvent until Gd-doped TiO2 nanofibres were obtained. The synthesized samples were characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that Gd-doped TiO2 nanofibre heat-treated by glycerol solvent can inhibit the agglomeration, so the grain diameter of the fibre is smaller than that without heat-treated with glycerol. Meanwhile, the diameter of the fibre decreases with the increase of the heating temperature and time. 97%- 98% of Gd-doped TiO2 nanofibre is anatase. The photocatalysis results showed that the photocatalysis activity of Gd-doped TiO2 nanofibre is just a little lower than that of TiO2 powder.

  18. Two-dimensional TiO2-based nanosheets co-modified by surface-enriched carbon dots and Gd2O3 nanoparticles for efficient visible-light-driven photocatalysis

    Science.gov (United States)

    Lu, Dingze; Fang, Pengfei; Ding, Junqian; Yang, Minchen; Cao, Yufei; Zhou, Yawei; Peng, Kui; Kondamareddy, Kiran Kumar; Liu, Min

    2017-02-01

    Two-dimensional TiO2-based nanosheets (TNSs) co-modified by surface-enriched carbon dots (CDs) and Gd2O3 nanoparticles: (Gd-C-TNSs), capable of exhibiting visible-light-driven photo catalysis were synthesized using a two-pot hydrothermal route. The samples had a sheet-like structure, thickness of approximately 3.6 nm, large specific surface area of 240-350 cm2/g. The CDs (2-3 nm) and Gd2O3 nanoparticles (1-2 nm) were highly dispersed over the surface of the nanosheets. The co-modification by Gd2O3 nanoparticles and CDs influenced the crystallinity, crystal structure, and surface area of the TNSs, and improved the visible-light absorption. Surface photocurrent and fluorescence spectral studies revealed that the photo-generated charge carrier separation efficiency could be improved by an appropriate amount of modification. A very high efficiency was obtained using 0.5 at% Gd/Ti and 3.0 g/L of CDs. The visible-light-induced photocatalytic activity is enhanced under the isolated Cr(VI) system, isolated Rhodamin B (RhB) system, and the synergism between RhB degradation and Cr(VI) reduction for the Gd-C-TNSs photocatalysts. Initially, the photocatalytic activity gradually increased with an increase in the amount of CDs, and then decreased after attaining a maximum, in the case where 0.5 at% Gd/Ti and 3.0 g/L of CDs were used. The enhancement in the photocatalytic activity was attributed to the synergetic effect of the Gd2O3 nanoparticles, TNSs, and CDs in the Gd-C-TNSs composites. The effect led to a fast separation and slow recombination of photo-induced electron-hole pairs. An alternate mechanism for enhanced visible-light photocatalytic activity was also considered.

  19. Effect of sunlight irradiation on photocatalytic pyrene degradation in contaminated soils by micro-nano size TiO2.

    Science.gov (United States)

    Chang Chien, S W; Chang, C H; Chen, S H; Wang, M C; Madhava Rao, M; Satya Veni, S

    2011-09-01

    The enhanced catalytic pyrene degradation in quartz sand and alluvial and red soils by micro-nano size TiO(2) in the presence and absence of sunlight was investigated. The results showed that the synergistic effect of sunlight irradiation and TiO(2) was more efficient on pyrene degradation in quartz sand and red and alluvial soils than the corresponding reaction system without sunlight irradiation. In the presence of sunlight irradiation, the photooxidation (without TiO(2)) of pyrene was very pronounced in alluvial and red soils and especially in quartz sand. However, in the absence of sunlight irradiation, the catalytic pyrene degradation by TiO(2) and the photooxidation (without TiO(2)) of pyrene were almost nil. This implicates that ultra-violet (UV) wavelength range of sunlight plays an important role in TiO(2)-enhanced photocatalytic pyrene degradation and in photooxidation (without TiO(2)) of pyrene. The percentages of photocatalytic pyrene degradation by TiO(2) in quartz sand, alluvial and red soils under sunlight irradiation were 78.3, 23.4, and 31.8%, respectively, at 5h reaction period with a 5% (w/w) dose of the amended catalyst. The sequence of TiO(2)-enhanced catalytic pyrene degradation in quartz sand and alluvial and red soils was quartz sand>red soil>alluvial soil, due to different texture and total organic carbon (TOC) contents of the quartz sand and other two soils. The differential Fourier transform infrared (FT-IR) spectra of degraded pyrene in alluvial soil corroborate that TiO(2)-enhanced photocatalytic degradation rate of degraded pyrene was much greater than photooxidation (without TiO(2)) rate of degraded pyrene. Based on the data obtained, the importance for the application of TiO(2)-enhanced photocatalytic pyrene degradation and associated organic contaminants in contaminated soils was elucidated.

  20. Formation of hydroxyl radicals and kinetic study of 2-chlorophenol photocatalytic oxidation using C-doped TiO2, N-doped TiO2, and C,N Co-doped TiO2 under visible light.

    Science.gov (United States)

    Ananpattarachai, Jirapat; Seraphin, Supapan; Kajitvichyanukul, Puangrat

    2016-02-01

    This work reports on synthesis, characterization, adsorption ability, formation rate of hydroxyl radicals (OH(•)), photocatalytic oxidation kinetics, and mineralization ability of C-doped titanium dioxide (TiO2), N-doped TiO2, and C,N co-doped TiO2 prepared by the sol-gel method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-visible spectroscopy were used to analyze the titania. The rate of formation of OH(•) for each type of titania was determined, and the OH-index was calculated. The kinetics of as-synthesized TiO2 catalysts in photocatalytic oxidation of 2-chlorophenol (2-CP) under visible light irradiation were evaluated. Results revealed that nitrogen was incorporated into the lattice of titania with the structure of O-Ti-N linkages in N-doped TiO2 and C,N co-doped TiO2. Carbon was joined to the Ti-O-C bond in the C-doped TiO2 and C,N co-doped TiO2. The 2-CP adsorption ability of C,N co-doped TiO2 and C-doped TiO2 originated from a layer composed of a complex carbonaceous mixture at the surface of TiO2. C,N co-doped TiO2 had highest formation rate of OH(•) and photocatalytic activity due to a synergistic effect of carbon and nitrogen co-doping. The order of photocatalytic activity per unit surface area was the same as that of the formation rate of OH(•) unit surface area in the following order: C,N co-doped TiO2 > C-doped TiO2 > N-doped TiO2 > undoped TiO2.

  1. Photoelectrochemical activity of liquid phase deposited TiO2 film for degradation of benzotriazole.

    Science.gov (United States)

    Ding, Yaobin; Yang, Changzhu; Zhu, Lihua; Zhang, Jingdong

    2010-03-15

    TiO(2) film deposited on glassy carbon electrode surface was prepared via the liquid phase deposition (LPD). The deposited TiO(2) film before and after calcination was characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Based on the high photoelectrochemical activity of calcined LPD TiO(2) film, the photoelectrocatalytic degradation of benzotriazole (BTA) was investigated. Compared with the electrochemical oxidation process, direct photolysis or photocatalysis for treatment of BTA, a synergetic photoelectrocatalytic degradation effect was observed using the LPD TiO(2) film-coated electrode. Various factors influencing the photoelectrocatalytic degradation of BTA such as film calcination, applied bias potential, pH value, supporting electrolyte concentration and initial concentration of BTA were investigated. The COD removal for BTA solution was analyzed to evaluate the mineralization of the PEC process. Based on the degradation experimental results, a possible photoelectrocatalytic degradation mechanism for BTA was proposed.

  2. Preparation of Activated Carbon Supported TiO2 and Its Application in Catalytic Ozonation Treatment of Papermaking Wastewater%活性炭负载TiO2的制备及催化臭氧处理造纸废水的应用

    Institute of Scientific and Technical Information of China (English)

    张贤贤; 雷利荣; 李友明; 马黎明

    2011-01-01

    以钛酸丁酯为钛源,用溶胶-凝胶法在活性炭(AC)表面负载HiO2,经焙烧后制得TiO2/AC催化剂,采用X射线衍射(XRD)和扫描电镜(SEM)对TiO2/AC催化剂表面形貌和晶型进行表征,并研究了该催化剂催化臭氧处理造纸废水时对废水CODcr和色度的去除效果。结果表明,TiO2均匀地涂覆于活性炭的表面,经500℃焙烧后的TiO2为钛锐矿晶型,TiO2负载量为3.38%的TiO2/AC催化臭氧处理造纸废水效果最好,当反应12 min时,废水的色度和CODcr去除率达到96.9%和54.4%,分别比单独臭氧化过程提高了12.3和21.7个百分点,比活性炭臭氧化过程提高了5.3和14.2个百分点,TiO2/AC催化臭氧处理造纸废水极大地提高了对废水CODCr的去除率。%Activated carbon(AC) supported TiO2 catalysts (TiO2/AC)were prepared by sol-gel method from Ti(Obu)4.The crystalline and morphology of TiO2/AC were characterized by XRD and SEM respectively.The removal rates of CODCr and color of the wastewater during catalytic ozonation with the presence of TiO2/AC were studied.The results indicated that anatase phase was detected after the TiO2/AC was heated at 500℃ for 3h,and TiO2 particles distributed uniformly on the surface of activated carbon.The best degradation rate during the treatment of papermaking wastewater by TiO2/AC catalytic ozonation process was 3.38% titania loading ,color and CODCr removal rates were up to 96.9% and 54.4% respectively when reaction time was 12 min.Which were increased by 12.3 units and 21.7 units compared with that of single ozonation process,and inceased by 5.3 units and 14.2 units compared with the activated carbon catalytic ozonation.The CODCr removal rate of papermaking wastewater was greatly increased by TiO2/AC catalytic ozonation.

  3. Preparation and enhanced photocatalytic activity of carbon nitride/titania(001 vs 101 facets)/reduced graphene oxide (g-C3N4/TiO2/rGO) hybrids under visible light

    Science.gov (United States)

    Huang, Meina; Yu, Jianhua; Hu, Qun; Su, Wenli; Fan, Minguang; Li, Bin; Dong, Lihui

    2016-12-01

    Herein, a novel photocatalyst, anatase TiO2 nanoparticles with both exposed (101) and (001) facets synchronously incorporated with g-C3N4 and graphene, was successfully prepared via a simple one-step solvothermal route. The morphology and structure of as-prepared composites were confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). Efficiency of the prepared samples was investigated by monitoring the degradation of Methyl Orange (MO), Rhodamine B (RhB) and phenol under visible light irradiation. Improved photocatalytic activity in g-C3N4/TiO2/rGO is observed owing to higher specific surface area and enhanced visible light absorption capability. Most importantly, the in situ g-C3N4 and rGO doping might enhance the interaction among g-C3N4, TiO2 (001 vs 101) and rGO, which generates more synergistic heteroconjunctions in g-C3N4/TiO2/rGO facilitating a fast electron transfer at the interface among them. This synergistic approach could prove useful for the design and development of other visible light active photocatalysts with high chemical stability.

  4. 活性碳纤维负载TiO2去除低浓度甲醛气体的实验研究%Study on the Degradation of Low Concentration Formaldehyde Gas by TiO2 Supported on Activated Carbon Fiber

    Institute of Scientific and Technical Information of China (English)

    胡军; 陈建华; 贾铭椿

    2011-01-01

    A photocatalytic gas reactor system was manufactured to model the special airtight environment, and in this system TiO2 supported on activated carbon fiber was tested to wipe off the gas of formaldehyde. TiO2 nano-material was prepared by sol-gel method. Different proportion of mater to compose TiO2 which effected the degradation rate of formaldehyde and the reaction kinetics of TiO2 supported on activated carbon fiber as a whole were discussed. The results showed that: the proportion of acetic acid , ethanol and water effected the degradation rate mutually as well as the temperature, the formaldehyde gas could reach a degradation rate of 78. 89% in 120 minutes. The reaction kinetics model of C=mo + (C0- mo)exp(- Kt) fits the removing of the formaldehyde gas by TiO2 supported on activated carbon fiber as a whole. The removal amount of the material was 4357. 78mg/(hX m2) ,and the performance stability of the material was 78. 3%.%利用自制的光催化气体反应系统,模拟有限密闭空间特殊环境,以甲醛气体为代表,用溶胶凝胶法制得不同配比的TiO2并负载在活性碳纤维上,将其放人马弗炉中在不同温度下煅烧,最后测试其对甲醛的去除效率,且研究了活性炭纤维负载TiO2作为整体材料对甲醛的去除动力学方程.结果表明,冰醋酸、无水乙醇、去离子水和煅烧温度对去除效果的影响是交互的,理想配比下两小时去除率可达78.89%;活性炭纤维负载TiO2作为整体材料对低浓度甲醛的去除满足动力学方程ρA =m0 +(ρ0A-m0)exp(-Kt);自制材料对甲醛的去除量为4 357.78 mg/(h×m2),稳定性为78.3%.

  5. Porous TiO2 Assembled from Monodispersed Nanoparticles.

    Science.gov (United States)

    Liu, Xu; Duan, Weijie; Chen, Yan; Jiao, Shihui; Zhao, Yue; Kang, Yutang; Li, Lu; Fang, Zhenxing; Xu, Wei; Pang, Guangsheng

    2016-12-01

    Porous TiO2 were assembled by evaporating or refluxing TiO2 colloid, which was obtained by dispersing the TiO2 nanoparticles with a crystallite size (d XRD) of 3.2 nm into water or ethanol without any additives. Porous transparent bulk TiO2 was obtained by evaporating the TiO2-C2H5OH colloid at room temperature for 2 weeks, while porous TiO2 nanospheres were assembled by refluxing the TiO2-H2O colloid at 80 °C for 36 h. Both of the porous TiO2 architectures were pore-size-adjustable depending on the further treating temperature. Porous TiO2 nanospheres exhibited enhanced photocatalysis activity compared to the nanoparticles.

  6. High-surface-area mesoporous TiO2 microspheres via one-step nanoparticle self-assembly for enhanced lithium-ion storage.

    Science.gov (United States)

    Wang, Hsin-Yi; Chen, Jiazang; Hy, Sunny; Yu, Linghui; Xu, Zhichuan; Liu, Bin

    2014-12-21

    Mesoporous TiO2 microspheres assembled from TiO2 nanoparticles with specific surface areas as high as 150 m(2) g(-1) were synthesized via a facile one-step solvothermal reaction of titanium isopropoxide and anhydrous acetone. Aldol condensation of acetone gradually releases structural H2O, which hydrolyzes and condenses titanium isopropoxide, forming TiO2 nanocrystals. Simultaneous growth and aggregation of TiO2 nanocrystals leads to the formation of high-surface-area TiO2 microspheres under solvothermal conditions. After a low-temperature post-synthesis calcination, carbonate could be incorporated into TiO2 as a dopant with the carbon source coming from the organic byproducts during the synthesis. Carbonate doping modifies the electronic structure of TiO2 (e.g., Fermi level, Ef), and thus influences its electrochemical properties. Solid electrolyte interface (SEI) formation, which is not common for titania, could be initiated in carbonate-doped TiO2 due to elevated Ef. After removing carbonate dopants by high-temperature calcination, the mesoporous TiO2 microspheres showed much improved performance in lithium insertion and stability at various current rates, attributed to a synergistic effect of high surface area, large pore size and good anatase crystallinity.

  7. Surface modification and enhanced photocatalytic CO2 reduction performance of TiO2: a review

    Science.gov (United States)

    Low, Jingxiang; Cheng, Bei; Yu, Jiaguo

    2017-01-01

    Recently, the excessive consumption of fossil fuels has caused high emissions of the greenhouse gases, CO2 into atmosphere and global energy crisis. Mimicking the natural photosynthesis by using semiconductor materials to achieve photocatalytic CO2 reduction into valuable solar fuels such as CH4, HCO2H, CH2O, and CH3OH is known as one of the best solutions for addressing the aforementioned issue. Among various proposed photocatalysts, TiO2 has been extensively studied over the past several decades for photocatalytic CO2 reduction because of its cheapness and environmental friendliness. Particularly, surface modification of TiO2 has attracted numerous interests due to its capability of enhancing the light absorption ability, facilitating the electron-hole separation, tuning the CO2 reduction selectivity and increasing the CO2 adsorption and activation ability of TiO2 for photocatalytic CO2 reduction. In this review, recent approaches of the surface modification of TiO2 for photocatalytic CO2 reduction, including impurity doping, metal deposition, alkali modification, heterojunction construction and carbon-based material loading, are presented. The photocatalytic CO2 reduction mechanism and pathways of TiO2 are discussed. The future research direction and perspective of photocatalytic CO2 reduction over surface-modified TiO2 are also presented.

  8. Enhanced photocatalytic degradation of dyes over graphene/Pd/TiO2 nanocomposites: TiO2 nanowires versus TiO2 nanoparticles.

    Science.gov (United States)

    Safajou, Hamed; Khojasteh, Hossein; Salavati-Niasari, Masoud; Mortazavi-Derazkola, Sobhan

    2017-07-15

    In this study, at first, TiO2 nanowire was prepared by an alkaline hydrothermal process. In the following, Gr/Pd/TiO2-NPs and Gr/Pd/TiO2-NWs were synthesized by a combination of hydrothermal and photodeposition methods. The properties of as prepared products were characterized using XRD, FT-IR, SEM, DRS, TEM, ICP-OES, EDS and TGA analysis. SEM results confirmed nanodimension structure for all samples. Also the band gap values obtained using DRS technique suggests that all the samples have semiconductor behavior. Using TGA analysis, the amount of graphene loaded onto the powders was confirmed. Photocatalytic degradation of rhodamine B by TiO2-NWs, Gr/Pd/TiO2-NPs and Gr/Pd/TiO2-NWs nanocomposites was compared under ultraviolet light irradiation. Results confirmed that the Gr/Pd/TiO2-NWs composite show the highest photocatalytic activity due to much higher available surface area of TiO2 substrate in nanowire structure. It is expected that the synthesis of the high surface area TiO2 nanowires, facile photodeposition of palladium into its texture, and simple conversion of GO to graphene during hydrothermal process without using strong reducing agents, could be a suitable rote for preparing different types of carbon based TiO2 nanocomposite photocatalysts.

  9. Preparation and solar-light photocatalytic activity of TiO2 composites: TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite

    Science.gov (United States)

    Li, Y.; Li, S. G.; Wang, J.; Li, Y.; Ma, C. H.; Zhang, L.

    2014-12-01

    Three TiO2 loaded composites, TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite, were prepared in order to improve the solar-light photocatalytic activity of TiO2. The results showed that the photocatalytic activity could obviously be enhanced by loading appropriate amount of inorganic mineral materials. Meanwhile, TiO2 content, heat-treatment temperature and heat-treatment time on the photocatalytic activity were reviewed. Otherwise, the effect of solar light irradiation time and dye concentration on the photocatalytic degradation of Acid Red B was investigated. Furthermore, the degradation mechanism and adsorption process were also discussed.

  10. Facile synthesis of hierarchical porous TiO(2) ceramics with enhanced photocatalytic performance for micropolluted pesticide degradation.

    Science.gov (United States)

    Xing, Zipeng; Zhou, Wei; Du, Fan; Zhang, Linlin; Li, Zhenzi; Zhang, Hang; Li, Wei

    2014-10-08

    In this research, hierarchical porous TiO2 ceramics were successfully synthesized through a camphene-based freeze-drying route. The well-dispersed TiO2 slurries were first frozen and dried at room temperature, followed by high-temperature sintering. The ceramics were analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. Results indicated that the obtained TiO2 ceramics could inhibit undesirable anatase-to-rutile phase transformation and grain growth even at temperatures as high as 800 °C. In this experiment, optimal compressive strength and porosity of the TiO2 ceramics were produced with the initial TiO2 slurry content of ∼15 wt %. The resultant TiO2 ceramics performed excellently in the photodegradation of atrazine and thiobencarb, and the total organic carbon removal efficiency was up to 95.7% and 96.7%, respectively. More importantly, the TiO2 ceramics were easily recyclable. No obvious changes of the photocatalytic performance were observed after six cycles. Furthermore, the ceramics also effectively degraded other pesticides such as dimethoate, lindane, dipterex, malathion, and bentazone. These hierarchical porous TiO2 ceramics have potential applications in environmental cleanup.

  11. 复合添加Al和TiO2对低碳镁碳砖基质物相组成及性能的影响%Effect of additives Al and TiO2 on the matrix phase composition and properties of low carbon MgO-C bricks

    Institute of Scientific and Technical Information of China (English)

    夏忠锋; 王周福; 王玺堂; 刘浩

    2013-01-01

    Low carbon MgO-C bricks were prepared with fused magnesia and fine flake graphite as the raw materials, thermosetting phenol-formaldehyde resin as the binder, added with Al and TiO2. The effect of additives Al and TiO2 on the matrix phase composition and properties of low carbon MgO-C bricks were investigated. The matrix phase composition' was analyzed by XRD, and the microstruc-ture was characterized by SEM and EDS. The results show that the formation of MgAl2O4 and TiN or Ti(C,N) from the reaction of additives with the matrix can significantly improve the oxidation resistance and cold crush strength of low carbon MgO-C bricks. In addition, the addition of Al and TiO2 can avoid the formation of Al4C3 and prevent the bricks from hydration.%以电熔镁砂、超细鳞片石墨为主要原料,以热固性酚醛树脂为结合剂,添加Al和TiO2制备低碳镁碳砖,研究复合引入Al粉和TiO2对低碳镁碳砖基质物相组成及性能的影响.结果表明,埋炭热处理后,添加剂与基质反应生成新相MgAl2O4和TiN或Ti(C,N),使低碳镁碳砖的抗氧化性能明显提高,材料的强度显著增加;此外,添加剂的复合引入有利于改善单独引入Al粉时镁碳砖埋炭处理后易水化的问题.

  12. Adsorption and solar light decomposition of acetone on anatase TiO2 and niobium doped TiO2 thin films.

    Science.gov (United States)

    Mattsson, Andreas; Leideborg, Michael; Larsson, Karin; Westin, Gunnar; Osterlund, Lars

    2006-01-26

    Adsorption and solar light decomposition of acetone was studied on nanostructured anatase TiO2 and Nb-doped TiO2 films made by sol-gel methods (10 and 20 mol % NbO2.5). A detailed characterization of the film materials show that films contain only nanoparticles with the anatase modification with pentavalent Nb oxide dissolved into the anatase structure, which is interpreted as formation of substituted Nb=O clusters in the anatase lattice. The Nb-doped films displayed a slight yellow color and an enhanced the visible light absorption with a red-shift of the optical absorption edge from 394 nm for the pure TiO2 film to 411 nm for 20 mol % NbO2.5. In-situ Fourier transform infrared (FTIR) transmission spectroscopy shows that acetone adsorbs associatively with eta1-coordination to the surface cations on all films. On Nb-doped TiO2 films, the carbonyl bonding to the surface is stabilized, which is evidenced by a lowering of the nu(C=O) frequency by about 20 cm(-1) to 1672 cm(-1). Upon solar light illumination acetone is readily decomposed on TiO2, and stable surface coordinated intermediates are formed. The decomposition rate is an order of magnitude smaller on the Nb-doped films despite an enhanced visible light absorption in these materials. The quantum yield is determined to be 0.053, 0.004 and 0.002 for the pure, 10% Nb:TiO2, and 20%Nb:TiO2, respectively. Using an interplay between FTIR and DFT calculations we show that the key surface intermediates are bidentate bridged formate and carbonate, and H-bonded bicarbonate, respectively, whose concentration on the surface can be correlated with their heats of formation and bond strength to coordinatively unsaturated surface Ti and Nb atoms at the surface. The oxidation rate of these intermediates is substantially slower than the initial acetone decomposition rate, and limits the total oxidation rate at t>7 min on TiO2, while no decrease of the rate is observed on the Nb-doped films. The rate of degradation of key surface

  13. Visible-light-Mediated TiO2 photocatalysis of fluoroquinolone antibacterial agents.

    Science.gov (United States)

    Paul, Tias; Miller, Penney L; Strathmann, Timothy J

    2007-07-01

    This study reports on the photocatalytic transformation of fluoroquinolone antibacterial agents (ciprofloxacin, enrofloxacin, norfloxacin, and flumequine) in aqueous titanium dioxide (TiO2) suspensions irradiated with ultraviolet (UV; lambda > 324 nm) or visible light (lambda > 400, > 420, or > 450 nm). Visible-light-mediated fluoroquinolone degradation is unexpected from direct photolysis or established TiO2 band gap photoexcitation mechanisms, which both require UV light. Visible-light-mediated photocatalysis requires an appropriate conduction band electron acceptor (e.g., O2, BrO3-), but is not dependent upon hydroxyl radical, superoxide, or other reactive oxygen species generated upon TiO2 band gap excitation. The process slows considerably when fluoroquinolone adsorption is inhibited. Whereas fluoroquinolone decomposition in UV-irradiated TiO2 suspensions is accompanied by mineralization, no changes in dissolved organic carbon occur during visible-light-photocatalyzed degradation. Results are consistent with a proposed charge-transfer mechanism initiated by photoexcitation of surface-complexed fluoroquinolone molecules. Complexation to the TiO2 surface causes a red shift in the fluoroquinolone absorption spectrum (via ligand-to-metal charge transfer), enabling photoexcitation by visible light. Fluoroquinolone oxidation then occurs by electron transfer into the TiO2 conduction band, which delivers the electron to an adsorbed electron acceptor. The lack of organic carbon mineralization indicates formation of stable organic byproducts that are resistant to further degradation by visible light. In UV-irradiated TiO2 suspensions, the charge-transfer mechanism acts in parallel with the semiconductor band gap photoexcitation mechanism.

  14. Porous TiO2 Assembled from Monodispersed Nanoparticles

    OpenAIRE

    Liu, Xu; Duan, Weijie; Chen, Yan; Jiao, Shihui; Zhao, Yue; Kang, Yutang; Li, Lu; Fang, Zhenxing; Xu, Wei; Pang, Guangsheng

    2016-01-01

    Porous TiO2 were assembled by evaporating or refluxing TiO2 colloid, which was obtained by dispersing the TiO2 nanoparticles with a crystallite size (d XRD) of 3.2 nm into water or ethanol without any additives. Porous transparent bulk TiO2 was obtained by evaporating the TiO2-C2H5OH colloid at room temperature for 2 weeks, while porous TiO2 nanospheres were assembled by refluxing the TiO2-H2O colloid at 80 °C for 36 h. Both of the porous TiO2 architectures were pore-size-adjustable depending...

  15. Preparation of photocatalytic Fe 2O 3-TiO 2 coatings in one step by metal organic chemical vapor deposition

    Science.gov (United States)

    Zhang, Xingwang; Lei, Lecheng

    2008-02-01

    There are two major difficulties in the TiO 2 liquid-solid photocatalytic system: effective immobilization of the TiO 2 particles; and improving the catalytic activity under visible light. To simultaneously solve these two problems, Fe 2O 3-TiO 2 coatings supported on activated carbon fiber (ACF), have been prepared in one step by a convenient and efficient method—metal organic chemical vapor deposition (MOCVD). XRD results revealed that Fe 2O 3-TiO 2 coatings mainly composed of anatase TiO 2, α-Fe 2O 3 phases and little Fe 2Ti 3O 9. The pore structure of ACF was preserved well after loading with Fe 2O 3-TiO 2 coatings. UV-vis diffuse reflectance spectra showed a slight shift to longer wavelengths and an enhancement of the absorption in the visible region for Fe 2O 3-TiO 2 coatings, compared to the pure TiO 2 sample. A moderate Fe 2O 3-TiO 2 loading (13.7 wt%) was beneficial to mineralizing wastewater because the intermediates could be adsorbed onto the surface of photocatalyst following decomposition. The stable performance revealed that the Fe 2O 3-TiO 2 coatings were strongly adhered to the ACF surface, and the as prepared catalysts could be reused showing potential application for wastewater treatment.

  16. Instability of Hydrogenated TiO2

    Energy Technology Data Exchange (ETDEWEB)

    Nandasiri, Manjula I.; Shutthanandan, V.; Manandhar, Sandeep; Schwarz, Ashleigh M.; Oxenford, Lucas S.; Kennedy, John V.; Thevuthasan, Suntharampillai; Henderson, Michael A.

    2015-11-06

    Hydrogenated TiO2 (H-TiO2) is toted as a viable visible light photocatalyst. We report a systematic study on the thermal stability of H-implanted TiO2 using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). Protons (40 keV) implanted at a ~2 atom % level within a ~120 nm wide profile of rutile TiO2(110) were situated ~300 nm below the surface. NRA revealed that this H-profile broadened preferentially toward the surface after annealing at 373 K, dissipated out of the crystal into vacuum at 473 K, and was absent within the beam sampling depth (~800 nm) at 523 K. Photoemission showed that the surface was reduced in concert with these changes. Similar anneals had no effect on pristine TiO2(110). The facile bulk diffusivity of H in rutile, as well as its activity toward interfacial reduction, significantly limits the utilization of H-TiO2 as a photocatalyst. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. The research was performed using the Environmental Molecular Sciences Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory.

  17. Photocatalytic degradation of aqueous propoxur solution using TiO2 and Hbeta zeolite-supported TiO2.

    Science.gov (United States)

    Mahalakshmi, M; Vishnu Priya, S; Arabindoo, Banumathi; Palanichamy, M; Murugesan, V

    2009-01-15

    Photocatalytic activity of TiO2 and zeolites supported TiO2 were investigated using propoxur as a model pollutant. Hbeta, HY and H-ZSM-5 zeolites were examined as supports for TiO2. Hbeta was chosen as the TiO2 support based on the adsorption capacity of propoxur on these zeolites (Hbeta>HY=H-ZSM-5). TiO2/Hbeta photocatalysts with different wt.% were prepared and characterized by XRD, FT-IR and BET surface area. The progress of photocatalytic degradation of aqueous propoxur solution using TiO2 (Degussa P-25) and TiO2 supported on Hbeta zeolite was monitored using TOC analyzer, HPLC and UV-vis spectrophotometer. The degradation of propoxur was systematically studied by varying the experimental parameters in order to achieve maximum degradation efficiency. The initial rate of degradation with TiO2/Hbeta was higher than with bare TiO2. TOC results revealed that TiO2 requires 600min for complete mineralization of propoxur whereas TiO2/Hbeta requires only 480min. TiO2/Hbeta showed enhanced photodegradation due to its high adsorption capacity on which the pollutant molecules are pooled closely and hence degraded effectively.

  18. A Cost-Effective Solid-State Approach to Synthesize g-C3N4 Coated TiO2 Nanocomposites with Enhanced Visible Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Min Fu

    2013-01-01

    Full Text Available Novel graphitic carbon nitride (g-C3N4 coated TiO2 nanocomposites were prepared by a facile and cost-effective solid-state method by thermal treatment of the mixture of urea and commercial TiO2. Because the C3N4 was dispersed and coated on the TiO2 nanoparticles, the as-prepared g-C3N4/TiO2 nanocomposites showed enhanced absorption and photocatalytic properties in visible light region. The as-prepared g-C3N4 coated TiO2 nanocomposites under 450°C exhibited efficient visible light photocatalytic activity for degradation of aqueous MB due to the increased visible light absorption and enhanced MB adsorption. The g-C3N4 coated TiO2 nanocomposites would have wide applications in both environmental remediation and solar energy conversion.

  19. Double-Shelled TiO2 Hollow Spheres Assembled with TiO2 Nanosheets.

    Science.gov (United States)

    Zhang, Chao; Zhou, Yuming; Zhang, Yiwei; Zhao, Shuo; Fang, Jiasheng; Sheng, Xiaoli; Zhang, Tao; Zhang, Hongxing

    2017-02-08

    High-quality double-shelled TiO2 hollow spheres (DHS-Ti) assembled with TiO2 nanosheets have been synthesized for the first time through a simple hydrothermal treatment of sSiO2 @TiO2 (TiO2 -coated solid SiO2 spheres). The double-shelled structure shows a high BET surface area up to 417.6 m(2)  g(-1) . Anatase DHS-Ti of high crystallinity can be obtained without structural collapse by calcination treatment. The effects of cetyl trimethylammonium bromide (CTAB) concentration, pH, and hydrothermal reaction temperature have also been investigated with a series of contrast experiments. A formation mechanism involving the in situ growth of amorphous TiO2 nanosheets followed by the redeposition of dissolved silica species is proposed. Lastly, the DHS-Ti forming strategy can be extended as a general strategy to fabricate various morphological hollow nanostructures and double-shelled Pt nanocatalysts by rationally selecting functional sSiO2 nanoparticles as core materials. This work could open up a new strategy for controllable synthesis of complex hollow structures and other functional materials.

  20. TiO2-TiO2 composite resistive humidity sensor: ethanol crosssensitivity

    Science.gov (United States)

    Ghalamboran, Milad; Saedi, Yasin

    2016-03-01

    The fabrication method and characterization results of a TiO2-TiO2 composite bead used for humidity sensing along with its negative cross-sensitivity to ethanol vapor are reported. The bead shaped resistive sample sensors are fabricated by the drop-casting of a TiO2 slurry on two Pt wire segments. The dried bead is pre-fired at 750°C and subsequently impregnated with a Ti-based sol. The sample is ready for characterization after a thermal annealing at 600°C in air. Structurally, the bead is a composite of the micron-sized TiO2 crystallites embedded in a matrix of nanometric TiO2 particle aggregates. The performance of the beads as resistive humidity sensors is recorded at room temperature in standard humidity level chambers. Results evince the wide dynamic range of the sensors fabricated in the low relative humidity range. While the sensor conductance is not sensitive to ethanol vapor in dry air, in humid air, sensor's responses are negatively affected by the contaminant.

  1. Remediation of 17-α-ethinylestradiol aqueous solution by photocatalysis and electrochemically-assisted photocatalysis using TiO2 and TiO2/WO3 electrodes irradiated by a solar simulator.

    Science.gov (United States)

    Oliveira, Haroldo G; Ferreira, Leticia H; Bertazzoli, Rodnei; Longo, Claudia

    2015-04-01

    TiO2 and TiO2/WO3 electrodes, irradiated by a solar simulator in configurations for heterogeneous photocatalysis (HP) and electrochemically-assisted HP (EHP), were used to remediate aqueous solutions containing 10 mg L(-1) (34 μmol L(-1)) of 17-α-ethinylestradiol (EE2), active component of most oral contraceptives. The photocatalysts consisted of 4.5 μm thick porous films of TiO2 and TiO2/WO3 (molar ratio W/Ti of 12%) deposited on transparent electrodes from aqueous suspensions of TiO2 particles and WO3 precursors, followed by thermal treatment at 450 (°)C. First, an energy diagram was organized with photoelectrochemical and UV-Vis absorption spectroscopy data and revealed that EE2 could be directly oxidized by the photogenerated holes at the semiconductor surfaces, considering the relative HOMO level for EE2 and the semiconductor valence band edges. Also, for the irradiated hybrid photocatalyst, electrons in TiO2 should be transferred to WO3 conduction band, while holes move toward TiO2 valence band, improving charge separation. The remediated EE2 solutions were analyzed by fluorescence, HPLC and total organic carbon measurements. As expected from the energy diagram, both photocatalysts promoted the EE2 oxidation in HP configuration; after 4 h, the EE2 concentration decayed to 6.2 mg L(-1) (35% of EE2 removal) with irradiated TiO2 while TiO2/WO3 electrode resulted in 45% EE2 removal. A higher performance was achieved in EHP systems, when a Pt wire was introduced as a counter-electrode and the photoelectrodes were biased at +0.7 V; then, the EE2 removal corresponded to 48 and 54% for the TiO2 and TiO2/WO3, respectively. The hybrid TiO2/WO3, when compared to TiO2 electrode, exhibited enhanced sunlight harvesting and improved separation of photogenerated charge carriers, resulting in higher performance for removing this contaminant of emerging concern from aqueous solution.

  2. Extraordinary Performance of Carbon‐Coated Anatase TiO2 as Sodium‐Ion Anode

    Science.gov (United States)

    Tahir, Muhammad Nawaz; Oschmann, Bernd; Buchholz, Daniel; Dou, Xinwei; Lieberwirth, Ingo; Panthöfer, Martin; Tremel, Wolfgang

    2015-01-01

    The synthesis of in situ polymer‐functionalized anatase TiO2 particles using an anchoring block copolymer with hydroxamate as coordinating species is reported, which yields nanoparticles (≈11 nm) in multigram scale. Thermal annealing converts the polymer brushes into a uniform and homogeneous carbon coating as proven by high resolution transmission electron microscopy and Raman spectroscopy. The strong impact of particle size as well as carbon coating on the electrochemical performance of anatase TiO2 is demonstrated. Downsizing the particles leads to higher reversible uptake/release of sodium cations per formula unit TiO2 (e.g., 0.72 eq. Na+ (11 nm) vs only 0.56 eq. Na+ (40 nm)) while the carbon coating improves rate performance. The combination of small particle size and homogeneous carbon coating allows for the excellent electrochemical performance of anatase TiO2 at high (134 mAh g−1 at 10 C (3.35 A g−1)) and low (≈227 mAh g−1 at 0.1 C) current rates, high cycling stability (full capacity retention between 2nd and 300th cycle at 1 C) and improved coulombic efficiency (≈99.8%). PMID:27134618

  3. Arsenic removal from water employing heterogeneous photocatalysis with TiO2 immobilized in PET bottles.

    Science.gov (United States)

    Fostier, Anne Hélène; Pereira, Maria do Socorro Silva; Rath, Susanne; Guimarães, José Roberto

    2008-05-01

    Arsenic oxidation (As(III) to As(V)) and As(V) removal from water were assessed by using TiO2 immobilized in PET (polyethylene terephthalate) bottles in the presence of natural sunlight and iron salts. The effect of many parameters was sequentially studied: TiO2 concentration of the coating solution, Fe(II) concentration, pH, solar irradiation time; dissolved organic carbon concentration. The final conditions (TiO2 concentration of the coating solution: 10%; Fe(II): 7.0 mg l(-1); solar exposure time: 120 min) were applied to natural water samples spiked with 500 microg l(-1) As(III) in order to verify the influence of natural water matrix. After treatment, As(III) and total As concentrations were lower than the limit of quantitation (2 microg l(-1)) of the voltammetric method used, showing a removal over 99%, and giving evidence that As(III) was effectively oxidized to As(V). The results obtained demonstrated that TiO2 can be easily immobilized on a PET surface in order to perform As(III) oxidation in water and that this TiO2 immobilization, combined with coprecipitation of arsenic on Fe(III) hydroxides(oxides) could be an efficient way for inorganic arsenic removal from groundwaters.

  4. Characterization and photocatalytic activity of Zn 2+-TiO 2/AC composite photocatalyst

    Science.gov (United States)

    Lu, Xincheng; Jiang, Jianchun; Sun, Kang; Cui, Dandan

    2011-12-01

    Activated carbon (AC) supported Zn 2+-TiO 2 photocatalyst was prepared by sol-gel method. The prepared samples were characterized by X-ray diffraction, scanning electron micrograph, nitrogen absorption, diffuse reflectance UV/VIS and X-ray photoelectron spectroscopy. Using toluene as a pollution target, the photocatalytic activity of photocatalyst was evaluated. The results showed that prepared photocatalyst was obviously helpful for the removal of toluene in air. The photocatalytic degradation of toluene by Zn 2+-TiO 2/AC reached 100% for 40 min and remained 75% after 160 min, while degradation by TiO 2 was only 30%. It indicated that the photocatalytic activity of prepared photocatalyst was enhanced. It is due to Zn 2+-doping increased the oxidation and reduction of hole-electron pairs, which was the important factor in heterogeneous photocatalysis.

  5. Hydrothermal preparation and electrochemical sensing properties of TiO(2)-graphene nanocomposite.

    Science.gov (United States)

    Fan, Yang; Lu, Hai-Ting; Liu, Jin-Hang; Yang, Chun-Peng; Jing, Qiang-Shan; Zhang, Yu-Xia; Yang, Xing-Kun; Huang, Ke-Jing

    2011-03-01

    A facile hydrothermal method has been developed and shown to be effective for the preparation of TiO(2)-graphene nanocomposite. The as-prepared nanocomposite was characterized using FT-IR spectroscopy, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The TiO(2)-graphene modified glassy carbon electrode (GCE) exhibited remarkable electron transfer kinetics and electrocatalytic activity toward the oxidation of dopamine (DA). Furthermore, the oxidation of common interfering agent such as ascorbic acid (AA) was significantly suppressed at this modified electrode, which resulted in good selectivity and sensitivity for electrochemical sensing of DA. These results demonstrate that the TiO(2)-graphene hybrid material has promising potential applications in electrochemical sensors and biosensors design.

  6. Free-standing arrays of isolated TiO2 nanotubes through supercritical fluid drying.

    Science.gov (United States)

    Deneault, James R; Xiao, Xiaoyin; Kang, Tae-Sik; Wang, Joanna S; Wai, Chien M; Brown, Gail J; Durstock, Michael F

    2012-01-16

    A common complication in fabricating arrays of TiO(2) nanotubes is that they agglomerate into tightly packed bundles during the inevitable solvent evaporation step. This problem is particularly acute for template-fabricated TiO(2) nanotubes, as the geometric tunability of this technique enables relatively large inter-pore spacings or, from another perspective, more space for lateral displacement. Our work showed that agglomeration results from the surface tension forces that are present as the ambient solvent is evaporated from the nanotube film. Herein, we report a processing and fabrication approach that utilizes supercritical fluid drying (CO(2)) to prepare arrays of template-fabricated TiO(2) nanotubes that are free-standing and spatially isolated. This approach could be beneficial to many emerging technologies, such as solid-state dye-sensitized solar cells and vertically-oriented carbon nanotube electrodes.

  7. Structural characterization and photocatalytic activity of hollow binary ZrO 2/TiO 2 oxide fibers

    Science.gov (United States)

    Wu, Baochao; Yuan, Rusheng; Fu, Xianzhi

    2009-03-01

    The formation of hollow binary ZrO 2/TiO 2 oxide fibers using mixed precursor solutions was achieved by activated carbon fibers templating technique combined with solvothermal process. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), N 2 adsorption, X-ray photoelectron spectroscopy (XPS), UV-vis, and infrared (IR) spectroscopy. The binary oxide system shows the anatase-type TiO 2 and tetragonal phase of ZrO 2, and the introduction of ZrO 2 notably inhibits the growth of TiO 2 nanocrystallites. Although calcined at 575 °C, all hollow ZrO 2/TiO 2 fibers exhibit higher surface areas (>113 m 2/g) than pure TiO 2 hollow fibers. The Pyridine adsorption on ZrO 2/TiO 2 sample indicates the presence of stronger surface acid sites. Such properties bring about that the binary oxide system possesses higher efficiency and durable activity stability for photodegradation of gaseous ethylene and trichloromethane than P25 TiO 2. In addition, the macroscopic felt form for the resulting materials is more beneficial for practical applications than traditional catalysts forms.

  8. Sol–gel synthesis of highly TiO2 aerogel photocatalyst via high temperature supercritical drying

    Directory of Open Access Journals (Sweden)

    Rebah Moussaoui

    2017-09-01

    Full Text Available Nanocrystalline powders of TiO2 xerogel and aerogel were prepared by using acid-modified sol–gel approach. For TiO2 aerogel material (TA, the solvent was high temperature supercritically extracted at 300 °C and 100 bars. However, the TiO2 xerogel material (TX was dried at 200 °C and ambient pressure. The effects of the drying processes on the crystalline structure, phase transformation and grain growth were determined by Raman spectroscopy, SAED and X-ray diffraction (XRD analyses using Rietveld refinement method. The TiO2 aerogel was composed of anatase crystalline structure. The TiO2 xerogel material was composed of anatase, brookite and small amount of amorphous phase with anatase as dominant phase. The TX sample still contains a relatively high concentration of carbon than that of TA, indicating the amorphous character of TiO2 xerogel. These materials were applied as catalyst for the degradation of indigo carmine in aqueous medium. Photo-degradation ability of TA and TX was compared to the TiO2 commercial Degussa P25. The photo-catalytic results showed that the degradation efficiency was in the order TA > P25 > TX. The photo-degradation of indigo carmine followed pseudo first order reaction kinetics.

  9. Efficient photodegradation of methyl violet dye using TiO2/Pt and TiO2/Pd photocatalysts

    Science.gov (United States)

    Saeed, Khalid; Khan, Idrees; Gul, Tamanna; Sadiq, Mohammad

    2017-02-01

    Titanium oxide supported palladium (TiO2/Pd) and titanium oxide supported platinum (TiO2/Pt) nanoparticles were prepared from their precursors through the incipient wetness method. The TiO2/Pd and TiO2/Pt nanoparticles were characterized by scanning electron microscopy (SEM), and energy dispersive X-rays (EDX), while the photodegradation study of methyl violet was performed by UV/VIS spectrophotometry. The morphological study shows that the Pd and Pt were well deposited on the surface of TiO2, which was confirmed by EDX. Both TiO2/Pd and TiO2/Pt nanoparticles were used as photocatalysts for the photodegradation of methyl violet in aqueous media under UV-light irradiation. The photodegradation study revealed that the TiO2/Pd and TiO2/Pt nanoparticles degraded about 95 and 78% of dye within 20 min, respectively. The effect of various parameters such as catalyst dosage, concentration of dye, and medium on the photocatalytic degradation was examined. The activity of recovered TiO2/Pd and TiO2/Pt nanoparticles was studied.

  10. Water Adsorption on TiO2

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Wendt, Stefan; Besenbacher, Flemming

    2010-01-01

    Scanning Tunneling Microscopy (STM) studies and Density Functional Theory (DFT) investigations of the interaction of water with the rutile TiO2 (110) surface are summarized. From high-resolution STM the following reactions have been revealed: water adsorption and diffusion in the Ti troughs, water...... dissociation in bridging oxygen vacancies, assembly of adsorbed water monomers into rapidly diffusing water dimers, and formation of water dimers by reduction of oxygen molecules. The STM results are rationalized based on DFT calculations, revealing the bonding geometries and reaction pathways of the water...

  11. Nanostructured TiO2 Doped with Nb as a Novel Support for PEMFC

    Directory of Open Access Journals (Sweden)

    Edgar Valenzuela

    2013-01-01

    Full Text Available Nowadays, one of the major issues of the PEMFC concerns the durability. Historically, carbon has been used as a catalyst support in PEMFC; nevertheless, under the environmental conditions of the cell, the carbon is oxidized, leaving the catalyst unsupported. In order to increase the stability and durability of the catalyst in the PEMFC, a novel nanostructured metallic oxide support is proposed. In this work, TiO2 was doped with Nb to obtain a material that combines chemical stability, high surface area, and an adequate electronic conductivity in order to be a successful catalyst support candidate for long-term PEMFC applications. The TiO2-Nb nanostructured catalyst support was physically and electrochemically characterized. According to the results, the TiO2-Nb offers high surface area and good particle dispersion; also, the electrochemical activity and stability of the support were evaluated under high potential conditions, where the TiO2-Nb proved to be much more stable than carbon.

  12. The effect of carbon spheres used as template on microstructure and photo-electric performance of TiO2 thin film%碳球模板剂对TiO_2光阳极微结构及其光电性能影响研究

    Institute of Scientific and Technical Information of China (English)

    张亚; 杨兵初; 周聪华; 王丽丽; 童思超

    2012-01-01

    Carbon spheres were synthesized by hydrothermal reaction using glucose as raw material. The carbon spheres were used as template so as the prepare mesoporous TiO2 thin film which acted as the photoanode of dye sensitized solar cells. Film thickness, surface morphology and scattering ability of the films were studied u- sing profiler, scanning electron microscopy, and UV-Vis spectroscopy respectively. Photovoltaic performance of the cells was evaluated, and the effect of carbon spheres on the cell performance was studied. It was found that with the increase of contents of carbon spheres, surface area in unit volume of the TiO2 film increased at first, and then decreased; similar trend was also observed in the light scattering ability of the TiO2 film. Due to both of the enlarged surface area and the enhanced light scattering ability, photocurrent density of the solar cell and hence the cell performance was optimized, reaching 5.15% at the testing condition.%以葡萄糖为原料水热合成碳球作为模板剂,将其与TiO2纳米晶共混制备纳米多孔TiO2光阳极。采用场发射电子扫描电镜(SEM)、台阶仪、紫外-可见分光光度计(UV-Vis)等对TiO2薄膜的表面形貌、厚度和散射能力进行表征。研究发现,随着碳球含量的增加,光阳极单位体积内的表面积先增加后减小;薄膜对光的散射能力也呈现同样趋势。采用所制备的光阳极组装染料敏化太阳能电池,性能测试结果表明,随着碳球含量的增加,电池短路电流密度先增加,后减小。当碳球加入量为TiO2纳米晶质量的3%时,电池光电转换效率达到最佳为5.15%。

  13. TiO2-NiO p-n nanocomposite with enhanced sonophotocatalytic activity under diffused sunlight.

    Science.gov (United States)

    Vinoth, R; Karthik, P; Devan, K; Neppolian, B; Ashokkumar, Muthupandian

    2017-03-01

    TiO2-NiO composites with p-n junction were developed by assembling p-type NiO on n-type TiO2 using ultrasound assisted wet impregnation method. The sonophotocatalytic efficiencies of pure TiO2 and TiO2-NiO composites were evaluated under diffused sunlight using methyl orange (MO) as a model pollutant. The impregnation of NiO nanoparticles on TiO2 considerably enhanced the optical absorption in visible region (500-800nm) due to the formation of p-n junctions at the interface between TiO2 and NiO. The internal electric field induced by the p-n junction led to effective separation of electron-hole pairs and thereby generating a large amount of reactive species for the degradation of MO. The individual effect of ultrasound and diffused sunlight for the degradation of MO was found to be 30% and 6%, respectively. A synergy of 4.8 fold was achieved when ultrasound was combined with photocatalytic degradation process in the presence of diffused sunlight. The sonophotocatalytic activity of TiO2-NiO photocatalysts with different NiO loading was also evaluated and 10wt% NiO loading was found to be optimal. Moreover, 66% of Total Organic Carbon (TOC) removal was achieved with the optimized TiO2-NiO composite in 140min. In addition, the TiO2-NiO composite exhibited an enhanced photocurrent response under visible light illumination.

  14. Growth of TiO2 nanofibers on FTO substrates and their application in dye-sensitized solar cells

    Science.gov (United States)

    Suryana, R.; Rahmawati, L. R.; Triyana, K.

    2016-11-01

    Growth of TiO2 nanofibers on fluorine-doped tin oxide (FTO) substrates have been performed using electrospinning method. Homogenous TiO2 solution as nanofibers material was prepared with titanium tetraisopropoxide (TTIP), ethanol, acetic acid and polyvinyl pyrrolidone (PVP) which was stirred for 24 h. TiO2 solution was loaded into the syringe pump. Electrospun voltage was operated under 15 kV with optimum distance between syringe tip and collector was 15 cm. FTO substrates were attached on the collector surface. Electrospinning coating time was varied at 15 min, 30 min, 45 min, and 60 min. Then TiO2 nanofibers layer was annealed at temperature of 450° C for 3 h. X-ray diffraction spectrum of TiO2 nanofibers showed major anatase peaks at 25.3°, 48.0° and 37.8° correlating crystal orientation of (101), (200), and (004), respectively while only one rutile peak at 27.5°(110). TiO2 nanofibers diameter was measured using atomic force microscopy (AFM). TiO2 nanofibers have diameter in range of 100-1000 nm. The obtained-TiO2 nanofibers were applied in dye-sensitized solar cell (DSSC) with beta-carotene as dye, carbon as catalyst, and I-/I3- redox couple as electrolyte. DSSC performance was analyzed from I-V characterization. Growth of TiO2 nanofibers at electrospinning time for 45 min has highest efficiency that is 0.016%. It is considered that TiO2 nanofibers at electrospinning time for 45 min can produce optimum thickness so that it is speculated many dyes adsorb on the nanofiber surfaces and many electrons diffuse toward the electrodes.

  15. Investigation of Ag-TiO2 Interfacial Reaction of Highly Stable Ag Nanowire Transparent Conductive Film with Conformal TiO2 Coating by Atomic Layer Deposition.

    Science.gov (United States)

    Yeh, Ming-Hua; Chen, Po-Hsun; Yang, Yi-Ching; Chen, Guan-Hong; Chen, Hsueh-Shih

    2017-03-29

    The atomic layer deposition (ALD) technique is applied to coat Ag nanowires (NWs) with a highly uniform and conformal TiO2 layer to improve the stability and sustainability of Ag NW transparent conductive films (TCFs) at high temperatures. The TiO2 layer can be directly deposited on Ag NWs with a surface polyvinylpyrrolidone (PVP) coat that acts a bed for TiO2 seeding in the ALD process. The ALD TiO2 layer significantly enhances the thermal stability at least 100 fold when aged between 200-400 °C and also provides an extra function of violet-blue light filtration for Ag NW TCFs. Investigation into the interaction between TiO2 and Ag reveals that the conformal TiO2 shell could effectively prevent Ag from 1D-to-3D ripening. However, Ag could penetrate the conformal TiO2 shell and form nanocrystals on the TiO2 shell surface when it is aged at 400 °C. According to experimental data and thermodynamic evaluation, the Ag penetration leads to an interlayer composed of mixed Ag-Ag2O-amorphous carbon phases and TiO2-x at the Ag-TiO2 interface, which is thought to be caused by extremely high vapor pressure of Ag at the Ag-TiO2 interface at a higher temperature (e.g., 400 °C).

  16. Enhanced conversion efficiency of dye-sensitized solar cells using a CNT-incorporated TiO2 slurry-based photoanode

    Directory of Open Access Journals (Sweden)

    Jiaoping Cai

    2015-02-01

    Full Text Available A new titanium dioxide (TiO2 slurry formulation is herein reported for the fabrication of TiO2 photoanode for use in dye-sensitized solar cells (DSSCs. The prepared TiO2 photoanode featured a highly uniform mesoporous structure with well-dispersed TiO2 nanoparticles. The energy conversion efficiency of the resulting TiO2 slurry-based DSSC was ∼63% higher than that achieved by a DSSC prepared using a commercial TiO2 slurry. Subsequently, the incorporation of acid-treated multi-walled carbon nanotubes (CNTs into the TiO2 slurry was examined. More specifically, the effect of varying the concentration of the CNTs in this slurry on the performance of the resulting DSSCs was studied. The chemical state of the CNTs-incorporated TiO2 photoanode was investigated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. A high energy conversion efficiency of 6.23% was obtained at an optimum CNT concentration of ∼0.06 wt.%. The obtained efficiency corresponds to a 63% enhancement when compared with that obtained from a DSSC based on a commercial TiO2 slurry. The higher efficiency was attributed to the improvement in the collection and transport of excited electrons in the presence of the CNTs.

  17. Enhanced conversion efficiency of dye-sensitized solar cells using a CNT-incorporated TiO2 slurry-based photoanode

    Science.gov (United States)

    Cai, Jiaoping; Chen, Zexiang; Li, Jun; Wang, Yan; Xiang, Dong; Zhang, Jijun; Li, Hai

    2015-02-01

    A new titanium dioxide (TiO2) slurry formulation is herein reported for the fabrication of TiO2 photoanode for use in dye-sensitized solar cells (DSSCs). The prepared TiO2 photoanode featured a highly uniform mesoporous structure with well-dispersed TiO2 nanoparticles. The energy conversion efficiency of the resulting TiO2 slurry-based DSSC was ˜63% higher than that achieved by a DSSC prepared using a commercial TiO2 slurry. Subsequently, the incorporation of acid-treated multi-walled carbon nanotubes (CNTs) into the TiO2 slurry was examined. More specifically, the effect of varying the concentration of the CNTs in this slurry on the performance of the resulting DSSCs was studied. The chemical state of the CNTs-incorporated TiO2 photoanode was investigated by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. A high energy conversion efficiency of 6.23% was obtained at an optimum CNT concentration of ˜0.06 wt.%. The obtained efficiency corresponds to a 63% enhancement when compared with that obtained from a DSSC based on a commercial TiO2 slurry. The higher efficiency was attributed to the improvement in the collection and transport of excited electrons in the presence of the CNTs.

  18. Evaluation of natural organic matter changes from Lake Hohloh by three-dimensional excitation-emission matrix fluorescence spectroscopy during TiO(2)/UV process.

    Science.gov (United States)

    Valencia, Sergio; Marín, Juan M; Restrepo, Gloria; Frimmel, Fritz H

    2014-03-15

    This study shows the changes of natural organic matter (NOM) from Lake Hohloh, (Black Forest, Germany) during heterogeneous photocatalysis with TiO2 (TiO2/UV). The effect of pH on the adsorption of NOM onto TiO2 in the dark and TiO2/UV degradation of NOM was followed using three-dimensional excitation-emission matrix (EEM) fluorescence. At pH values between 4 and 9, the NOM was adsorbed onto TiO2 in the dark with a greater decrease in the fluorescence intensity and in the spectral shapes, especially under acidic pH conditions. However, at pH = 10 there was not adsorption on NOM which led to a negligible changes the fluorescence intensity. A significant high linear correlation was observed between the DOC adsorption onto TiO2 and the maximum fluorescence intensity. Additionally, the NOM adsorption onto TiO2 and its TiO2/UV degradation shifted the fluorescence maxima toward shorter wavelengths in the EEM contour plots, with a decrease in aromaticity. These changes were accompanied by a substantial decrease in the organically bound halogens adsorbable on activated carbon (AOXFP) and the trihalomethane formation potential (THMFP). Thus, the decrease in maximum fluorescence intensity can be used as an indicator of AOXFP and TTHMFP removal efficiency. Therefore, fluorescence spectroscopy is a robust analytical technique for evaluate TiO2/UV removal of NOM.

  19. Mixed matrix membranes prepared from high impact polystyrene with dispersed TiO2 nanoparticles for gas separation

    Directory of Open Access Journals (Sweden)

    P. Safaei

    2016-01-01

    Full Text Available The current study presents synthesis and characterization of high impact polystyrene - TiO2 nanoparticles mixed matrix membranes for separation of carbon dioxide from nitrogen. The solution-casting method was used for preparation of membranes. The nano mixed matrix membranes were characterized using scanning electron microscopy to ensure the suitable dispersion of nano particles in high impact polystyrene matrix. The effect of TiO2 nanoparticles loading on membrane performance was investigated. The separation performance of synthesized membranes was investigated in separation of CO2 from CO2/N2 mixture. Effect of feed pressure and TiO2 content on separation of CO2 was studied. The results revealed that increase of feed pressure decreases flux of gases through the mixed matrix membrane. The results also confirmed that the best separation performance can be obtained at TiO2 nanoparticles loading of 7 wt.%.

  20. Influence of Aqueous Inorganic Anions on the Reactivity of Nanoparticles in TiO2 Photocatalysis.

    Science.gov (United States)

    Farner Budarz, Jeffrey; Turolla, Andrea; Piasecki, Aleksander F; Bottero, Jean-Yves; Antonelli, Manuela; Wiesner, Mark R

    2017-03-21

    The influence of inorganic anions on the photoreactivity and aggregation of titanium dioxide nanoparticles (NPs) was assessed by dosing carbonate, chloride, nitrate, phosphate, and sulfate as potassium salts at multiple concentrations. NP stability was monitored in terms of aggregate morphology and electrophoretic mobility (EPM). Aggregate size and fractal dimension were measured over time by laser diffraction, and the isoelectric point (IEP) as a function of anion and concentration was obtained by measuring EPM versus pH. Phosphate, carbonate, and to a lesser extent, sulfate decreased the IEP of TiO2 and stabilized NP suspensions owing to specific surface interactions, whereas this was not observed for nitrate and chloride. TiO2 NPs were exposed to UV-A radiation, and the photoreactivity was assessed by monitoring the production of reactive species over time both at the NP surface (photogenerated holes) and in the bulk solution (hydroxyl radicals) by observing their reactions with the selective probe compounds iodide and terephthalic acid, respectively. The generation of photogenerated holes and hydroxyl radicals was influenced by each inorganic anion to varying degrees. Carbonate and phosphate inhibited the oxidation of iodide, and this interaction was successfully described by a Langmuir-Hinshelwood mechanism and related to the characteristics of TiO2 aggregates. Chloride and nitrate do not specifically interact with TiO2, and sulfate creates relatively weak interactions with the TiO2 surface such that no decrease in photogenerated hole reactivity was observed. A decrease in hydroxyl radical generation was observed for all inorganic anions. Quenching rate constants for the reaction of hydroxyl radicals with each inorganic anion do not provide a comprehensive explanation for the magnitude of this decrease, which arises from the interplay of several physicochemical phenomena. This work shows that the reactivity of NPs will be strongly influenced by the makeup of

  1. Toward a high-activity photocatalyst via controllable synthesis of nano Ag-carbon nanotube-mixed crystal TiO2 composite fibers%高活性光催化剂纳米Ag-碳纳米管-混晶TiO2复合纤维的可控制备

    Institute of Scientific and Technical Information of China (English)

    王翠娥; 刘新华; 万鹏; 张广知

    2016-01-01

    In order to solve the application problems of TiO2 such as the poor effective utilization rate for solar en-ergy,high recombination rate of photoinduced electrons and holes,low photocatalytic activity and difficulty in recy-cle etc.,nano Ag-carbon nanotube (CNT)-mixed crystal TiO2 composite fibers were synthesized successfully by electrospinning technology,and the microstructures and constructions of the materials were analyzed in detail by characterization methods such as SEM,XRD,EDS and Raman etc.,thus the photocatalytic activities of nano Ag-CNT-mixed crystal TiO2 composite fibers for methylene blue were investigated.The results show that the mixed crystal of anatase-and rutile-TiO2 can not only reduce the band gap,but also slow down the combination and cancel-lation of photoinduced electrons and holes.The localized surface plasmon resonance of Ag nanoparticles can enhance the light absorption of nano Ag-CNT-mixed crystal TiO2 composite fibers,and CNT can promote the effective segre-gation of photoinduced electrons and holes.The degradation rate of nano Ag-CNT-mixed crystal TiO2 composite fi-bers for methylene blue in the first cycle reaches 9 7.5%,and the degradation rate for methylene blue after 5 catalyt-ic cycles still retains above 90.0%.The conclusions obtained show that the new type nano Ag-CNT-mixed crystal TiO2 composite fiber prepared by electrospinning is a high-activity photocatalyst and is easy to be recycled,which has application prospects for the photo degradation of methylene blue.%为解决TiO2对太阳能有效利用率低、光生电子与空穴再复合率高、光催化活性低且难回收等应用难题,利用静电纺丝技术成功地制备了纳米 Ag-碳纳米管(CNT)-混晶 TiO2复合纤维,并采用 SEM、XRD、EDS 及 Ra-man等表征方法详细分析了材料的微观结构与组分,研究了纳米 Ag-CNT-混晶TiO2复合纤维对亚甲基蓝的光催化活性。结果表明:锐钛矿与金红石相TiO2混晶不仅可降低材

  2. High Mobility of Graphene-Based Flexible Transparent Field Effect Transistors Doped with TiO2 and Nitrogen-Doped TiO2.

    Science.gov (United States)

    Wu, Yu-Hsien; Tseng, Po-Yuan; Hsieh, Ping-Yen; Chou, Hung-Tao; Tai, Nyan-Hwa

    2015-05-13

    Graphene with carbon atoms bonded in a honeycomb lattice can be tailored by doping various species to alter the electrical properties of the graphene for fabricating p-type or n-type field-effect transistors (FETs). In this study, large-area and single-layer graphene was grown on electropolished Cu foil using the thermal chemical vapor deposition method; the graphene was then transferred onto a poly(ethylene terephthalate) (PET) substrate to produce flexible, transparent FETs. TiO2 and nitrogen-doped TiO2 (N-TiO2) nanoparticles were doped on the graphene to alter its electrical properties, thereby enhancing the carrier mobility and enabling the transistors to sense UV and visible light optically. The results indicated that the electron mobility of the graphene was 1900 cm(2)/(V·s). Dopings of TiO2 and N-doped TiO2 (1.4 at. % N) lead to n-type doping effects demonstrating extremely high carrier mobilities of 53000 and 31000 cm(2)/(V·s), respectively. Through UV and visible light irradiation, TiO2 and N-TiO2 generated electrons and holes; the generated electrons transferred to graphene channels, causing the FETs to exhibit n-type electric behavior. In addition, the Dirac points of the graphene recovered to their original state within 5 min, confirming that the graphene-based FETs were photosensitive to UV and visible light. In a bending state with a radius of curvature greater than 2.0 cm, the carrier mobilities of the FETs did not substantially change, demonstrating the application possibility of the fabricated graphene-based FETs in photosensors.

  3. Influence of heat treatment temperature on bonding and oxidation resistance of diamond particles coated with TiO2 film

    Indian Academy of Sciences (India)

    Xiao-Pan Liu; Dong-Dong Song; Long Wan; Xian-Bing Pang; Zheng Li

    2015-09-01

    In this paper, TiO2 films were coated on the surface of diamond particles using a sol–gel method. The effects of heat treatment temperature on the morphology, composition, chemical bonds, oxidation resistance and compressive strength of diamond particles coated with TiO2 films were characterized through scanning electron microscopy, Fourier transform infrared, Raman spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, thermogravimetric–differential scanning calorimetry and compressive strength test. The results showed that when the temperature reached 600°C, the amorphous TiO2 on the diamond particles surface exhibited as a dense anatase film and the Ti–O–C bond formed between TiO2 and the diamond substrates. When temperature reached 800°C, TiO2 films were still in anatase phase and part of the diamond carbon began to graphitize. The graphitizated carbon can also form the Ti–O–C bond with TiO2 film, although TiO2 film would tend to crack in this condition. Meanwhile, the temperature had a serious influence on the oxidation resistance of diamond particles coated with TiO2 films in air. When the heat treatment temperature reached 600°C, the initial oxidation temperature of the coated diamond particles reached the maximum value of 754°C. When the diamond particles were oxidized at 800°C for 0.5 h in air, the weight loss rate reached the minimum value of 6.7 wt% and the compressive strength reached the maximum value of 15.7 N.

  4. Improvement of NO Gas Sensing Properties of Polyaniline/MWCNT Composite by Photocatalytic Effect of TiO2

    Directory of Open Access Journals (Sweden)

    Jumi Yun

    2013-01-01

    Full Text Available The highly sensitive and rapid NO gas sensor was prepared with polyaniline/TiO2/carbon nanotube composites. Aniline was polymerized on the surface of carbon nanotube (p-type semiconductor with embedding TiO2. The gas sensing property was measured by the changes of electrical resistance without or with UV irradiation to investigate the photodegradation of NO by TiO2. The photo-degraded products such as HNO2, NO2, and HNO3, which were adsorbed on the PANi-coated carbon nanotubes, resulted in the decreased electrical resistance in the p-type semiconductors of carbon nanotube and polyaniline. The advantages of TiO2 photocatalyst in gas sensing were apparent in the improvement in both sensitivity and response rate.

  5. Suggestion for the detection of TiO2 in interstellar medium

    Science.gov (United States)

    Kumar Sharma, Mohit; Sharma, Monika; Chandra, Suresh

    2017-09-01

    Since all the carbon in oxygen-rich stars is locked into carbon monoxide (CO), how the formation of dust takes place in their environment is a matter of great interest. Being a refractory species, the titanium dioxide (TiO2) is thought to play important role in the dust-condensation sequence. The TiO2 is detected in the environment of red supergiant VY Canis Majoris through sub-millimeter wavelengths. All these lines are between the levels lying at high energies for which large kinetic temperature in the region is required. Based on the detailed study of transfer of radiation, we propose for the identification of TiO2 through its transitions between low lying levels. Using spectroscopic data, we have calculated energies of 100 rotational levels of para-TiO2 (up to 82 cm^{-1}) and the Einstein A-coefficients for radiative transitions between the levels. These Einstein A-coefficients along with the scaled values of collisional rate coefficients, we have solved a set of 100 statistical equilibrium equations coupled with 436 equations of radiative transfer. We have found 9 transitions having anomalous absorption and 6 transitions showing emission features. These transitions may help in identification of TiO2 in a cosmic object.

  6. Preparation and application of efficient TiO2/ACFs photocatalyst

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-hua; YANG Rong; LI Song-mei

    2006-01-01

    Activated carbon fibers (ACFs) supported titanium dioxide (TiO2) photocatalyst was developed by sol-gel method. The surface morphology and microstructure of the photocatalyst were characterized with scan electron microscope(SEM), X-ray diffiaction patterns and specific surface area analysis. The prepared photocatalyst is specially helpful for the removal of low molecular weight organic pollutants in wastewater. Decomposition efficiency of methylene blue solution by TiO2/ACFs catalyst reached almost 100% under 60 min reaction, while the decomposition efficiency by pure TiO2 was only 25% under 3 h reaction. The mineralization of toluene aqueous solution was measured by total organic carbon instrument, and the evolution of intermediate species was detected by gas chromatograph instrument. The results indicated that the prepared photocatalyst not only enhanced the photoactivity of TiO2, but also suppressed the emergence of intermediate species, which may be more deleterious to human. The enhancement of photocatalysis was due to increased efficiency of adsorption and desorption, which were control steps in heterogeneous photocatalysis.

  7. Electrorheological Effects of Cerium-Doped TiO2

    Institute of Scientific and Technical Information of China (English)

    尹剑波; 赵晓鹏

    2001-01-01

    It is found that the doping of cerium ion into anatase TiO2 can improve the electrorheological (ER) effects of TiO2 and broaden the operational temperature range. Especially, the substitution of 7-11 mol% of the cerium dopant for Ti can obtain a relatively high shear stress, t-7.4kPa (at 4kV/mm), which is ten times larger than that of pure TiO2 ER fluid. Also, the typical Ce-doped TiO2 ER fluid shows the highest shear stress at 80℃, but 40℃ for pure TiO2 ER fluid. The dielectric loss and dielectric constant at a low frequency of TiO2 is improved by the doping of cerium, and the temperature dependence of the dielectric properties shows an obvious differnce between pure and doped TiO2 ER fluids. These can well explain the ER behaviour of doped TiO2. Furthermore, the change of rheological and dielectric properties is discussed on the basis of the lattice distortion and defects in TiO2 arising from the doping of cerium.

  8. ADSORPTION OF UNSATURATED ALDEHYDES ON TiO2

    OpenAIRE

    Natalia Ortega; Oswaldo Núñez

    2012-01-01

    In this work, the unsaturated aldehydes adsorption on TiO2 surface was studied. To test their efficiency as catalyst, experiments on heterogeneous photocatalysis of p-nitrophenol (PNP) and a sample obtained from an oil industry effluent were carried out using a solar simulator and modified-TiO2 systems. The systems of TiO2 used were: TiO2 pure (without modifying) and TiO2-dienal systems constituted by the chemical adsorption of 2,4 hexadienal, 2,4 heptadienal and trans-cinamaldehyde on the su...

  9. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes) junction for dye sensitized solar cells

    Institute of Scientific and Technical Information of China (English)

    Nguyen Huy Hao; Gobinda Gyawali; Tohru Sekino; Soo Wohn Lee

    2016-01-01

    The dye sensitized solar cell (DSSC), which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one con-taining a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  10. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes junction for dye sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Nguyen Huy Hao

    2016-08-01

    Full Text Available The dye sensitized solar cell (DSSC, which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  11. Energetics of nanocrystalline TiO2

    Science.gov (United States)

    Ranade, M. R.; Navrotsky, A.; Zhang, H. Z.; Banfield, J. F.; Elder, S. H.; Zaban, A.; Borse, P. H.; Kulkarni, S. K.; Doran, G. S.; Whitfield, H. J.

    2002-01-01

    The energetics of the TiO2 polymorphs (rutile, anatase, and brookite) were studied by high temperature oxide melt drop solution calorimetry. Relative to bulk rutile, bulk brookite is 0.71 ± 0.38 kJ/mol (6) and bulk anatase is 2.61 ± 0.41 kJ/mol higher in enthalpy. The surface enthalpies of rutile, brookite, and anatase are 2.2 ± 0.2 J/m2, 1.0 ± 0.2 J/m2, and 0.4 ± 0.1 J/m2, respectively. The closely balanced energetics directly confirm the crossover in stability of nanophase polymorphs inferred by Zhang and Banfield (7). An amorphous sample with surface area of 34,600 m2/mol is 24.25 ± 0.88 kJ/mol higher in enthalpy than bulk rutile. PMID:11880610

  12. Increased visible-light photocatalytic activity of TiO2 via band gap manipulation

    Science.gov (United States)

    Pennington, Ashley Marie

    Hydrogen gas is a clean burning fuel that has potential applications in stationary and mobile power generation and energy storage, but is commercially produced from non-renewable fossil natural gas. Using renewable biomass as the hydrocarbon feed instead could provide sustainable and carbon-neutral hydrogen. We focus on photocatalytic oxidation and reforming of methanol over modified titanium dioxide (TiO2) nanoparticles to produce hydrogen gas. Methanol is used as a model for biomass sugars. By using a photocatalyst, we aim to circumvent the high energy cost of carrying out endothermic reactions at commercial scale. TiO2 is a semiconductor metal oxide of particular interest in photocatalysis due to its photoactivity under ultraviolet illumination and its stability under catalytic reaction conditions. However, TiO2 primarily absorbs ultraviolet light, with little absorption of visible light. While an effective band gap for absorbance of photons from visible light is 1.7 eV, TiO2 polymorphs rutile and anatase, have band gaps of 3.03 eV and 3.20 eV respectively, which indicate ultraviolet light. As most of incident solar radiation is visible light, we hypothesize that decreasing the band gap of TiO2 will increase the efficiency of TiO2 as a visible-light active photocatalyst. We propose to modify the band gap of TiO2 by manipulating the catalyst structure and composition via metal nanoparticle deposition and heteroatom doping in order to more efficiently utilize solar radiation. Of the metal-modified Degussa P25 TiO2 samples (P25), the copper and nickel modified samples, 1%Cu/P25 and 1%Ni/P25 yielded the lowest band gap of 3.05 eV each. A difference of 0.22 eV from the unmodified P25. Under visible light illumination 1%Ni/P25 and 1%Pt/P25 had the highest conversion of methanol of 9.9% and 9.6%, respectively.

  13. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes) junction for dye sensitized solar cells

    OpenAIRE

    Nguyen Huy Hao; Gobinda Gyawali; Tohru Sekino; Soo Wohn Lee

    2016-01-01

    The dye sensitized solar cell (DSSC), which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double...

  14. The FTIR studies of gels and thin films of Al2O3-TiO2 and Al2O3-TiO2-SiO2 systems.

    Science.gov (United States)

    Adamczyk, Anna; Długoń, Elżbieta

    2012-04-01

    In this work, samples in form of bulk ones and thin films were obtained using the sol-gel method. The bulk samples were heated at different temperatures (500 °C, 850 °C and 1100 °C) corresponding to the annealing process of coatings, deposited on different substrates by dipping and pulling out samples from the proper sol with the stable speed. Thin films of both Al2O3-TiO2 and Al2O3-TiO2-SiO2 systems were deposited on carbon, steel and titanium substrates in two different ways: as single layers obtained from Al2O3 sol, TiO2 sol and Al2O3 sol or deposited as mixed coatings from Al2O3-TiO2 sol as well as Al2O3-TiO2-SiO2 one. All bulk samples were studied by the FTIR spectroscopy and the X-ray diffractometry while thin films were also investigated by the electron microscopy. In the IR spectra of Al2O3-TiO2 samples, as well as gels and coatings, bands due to the vibrations of AlO bonds of the octahedrally and tetrahedrally coordinated aluminum were observed. The IR spectra of samples of Al2O3-TiO2-SiO2 system differ from that of Al2O3-TiO2 ones in presence of bands assigned to the SiO bond vibrations and in positions of bands due to AlO bond vibrations. In all spectra of bulk samples and coatings, the positions of TiO bond vibrations were ascribed basing on the IR spectra of the pure anatase and rutile.

  15. Effect of sintering temperatures and screen printing types on TiO2 layers in DSSC applications

    Science.gov (United States)

    Supriyanto, Agus; Furqoni, Lutfi; Nurosyid, Fahru; Hidayat, Jojo; Suryana, Risa

    2016-03-01

    Dye-Sensitized Solar Cell (DSSC) is a candidate solar cell, which has a big potential in the future due to its eco-friendly material. This research is conducted to study the effect of sintering temperature and the type of screen-printing toward the characteristics of TiO2 layer as a working electrode in DSSC. TiO2 layers were fabricated using a screen-printing method with a mesh size of T-49, T-55, and T-61. TiO2 layers were sintered at temperatures of 600°C and 650°C for 60 min. DSSC structure was composed of TiO2 as semiconductors, ruthenium complex as dyes, and carbon as counter electrodes. The morphology of TiO2 layer was observed by using Nikon E2 Digital Camera Microscopy. The efficiencies of DSSC were calculated from the I-V curves. The highest efficiency is 0.015% at TiO2 layer fabricated with screen type T-61 and at a sintering temperature of 650°C.

  16. TiO2-induced heterogeneous photodegradation of a fluorotelomer alcohol in air.

    Science.gov (United States)

    Kutsuna, Shuzo; Nagaoka, Yumiko; Takeuchi, Koji; Hori, Hisao

    2006-11-01

    Degradation of C4F9C2H4OH in air over TiO2 particles was examined in this first report of gas-solid heterogeneous photochemical degradation of fluorotelomer alcohols (FTOHs), which may be precursors of perfluorocarboxylic acids (PFCAs) in the environment. Photoirradiation (>290 nm) of C4F9C2H4OH in air flowing over TiO2 produced CO2, via C4F9CH2CHO, C4F9CHO, CnF(2n+1)COF (n=2 and/or 3), and COF2, in that order. X-ray photoelectron spectroscopy of the Ti02 surface showed a decrease in the amount of fluorine bonded to carbon and an increase in the amount of F- as the degradation of C4F9C2H4OH in air proceeded. Of the carbon content in the initial C4F9C2H4OH (78.8 ppmv), 90.7% was transformed to CO2, and the predominant fluorine species produced on the TiO2 surface was F-. Fluorotelomer unsaturated acids, which are considered to be toxic and have been observed in the biodegradation of FTOHs, did notform. Increased relative humidity in the air accelerated the decomposition of the reaction intermediates, which led to increased CO2 and F- formation. This result indicates that humidity is a key factor for counteracting FTOHs in indoor air. Although perfluoroalkyl substances such as PFCAs in water reportedly undergo little photodegradation over TiO2, our data show that mineralization of C4F9C2H4OH in air can be achieved with TiO2.

  17. Preparation and Photocatalytic Characterization of Nanoporous TiO2

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Nanoporous TiO2 photocatalysts were prepared by use of controlled drying method with surfactants. The surface area and porous properties are dependent on the chain length of incorporated surfactant cation. The TiO2 materials prepared in the presence of surfactant molecules during the gel formation exhibit much higher photocatalytic activity than that prepared in the absence of surfactants.

  18. PEMILIHAN JENIS BULIR POLIMER SEBAGAI PENYANGGA MATERIAL FOTOKATALIS TIO2

    Directory of Open Access Journals (Sweden)

    Hasniah Aliah

    2014-05-01

    Full Text Available Salah satu cara untuk meningkatkan aktivitas fotokatalitik suatu material katalis adalah dengan melapiskan material katalis Titanium dioksida (TiO2  pada permukaan polimer yang berukuran cukup besar, ringan, transparan dan bersifat termoplastik.  Untuk memilih jenis polimer terbaik sebagai material penyangga katalis, dilakukan pengujian pelapisan partikel TiO2 pada tiga jenis polimer berbentuk bulir, yaitu polystyrene (PS, linear-low density polyethylene (LLDPE, dan polypropilene (PP.Pelapisan material TiO2 di permukaan polimer dilakukan dengan menggunakan teknik thermalmilling berbasis oven listrik. Temperatur dalam proses milling diatur di sekitar titik HDT (Heat Deflection Temperaturematerial polimer dan berlangsung selama 60 menit.  Massa jenis dan transmitansi polimer setelah dilapisi TiO2 merupakan parameter fisik yang menjadi acuan dalam pemilihan polimer penyangga katalis. Imobilisasi menggunakan teknik thermal milling menghasilkan polimer PP berlapis katalis TiO2 yang homogen. Pabrikasi dengan parameter milling 100°C dan 60 menit menghasilkan PP berlapis katalis TiO2 dengan massa jenis rata-rata 0,872 g/cm3 sehingga dapat mengapung di permukaan air.  Di samping itu, PP berlapis TiO2 mempunyai transmitansi 58%. Polimer PP inilah yang kemudian dipilih sebagai material penyangga katalis TiO2 dalam proses penelitian selanjutnya.

  19. Fe-Doped TiO2 Thin Films for CO Gas Sensing

    Science.gov (United States)

    Kumar, Mukesh; Kumar, Dinesh; Gupta, Anil Kumar

    2015-01-01

    Fe-doped TiO2 thin films were prepared by the sol-gel technique on silicon substrate. The thin films were evaluated for detection of carbon monoxide (CO) gas at room temperature. The TiO2 films were characterized by x-ray diffraction (XRD) analysis, field-emission scanning electron microscopy, and ultraviolet-visible (UV) spectroscopy. The characterization revealed that, as the doping concentration was increased, the grain size decreased. XRD patterns revealed the phase transition from rutile to anatase with addition of different percentages (weight/volume) of Fe. The bandgap determined from UV spectroscopy was found to decrease with increasing Fe doping concentration. Fe doping was observed to have a significant effect on the resistivity of the doped TiO2 thin films. The gas sensing behavior of the films was studied by exposure to different concentrations of CO gas with measurement of the electrical resistance. It was observed that Fe-doped (7% weight/volume) TiO2 exhibited high sensitivity and good response/recovery on exposure to CO gas in the concentration range from 100 ppm to 900 ppm in Ar.

  20. Synthesis of TiO2 /CNT Composites and its Photocatalytic Activity Toward Sudan (I) Degradation.

    Science.gov (United States)

    Miribangul, Amat; Ma, Xiaoli; Zeng, Chen; Zou, Huan; Wu, Yahui; Fan, Tengpeng; Su, Zhi

    2016-07-01

    Semiconductor photocatalysis has the potential for achieving sustainable energy generation and degrading organic contaminants. In TiO2 , the addition of carbonaceous nanomaterials has attracted extensive attention as a means to increase its photocatalytic activity. In this study, composites of TiO2 and carbon nanotubes (CNT) in various proportions were synthesized by the hydrothermal method. The crystalline structures, morphologies, and light absorption properties of the TiO2 /CNT photocatalysts were characterized by PXRD, TEM and UV-Vis absorption spectra. The photocatalytic efficiency of the composites was evaluated by the degradation of Sudan (I) in UV-Vis light. Introducing 0.1-0.5 wt% CNT was shown to substantially improve the photoactivity of TiO2 . The composite with 0.3 wt% CNT showed the best catalytic activity, and its reaction activation energy was calculated as 39.57 kJ mol(-1) from experimental rates. The degradation products of Sudan (I) with different irradiation durations were characterized by Fourier transform infrared spectroscopy, and a degradation reaction process was proposed. © 2016 The American Society of Photobiology.

  1. Acetaldehyde photochemistry on TiO2(110)

    Energy Technology Data Exchange (ETDEWEB)

    Zehr, Robert T.; Henderson, Michael A.

    2008-07-01

    The ultraviolet (UV) photon induced decomposition of acetaldehyde absorbed on the oxidized retile TIO2(110) surface was studied with photon stimulated desorption (PSD) and theral programmed desorption (TPD). Acetaldehyde desorbs molecularly from TiO2(110) with minor decomposition channels yielding butene on the reduced TiO2 surface and acetate on the oxidized TiO2 surface. Acetaldehyde absorbed on oxidized TiO2(110) undergoes a facile thermal reaction to form a photoactive acetaldehyde-oxygen complex. UV irradiation of the acetaldehyde-oxygen complex resulting in the ejection of methyl radical into gas phase and conversion of the surface bound fragment to formate.

  2. Black TiO2 for solar hydrogen conversion

    Directory of Open Access Journals (Sweden)

    Bin Wang

    2017-06-01

    Full Text Available Titanium dioxide (TiO2 has been widely investigated for photocatalytic H2 evolution and photoelectrochemical (PEC water splitting since 1972. However, its wide bandgap (3.0–3.2 eV limits the optical absorption of TiO2 for sufficient utilization of solar energy. Blackening TiO2 has been proposed as an effective strategy to enhance its solar absorption and thus the photocatalytic and PEC activities, and aroused widespread research interest. In this article, we reviewed the recent progress of black TiO2 for photocatalytic H2 evolution and PEC water splitting, along with detailed introduction to its unique structural features, optical property, charge carrier transfer property and related theoretical calculations. As summarized in this review article, black TiO2 could be a promising candidate for photoelectrocatalytic hydrogen generation via water splitting, and continuous efforts are deserved for improving its solar hydrogen efficiency.

  3. Plasma Treated TiO2 Nanoparticles for Dispersion Enhancement

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; LI Chun; ZHANG Jing

    2009-01-01

    TiO2 nanoparticles were treated in a fluidized reactor by introducing Hexamethyldisiloxane(HMDSO)plasma monomer.The organic HMDSO-polymer vapor was condensed on the nanoparticles and lowered their surface energy.This plasma treatment was harmless to the crystal lattice of the TiO2 nanoparticles.The treated nanoparticles were mixed in glycol solutions and polymerized into TiO2-polyester composites for studying the effect of plasma deposition on dispersion.It Was found that the dispersion of the TiO2 nanoparticles in both glycol and the polyester matrix Was significantly improved due to lower surface energy and HMDSO plasma treatment, as from ultraviolet absorbency measurements and scanning electron microscopy observation.The theory of colloid stability successfully explained the dispersion enhancement of TiO2 nanoparticles in glycol.

  4. Ellipsoidal TiO2 hierarchitectures with enhanced photovoltaic performance.

    Science.gov (United States)

    Peng, Wenqin; Yanagida, Masatoshi; Chen, Han; Han, Liyuan

    2012-04-23

    Hierarchical TiO(2) ellipsoids 250-500 nm in size have been synthesized on a large scale by a template-free hydrothermal route. The submicrometer-sized hierarchitectures are assembled from highly crystallized anatase nanorods about 17 nm in diameter with macroporous cavities on the outer shells. Based on the time-dependent morphological evolution under hydrothermal conditions, an oriented attachment process is proposed to explain formation of the hierarchical structures. Such hierarchical TiO(2) not only adsorbs large amounts of dye molecules due to high surface area, but also shows good light scattering caused by the submicrometer size. The TiO(2) hierarchitectures were deposited on top of a transparent TiO(2) nanocrystalline main layer to construct a double-layered photoanode for dye-sensitized solar cell (DSC) application, exhibiting enhanced light harvesting and power-conversion efficiency compared to a commercial TiO(2)-based electrode.

  5. Comparative activity of TiO2 microspheres and P25 powder for organic degradation: Implicative importance of structural defects and organic adsorption

    Science.gov (United States)

    Wang, Chuan; Liu, Hong; Liu, Yuan; He, Guang'an; Jiang, Chengchun

    2014-11-01

    TiO2 microspheres have been employed as a promisingly new photocatalyst for water and wastewater treatment. P25 TiO2 is commonly employed and its properties are well established as photocatalyst. In this study, photocatalytic activities of the two TiO2 samples are compared by degrading sulfosalicylic acid (SSA), phenol, and 2,4-Dichlorophenoxyacetic acid (2,4-D) under 365 nm UV illumination in a suspension system at neutral pH and associated optimized TiO2 dosages. The results showed that the three organic compounds unexceptionally degraded more rapidly on P25 than on TiO2 microspheres in terms of the concentration-time curves and total organic carbon removals at 120 min. This might me attributed the presence of oxygen vacancies and Ti(III) defects already present on P25 as determined by electron paramagnetic resonance, implying that the defects played an important role for the enhancement of the charge transfer step as rate-determining step. The degradations of three organic compounds on P25 and TiO2 microspheres could be well described by the first-order rate equation, while the degradation kinetics of SSA on TiO2 microspheres was quite different. The difference was ascribed to the medium adsorption ability of SSA on the TiO2 surface.

  6. Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts.

    Science.gov (United States)

    Rajamanickam, D; Shanthi, M

    2014-07-15

    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.

  7. Photocatalytic degradation of an azo dye Sunset Yellow under UV-A light using TiO2/CAC composite catalysts

    Science.gov (United States)

    Rajamanickam, D.; Shanthi, M.

    2014-07-01

    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.

  8. Folic acid-conjugated TiO2-doped mesoporous carbonaceous nanocomposites loaded with Mitoxantrone HCl for chemo-photodynamic therapy.

    Science.gov (United States)

    Li, Zhi; Ou-Yang, Ya; Liu, Yang; Wang, Yi-Qiu; Zhu, Xia-Li; Zhang, Zhen-Zhong

    2015-06-01

    Recently, porous carbons have showed great potential in many areas. In this study, TiO2-doped mesoporous carbonaceous (TiO2@C) nanoparticles were obtained by a simple one-pot hydrothermal treatment, folic acid (FA) was conjugated to TiO2@C through an amide bond, then Mitoxantrone HCl (MTX) was adsorbed onto TiO2@C-FA and a drug delivery system, TiO2@C-FA/MTX was obtained. TiO2@C-FA/MTX showed a much faster MTX release at pH 4.5 than at pH 6.0 and pH 7.4. Furthermore, compared with free MTX, this drug delivery system showed a dose-dependent cytotoxicity by varying the irradiance, and afforded higher antitumor efficacy in cultured PC3 cells in vitro. The ability of TiO2@C-FA/MTX to combine chemotherapy with photodynamic activity enhanced the cancer cell killing effect in vitro, demonstrating that TiO2@C-FA/MTX has a great potential for cancer therapy in the future.

  9. Photovoltaic Characterization and Electrochemical Impedance Spectroscopy Analysis of Dye-Sensitized Solar Cells Based on Composite TiO2-MWCNT Photoelectrodes

    Science.gov (United States)

    Parvazian, E.; Karimzadeh, F.; Enayati, M. H.

    2014-05-01

    Dye-sensitized solar cells (DSSCs) use the effect of light on dye molecules to generate electricity through a photoelectrochemical mechanism. The aim of this study is to synthesize nanostructured DSSCs based on titania-multiwalled carbon nanotube (TiO2-MWCNT) composite photoelectrodes and improve their performance and efficiency. DSSCs were fabricated based on single-layer TiO2-MWCNT photoelectrodes with various weight percentages of multiwalled carbon nanotubes and bilayer TiO2/TiO2-2%MWCNT photoelectrodes. The microstructure and thickness of the anodic layers were characterized by field-emission scanning electron microscopy and optical microscopy. Also, to compare the conversion efficiency and determine the electron behavior in the electrical equivalent circuit of these cells, photovoltaic characterization and electrochemical impedance spectroscopy (EIS) analysis were used. The DSSC based on a single-layer TiO2-2%MWCNT electrode, compared with other single-layer DSSCs in this study, had the highest conversion efficiency of 3.9% (for anodic layer thickness of 9 μm). The efficiency of the solar cell with the bilayer TiO2/TiO2-2%MWCNT photoelectrode, in comparison with the single-layer solar cell with the TiO2-2%MWCNT electrode, showed a 23% increase from 4.33% to 5.35% (for anodic layer thickness of 18 μm). EIS analysis indicated that the charge-transport resistance of the DSSC based on the bilayer photoelectrode, in comparison with the single-layer TiO2 and TiO2-2%MWCNT solar cells, was decreased by 68% and 57%, respectively.

  10. Synthesis of C-N-Y tri-doped TiO2 photo-catalyst for MO degradation and characterization

    Science.gov (United States)

    Hoseinian-Maleki, F.; Nemati, A.; Joya, Yasir F.

    2015-10-01

    In this research C-N-Y tri-doped TiO2 nanopowders were synthesized by the sol-gel method. The C-N-Y TiO2 photo-catalyst was prepared using hexamine and yttrium nitrate Hexahydrate as the dopant precursors. Methyl-orange (MO) was used to study the photocatalytic performance of the doped TiO2 under UV irradiation. The synthesized samples were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, Transmission electron microscopy, Photoluminescence and Field emission scanning electron microscopy. The tri-doped sample with 8% N, 0.4% Y and 1.5% C exhibited enhanced photocatalytic efficiencies. After 100 min of irradiation with UV light, 87% of MO was decomposed by C-N-Y tri-doped TiO2 sample. It is suggested that the co-activity of C and N could make the intra-gap localized states above the valence band of TiO2, and carbon in TiO2 structure causes carbonate species to appear. These carbonate species acted as photosensitizer on the TiO2 surface to promote photo-catalytic activity of the as synthesized sample.

  11. Antibacterial Properties of TiO_2 Ceramic Pellets Prepared Using Nano TiO_2 Powder

    Institute of Scientific and Technical Information of China (English)

    YAO Yadong; LI Yongdi; SHAO Wei; KANG Yunqing; WANG Hongjing; HUANG Zhongbin; LIAO Xiaoming; YIN Guangfu

    2009-01-01

    Titanium dioxide(TiO_2)porous ceramic pellets with three dimension nano-structure were prepared using nano TiO_2 powder.The TiO_2 porous ceramic pellets were composed of TiO_2 nanoparticles with 14-16 nm in diameter and had porosity of 74.85%.The mean pore size of the TiO_2 porous ceramic pellets was 20.73 nm and the main pore size ranged from 3 to 16 nm.The mass loss of the TiO_2 ceramic pellets was less than 5%after 20 d immersion in water.The antibacterial properties of the TiO_2 pellets were studied.The sterilization rate of Colibacillus(hospital polluted water with bacterium)can reach 99%after 3 h photocatalytic process and these TiO_2 pellets are easy to be re-activated and cyclically be used.The shaping mechanism and photocatalysis sterilization mechanism of the TiO_2 pellets were discussed.

  12. 硼原子掺杂对碳纳米管吸附 Ne 原子影响的第一性原理计算%First-principle calculations for the adsorption of neon atom in carbon nanotube doped with boron atom

    Institute of Scientific and Technical Information of China (English)

    温述龙; 王茜; 潘敏; 闫跃阳; 黄整

    2015-01-01

    采用基于第一性原理的密度泛函理论( DFT)和局域密度近似( LDA)方法,优化计算得到碳纳米管( CNT),硼原子取代碳原子及其吸附氖原子前后系统的几何结构,能量,电子能带和态密度.结果显示,碳纳米管的能带结构与石墨的层状几何结构相似,能量的变化只在kz =0和kz =0.5平面之间沿着c轴方向出现.B原子取代C原子使价带和导带分别分裂为两个和三个能带.对Ne原子的吸附使价带能量沿着c轴方向升高并导致Fermi面附近的态密度下降.Ne原子的吸附在谷位H最稳定,顶位A其次.C-C间σ键的弯曲使Ne原子吸附在桥位b1比桥位b2处更为稳定.Ne原子在管外的吸附均为放热过程,而管内则为吸热过程.结构分析表明Ne原子对C原子有排斥作用,对B原子却具有吸引作用.B原子取代C原子的位置略凸出于CNT的管壁之外,使Ne原子的吸附能增加.%Based on density functional theory (DFT) and local density approximation (LDA) methods, the ge-ometries, the energies, electronic bands and density of states are optimized and calculated for the adsorption of neon atoms on carbon nanotubes (CNT) doped with boron atoms.The results show that the energy bands of CNT have a topology similar to the layered geometry of graphite .The energy changes of the bands between the two planes of kz=0 and kz=0.5 occur only along the c-axis direction.The substituting boron atom splits the va-lence and conduction bands into two and three energy bands , respectively .The adsorption of neon atom makes the energy of the valence band rise along the c -axis direction , and the density of states near the Fermi surface decreases .The valley site H is the most stable site for the adsorption of neon atom , and the top site A is the sec-ond .The bending of the carbonic σbond along the circumferential direction makes the bridge site b 1 more stable for the adsorption of neon than

  13. Structural and electrochemical properties of PEMA with the influence of MWCNT / TiO2 filler

    Science.gov (United States)

    Pradeepa, P.; Raj, S. Edwin; Kalaiselvimary, J.; Sowmya, G.; Selvakumar, K.; Prabhu, M. Ramesh

    2016-05-01

    An attempt has been made to prepare a hybrid Nano composite polymer electrolytes (NCPES) based on Poly(ethyl methacrylate) (PEMA) doped with multiwalled carbon nanotubes (MWCNT) and Titanium oxide (TiO2) as additives, Lithium per chlorate (LiClO4) as ionic salt and Propylene Carbonate as plasticizer (PC) by using solvent casting technique. X-ray diffraction analysis (XRD) confirms the miscibility and amorphous nature of the prepared electrolytes. It has been found from the a.c impedance analysis that the inorganic filler reduces the bulk resistance of the electrolytes and thus ionic conductivity enhanced. A high dielectric loss value is observed for the case of doped MWCNT-PEMA in comparison with pure PEMA and doped TiO2 -PEMA membranes. Based on the study of relaxation spectra, it is found that the relaxation time decreases with increase in temperature.

  14. Photo-Catalytic Properties of TiO2 Supported on MWCNTs, SBA-15 and Silica-Coated MWCNTs Nanocomposites

    Science.gov (United States)

    Ramoraswi, Nteseng O.; Ndungu, Patrick G.

    2015-10-01

    Mesoporous silica, specifically SBA-15, acid-treated multi-walled carbon nanotubes and a hybrid nanocomposite of SBA-15 coated onto the sidewalls acid-treated multi-walled carbon nanotubes (CNTs) were prepared and used as supports for anatase TiO2. Sol-gel methods were adapted for the synthesis of selected supports and for coating the materials with selected wt% loading of titania. Physical and chemical properties of the supports and catalyst composite materials were investigated by powder X-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis, scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), UV-vis diffuse reflectance spectroscopy and fluorescence spectroscopy. The photo-activity of the catalyst composites were evaluated on the decolorisation of methylene blue as a model pollutant. Coating CNTs with SBA-15 improved the thermal stability and textural properties of the nanotubes. All supported titania composites had high surface areas (207-301 m2/g), altered band gap energies and reduced TiO2 crystallite sizes. The TiO2/SBA-CNT composite showed enhanced photo-catalytic properties and activity than the TiO2/SBA-15 and TiO2/CNT composites. In addition, an interesting observation was noted with the TiO2/SBA-15 nanocomposites, which had a significantly greater photo-catalytic activity than the TiO2/CNT nanocomposites in spite of the high electron-hole recombination phenomena observed with the photoluminescence results. Discussions in terms of morphological, textural and physical-chemical aspects to account for the result are presented.

  15. Effect of TiO2 blocking layer on TiO2 nanorod arrays based dye sensitized solar cells

    Science.gov (United States)

    Sivakumar, R.; Paulraj, M.

    2016-05-01

    Highly ordered rutile titanium dioxide nanorod (TNR) arrays (1.2 to 6.2 μm thickness) were grown on TiO2 blocking layer chemically deposited on fluorine doped tin oxide (FTO) substrate and were used as photo-electrodes to fabricate dye sensitized solar cells (DSSC's). Homogeneous layer of TiO2 on FTO was achieved by using aqueous peroxo- titanium complex (PTC) solutions via chemical bath deposition. Structural and morphological properties of the prepared samples were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) measurements. TNR arrays (6.2 μm) with TiO2 blocking layer showed higher energy conversion efficiency (1.46%) than that without TiO2 blocking layer. The reason can be ascertained to the suppression of electron-hole recombination at the semiconductor/electrolyte interface by the effect of TiO2 blocking layer.

  16. Preparation and photocatalytic activity of bicrystal phase TiO2 nanotubes containing TiO2-B and anatase

    Science.gov (United States)

    Huang, Chuanxi; Zhu, Kerong; Qi, Mengyao; Zhuang, Yonglong; Cheng, Chao

    2012-06-01

    Bicrystal phase TiO2 nanotubes (NTS) containing monoclinic TiO2-B and anatase were prepared by the hydrothermal reaction of anatase nanoparticles with NaOH aqueous solution and a heat treatment. Their structure was characterized by XRD, TEM and Raman spectra. The results showed that the bicrystal phase TiO2 NTS were formed after calcining H2Ti4O9·H2O NTS at 573 K. The bicrystal phase TiO2 NTS exhibit significantly higher photocatalytic activity than the single phase anatase NTS and Dessuga P-25 nanoparticles in the degradation of Methyl Orange aqueous solution under ultraviolet light irradiation, which is attributed to the large surface and interface areas of the bicrystal phase TiO2 NTS.

  17. Preparation of High-Orderly TiO2 Nanotubes in Organic Solution and Characterization of C-doped TiO2

    Science.gov (United States)

    Fan, Xiao-yan; Zhang, Yun-huai; Xiao, Peng; Hu, Fu; Zhang, Huai

    2007-12-01

    High-orderly TiO2 nanotube arrays were fabricated by anodic oxidation of pure titanium substrate in organic electrolyte containing fluoride. Different morphological nanotubes of titania were obtained through controlling the different anodization voltages and durations. The length of the longest nanotubes was approximately 60 μm and the length-to-width aspect ratio was about 600. The nanotube layers were then annealed at different temperatures (450, 550, and 650°C) in air for 2 h. The samples were characterized by scanning electron microscopy, X-ray diffraction (XRD), energy dispersive X-Ray (EDS) and UV-Vis spectrometer. The XRD results demonstrated that the as-anodized samples were amorphous and the structure changed to antanse and rutile when the samples were annealed at higher temperature. The EDS microanalysis indicated the presence of carbon in the TiO2 nanotubes. The result of degradation of methylene blue showed clearly that the photocatalytic activity of C-doped TiO2 nanotubes increased by 10%.

  18. Synthesis of Br-doped TiO2 hollow spheres with enhanced photocatalytic activity

    Science.gov (United States)

    Wang, Qianqian; Zhu, Shengli; Liang, Yanqin; Cui, Zhenduo; Yang, Xianjin; Liang, Chunyong; Inoue, Akihisa

    2017-02-01

    The Br-doped hollow TiO2 photocatalysts were prepared by a simple hydrothermal process on the carbon sphere template following with calcination at 400 °C. The structure and properties of photocatalysts were characterized by X-ray diffraction, Raman spectrum, scanning electron microscope, transmission electron microscopy, N2 desorption-adsorption, UV-Vis spectroscopy, and X-ray photoelectron spectroscopy. The TiO2 hollow spheres are in diameter of 500 nm with shell thickness of 50 nm. The shell is composed of small anatase nanoparticles with size of about 10 nm. The TiO2 hollow spheres exhibit high crystalline and high surface area of 89.208 m2/g. With increasing content of Br doping, the band gap of TiO2 hollow spheres decreased from 2.85 to 1.75 eV. The formation of impurity band in the band gap would narrow the band gap and result in the red shift of absorption edge from 395 to 517 nm, which further enhances the photocatalytic activity. The appropriate Br doping improves the photocatlytic activity significantly. The TiO2 hollow spheres with 1.55% Br doping (0.5Br-TiO2) exhibit the highest photocatalytic activity under full light. More than 98% of RhB, MO, and MB can be photodegraded using 0.5Br-TiO2 with concentration of 10 mg/L in 40, 30, and 30 min, respectively. The degradation rate of Br-doped photocatalysts was 40% faster than undoped ones.

  19. SYNTESIST AND CHARACTERISATION TiO2-Cu PHOTOCATALYST

    Directory of Open Access Journals (Sweden)

    Kapti Riyani

    2015-11-01

    Full Text Available This study begins with the manufacture of TiO2 -Cu photocatalyst by means of wet impregnation and fotodeposisi, the mole ratio of TiO2: Cu2+ is 100: 0; 99: 1; 98: 2; 97: 3 and 96: 4. Photocatalysts were characterized using SEM, UV-Vis DRS, FTIR and XRD. The results showed has been successfully carried out the synthesis of TiO2-Cu. From SEM characterization shows that the addition of Cu metal will alter the morphology of TiO2 photocatalysts. Based on analysis of UV-Vis DRS, the addition of Cu metal dopant to decrease the energy band gap of TiO2. From XRD analysis appears 2θ value at 29.607 and 48.401 which indicates the formation of monoclinic crystal H2Ti3O7. FTIR analysis results indicate a change in the specific uptake of TiO2 indicating a change in the structure of TiO2

  20. Facile one-pot synthesis of uniform TiO2-Ag hybrid hollow spheres with enhanced photocatalytic activity.

    Science.gov (United States)

    Wang, Sunli; Qian, Huanhuan; Hu, Yong; Dai, Wei; Zhong, Yijun; Chen, Jiafu; Hu, Xiao

    2013-01-28

    TiO(2)-Ag hybrid hollow spheres (about 700 nm in diameter) with a highly uniform morphology and good structural stability were facilely prepared via a one-pot hydrothermal method, using carbon spheres as templates followed by an annealing treatment. Through this route, the as-prepared hybrid hollow spheres preserved the uniformity of the initial carbon sphere templates and the loading amount of the Ag nanocrystals can be conveniently varied or controlled by the concentration of the Ag precursor. The investigation of the photocatalytic ability demonstrated that the as-prepared TiO(2)-Ag hybrid hollow spheres possess excellent photocatalytic activity, superior to commercial TiO(2) nanoparticles (Degussa P25), for the degradation of rhodamine B (RhB) and methyl orange (MO) dyes under visible-light illumination. Furthermore, the ˙OH radicals formed during photocatalysis with different Ag content hybrids were revealed by means of a terephthalic acid fluorescence probe method, which uncovers that the Ag content in the TiO(2)-Ag hybrids was crucial to obtain an optimal synergistic effect between the Ag and TiO(2) for the degradation of organic pollutants. Accordingly, the optimum matching for the best photocatalytic activity was investigated thoroughly and a reasonable mechanism was also proposed.

  1. Anatase TiO2@C composites with porous structure as an advanced anode material for Na ion batteries

    Science.gov (United States)

    Shi, Xiaodong; Zhang, Zhian; Du, Ke; Lai, Yanqing; Fang, Jing; Li, Jie

    2016-10-01

    In this paper, we propose a facile strategy to synthesize the porous structure TiO2@C composites through a two-step method, in which the precursor of MIL-125(Ti) was firstly prepared by solvent thermal method and then calcined under inert atmosphere. When employed as anodes for Na ion batteries, TiO2@C composites can exhibit a superior cyclability with a reversible sodium storage capacity of 148 mAh g-1 at the current density 0.5 A g-1 after 500 cycles and an excellent rate performance with a capacity of 88.9 mAh g-1 even the current reached to 2.5 A g-1 due to the dispersion of anatase TiO2 throughout amorphous carbon matrix and the synergistic effect between the anatase TiO2 nanocrystals and carbon matrix, which can availably enhance the electric conductivity and alleviate the volumetric variation of TiO2 during the insertion/extraction process of Na+.

  2. Photocatalytic Degradation of Atrazine with TiO2 Fixed on Granular Activated Carbon (GAC)%固定在颗粒活性炭中的TiO2光催化降解阿特拉津

    Institute of Scientific and Technical Information of China (English)

    何亚明; 单建国; 朱元春; 曲强

    2004-01-01

    利用30 W低压汞灯作光源,采用固定颗粒活性炭中的TiO2(TiO2/GAC)作光催化剂,在浅盘反应器中考察了阿特拉津溶液的光催化降解.结果表明,在平均光强为4.38 mW·cm-2,光催化剂投加量为7.0 g·L-1,阿特拉津初始浓度为2 1.9 mg·L,3wt%H2O2用量为30μL·15mL-1,投加方式为1次·2h-1,光照时间为6~10 h时,去除率可达92.7%~94.7%,TOC去除率可达67.1%~78.3%.光催化剂增至10 g·L-1,H2O2用量一次性加60μL,光照时间为3~4 h时,去除率可达91.6%~93.7%,TOC去除率可达65.9%~73.9%.通过组合实验和紫外光谱图分析,估计了体系中影响去除率的光催化、吸附、光降解、H2O2的作用性质和大小,并估计了降解途径,认为同时存在侧链脱烷基反应和OH取代Cl的反应,在有H2O2存在时,使前反应较强.TOC值测定表明阿特拉津已从8个碳降至含2~3个碳的物质.

  3. Photocatalytic TiO2 nanoparticles enhanced polymer antimicrobial coating

    Science.gov (United States)

    Wei, Xiaojin; Yang, Zhendi; Tay, See Leng; Gao, Wei

    2014-01-01

    Copper (Cu) containing coatings can provide sustainable protection against microbial contamination. However, metallic Cu coatings have not been widely used due to the relatively high cost, poor corrosion resistance, and low compatibility with non-metal substrates. Titanium dioxide (TiO2) possesses antibacterial functions by its photocatalytic properties which can destroy bacteria or suppress their reproduction. TiO2 also has the function of improving the mechanical properties through particle dispersion strengthening. We have recently developed an innovative polymer based coating system containing fine particles of Cu and TiO2 nanoparticles. These polymer based coatings simultaneously display excellent antimicrobial and good mechanical properties. The results showed that the addition of TiO2 has improved the antimicrobial property under sunlight, which provides extended applications in outdoor environment. The elimination of 106 bacterial by contacting the coatings without TiO2 needs 5 h, while contacting with the Cu/TiO2- 1 wt.% TiO2 took only 2 h to kill the same amount of bacteria. The coatings also presented enhanced hardness and wear resistance after adding TiO2. The width of wear track decreased from 270 μm of the Cu-polymer coating to 206 μm of Cu/TiO2-polymer coatings with 10 wt.% TiO2. Synchrotron Infrared Microscopy was used to in-situ and in-vivo study the bacteria killing process at the molecular level. The real-time chemical images of bacterial activities showed that the bacterial cell membranes were damaged by the Cu and TiO2 containing coatings

  4. Highly active nanocrystalline TiO2 photoelectrodes

    Science.gov (United States)

    Paronyan, Tereza M.; Kechiantz, A. M.; Lin, M. C.

    2008-03-01

    A simple method for the fabrication of highly photoactive nanocrystalline two-layer TiO2 electrodes for solar cell applications is presented. Diluted titanium acetylacetonate has been used as a precursor for covering SnO2:F (FTO) films with dense packed TiO2 nanocrystallites. The nanoporous thick TiO2 film follows the dense packed thin TiO2 film as a second layer. For the latter, amorphous TiO2 nanoparticles have been successfully synthesized by a sol-gel technique in an acidic environment with pHacidic nanoparticle gel was neutralized by basic ammonia and a TiO2 gel of pH 5 was obtained; this pH value is higher than the recently reported value of 3.1 (Park et al 2005 Adv. Mater. 17 2349-53). Highly interconnected, nanoporous, transparent and active TiO2 films have been fabricated from the pH 5 gel. SEM, AFM and XRD analyses have been carried out for investigation of the crystal structure and the size of nanoparticles as well as the surface morphology of the films. Investigation of the photocurrent-voltage characteristics has shown improvement in cell performance along with the modification of the surface morphology, depending on pH of the TiO2 gel. Increasing the pH of the gel from 2.1 to 5 enhanced the overall conversion efficiency of the dye-sensitized solar cells by approximately 30%. An energy conversion efficiency of 8.83% has been achieved for the cell (AM1.5, 100 mWcm-2 simulated sunlight) compared to 6.61% efficiency in the absence of ammonia in the TiO2 gel.

  5. Electrospun TiO2/C Nanofibers As a High-Capacity and Cycle-Stable Anode for Sodium-Ion Batteries.

    Science.gov (United States)

    Xiong, Ya; Qian, Jiangfeng; Cao, Yuliang; Ai, Xinping; Yang, Hanxi

    2016-07-06

    Nanosized TiO2 is now actively developed as a low-cost and potentially high capacity anode material of Na-ion batteries, but its poor capacity utilization and insufficient cyclability remains an obstacle for battery applications. To overcome these drawbacks, we synthesized electrospun TiO2/C nanofibers, where anatase TiO2 nanocrystals with a diameter of ∼12 nm were densely embedded in the conductive carbon fibers, thus preventing them from aggregating and attacking by electrolyte. Due to its abundant active surfaces of well-dispersed TiO2 nanocrytals and high electronic conductivity of the carbon matrix, the TiO2/C anode shows a high redox capacity of ∼302.4 mA h g(-1) and a high-rate capability of 164.9 mAh g(-1) at a very high current of 2000 mA g(-1). More significantly, this TiO2/C anode can be cycled with nearly 100% capacity retention over 1000 cycles, showing a sufficiently long cycle life for battery applications. The nanofibrous architecture of the TiO2/C composite and its superior electrochemical performance may provide new insights for development of better host materials for practical Na-ion batteries.

  6. Anatase TiO2 sheet-assisted synthesis of Ti(3+) self-doped mixed phase TiO2 sheet with superior visible-light photocatalytic performance: Roles of anatase TiO2 sheet.

    Science.gov (United States)

    Zhang, Xiaojie; Zuo, Guoqing; Lu, Xin; Tang, Changqing; Cao, Shuo; Yu, Miao

    2017-03-15

    On the basis of measurements, such as field emission scanning electron microscope, UV-Vis diffuse reflectance spectra, X-ray diffraction, electron paramagnetic resonance, photoluminescence spectra, and photocurrent measurements, the roles of anatase TiO2 sheet on synthesizing Ti(3+) self-doped mixed phase TiO2 nanosheets (doped TiO2 (A/R, TiO2 (A))) and on improving the performance for photocatalytic CO2 reduction were explored systematically. High surface area anatase TiO2 nanosheets (TiO2 (A)) as a substrate, structure directing agent, and inhibitor, mediated the synthesis of Ti(3+) self-doped mixed phase TiO2 nanosheets. Addition of TiO2 (A) significantly improved not only visible light absorption of doped TiO2 (A/R, TiO2 (A)), but also the efficiency of photo-excited charges separations due to the existence of interfacial regions of anatase-rutile TiO2 junctions. Finally, a possible mechanism for interfacial charge transfer at the anatase-rutile TiO2 interface and for photocatalytic CO2 reduction over Pt loaded doped TiO2 (A/R, TiO2 (A)) were proposed.

  7. Formation Process of a TiO2 Inverse Opal

    Institute of Scientific and Technical Information of China (English)

    倪培根; 程丙英; 张道中

    2002-01-01

    Inverse opals of TiO2 with different filling fractions were fabricated by using an opal of polystyrene spheres as a template. Scanning electron microscopy showed the accumulative process of TiO2. The transmission spectra of inverse opals with different filling fractions were measured and the shifts of transmission dip with the filling fraction were observed. Our investigation made the infiltration process clear, and it might be helpful for further improvement of the fabrication of TiO2 inverse opals.

  8. Photoinduced underwater superoleophobicity of TiO2 thin films.

    Science.gov (United States)

    Sawai, Yusuke; Nishimoto, Shunsuke; Kameshima, Yoshikazu; Fujii, Eiji; Miyake, Michihiro

    2013-06-11

    The photoinduced wettabilities of water, n-hexadecane, dodecane, and n-heptane on a flat TiO2 surface prepared by a sol-gel method-based coating were investigated. An amphiphilic surface produced by UV irradiation exhibited underwater superoleophobicity with an extremely high static oil contact angle (CA) of over 160°. The TiO2 surface almost completely repelled the oil droplet in water. A robust TiO2 surface with no fragile nanomicrostructure was fabricated on a Ti mesh with a pore size of approximately 150 μm. The fabricated mesh was found to be applicable as an oil/water separation filter.

  9. Growth of TiO2 nanoparticles under heat treatment

    Science.gov (United States)

    Bahadur, J.; Sen, D.; Mazumder, S.; Sastry, P. U.; Paul, B.

    2013-02-01

    The effect of heat treatment, on growth of NiO doped TiO2, have been investigated. The nanoparticle size has been estimated by small-angle x-ray scattering. The average particle size increases with increasing temperature. The growth of crystallite size has been probed by X-ray diffraction. A polymorphic phase transition of TiO2 is observed beyond 600°C due to growth of TiO2 nanoparticles beyond 14 nm of size.

  10. Controlled Directional Growth of TiO2 Nanotubes

    DEFF Research Database (Denmark)

    In, Su-il; Hou, Yidong; Abrams, Billie

    2010-01-01

    We demonstrate how the anodization direction and growth rate of vertically aligned, highly ordered TiO2 nanotube (NT) arrays can be controlled and manipulated by the local concentration of O-2 in the electrolyte. This leads to the growth of highly active TiO2 NT arrays directly on nonconducting...... substrates in a single step. By controlling the oxygen concentration, the electrical contact to the titanium film can be preserved until the entire film is anodized. This approach to growing transparent TiO2 NT films yields possibilities for using glass without any transparent conducting oxide coating...

  11. Photocatalytic hollow TiO2 and ZnO nanospheres prepared by atomic layer deposition.

    Science.gov (United States)

    Justh, Nóra; Bakos, László Péter; Hernádi, Klára; Kiss, Gabriella; Réti, Balázs; Erdélyi, Zoltán; Parditka, Bence; Szilágyi, Imre Miklós

    2017-06-28

    Carbon nanospheres (CNSs) were prepared by hydrothermal synthesis, and coated with TiO2 and ZnO nanofilms by atomic layer deposition. Subsequently, through burning out the carbon core templates hollow metal oxide nanospheres were obtained. The substrates, the carbon-metal oxide composites and the hollow nanospheres were characterized with TG/DTA-MS, FTIR, Raman, XRD, SEM-EDX, TEM-SAED and their photocatalytic activity was also investigated. The results indicate that CNSs are not beneficial for photocatalysis, but the crystalline hollow metal oxide nanospheres have considerable photocatalytic activity.

  12. Preparation and characterization of SO42-/TiO2 and S2O82-/TiO2 catalysts

    Institute of Scientific and Technical Information of China (English)

    MA Xuedan; GUO Daishi; JIANG Qizhong; MA Zifeng; MA Zhengfei; YE Weidong; LI Chunbo

    2007-01-01

    Nanosizedsolid superacidsSO42-/TiO2and S2O82-/TiO2,as well as MCM-41-supported SO42-/ZrO2,were prepared.Their structures,acidities,and catalytic activities were investigated and compared using XRD,N2 adsorptiondesorption,and in situ FTIR-pyridine adsorption,as well as an evaluation reaction with pseudoionone cyclization.The results showed that SO42-/TIO2 and S2Os2-/TiO2 possess not only nanosized particles with diameters < 7.0 nm,a BET surface greater than 140 cm2/g and relatively regular mesostructures with pores around 4.0 nm,but also a pure anatase phase and strong acidity.Different from the Lewis acid nature of SO42-/ZrO2/MCM-41,SO42-/TIO2 and S2O8Z-/TiO2 exhibit mainly Bronsted acidities.The strongest Bronsted acid sites were produced on SO42-/TIO2 promoted with H2804,while Lewis acid sites on S2082-/TIO2 even stronger than those on SO42-/ZrO2/MCM-41 were generated when persulfate solution was used as sulfating agent.Because of their distinct acid natures,SO42-/TIO2 and $2082-/TIO2 exhibited catalytic activities for the cyclization ofpseudoionone that were much higher than that of SO42-/ZrO2/MCM-41.It can be concluded that the existence of more Bronsted acid sites was favorable for proton participation in the cyclization reaction.

  13. STS study of TiO2 film and Pt-deposited TiO2 film in air

    Institute of Scientific and Technical Information of China (English)

    Zhang Min; Jin Zhensheng

    2004-01-01

    Direct investigation of the electronic structure of catalyst surfaces on the near-atomic scale in general has not been impossible in the past. However, with the advent of the scanning tunneling microscope (STM), the opportunity arises for incorporating the scanning tunneling spectroscopy (STS) for correlation in-situ surface electronic structure with topography on a sub-nanometer scale. In this paper, we report the STS results of thin film TiO2 and Pt-deposited TiO2 annealed at 450℃. It was found that the TiO2 semiconductor changes from n-type to p-type after Pt deposition.Fig. 1 shows the surface electronic property (Ⅰ-Ⅴ curve) of thin TiO2 film measured in air by STS. A steep descent of the anodic tunneling current at ca.- 1.0 Ⅴ and a rapid ascent of cathodic tunneling current at ca. +2.0V. The zero bias represents the Fermi level (Ef). Ef is situated at the Ecb side indicating that the thin TiO2 film possesses the same band gap as that of bulk TiO2 phase ( Egs =3.0 to 3.2 eV). For the sample of Pt-deposited TiO2 film, Pt/(Pt+Ti+O) atomic ratio≈0.2, which indicates that the surface of TiO2 film is partly covered by Pt particles, and there are two types of Ⅰ-Ⅴ curves to be detected. One of them (Fig.2a)is attributed to the electronic property of TiO2, which has same Egs as that shown in Fig. 1. However, the Ef is transferred to valence side (△≈1eV). This phenomenon hints that TiO2 is doped by an impurity which can introduce h+ into TiO2 lattice.Such a type of defects may be described by Ti1-xPtxO2(h )2x, here Pt+2 as a substitutional site of Ti+4. Fig.2b is the Ⅰ-Ⅴ curve of a Pt particle situated on a TiO2 particle contained Ti1-xPtxO2(h )2x.

  14. N-doped TiO2/C nanocomposites and N-doped TiO2 synthesised at different thermal treatment temperatures with the same hydrothermal precursor.

    Science.gov (United States)

    Wang, Jia; Fan, Chenyao; Ren, Zhimin; Fu, Xinxin; Qian, Guodong; Wang, Zhiyu

    2014-09-28

    A hydrothermal precursor was first obtained by isopropyl titanate reacting with tetramethylammonium hydroxide (TMAOH), which acts as a source of nitrogen and carbon. A facile post-thermal treatment was employed to enhance the crystallinity and visible light photocatalytic activity of the as-prepared precursor. The resulting products of post-thermal treatment between 200 °C and 700 °C display different colours from brown to white. Black N-doped TiO2 nanoparticles modified with carbon (denoted as N-TiO2/C) were obtained at 300 °C, while yellow N-doped TiO2 nanoparticles (denoted as N-TiO2) were obtained at 500 °C. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were applied to characterize N-TiO2/C, N-TiO2 and the evolution process during thermal treatment. The results show that for both N-TiO2/C and N-TiO2, nitrogen was doped into the lattice, thus narrowing the band gap and increasing the absorption in the visible light region. Moreover, for N-TiO2/C, the carbon species modified on the surface and between the nanocrystals enhanced the visible light harvesting and increased the adsorption of the dye in the photodegradation measurement. The photocatalytic performance under visible light irradiation is N-TiO2/C > N-TiO2 > undoped TiO2.

  15. C-doped mesoporous anatase TiO2 comprising 10nm crystallites.

    Science.gov (United States)

    Xie, Chong; Yang, Shenghui; Li, Beibei; Wang, Hongkong; Shi, Jian-Wen; Li, Guodong; Niu, Chunming

    2016-08-15

    We report a C-doped mesoporous anatase TiO2 with high surface area synthesized using multi-walled carbon nanotube (MWCNT) mat as a "rigid" template and carbon doping source. The characterization by SEM, HRTEM, X-ray diffraction and nitrogen adsorption revealed that TiO2 samples have a porous structure which are figuratively a inverse copy of MWCNT network and pore walls are formed by interconnected TiO2 nanoparticles with average diameter of ∼10nm. We found that annealing temperatures from 400 to 1000°C before MWCNT template removal had very limited effect on particle size (∼10nm), surface area (112-129m(2)/g) and total pore volume (0.74-0.85m(2)/g) of the samples through a significantly delayed phase transition from anatase to rutile started at 800°C, resulting in only ∼9.1% conversion at 1000°C. The pore size distribution is in mesopore range from 6 to 60nm peaked at ∼24nm. XPS analysis showed a relatively strong C1s peak at 288.4eV, indicating C doping at Ti sites, which is responsible for red shift of adsorption edge of UV-vis spectra and photocatalytic activity in visible-light region.

  16. Integrated TiO2 resonators for visible photonics

    CERN Document Server

    Choy, Jennifer T; Deotare, Parag B; Burgess, Ian B; Evans, Christopher C; Mazur, Eric; Loncar, Marko

    2011-01-01

    We demonstrate waveguide-coupled titanium dioxide (TiO2) racetrack resonators with loaded quality factors of 2x10^4 for the visible wavelengths. The structures were fabricated in sputtered TiO2 thin films on oxidized silicon substrates using standard top-down nanofabrication techniques, and passively probed in transmission measurements using a tunable red laser. Devices based on this material could serve as integrated optical elements as well as passive platforms for coupling to visible quantum emitters.

  17. Highly active nanocrystalline TiO(2) photoelectrodes.

    Science.gov (United States)

    Paronyan, Tereza M; Kechiantz, A M; Lin, M C

    2008-03-19

    A simple method for the fabrication of highly photoactive nanocrystalline two-layer TiO(2) electrodes for solar cell applications is presented. Diluted titanium acetylacetonate has been used as a precursor for covering SnO(2):F (FTO) films with dense packed TiO(2) nanocrystallites. The nanoporous thick TiO(2) film follows the dense packed thin TiO(2) film as a second layer. For the latter, amorphous TiO(2) nanoparticles have been successfully synthesized by a sol-gel technique in an acidic environment with pHTiO(2) gel of pH 5 was obtained; this pH value is higher than the recently reported value of 3.1 (Park et al 2005 Adv. Mater. 17 2349-53). Highly interconnected, nanoporous, transparent and active TiO(2) films have been fabricated from the pH 5 gel. SEM, AFM and XRD analyses have been carried out for investigation of the crystal structure and the size of nanoparticles as well as the surface morphology of the films. Investigation of the photocurrent-voltage characteristics has shown improvement in cell performance along with the modification of the surface morphology, depending on pH of the TiO(2) gel. Increasing the pH of the gel from 2.1 to 5 enhanced the overall conversion efficiency of the dye-sensitized solar cells by approximately 30%. An energy conversion efficiency of 8.83% has been achieved for the cell (AM1.5, 100  mWcm(-2) simulated sunlight) compared to 6.61% efficiency in the absence of ammonia in the TiO(2) gel.

  18. Synthesis of gold-doped TiO2 nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHU Baolin; SUI Zhenming; CHEN Xiao; WANG Shurong; ZHANG Shoumin; WU Shihua; HUANG Weiping

    2005-01-01

    Nanostructured materials have been the focus of scientific research due to their unusual physical and chemical properties[1-4]. Therein, nanoscale TiO2 is one of the most investigated materials owing to its significance for applications in heterogeneous catalysis, nonlinear optical devices, gas sensors and photoelectrochemical solar cells[2,3].Many studies have been devoted to the improvement of TiO2 activity by doping noble metals[5-7].

  19. Supercritical Flow Synthesis of TiO2

    DEFF Research Database (Denmark)

    Hellstern, Henrik Christian; Becker, Jacob; Hald, Peter

    2014-01-01

    A new, up-scaled supercritical flow synthesis apparatus has been constructed in Aarhus. A module based system allows for a range of parameter studies with improved parameter control. The dual-reactor setup enables both single phase and core-shell nanoparticle synthesis. TiO2 is a well......-known material and has been synthesized to evaluate the performance of the new super critical reactor setup. TiO2 will form the basis for planned core-shell syntheses....

  20. Field emission properties of capped carbon nanotubes doped by alkali metals:a theoretical investigation

    Institute of Scientific and Technical Information of China (English)

    Jin Lei; Fu Hong-Gang; Xie Ying; Yu Hai-Tao

    2012-01-01

    The electronic structures and field emission properties of capped CNT55 systems with or without alkali metal atom adsorption were systematically investigated by density functional theory calculation.The results indicate that the adsorption of alkali metal on the center site of a CNT tip is energetically favorable.In addition,the adsorption energies increase with the introduction of the electric field.The excessive negative charges on CNT tips make electron emittance much easier and result in a decrease in work function.Furthermore,the inducing effect by positively charged alkali metal atoms can be reasonably considered as the dominant reason for the improvement in field emission properties.

  1. Wire-shaped perovskite solar cell based on TiO2 nanotubes

    Science.gov (United States)

    Wang, Xiaoyan; Kulkarni, Sneha A.; Li, Zhen; Xu, Wenjing; Batabyal, Sudip K.; Zhang, Sam; Cao, Anyuan; Wong, Lydia Helena

    2016-05-01

    In this work, a wire-shaped perovskite solar cell based on TiO2 nanotube (TNT) arrays is demonstrated for the first time by integrating a perovskite absorber on TNT-coated Ti wire. Anodization was adopted for the conformal growth of TNTs on Ti wire, together with the simultaneous formation of a compact TiO2 layer. A sequential step dipping process is employed to produce a uniform and compact perovskite layer on top of TNTs with conformal coverage as the efficient light absorber. Transparent carbon nanotube film is wrapped around Ti wire as the hole collector and counter electrode. The integrated perovskite solar cell wire by facile fabrication approaches shows a promising future in portable and wearable textile electronics.

  2. Wire-shaped perovskite solar cell based on TiO2 nanotubes.

    Science.gov (United States)

    Wang, Xiaoyan; Kulkarni, Sneha A; Li, Zhen; Xu, Wenjing; Batabyal, Sudip K; Zhang, Sam; Cao, Anyuan; Wong, Lydia Helena

    2016-05-20

    In this work, a wire-shaped perovskite solar cell based on TiO2 nanotube (TNT) arrays is demonstrated for the first time by integrating a perovskite absorber on TNT-coated Ti wire. Anodization was adopted for the conformal growth of TNTs on Ti wire, together with the simultaneous formation of a compact TiO2 layer. A sequential step dipping process is employed to produce a uniform and compact perovskite layer on top of TNTs with conformal coverage as the efficient light absorber. Transparent carbon nanotube film is wrapped around Ti wire as the hole collector and counter electrode. The integrated perovskite solar cell wire by facile fabrication approaches shows a promising future in portable and wearable textile electronics.

  3. COMBINING A SEQUENCING BATCH REACTOR WITH HETEROGENEOUS PHOTOCATALYSIS (TiO2/UV FOR TREATING A PENCIL MANUFACTURER'S WASTEWATER

    Directory of Open Access Journals (Sweden)

    R. N. Padovan

    2015-03-01

    Full Text Available Abstract A Sequencing Batch Reactor (SBR was combined with heterogeneous photocatalysis (TiO2/UV as a tertiary treatment for a pencil manufacturer's wastewater. The SBR removed almost all Chemical Oxygen Demand (COD from the wastewater, although color was barely removed. Photocatalysis was optimized using a factorial design. Final COD, Dissolved Organic Carbon (DOC, and color removals were 95%, 80%, and 93%, respectively. Treated wastewater showed no ecotoxicity towards Lactuca sativa. Color removal kinetics (photocatalysis followed a pseudo-first order model. The SBR + AOP (Advanced Oxidation Process, TiO2/UV combination was a feasibility choice for removing both COD and color from this wastewater.

  4. Fabrication and Characteristics of Macroporous TiO2 Photocatalyst

    Directory of Open Access Journals (Sweden)

    Guiyun Yi

    2014-01-01

    Full Text Available Macroporous TiO2 photocatalyst was synthesized by a facile nanocasting method using polystyrene (PS spherical particles as the hard template. The synthesized photocatalyst was characterized by transmission electron microscope (TEM, scanning electron microscopy (SEM, thermogravimetry-differential thermogravimetry (TG-DTG, X-ray diffraction (XRD, and N2-sorption. TEM, SEM, and XRD characterizations confirmed that the macroporous TiO2 photocatalyst is composed of anatase phase. The high specific surface area of 87.85 m2/g can be achieved according to the N2-sorption analysis. Rhodamine B (RhB was chosen as probe molecule to evaluate the photocatalytic activity of the TiO2 catalysts. Compared with the TiO2 materials synthesized in the absence of PS spherical template, the macroporous TiO2 photocatalyst sintered at 500°C exhibits much higher activity on the degradation of RhB under the UV irradiation, which can be assigned to the well-structured macroporosity. The macroporous TiO2 material presents great potential in the fields of environmental remediation and energy conversion and storage.

  5. Silicon protected with atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Seger, Brian; Tilley, S. David; Pedersen, Thomas

    2013-01-01

    The present work demonstrates that tuning the donor density of protective TiO2 layers on a photocathode has dramatic consequences for electronic conduction through TiO2 with implications for the stabilization of oxidation-sensitive catalysts on the surface. Vacuum annealing at 400 °C for 1 hour...... of atomic layer deposited TiO2 increased the donor density from an as-deposited value of 1.3 × 1019 cm -3 to 2.2 × 1020 cm-3 following the annealing step. Using an Fe(ii)/Fe(iii) redox couple it was shown that the lower dopant density only allows electron transfer through TiO2 under conditions of weak band...... bending. However it was shown that increasing the dopant density to 2.2 × 1020 cm-3 allows tunneling through the surface region of TiO2 to occur at significant band bending. An important implication of this result is that the less doped material is unsuitable for electron transfer across the TiO2...

  6. Effect of LiBF4 Salt Concentration on the Properties of Plasticized MG49-TiO2 Based Nanocomposite Polymer Electrolyte

    OpenAIRE

    Ahmad, A.; M. Y. A. Rahman; S. P. Low; H. Hamzah

    2011-01-01

    A nanocomposite polymer electrolyte (NCPE) comprising of 49% poly(methyl methacrylate) grafted natural rubber (MG49) as polymer host, titanium dioxide (TiO2) as a ceramic filler, lithium tetrafluoroborate (LiBF4) as dopant salt, and ethylene carbonate (EC) as plasticizer was prepared by solution casting technique. The ceramic filler, TiO2, was synthesized in situ by a sol-gel process. The ionic conductivity, chemical interaction, structure, and surface morphology of nanocomposite polymer elec...

  7. Single-step preparation of TiO2/MWCNT Nanohybrid materials by laser pyrolysis and application to efficient photovoltaic energy conversion.

    Science.gov (United States)

    Wang, Jin; Lin, Yaochen; Pinault, Mathieu; Filoramo, Arianna; Fabert, Marc; Ratier, Bernard; Bouclé, Johann; Herlin-Boime, Nathalie

    2015-01-14

    This paper presents the continuous-flowand single-step synthesis of a TiO2/MWCNT (multiwall carbon nanotubes) nanohybrid material. The synthesis method allows achieving high coverage and intimate interface between the TiO2particles and MWCNTs, together with a highly homogeneous distribution of nanotubes within the oxide. Such materials used as active layer in theporous photoelectrode of solid-state dye-sensitized solar cells leads to a substantial performance improvement (20%) as compared to reference devices.

  8. Electrospun Nb-doped TiO2 nanofiber support for Pt nanoparticles with high electrocatalytic activity and durability.

    Science.gov (United States)

    Kim, MinJoong; Kwon, ChoRong; Eom, KwangSup; Kim, JiHyun; Cho, EunAe

    2017-03-14

    This study explores a facile method to prepare an efficient and durable support for Pt catalyst of polymer electrolyte membrane fuel cell (PEMFC). As a candidate, Nb-doped TiO2 (Nb-TiO2) nanofibers are simply fabricated using an electrospinning technique, followed by a heat treatment. Doping Nb into the TiO2 nanofibers leads to a drastic increase in electrical conductivity with doping level of up to 25 at. % (Nb0.25Ti0.75O2). Pt nanoparticles are synthesized on the prepared 25 at. % Nb-doped TiO2-nanofibers (Pt/Nb-TiO2) as well as on a commercial powdered carbon black (Pt/C). The Pt/Nb-TiO2 nanofiber catalyst exhibits similar oxygen reaction reduction (ORR) activity to that of the Pt/C catalyst. However, during an accelerated stress test (AST), the Pt/Nb-TiO2 nanofiber catalyst retained more than 60% of the initial ORR activity while the Pt/C catalyst lost 65% of the initial activity. The excellent durability of the Pt/Nb-TiO2 nanofiber catalyst can be attributed to high corrosion resistance of TiO2 and strong interaction between Pt and TiO2.

  9. Electrospun Nb-doped TiO2 nanofiber support for Pt nanoparticles with high electrocatalytic activity and durability

    Science.gov (United States)

    Kim, Minjoong; Kwon, Chorong; Eom, Kwangsup; Kim, Jihyun; Cho, Eunae

    2017-03-01

    This study explores a facile method to prepare an efficient and durable support for Pt catalyst of polymer electrolyte membrane fuel cell (PEMFC). As a candidate, Nb-doped TiO2 (Nb-TiO2) nanofibers are simply fabricated using an electrospinning technique, followed by a heat treatment. Doping Nb into the TiO2 nanofibers leads to a drastic increase in electrical conductivity with doping level of up to 25 at. % (Nb0.25Ti0.75O2). Pt nanoparticles are synthesized on the prepared 25 at. % Nb-doped TiO2-nanofibers (Pt/Nb-TiO2) as well as on a commercial powdered carbon black (Pt/C). The Pt/Nb-TiO2 nanofiber catalyst exhibits similar oxygen reaction reduction (ORR) activity to that of the Pt/C catalyst. However, during an accelerated stress test (AST), the Pt/Nb-TiO2 nanofiber catalyst retained more than 60% of the initial ORR activity while the Pt/C catalyst lost 65% of the initial activity. The excellent durability of the Pt/Nb-TiO2 nanofiber catalyst can be attributed to high corrosion resistance of TiO2 and strong interaction between Pt and TiO2.

  10. Examination of the sintering process-dependent properties of TiO2 on glass and textile substrates

    Science.gov (United States)

    Junger, Irén Juhász; Homburg, Sarah Vanessa; Grethe, Thomas; Herrmann, Andreas; Fiedler, Johannes; Schwarz-Pfeiffer, Anne; Blachowicz, Tomasz; Ehrmann, Andrea

    2017-01-01

    In recent years, the development of smart textiles has attracted great attention. Such textiles can contain small electrical devices, which need a power supply. Dye-sensitized solar cells, which can be produced from nontoxic, cheap, low-purity materials, could fill this purpose. However, to reach reasonable cell properties, sintering the TiO2 layer on the substrate is necessary. Unfortunately, only a few textile materials can withstand a sintering process at high temperatures. Therefore, it is important to find an optimal temperature leading to a reasonable improvement of the cell characteristics without damaging the textile substrate. The influence of the sintering temperature on different properties is investigated. For this, the surface properties of the TiO2 coating, such as adhesion to the substrate, dye adsorption characteristic, and film stability, are investigated on different substrates, i.e., a glass plate, a stainless steel nonwoven fabric, and a carbon woven fabric. Two commercially available TiO2 sources are used: a TiO2 dispersion obtained from Man Solar and a water-based solution of TiO2 particles purchased from Kronos. The influence of the sintering temperature on short-circuit current and open-circuit voltage of solar cells on the aforementioned substrates is also examined.

  11. Electrospun Nb-doped TiO2 nanofiber support for Pt nanoparticles with high electrocatalytic activity and durability

    Science.gov (United States)

    Kim, MinJoong; Kwon, ChoRong; Eom, KwangSup; Kim, JiHyun; Cho, EunAe

    2017-01-01

    This study explores a facile method to prepare an efficient and durable support for Pt catalyst of polymer electrolyte membrane fuel cell (PEMFC). As a candidate, Nb-doped TiO2 (Nb-TiO2) nanofibers are simply fabricated using an electrospinning technique, followed by a heat treatment. Doping Nb into the TiO2 nanofibers leads to a drastic increase in electrical conductivity with doping level of up to 25 at. % (Nb0.25Ti0.75O2). Pt nanoparticles are synthesized on the prepared 25 at. % Nb-doped TiO2-nanofibers (Pt/Nb-TiO2) as well as on a commercial powdered carbon black (Pt/C). The Pt/Nb-TiO2 nanofiber catalyst exhibits similar oxygen reaction reduction (ORR) activity to that of the Pt/C catalyst. However, during an accelerated stress test (AST), the Pt/Nb-TiO2 nanofiber catalyst retained more than 60% of the initial ORR activity while the Pt/C catalyst lost 65% of the initial activity. The excellent durability of the Pt/Nb-TiO2 nanofiber catalyst can be attributed to high corrosion resistance of TiO2 and strong interaction between Pt and TiO2. PMID:28290503

  12. One-Step Synthesis of TiO2/Perlite Composites by Flame Spray Pyrolysis and Their Photocatalytic Behavior

    Directory of Open Access Journals (Sweden)

    M. Giannouri

    2013-01-01

    Full Text Available TiO2/perlite composites were prepared via facile one-step flame spray pyrolysis (FSP route. Titanium alkoxide (TIPO and expanded perlite were used as Ti source and substrate, respectively. Precursor TIPO-ethanol solutions containing homogeneously dispersed perlite particles were processed through FSP setup at different experimental conditions regarding the gas flow and precursor supply rates. The structure, morphology, and the composition of the obtained powders were investigated. The porosity and the light absorbance of the TiO2/perlite composites were examined and their photocatalytic activity in NO oxidation was evaluated. Commercial titania powder P25 was also FSP processed and investigated for comparison. The XRD analysis revealed that biphased titania with different anatase-rutile ratio and particles size 20–40 nm was synthesized onto the perlite which according to microscopy results was covered by neck-connected TiO2 nanoparticles. The anatase-rutile interplay was also demonstrated by the Raman spectra where presence of Si-O-Ti vibrational modes was observed for some samples. The UV-Vis diffuse reflectance spectra of the TiO2/perlite composites revealed up to 70% reflection that was connected to the presence of the gray perlite and superficial carbon. The best photocatalytic activity of the composites was connected to almost equal anatase-rutile ratio and possible synergetic effect of the two TiO2 phases.

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

    Science.gov (United States)

    Alosfur, Firas K. Mohamad; Jumali, Mohammad Hafizuddin Haji; Radiman, Shahidan; Ridha, Noor J.; Yarmo, Mohd Ambar; Umar, Akrajas Ali

    2013-08-01

    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.

  14. Apatite formation on alkaline-treated dense TiO2 coatings deposited using the solution precursor plasma spray process.

    Science.gov (United States)

    Chen, Dianying; Jordan, Eric H; Gell, Maurice; Wei, Mei

    2008-05-01

    A dense titania (TiO2) coating was deposited from an ethanol-based solution containing titanium isopropoxide using the solution precursor plasma spray (SPPS) process. XRD and Raman spectrum analyses confirmed that the coating is exclusively composed of rutile TiO2. SEM micrographs show the as-sprayed coating is dense with a uniform thickness and there are no coarse splat boundaries. The as-sprayed coating was chemically treated in 5M NaOH solution at 80 degrees C for 48 h. The bioactivity of as-sprayed and alkaline-treated coatings was investigated by immersing the coatings in simulated body fluid (SBF) for 14-28 days, respectively. After 28 days immersion, there is a complete layer of carbonate-containing apatite formed on the alkaline-treated TiO2 coating surface, but none formed on the as-sprayed coating.

  15. The effect of substrate temperature on the spray-deposited TiO2 nanostructured films for dye-sensitized solar cells.

    Science.gov (United States)

    Hossain, Md Faruk; Takahashi, Takakazu

    2011-04-01

    The nanostructured TiO2 films have deposited on SnO2:F (FTO) coated glass substrate by spray pyrolysis technique at different substrate temperatures of 200-500 degrees C. The structural, surface morphological and optical properties of TiO2 films significantly vary with the substrate temperature. The surface of the TiO2 films deposited at 400 degrees C shows the nanoflakes and short nanorods (approximately 130 nm) like structures while the TiO2 films prepared at 500 degrees C shows only the nanoflakes like structures. The band gap of the TiO2 films prepared at higher temperatures (300-500 degrees C) becomes narrow due to presence the rutile phases in their crystal structure. Ruthenium (II) complex as a dye, KI/I2 as an electrolyte and carbon on FTO glass as a counter electrode has used to fabricate the dye-sensitized solar cell (DSC). The TiO2 film deposited at 400 degrees C has showed the best photovoltaic performance in DSC with the efficiency of 3.81%, the photovoltage of 773 mV, the photocurrent of 8.34 mA/cm2, and the fill factor of 56.17%. The photovoltage of the DSC increases with the increase of substrate temperature during the deposition of TiO2 films. Moreover, all the DSCs exhibit reasonably high fill factor value.

  16. Enhanced performance of g-C3N4/TiO2 photocatalysts for degradation of organic pollutants under visible light☆

    Institute of Scientific and Technical Information of China (English)

    Gaixue Song; Zhenyu Chu; Wanqin Jin; Hongqi Sun

    2015-01-01

    Photocatalytic degradation is one of the most promising remediation technologies in terms of advanced oxida-tion processes (AOPs) for water treatment. In this study, novel graphitic carbon nitride/titanium dioxide (g-C3N4/TiO2) composites were synthesized by a facile sonication method. The physicochemical properties of the photocatalyst with different mass ratios of g-C3N4 to TiO2 were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), N2 sorption, Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and UV–vis DRS. The photocatalytic performances were evaluated by degradation of methylene blue. It was found that g-C3N4/TiO2 with a mass ratio of 1.5:1 exhib-ited the best degradation performance. Under UV, the degradation rate of g-C3N4/TiO2 was 6.92 and 2.65 times higher than g-C3N4 and TiO2, respectively. While under visible light, the enhancement factors became 9.27 (to g-C3N4) and 7.03 (to TiO2). The improved photocatalytic activity was ascribed to the interfacial charge transfer between g-C3N4 and TiO2. This work suggests that hybridization can produce promising solar materials for envi-ronmental remediation.

  17. Confirmation of hydroxyl radicals (•OH) generated in the presence of TiO2 supported on AC under microwave irradiation.

    Science.gov (United States)

    Zhang, Zhaohong; Yu, Fengyang; Huang, Lirong; Jiatieli, Jianaerguli; Li, Yuanyuan; Song, Lijun; Yu, Ning; Dionysiou, Dionysios D

    2014-08-15

    In order to study the degradation mechanism of technology of microwave (MW) combined with TiO2 supported on activated carbon (TiO2/AC), the reactive oxygen species (ROS) was explored through oxidation of 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). Furthermore, 2,6-di-tert-butyl-4-methylphenol (BHT), Mannitol (MT) and Vitamin C (VC) were used as radical scavengers to confirm the generation of the hydroxyl radicals ((•)OH). In addition, the influence of some parameters such as TiO2 mass ratio content, irradiation time, material dose, DPCI concentration and MW power on the determination of (•)OH were examined. The results showed that the (•)OH could be generated under MW combined with loaded TiO2/AC. Also, anatase TiO2/AC can generate more (•)OH radicals than rutile TiO2/AC under MW irradiation. This work would provide new mechanistic insights on the enhanced degradation effect of organic pollutants in water using the supported TiO2/AC coupled with MW technology.

  18. Facile fabrication of transparent TiO2-C@TiO2-C free-standing film for visible-light photocatalytic application

    Science.gov (United States)

    Hu, Luyang; Zhang, Yumin; Zhang, Shanmei; Li, Benxia

    2017-02-01

    A transparent TiO2-C@TiO2-C free-standing film has been synthesized by two-step hydrothermal method and subsequent thermal annealing. The chemical composition and morphological features of the TiO2-C@TiO2-C film are characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and N2 adsorption-desorption measurement. The results indicate that the flower-like micro/nanostructure TiO2-C particle layers are intimately inhered to porous TiO2-C fibers. The fibers in film are interconnected each other to form a three-dimensional reticulate microstructure, and exhibit intense visible light absorption and high adsorptivity of dye molecules. The interaction between TiO2 and its surface carbon layer in TiO2-C particle promotes the generation of Ti-O-C bonds, which leads to effective charge transfer. Under visible-light irradiation, TiO2-C@TiO2-C film presents enhanced photocatalytic activity for degradation of methylene blue. This work may provide a new viewpoint for designing transparent photocatalytic film for promising applications in heterogeneous photocatalysis.

  19. TiO2-ITO and TiO2-ZnO nanocomposites: application on water treatment

    Directory of Open Access Journals (Sweden)

    Bessais B.

    2012-06-01

    Full Text Available One of the most promising ideas to enhance the photocatalytic efficiency of the TiO2 is to couple this photocatalyst with other semiconductors. In this work, we report on the development of photo-catalytic properties of two types of composites based on TiO2 – ITO (Indium Tin Oxide and TiO2 – ZnO deposited on conventional ceramic substrates. The samples were characterized by X-ray diffraction (XRD and transmission Electron Microscopy (TEM. The photo-catalytic test was carried out under UV light in order to reduce/oxidize a typical textile dye (Cibacron Yellow. The experiment was carried out in a bench scale reactor using a solution having a known initial dye concentration. After optimization, we found that both nanocomposites exhibit better photocatalytic activity compared to the standard photocatalyst P25 TiO2.

  20. TiO2-ITO and TiO2-ZnO nanocomposites: application on water treatment

    Science.gov (United States)

    Chorfi, H.; Saadoun, M.; Bousselmi, L.; Bessais, B.

    2012-06-01

    One of the most promising ideas to enhance the photocatalytic efficiency of the TiO2 is to couple this photocatalyst with other semiconductors. In this work, we report on the development of photo-catalytic properties of two types of composites based on TiO2 - ITO (Indium Tin Oxide) and TiO2 - ZnO deposited on conventional ceramic substrates. The samples were characterized by X-ray diffraction (XRD) and transmission Electron Microscopy (TEM). The photo-catalytic test was carried out under UV light in order to reduce/oxidize a typical textile dye (Cibacron Yellow). The experiment was carried out in a bench scale reactor using a solution having a known initial dye concentration. After optimization, we found that both nanocomposites exhibit better photocatalytic activity compared to the standard photocatalyst P25 TiO2.

  1. TiO2 ve ZrO2/TiO2 Kompozit Mikrokürecik Sentezi ve Metilen Mavisinin Degradasyonunda Fotokatalitik Aktiviteleri

    OpenAIRE

    Vaizoğulları, Ali İmran; Balcı, Ahmet; Uğurlu, Mehmet; KARAOĞLU, Muhammet Hamdi

    2016-01-01

    TiO2 and ZrO2/TiO2 composite microsphere particles were synthesized using the sol‐gel method. Photoactivity of TiO2 and ZrO2/TiO2 were compared.  Particles were characterized using X‐ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM) of X‐ray (EDAX), and transmission electron microscopy (TEM). The study revealed that TiO2 particles were microspheres.    The decorating of ZrO2 particles on TiO2 surface was successfully carried out that was pr...

  2. Synthesis of TiO2 and ZrO2/TiO2 Composite Microspheres and Their Photo‐Catalytic Degradation of Methylene Blue

    OpenAIRE

    Vaizoğulları, Ali İmran; Balcı, Ahmet; UĞURLU, Mehmet; Karaoğlu, Muhammet Hamdi

    2016-01-01

    TiO2 and ZrO2/TiO2 composite microsphere particles were synthesized using the sol‐gel method. Photoactivity of TiO2 and ZrO2/TiO2 were compared.  Particles were characterized using X‐ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM) of X‐ray (EDAX), and transmission electron microscopy (TEM). The study revealed that TiO2 particles were microspheres.    The decorating of ZrO2 particles on TiO2 surface was successfully carried out that was pr...

  3. Selective aerobic oxidation mediated by TiO(2) photocatalysis.

    Science.gov (United States)

    Lang, Xianjun; Ma, Wanhong; Chen, Chuncheng; Ji, Hongwei; Zhao, Jincai

    2014-02-18

    TiO2 is one of the most studied metal oxide photocatalysts and has unparal-leled efficiency and stability. This cheap, abundant, and non-toxic material has the potential to address future environmental and energy concerns. Understanding about the photoinduced interfacial redox events on TiO2 could have profound effect on the degradation of organic pollutants, splitting of H2O into H2 and O2, and selective redox organic transformations. Scientists traditionally accept that for a semiconductor photocatalyst such as TiO2 under the illumination of light with energy larger than its band gap, two photocarriers will be created to carry out their independent reduction and oxidation processes. However, our recent discoveries indicate that it is the concerted rather than independent effect of both photocarriers of valence band hole (hvb(+)) and conduction band electron (ecb(-)) that dictate the product formation during interfacial oxidation event mediated by TiO2 photocatalysis. In this Account, we describe our recent findings on the selective oxidation of organic substrates with O2 mediated by TiO2 photocatalysis. The transfer of O-atoms from O2 to the corresponding products dominates the selective oxidation of alcohols, amines, and alkanes mediated by TiO2 photocatalysis. We ascribe this to the concerted effect of both hvb(+) and ecb(-) of TiO2 in contribution to the oxidation products. These findings imply that O2 plays a unique role in its transfer into the products rather than independent role of ecb(-) scavenger. More importantly, ecb(-) plays a crucial role to ensure the high selectivity for the oxygenation of organic substrates. We can also use the half reactions such as those of the conduction band electron of TiO2 for efficient oxidation reactions with O2. To this end, efficient selective oxidation of organic substrates such as alcohols, amines, and aromatic alkanes with O2 mediated by TiO2 photocatalysis under visible light irradiation has been achieved. In summary, the concerted effect of hvb(+) and ecb(-) to implement one oxidation event could pave the way for selective oxofunctionalization of organic substrates with O2 by metal oxide photocatalysis. Furthermore, it could also deepen our understanding on the role of O2 and the elusive nature of oxygen species at the interface of TiO2, which, in turn, could shed new light on avant-garde photocatalytic selective redox processes in addressing the energy and environmental challenges of the future.

  4. Catalysis by Using TiO2 Nanoparticles and Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Chien Shu-Hua; Kuo Ming-Chih; Liou Yuh-Cherng

    2004-01-01

    TiO2 has attracted considerable attention due to its stability, non-toxicity, low cost, and great potential for use as a photocatalyst in environmental applications. Since strong metal-support interaction (SMSI) of titania-supported noble metals was first reported in 1978, titania supported catalyst has been intensively studied in heterogeneous catalysis. However, the effective catalytic activity was restricted due to the low surface area of TiO2. Recently, TiO2-based nanotubes were extensively investigated because of their potentials in many areas such as highly efficient photocatalysis and hydrogen sensor.In the present study, formation of titanium oxide (TiO2) nanotubes was carried out by hydrothermal method, with TiO2 nanoparticle-powders immersed in concentrated NaOH solution in an autoclave at 110 ℃. Preparation of nano-size Pt on TiO2-nanoparticles or TiO2-nanotubes was performed by photochemical deposition method with UV irradiation on an aqueous solution containing TiO2 and hexachloroplatinic acid or tetrachloroauric acid. The TEM micrographs show that TiO2-nanotubes exhibit ~300 nm in length with an inner diameter of ~ 6 nm and the wall thickness of ~ 2 nm, and homogeneous nanosize Pt particles (~ 2 nm) were well-dispersed on both nanoparticle- and nanotube- titania supports. It also shows the nanotube morphology was retained up2o n Pt-immobilization. Nitrogen adsorption isotherm at 77K resulted a high surface area (~ 200m/g) of TiO2-nanotubes, which is about 40 times greater than that of "mother" TiO2 nanoparticles (~5 m/g). All the spectroscopic results exhibited that the nanotube structure was not significantly affected by the immobilized Pt particles. Ti K-edge XANES spectra of TiO2 nanotube and Pt/TiO2-nanotube represent that most titanium are in a tetrahedral coordination with few retained in the octahedral structure.In the in-situ FT-IR experiments, an IR cell was evacuated to a pressure of 10-5 torr at room temperature as soon as the catalyst-pellet, Pt/TiO2 or Pt/TiO2-nanotube, was placed inside the cell.Then, 60 torr of hydrogen was introduced into the cell and subsequently the temperature was programmed to increase from room temperature to 300℃ at a constant heating rate of 5℃/min.For Pt/TiO2, an IR peak at 2083 em-1 started to appear at 200℃ with a maximum intensity at 250℃ and then decreasing as temperature increased. The 2083 em-1 IR peak corresponds to the linearly adsorption of CO on the well-dispersed Pt sites. Simultaneously, the IR bands of gaseous methane at 3016 em-1 started to appear at 225℃ and the peak intensity increased with temperature. The results reveal that Pt/TiO2 can adsorb gaseous CO2 and further catalyzes the reduction of CO2 by H2 through the intermediate CO, which further produces gaseous methane. While for the Pt/TiO2-nanotube catalyst, methane was produced at relatively low temperature, 100℃, and it catalyzed the direct conversion of CO2 to CH4. The absence of intermediate CO-adsorption signals durinng the temperature programmed process indicates that the prepared TiO2 nanotube-supported nanosize Pt possesses a potent capability for CO2 adsorption and highly catalytic activity in the hydrogenation of CO2, and was superior to the conventional Pt/TiO2 catalyst. The catalytic activity of Pt/TiO2-nanotube was indeed significantly enhanced by the high surface area of TiO2-nanotubes.Details will be discussed.

  5. Lithium insertion in nanostructured TiO(2)(B) architectures.

    Science.gov (United States)

    Dylla, Anthony G; Henkelman, Graeme; Stevenson, Keith J

    2013-05-21

    Electric vehicles and grid storage devices have potentialto become feasible alternatives to current technology, but only if scientists can develop energy storage materials that offer high capacity and high rate capabilities. Chemists have studied anatase, rutile, brookite and TiO2(B) (bronze) in both bulk and nanostructured forms as potential Li-ion battery anodes. In most cases, the specific capacity and rate of lithiation and delithiation increases as the materials are nanostructured. Scientists have explained these enhancements in terms of higher surface areas, shorter Li(+) diffusion paths and different surface energies for nanostructured materials allowing for more facile lithiation and delithiation. Of the most studied polymorphs, nanostructured TiO2(B) has the highest capacity with promising high rate capabilities. TiO2(B) is able to accommodate 1 Li(+) per Ti, giving a capacity of 335 mAh/g for nanotubular and nanoparticulate TiO2(B). The TiO2(B) polymorph, discovered in 1980 by Marchand and co-workers, has been the focus of many recent studies regarding high power and high capacity anode materials with potential applications for electric vehicles and grid storage. This is due to the material's stability over multiple cycles, safer lithiation potential relative to graphite, reasonable capacity, high rate capability, nontoxicity, and low cost (Bruce, P. G.; Scrosati, B.; Tarascon, J.-M. Nanomaterials for Rechargeable Lithium Batteries. Angew. Chem., Int. Ed.2008, 47, 2930-2946). One of the most interesting properties of TiO2(B) is that both bulk and nanostructured forms lithiate and delithiate through a surface redox or pseudocapacitive charging mechanism, giving rise to stable high rate charge/discharge capabilities in the case of nanostructured TiO2(B). When other polymorphs of TiO2 are nanostructured, they still mainly intercalate lithium through a bulk diffusion-controlled mechanism. TiO2(B) has a unique open crystal structure and low energy Li(+) pathways from surface to subsurface sites, which many chemists believe to contribute to the pseudocapacitive charging. Several disadvantages exist as well. TiO2(B), and titania in general, suffers from poor electronic and ionic conductivity. Nanostructured TiO2(B) also exhibits significant irreversible capacity loss (ICL) upon first discharge (lithiation). Nanostructuring TiO2(B) can help alleviate problems with poor ionic conductivity by shortening lithium diffusion pathways. Unfortunately, this also increases the likelihood of severe first discharge ICL due to reactive Ti-OH and Ti-O surface sites that can cause unwanted electrolyte degradation and irreversible trapping of Li(+). Nanostructuring also results in lowered volumetric energy density, which could be a considerable problem for mobile applications. We will also discuss these problems and proposed solutions. Scientists have synthesized TiO2(B) in a variety of nanostructures including nanowires, nanotubes, nanoparticles, mesoporous-ordered nanostructures, and nanosheets. Many of these structures exhibit enhanced Li(+) diffusion kinetics and increased specific capacities compared to bulk material, and thus warrant investigation on how nanostructuring influences lithiation behavior. This Account will focus on these influences from both experimental and theoretical perspectives. We will discuss the surface charging mechanism that gives rise to the increased lithiation and delithiation kinetics for TiO2(B), along with the influence of dimensional confinement of the nanoarchitectures, and how nanostructuring can change the lithiation mechanism considerably.

  6. 活性炭纤维水热法负载TiO2光电催化氧化As(Ⅲ)%Photo-electro-catalytic oxidation of Arsenic (Ⅲ) with nano TiO2 loaded on activated carbon fiber by hydrothermal method

    Institute of Scientific and Technical Information of China (English)

    潘湛昌; 谢英豪; 魏志钢; 左俊辉; 胡光辉; 肖楚民; 冯玮琳

    2013-01-01

    采用水热法在ACF上负载纳米TiO2制备得TiO2/ACF光电极,利用XRD、SEM、TEM对其进行了晶体结构、表观形貌、粒径大小的分析.并将其用于光电催化氧化As(Ⅲ),探讨了外加偏压和氧气对氧化As(Ⅲ)的影响.电极暗态通电无法氧化As(Ⅲ),外加偏压对光电催化氧化As(Ⅲ)有最佳值0.5 V,在此条件下通氧气对氧化As(Ⅲ)无促进作用.在初始As(Ⅲ)为2.0 mg/L,pH=7,固液比1.0 g/L,外加偏压0.5 V条件下,紫外光照射60 min后As(Ⅲ)转化率达到86.7%.%Nano TiO2 loaded on activated carbon fiber(ACF) has been used for preparing TiO2/ACF photo-electrode by hydrothermal method.Its crystal structure,superficial appearance,and particle size are analyzed by XRD,SEM and TEM.It is applied to the photo-electro-catalytic oxidation of As (Ⅲ).The effects of plus bias voltage and oxygen on the oxidation of As (Ⅲ) are discussed.As (Ⅲ) cannot be oxidized by electrode without illumination.The results show that the optimum value of the external bias potential is 0.5 V,and under these conditions,oxygen does not have any promoting effect on the oxidation of As(Ⅲ).As(Ⅲ) conversion rate is up to 86.7%,when the initial concentration of As (Ⅲ) is 2.0 mg/L,pH--7,solid/solution ratio 1.0 g/L,plus bias voltage 0.5 V,and under UV irradiation for 60 min.

  7. 间苯二酚在TiO2-石墨烯修饰玻碳电极上的电化学行为及测定%Electrochemical behavior of resorcinol and its determination at TiO2-graphene modified glassy carbon electrode

    Institute of Scientific and Technical Information of China (English)

    韩金土; 王兰; 吴志伟; 张继宗

    2012-01-01

    制备了TiO2-石墨烯修饰玻碳电极.用循环伏安法(CV)和差分脉冲伏安法(DPV)对间苯二酚在该修饰电极的电化学行为进行了研究.实验结果表明,在pH值为6.0的磷酸盐缓冲液(PBS)中,该修饰电极对间苯二酚具有良好的电催化作用.对TiO2-石墨烯用量、支持电解质、pH和扫描速度等实验条件进行了优化.在优化条件下,利用DPV测定,间苯二酚的氧化峰电流与其浓度在1.0× 10-6 ~1.0× 10-4 mol/L范围内呈良好的线性关系,线性相关系数为0.995.检出限为2×10-7 mol/L.将该方法应用于模拟水样中间苯二酚的测定,回收率为96.5~104.2%.%An electrochemical sensor is fabricated based on TiO2-graphene nanocomposite film on modified glass carbon electrode. The electrochemical behavior of resorcinol( RS) at the modified electrode was investigated by cyclic voltametry( CV) and different pulse voltametry( DPV). In pH 6.0 phosphate buffer solution( PBS) ,the modified electrode showed excellent electrocatalytic activity for the redox of RS. The experimental conditions including amount of TiO2-graphene,supported electrolyte,pH and scan rate were optimized. Under the optimization condition,the concentration of RS showed good linear relationships with the oxidation peak current in the range of 1. 0×l0-6-l.0×10-4mol/L mol/L,with the limits of detection of 2×10-7mol/L(S/N=3). The method was applied to determine RS in simulated water samples with recoveries of 96. 5-104.2%.

  8. Sodium Carbonate Catalyzed Photoelectrochemical Water Splitting over TiO2 Nanotubes Photoanode%Na2CO3对TiO2纳米管电极表面光电化学水分解反应的催化作用研究

    Institute of Scientific and Technical Information of China (English)

    孔德生; 王静; 张学迪; 赵曦; 王超; 冯媛媛; 李文娟

    2013-01-01

    Surface recombination of the photogenerated electron-hole pairs at semiconductor/electrolyte interface is one of the most essential reasons responsible for lowering photoconversion efficiency (φ) of light to chemical energy for photoelectrochemical (PEC) water splitting reaction. In this paper,the catalytic effect of sodium carbonate on the oxygen evolution reaction(OER) over TiO2 nanotube photoanode during PEC water splitting was investigated by performing photocurrent and ac impedance measurements. It was demonstrated that the addiction of 1 mmol-L-1 Na2CO3 in 0.5 mol·L-1 NaClO4 electrolyte can effectively improve the charge transfer properties for the photogenerated holes across TiO2/electrolyte interface and inhibit the recombination of photogenerated carriers at this interface. As a result,both the measured photocurrent was increased and the photoconversion efficiency was enhanced.%光生载流子在半导体/溶液界面处发生的表面复合过程,是制约半导体光电极体系光-电转化效率提高的关键因素之一.本文利用光电流测量和交流阻抗等技术,初步研究了Na2CO3对TiO2纳米管电极表面光电化学水分解反应的催化作用,并对“TiO2/溶液”界面处与阳极析氧有关的光生电荷传输过程及特点进行了探讨.结果表明,在0.5 mol·L-1 NaC1O4溶液中加入少量的Na2CO3(1 mmol· L-1),能够显著促进光生空穴穿过TiO2/溶液界面向溶液中的传输,有效地抑制光生载流子的表面复合过程,从而相应地增大了外电路的光电流,并使TiO2光电极体系的光-电转化效率得到提高.

  9. Liquid-exfoliation of layered MoS2 for enhancing photocatalytic activity of TiO2/g-C3N4 photocatalyst and DFT study

    Science.gov (United States)

    Zhang, Weiping; Xiao, Xinyan; Li, Yang; Zeng, Xingye; Zheng, Lili; Wan, Caixia

    2016-12-01

    A new combined method of liquid-exfoliation and solvothermal process was employed for synthesizing TiO2/g-C3N4/MoS2 photocatalysts. In this typical process, the MoS2/g-C3N4 nano-sheets was prepared by liquid-exfoliation method from the bulk MoS2 and bulk carbon nitride in the alcohol system, and then the TiO2 nanoparticles (NPs) were grown on the MoS2/g-C3N4 nano-sheets by in-situ synthesis technique. The evaluation of photocatalytic degradation reaction showed that the as-prepared TiO2/g-C3N4/MoS2 photocatalysts exhibited higher photocatalytic activity as compared to the pure TiO2, pure g-C3N4 and TiO2/g-C3N4 composite. The enhanced photocatalytic activities of TiO2/g-C3N4/MoS2 photocatalysts are attributed to positive synergetic effect of heterostructure between g-C3N4/MoS2 hybrid and TiO2 nano-structure, which not only enlarged spectral response and also enhanced the utilization rate of photons. Furthermore, DFT (Density Functional Theory) was employed to investigate the formation mechanism of the interfaces between TiO2 NPs and g-C3N4/MoS2 nano-sheets, which would be of great importance in revealing the electron-transfer at the interfaces of composites and the mechanism for the great improvement for the activity of TiO2/g-C3N4/MoS2 photocatalysts.

  10. A self-supported peapod-like mesoporous TiO2-C array with excellent anode performance in lithium-ion batteries

    Science.gov (United States)

    Peng, Liang; Zhang, Huijuan; Bai, Yuanjuan; Zhang, Yan; Wang, Yu

    2015-05-01

    Herein, we introduce a novel peapod-like architectural array with TiO2 nanoparticles encapsulated in graphitized carbon fibers for the first time. The unique peapod-like TiO2 arrays with high conductivity architectures are designed and fabricated for application in Li-ion batteries. Since the as-synthesized TiO2 peapod array is characterized with the large surface area derived from the mesoporous carbon fiber, as well as the high conductivity further enhanced by a thin carbon coating layer, it has shown superior rate capability, high specific capacitances, and excellent cycling stability, e.g. the specific capacity can reach up to 162 mA h g-1 over 200 cycles. A rational and universal approach to fabricate a high-performance TiO2 peapod array for constructing next-generation Li-ion batteries is demonstrated in this paper. Furthermore, due to the specificity of the structure and the versatility of TiO2, the nanocomposite can also be applied in photochemical catalysis, electronics, biomedicine, gas sensing and so on.Herein, we introduce a novel peapod-like architectural array with TiO2 nanoparticles encapsulated in graphitized carbon fibers for the first time. The unique peapod-like TiO2 arrays with high conductivity architectures are designed and fabricated for application in Li-ion batteries. Since the as-synthesized TiO2 peapod array is characterized with the large surface area derived from the mesoporous carbon fiber, as well as the high conductivity further enhanced by a thin carbon coating layer, it has shown superior rate capability, high specific capacitances, and excellent cycling stability, e.g. the specific capacity can reach up to 162 mA h g-1 over 200 cycles. A rational and universal approach to fabricate a high-performance TiO2 peapod array for constructing next-generation Li-ion batteries is demonstrated in this paper. Furthermore, due to the specificity of the structure and the versatility of TiO2, the nanocomposite can also be applied in

  11. TiO2 nanotubes and mesoporous silica as containers in self-healing epoxy coatings

    Science.gov (United States)

    Vijayan P., Poornima; Al-Maadeed, Mariam Ali S. A.

    2016-12-01

    The potential of inorganic nanomaterials as reservoirs for healing agents is presented here. Mesoporous silica (SBA-15) and TiO2 nanotubes (TNTs) were synthesized. Both epoxy-encapsulated TiO2 nanotubes and amine-immobilized mesoporous silica were incorporated into epoxy and subsequently coated on a carbon steel substrate. The encapsulated TiO2 nanotubes was quantitatively estimated using a ‘dead pore ratio’ calculation. The morphology of the composite coating was studied in detail using transmission electron microscopic (TEM) analysis. The self-healing ability of the coating was monitored using electrochemical impedance spectroscopy (EIS); the coating recovered 57% of its anticorrosive property in 5 days. The self-healing of the scratch on the coating was monitored using Scanning Electron Microscopy (SEM). The results confirmed that the epoxy pre-polymer was slowly released into the crack. The released epoxy pre-polymer came into contact with the amine immobilized in mesoporous silica and cross-linked to heal the scratch.

  12. Photocatalytic oxidation of gaseous DMF using thin film TiO2 photocatalyst.

    Science.gov (United States)

    Chang, Chiu-Ping; Chen, Jong-Nan; Lu, Ming-Chun; Yang, He-Yuan

    2005-02-01

    The heterogeneous photocatalytic oxidation of gaseous N,N'-dimethylformamide (DMF) widely used in the manufacture of synthetic leather and synthetic textile was investigated. The experiments were carried out in a plug flow annular photoreactor coated with Degussa P-25 TiO2. The oxidation rate was dependent on DMF concentration, reaction temperature, water vapor, and oxygen content. Photocatalytic deactivation was observed in these reactions. The Levenspiel deactivation kinetic model was used to describe the decay of catalyst activity. Fourier transform infrared (FTIR) was used to characterize the surface and the deactivation mechanism of the photocatalyst. Results revealed that carbonylic acids, aldehydes, amines, carbonate and nitrate were adsorbed on the TiO2 surface during the photocatalytic reaction. The ions, NH4+ and NO3-, causing the deactivation of catalysts were detected on the TiO2 surface. Several treatment processes were applied to find a suitable procedure for the regeneration of catalytic activity. Among these procedures, the best one was found to be the H2O2/UV process.

  13. Nanoimprint lithography using TiO2-SiO2 ultraviolet curable materials

    Science.gov (United States)

    Takei, Satoshi

    2015-05-01

    Ultraviolet nanoimprint lithography has great potential for commercial device applications that are closest to production such as optical gratings, planar waveguides, photonic crystals, semiconductor, displays, solar cell panel, sensors, highbrightness LEDs, OLEDs, and optical data storage. I report and demonstrate the newly TiO2-SiO2 ultraviolet curable materials with 20-25 wt% ratio of high titanium for CF4/O2 etch selectivity using nanoimprint lithography process. The multiple structured three-dimensional micro- and nanolines patterns were observed to be successfully patterned over the large areas. The effect of titanium concentration on CF4/O2 etch selectivity with pattern transferring carbon layer imprinting time was investigated. CF4/O2 etching rate of the TiO2-SiO2 ultraviolet curable material was approximately 3.8 times lower than that of the referenced SiO2 sol-gel ultraviolet curable material. The TiO2-SiO2 ultraviolet curable material with high titanium concentration has been proved to be versatile in advanced nanofabrication.

  14. Photocatalytic synthesis of 2-methylquinolines with TiO2 Wackherr and Home Prepared TiO2 – A comparative study

    National Research Council Canada - National Science Library

    Selvam, Kaliyamoorthy; Swaminathan, Meenakshisundaram

    2017-01-01

    A comparative study was carried out on the efficiency of titanium dioxide specimens Wackherr TiO2, prepared TiO2 and Aeroxide P25 toward the photocatalytic synthesis of pharmaceutically important 2-methylquinolines...

  15. Dynamics of fibronectin adsorption on TiO2 surfaces.

    Science.gov (United States)

    Sousa, S R; Brás, M Manuela; Moradas-Ferreira, P; Barbosa, M A

    2007-06-19

    In the present work we analyze the dynamics of fibronectin (FN) adsorption on two different stable titanium oxides, with varied surface roughness, and chemically similar to those used in clinical practice. The two types of titanium oxide surfaces used were TiO2 sputtered on Si (TiO2 sp) and TiO2 formed on commercially pure titanium after immersion in H2O2 (TiO2 cp). Surface characterization was previously carried out using different techniques (Sousa, S. R.; Moradas-Ferreira, P.; Melo, L. V.; Saramago, B.; Barbosa, M. A. Langmuir 2004, 20 (22), 9745-9754). Imaging and roughness analysis before and after FN adsorption used atomic force microscopy (AFM) in tapping mode, in air, and in magnetic alternating current mode, in liquid (water). FN adsorption as a function of time was followed by X-ray photoelectron spectroscopy (XPS), by radiolabeling of FN with 125I (125I-FN), and by ellipsometry. Exchangeability studies were performed using FN and HSA. AFM roughness analysis revealed that, before FN adsorption, both TiO2 surfaces exhibited a lower root-mean-square (Rq) and maximum peak with the depth of the maximum valley (Rmax) roughness in air than in water, due to TiO2 hydration. After protein adsorption, the same behavior was observed for the TiO2 sp substrate, while Rq and Rmax roughness values in air and in water were similar in the case of the TiO2 cp substrate, for the higher FN concentration used. Surface roughness was always significantly higher on the TiO2 cp surfaces. AFM led to direct visualization of adsorbed FN on both surfaces tested, indicating that after 10 min of FN incubation the TiO2 sp surface was partially covered by FN. The adsorbed protein seems to form globular aggregates or ellipsoids, and FN aggregates coalesce, forming clusters as the time of adsorption and the concentration increase. Radiolabeling of FN revealed that a rapid adsorption occurs on both surfaces and the amount adsorbed increased with time, reaching a maximum after 60 min of incubation. Time dependence is also observed for the evolution of the atomic (%) of N determined by XPS and by the increase of the thickness by ellipsometry. TiO2 cp adsorbs more FN than the TiO2 sp surfaces, after 60 min of adsorption, as shown by the radiolabeling data. FN molecules are also more strongly attached to the former surface as indicated by the exchangeability studies. The overall results provide novel evidence that FN spontaneously adsorbs as a self-assembly at TiO2 surfaces as a function of time. The aggregate structure is an intermediate feature shared by some protein fibrillar assemblies at interfaces, which is believed to promote cell adhesion and cytoskeleton organization (Pellenc, D.; Berry, H.; Gallet, O. J. Colloid Interface Sci. 2006, 298 (1), 132-144. Maheshwari, G.; Brown, G.; Lauffenburger, D. A.; Wells, A.; Griffith, L. G. J. Cell Sci. 2000, 113 (10), 1677-1686).

  16. Composite TiO2/clays materials for photocatalytic NOx oxidation

    Science.gov (United States)

    Todorova, N.; Giannakopoulou, T.; Karapati, S.; Petridis, D.; Vaimakis, T.; Trapalis, C.

    2014-11-01

    TiO2 photocatalyst received much attention for air purification applications especially for removal of air pollutants like NOx, VOCs etc. It has been established that the activity of the photocatalyst can be significantly enhanced by its immobilization onto suitable substrates like inorganic minerals, porous silica, hydroxyapatite, adsorbent materials like activated carbon, various co-catalysts such as semiconductors, graphene, reduced graphite oxide, etc. In the present work, photocatalytic composite materials consisted of mineral substrate and TiO2 in weight ratio 1:1 were manufactured and examined for oxidation and removal of nitric oxides NOx (NO and NO2). Commercial titania P25 (Evonik-Degussa) and urea-modified P25 were used as photocatalytically active components. Inorganic minerals, namely kunipia, talk and hydrotalcite were selected as supporting materials due to their layered structure and expected high NOx adsorption capability. Al3+ and Ca2+ intercalation was applied in order to improve the dispersion of TiO2 and its loading into the supporting matrix. The X-ray diffraction analysis and Scanning Electron Microscopy revealed the binary structure of the composites and homogeneous dispersion of the photocatalyst into the substrates. The photocatalytic behavior of the materials in NOx oxidation and removal was investigated under UV and visible light irradiation. The composite materials exhibited superior photocatalytic activity than the bare titania under both types of irradiation. Significant visible light activity was recorded for the composites containing urea-modified titania that was accredited to the N-doping of the semiconductor. Among the different substrates, the hydrotalcite caused highest increase in the NOx removal, while among the intercalation ions the Ca2+ was more efficient. The results were related to the improved dispersion of the TiO2 and the synergetic activity of the substrates as NOx adsorbers.

  17. Photocatalytic Properties of TiO2 Porous Network Film.

    Science.gov (United States)

    Yu, Lianqing; Zhi, Qianqian; Huang, Chengxing; Zhang, Yaping; Dong, Kaituo; Neppolian, B

    2015-09-01

    Three-dimensional porous network TiO2 film (PW-film) and nanoparticles film were synthesized on surface of the Ti foil by a facile method to investigate both the photoelectrochemical and photocatalytic properties. The prepared samples were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction spectroscopy (XRD) techniques. Methylene blue was used as a target molecule to estimate the photocatalytic activity of the films. Results revealed that the hydrothermal temperature and time have great influence on the crystal type and film morphology of TiO2 catalysts. A higher hydrothermal temperature is benefit for the formation of anatase phase of TiO2 nanotubes with PW-film, which had a large number of nodes. After investigation of the photoelectrochemical properties, a maximum photoconversion efficiency of 4.79% is observed for nanoparticles film with rutile phase of TiO2 under UV light illumination, which was incredible 2 times higher than that of the PW-film with anatase phase. It was shown that the morphology of TiO2 film contributes more significant effect on photocatalytic and photoelectric performance than its crystal type.

  18. Growing TiO2 nanowires on the surface of graphene sheets in supercritical CO2: characterization and photoefficiency

    Science.gov (United States)

    Farhangi, Nasrin; Medina-Gonzalez, Yaocihuatl; Chowdhury, Rajib Roy; Charpentier, Paul A.

    2012-07-01

    Tremendous interest exists towards synthesizing nanoassemblies for dye-sensitized solar cells (DSSCs) using earth-abundant and -friendly materials with green synthetic approaches. In this work, high surface area TiO2 nanowire arrays were grown on the surface of functionalized graphene sheets (FGSs) containing -COOH functionalities acting as a template by using a sol-gel method in the green solvent, supercritical carbon dioxide (scCO2). The effect of scCO2 pressure (1500, 3000 and 5000 psi), temperature (40, 60 and 80 °C), acetic acid/titanium isopropoxide monomer ratios (HAc/TIP = 2, 4 and 6), functionalized graphene sheets (FGSs)/TIP weight ratios (1:20, 1:40 and 1:60 w/w) and solvents (EtOH, hexane) were investigated. Increasing the HAc/TIPweight ratio from 4 to 6 in scCO2 resulted in increasing the TiO2 nanowire diameter from 10 to 40 nm. Raman and high resolution XPS showed the interaction of TiO2 with the -COOH groups on the surface of the graphene sheets, indicating that graphene acted as a template for polycondensation growth. UV-vis diffuse reflectance and photoluminescence spectroscopy showed a reduction in titania’s bandgap and also a significant reduction in electron-hole recombination compared to bare TiO2 nanowires. Photocurrent measurements showed that the TiO2nanowire/graphene composites prepared in scCO2 gave a 5× enhancement in photoefficiency compared to bare TiO2 nanowires.

  19. One-step synthesis of visible active Csbnd Nsbnd S-tridoped TiO2 photocatalyst from biomolecule cystine

    Science.gov (United States)

    Cheng, Xiuwen; Yu, Xiujuan; Xing, Zipeng

    2012-07-01

    Csbnd Nsbnd S-tridoped TiO2 nano-particles were synthesized through simple one-step sol-gel reactions in the presence of biomolecule cystine. This biomolecule could not only serve as the source for C, N and S tridoping, but also could control the light absorption in visible region and separation efficiency of photogenerated charge carriers. The resulting materials were characterized by X-ray diffraction (XRD), Nitrogen adsorption-desorption, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and surface photovoltage spectrum (SPS). It was found that S6+ was incorporated into the lattice of TiO2 through substituting titanium atoms; N might coexist in the forms of substituted N (Nsbnd Osbnd Ti) and interstitial N (Osbnd Tisbnd N) in TiO2; and C could form a mixed layer of carbonate on the surface of TiO2. Further, the addition of cystine greatly improved the light absorption in visible region and the separation efficiency of photogenerated charge carriers. The photocatalytic activities of the as-synthesized samples were evaluated for the degradation of phenol under simulated sunlight irradiation. Results showed that Csbnd Nsbnd S-tridoped TiO2 exhibited higher sunlight photocatalytic degradation efficiency than that of undoped and P25 TiO2 samples. The enhanced photocatalytic activity could be attributed to the small crystallite size, intense light absorption in visible region, large amount of surface hydroxyl groups and high separation efficiency of photogenerated charger carriers.

  20. Uniform Gold Nanoparticles Decorated {001}-Faceted Anatase TiO2 Nanosheets for Enhanced Solar Light Photocatalytic Reactions.

    Science.gov (United States)

    Shi, Huimin; Zhang, Shi; Zhu, Xupeng; Liu, Yu; Wang, Tao; Jiang, Tian; Zhang, Guanhua; Duan, Huigao

    2017-10-09

    The {001}-faceted anatase TiO2 micro/nanocrystals have been widely investigated for enhancing the photocatalysis and photoelectrochemical performance of TiO2 nanostructures but their practical applications still require improved energy conversion efficiency under solar light and enhanced cycling stability. In this work, we demonstrate the controlled growth of ultrathin {001}-faceted anatase TiO2 nanosheets on flexible carbon cloth for enhancing the cycling stability, and the solar light photocatalytic performance of the synthesized TiO2 nanosheets can be significantly improved by decorating with vapor-phase deposited uniformly-distributed plasmonic gold nanoparticles. The fabricated Au-TiO2 hybrid system shows an eight-fold solar light photocatalysis enhancement factor in photo-degrading Rhodamine B, a high photocurrent density of 300 μA cm-2 under the illumination of AM 1.5G, and 100% recyclability under consecutive long-term cycling measurement. Combined with electromagnetic simulations and systematic control experiments, it is believed that the tandem type separation and transition of plasmon-induced hot electrons from Au nanoparticles to {001} facet of anatase TiO2, and then to neighboring {101} facet is responsible to the enhanced solar light photochemical performance of the hybrid system. The Au-TiO2 nanosheet system well addresses the problems of limited solar-light response of anatase TiO2 and fast recombination of photo-generated electron-hole pairs, representing a promising high-performance recyclable solar light responded system for practical photocatalytic reactions.

  1. Superiority of solar Fenton oxidation over TiO2 photocatalysis for the degradation of trimethoprim in secondary treated effluents.

    Science.gov (United States)

    Michael, I; Hapeshi, E; Michael, C; Fatta-Kassinos, D

    2013-01-01

    The overall aim of this work was to examine the degradation of trimethoprim (TMP), which is an antibacterial agent, during the application of two advanced oxidation process (AOP) systems in secondary treated domestic effluents. The homogeneous solar Fenton process (hv/Fe(2+)/H2O2) and heterogeneous photocatalysis with titanium dioxide (TiO2) suspensions were tested. It was found that the degradation of TMP depends on several parameters such as the amount of iron salt and H2O2, concentration of TiO2, pH of solution, solar irradiation, temperature and initial substrate concentration. The optimum dosages of Fe(2+) and H2O2 for homogeneous ([Fe(2+)] = 5 mg L(-1), [H2O2] = 3.062 mmol L(-1)) and TiO2 ([TiO2] = 3 g L(-1)) for heterogeneous photocatalysis were established. The study indicated that the degradation of TMP during the solar Fenton process is described by a pseudo-first-order reaction and the substrate degradation during the heterogeneous photocatalysis by the Langmuir-Hinshelwood kinetics. The toxicity of the treated samples was evaluated using a Daphnia magna bioassay and was finally decreased by both processes. The results indicated that solar Fenton is more effective than the solar TiO2 process, yielding complete degradation of the examined substrate within 30 min of illumination and dissolved organic carbon (DOC) reduction of about 44% whereas the respective values for the TiO2 process were ∼70% degradation of TMP within 120 min of treatment and 13% DOC removal.

  2. Chemical modification of nanometric TiO2 particles by anchoring functional silane molecules in supercritical CO2

    Science.gov (United States)

    López-Periago, Ana M.; Sandoval, Wendy; Domingo, Concepción

    2014-03-01

    Supercritical carbon dioxide (scCO2) was used as a green solvent for the grafting of complex functional organosilanes containing nitrogen moieties on titanium dioxide (TiO2) nanoparticles using two strategies. The first strategy involved the preparation of two functional silanes, 4-nitrophenyl-(3-(trimethoxysilyl)-propyl)methanimine (NPTMS) and 4-(((3-(trimethoxysilyl)propyl)imino)methyl)-benzaldehyde (FPTMS) and further deposited under anhydrous conditions and scCO2 onto the TiO2 surface. The second strategy involved the scCO2 anhydrous deposition of bifunctional commercial silanes on the TiO2 surface. Two structures were synthesized. The first consisted in grafted TiO2 nanoparticles prepared by addition of the ligand, ((1R,2R)-N-(pyridin-2-ylmethyl)-2-(((E)-pyridin-2-ylmethylene) amino)-cyclohexan-1-amine (LPy-red), and designated as Ti-Cl-LPy-red. The second structure was synthesized by the reaction of (1,2)-diaminocylohexane (Dac), through the reactive site of 3-(Trimethoxysilyl)propyl methacrylate (MPTMS) previously deposited on the TiO2 surface and designated as Ti-MP-Dac. The synthesized silanes were characterized by ATR-FT and NMR spectroscopies and mass spectrometry. ATR-FT spectroscopy confirmed the presence of the silanes on the surface of the hybrid nanoparticles. Thermogravimetic analysis was used to estimate the loading of the silane grafted through both hydrogen and covalent bonding on the TiO2 surface. Further characterization of the solid samples was done by N2 adsorption-desorption and UV-vis diffuse reflectance.

  3. PHOTOCATALYTIC ACTIVITY OF LANTHANUM DOPING TiO2

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The photocatalytic activity of the mixtures of TiO2 with the rare earth oxide La was investigated. The study on the effect of the rare earth oxide content, calcinating temperature and calcinating time on the performance of the mixture revealed that sample treated under higher temperature and longer time had higher photoactivity than pure TiO2. The experimental results of polycrystalline X-ray diffraction showed that the extent of the lattice expansion varied with the variation of calcinating temperature or time. It is suggested that this might be due to the variation of La content diffused into the TiO2 lattice. The La in the lattice may inhibit the recombinatin of photogenerated electron-hole pairs and thus enhance the photoactivity.

  4. Synthesis and characterization of TiO2/cellulose nanocomposites

    OpenAIRE

    Gonçalves, Gil Alberto Batista

    2007-01-01

    O objectivo principal desta tese foi a preparação, caracterização e estudo de possíveis aplicações de novos nanocompósitos de TiO2/celulose. Numa primeira fase, os nanocompósitos de TiO2/celulose foram preparados a partir da síntese in situ do TiO2 na presença de fibras celulósicas. Para esta síntese estudaram-se os parâmetros experimentais que permitem controlar a hidrólise do tetracloreto de titânio (TiCl4) e ureia, na presença de fibras celulósicas. Através desta abordage...

  5. Effect of TiO2 on the Gas Sensing Features of TiO2/PANi Nanocomposites

    Science.gov (United States)

    Huyen, Duong Ngoc; Tung, Nguyen Trong; Thien, Nguyen Duc; Thanh, Le Hai

    2011-01-01

    A nanocomposite of titanium dioxide (TiO2) and polyaniline (PANi) was synthesized by in-situ chemical polymerization using aniline (ANi) monomer and TiCl4 as precursors. SEM pictures show that the nanocomposite was created in the form of long PANi chains decorated with TiO2 nanoparticles. FTIR, Raman and UV-Vis spectra reveal that the PANi component undergoes an electronic structure modification as a result of the TiO2 and PANi interaction. The electrical resistor of the nanocomposite is highly sensitive to oxygen and NH3 gas, accounting for the physical adsorption of these gases. A nanocomposite with around 55% TiO2 shows an oxygen sensitivity of 600–700%, 20–25 times higher than that of neat PANi. The n-p contacts between TiO2 nanoparticles and PANi matrix give rise to variety of shallow donors and acceptor levels in the PANi band gap which enhance the physical adsorption of gas molecules. PMID:22319389

  6. Effect of TiO2 on the Gas Sensing Features of TiO2/PANi Nanocomposites

    Directory of Open Access Journals (Sweden)

    Duong Ngoc Huyen

    2011-02-01

    Full Text Available A nanocomposite of titanium dioxide (TiO2 and polyaniline (PANi was synthesized by in-situ chemical polymerization using aniline (ANi monomer and TiCl4 as precursors. SEM pictures show that the nanocomposite was created in the form of long PANi chains decorated with TiO2 nanoparticles. FTIR, Raman and UV-Vis spectra reveal that the PANi component undergoes an electronic structure modification as a result of the TiO2 and PANi interaction. The electrical resistor of the nanocomposite is highly sensitive to oxygen and NH3 gas, accounting for the physical adsorption of these gases. A nanocomposite with around 55% TiO2 shows an oxygen sensitivity of 600–700%, 20–25 times higher than that of neat PANi. The n-p contacts between TiO2 nanoparticles and PANi matrix give rise to variety of shallow donors and acceptor levels in the PANi band gap which enhance the physical adsorption of gas molecules.

  7. Different methods in TiO2 photodegradation mechanism studies: gaseous and TiO2-adsorbed phases.

    Science.gov (United States)

    Deveau, Pierre-Alexandre; Arsac, Fabrice; Thivel, Pierre-Xavier; Ferronato, Corinne; Delpech, Françoise; Chovelon, Jean-Marc; Kaluzny, Pascal; Monnet, Christine

    2007-06-18

    The development of photocatalysis processes offers a significant number of perspectives especially in gaseous phase depollution. It is proved that the photo-oxidizing properties of photocatalyst (TiO(2)) activated by UV plays an important role in the degradation of volatile organic compounds (VOC). Heterogeneous photocatalysis is based on the absorption of UV radiations by TiO(2). This phenomenon leads to the degradation and the oxidation of the compounds, according to a mechanism that associates the pollutant's adsorption on the photocatalyst and radical degradation reactions. The main objective of the study is the understanding of the TiO(2)-photocatalysis phenomenon including gaseous and adsorbed phase mechanisms. Results obtained with three different apparatus are compared; gaseous phases are analysed and mechanisms at the gaseous phase/photocatalyst interface are identified. This study leads to improve understanding of various mechanisms during pollutant photodegradation: adsorption of pollutants on TiO(2) first takes place, then desorption and/or photodegradation, and finally, desorption of degradation products on TiO(2). The association of analytical methods and different processes makes the determination of all parameters that affect the photocatalytic process possible. Mastering these parameters is fundamental for the design and construction of industrial size reactors that aim to purify the atmosphere.

  8. Influence of Pore Size on the Optical and Electrical Properties of Screen Printed TiO2 Thin Films

    Directory of Open Access Journals (Sweden)

    Dinfa Luka Domtau

    2016-01-01

    Full Text Available Influence of pore size on the optical and electrical properties of TiO2 thin films was studied. TiO2 thin films with different weight percentages (wt% of carbon black were deposited by screen printing method on fluorine doped tin oxide (FTO coated on glass substrate. Carbon black decomposed on annealing and artificial pores were created in the films. All the films were 3.2 µm thick as measured by a surface profiler. UV-VIS-NIR spectrophotometer was used to study transmittance and reflectance spectra of the films in the photon wavelength of 300–900 nm while absorbance was studied in the range of 350–900 nm. Band gaps and refractive index of the films were studied using the spectra. Reflectance, absorbance, and refractive index were found to increase with concentrations of carbon black. There was no significant variation in band gaps of films with change in carbon black concentrations. Transmittance reduced as the concentration of carbon black in TiO2 increased (i.e., increase in pore size. Currents and voltages (I-V characteristics of the films were measured by a 4-point probe. Resistivity (ρ and conductivity (σ of the films were computed from the I-V values. It was observed that resistivity increased with carbon black concentrations while conductivity decreased as the pore size of the films increased.

  9. Silicon protected with atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Seger, Brian; Tilley, David S.; Pedersen, Thomas

    2013-01-01

    dioxide (TiO2) overlayers on silicon-based photocathodes generate extremely stable electrodes. These electrodes can produce an onset potential of +0.510 V vs. RHE and a hydrogen evolution saturation current of 22 mA cm−2 using the red part of the AM1.5 solar spectrum (λ > 635 nm, 38.6 mW cm−2). A PEC...... chronoamperometry experiment was carried out for 2 weeks under constant illumination at +0.300 V vs. RHE with negligible degradation (TiO2 overlayers may have...

  10. Photocatalytic antibacterial performance of TiO2 and Ag-doped TiO2 against S. aureus. P. aeruginosa and E. coli

    OpenAIRE

    Gupta, Kiran; Singh, R. P.; Pandey, Ashutosh; Pandey, Anjana

    2013-01-01

    This paper reports the structural and optical properties and comparative photocatalytic activity of TiO2 and Ag-doped TiO2 nanoparticles against different bacterial strains under visible-light irradiation. The TiO2 and Ag-doped TiO2 photocatalysts were synthesized by acid catalyzed sol–gel technique and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy and photoluminescence (PL). The XRD pattern revealed that the annealed sample of TiO2 has ...

  11. In-situ TEM Study on Microstructural Evolution of Nanostructured TiO2

    Institute of Scientific and Technical Information of China (English)

    SHAO Yanqun; TANG Dian; XIONG Weihao

    2007-01-01

    The effect of electron beam on the microstructures and phase transformation of nanostructured TiO2 heat treated at various temperatures for different time was studied by in-situ TEM and SAED. Anatase ex-situ heated at 250℃ and 360℃ transformed to rutile while irradiated by the electron beam. With the increasing sizes and distribution of the powders on the amorphous carbon, the process of phase transformation by the electron beam was encumbered. These evolutions may be due to the changes of vacuum atmosphere and the properties of powders.

  12. Band structures of TiO2 doped with N, C and B*

    OpenAIRE

    2006-01-01

    This study on the band structures and charge densities of nitrogen (N)-, carbon (C)- and boron (B)-doped titanium dioxide (TiO2) by first-principles simulation with the CASTEP code (Segall et al., 2002) showed that the three 2p bands of impurity atom are located above the valence-band maximum and below the Ti 3d bands, and that along with the decreasing of impurity atomic number, the fluctuations become more intensive. We cannot observe obvious band-gap narrowing in our result. Therefore, the...

  13. A review on the effects of TiO2 surface point defects on CO2 photoreduction with H2O

    Directory of Open Access Journals (Sweden)

    Huilei Zhao

    2017-03-01

    Full Text Available Photocatalytic reduction of CO2 with water by photocatalysts such as TiO2 to produce solar fuels is an attractive approach to alleviate the environmental influences of greenhouse gases and in the meantime produce valuable carbon-neutral fuels. Among the materials properties that affect catalytic activity of CO2 photoreduction, the point defect on TiO2 is one of the most important but not frequently addressed and well understood in the literature. In this review, we have examined the major influences of TiO2 point defects on CO2 photoreduction with H2O, by changing the catalysts' gas adsorption capabilities, optical properties, and electronic structures. In addition, the performances of various defective TiO2 toward CO2 photoreduction are summarized and compared in terms of productivity, selectivity, and stability. We hope this review can contribute to understanding the mechanism of CO2 photoreduction on defective TiO2 and provide insights to the design of highly efficient defect-rich TiO2 to boost the CO2 utilization.

  14. High photocatalytic activity of hierarchical SiO2@C-doped TiO2 hollow spheres in UV and visible light towards degradation of rhodamine B.

    Science.gov (United States)

    Zhang, Ying; Chen, Juanrong; Hua, Li; Li, Songjun; Zhang, Xuanxuan; Sheng, Weichen; Cao, Shunsheng

    2017-10-15

    Ongoing research activities are targeted to explore high photocatalytic activity of TiO2-based photocatalysts for the degradation of environmental contaminants under UV and visible light irradiation. In this work, we devise a facile, cost-effective technique to in situ synthesize hierarchical SiO2@C-doped TiO2 (SCT) hollow spheres for the first time. This strategy mainly contains the preparation of monodisperse cationic polystyrene spheres (CPS), sequential deposition of inner SiO2, the preparation of the sandwich-like CPS@SiO2@CPS particles, and formation of outer TiO2. After the one-step removal of CPS templates by calcination at 450°C, hierarchical SiO2@C-doped TiO2 hollow spheres are in situ prepared. The morphology, hierarchical structure, and properties of SCT photocatalyst were characterized by TEM. SEM, STEM Mapping, BET, XRD, UV-vis spectroscopy, and XPS. Results strongly confirm the carbon doping in the outer TiO2 lattice of SCT hollow spheres. When the as-synthesized SCT hollow spheres were employed as a photocatalyst for the degradation of Rhodamine B under visible-light and ultraviolet irradiation, the SCT photocatalyst exhibits a higher photocatalytic activity than commercial P25, effectively overcoming the limitations of poorer UV activity for many previous reported TiO2-based photocatalysts due to doping. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Enhanced photocatalytic activity of TiO2-impregnated with MgZnAl mixed oxides obtained from layered double hydroxides for phenol degradation

    Science.gov (United States)

    de Almeida, Marciano Fabiano; Bellato, Carlos Roberto; Mounteer, Ann Honor; Ferreira, Sukarno Olavo; Milagres, Jaderson Lopes; Miranda, Liany Divina Lima

    2015-12-01

    A series of TiO2/MgZnAl photocatalysts were successfully synthesized from ternary (Mg, Zn and Al) layered double hydroxides impregnated with TiO2 nanoparticles by the co-precipitation method at variable pH with different Zn2+/Mg2+ molar ratios. The composite photocatalysts were calcined at 500 °C resulting in the incorporation of oxide zinc, in the calcined MgZnAl LDH structure. Synergistic effect between ZnO and TiO2 lead to significant enhancement of TiO2/MgZnAl photocatalytic activity. Composite photocatalysts were characterized by ICP-MS, N2 adsorption-desorption, XRD, SEM, EDS, IR and UV-vis DRS. Phenol in aqueous solution (50 mg/L) was used as a model compound for evaluation of UV-vis (filter cut-off for λ > 300 nm) photocatalytic activity. The most efficient photocatalyst composite was obtained at a 5% Zn2+/Mg2+ molar ratio, in the catalyst identified as TiO2/MgZnAl-5. This composite catalyst had high photocatalytic activity, completely destroying phenol and removing 80% of total organic carbon in solution after 360 min. The TiO2/MgZnAl-5 catalyst remained relatively stable, presenting a 15% decrease in phenol degradation efficiency after five consecutive photocatalytic cycles.

  16. Photocatalytic behaviour of WO3/TiO2-N for diclofenac degradation using simulated solar radiation as an activation source.

    Science.gov (United States)

    Cordero-García, A; Turnes Palomino, G; Hinojosa-Reyes, L; Guzmán-Mar, J L; Maya-Teviño, L; Hernández-Ramírez, A

    2017-02-01

    In this study, the photocatalytic removal of an emerging contaminant, diclofenac (DCF) sodium, was performed using the nitrogen-doped WO3/TiO2-coupled oxide catalyst (WO3/TiO2-N). The catalyst synthesis was accomplished by a sol-gel method using tetrabutyl orthotitanate (C16H36O4Ti), ammonium p-tungstate [(NH4)10H2W12O42·4H2O] and ammonium nitrate (NH4NO3) as the nitrogen source. For comparison, TiO2 and WO3/TiO2 were also prepared under similar conditions. Analysis by X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV-Vis spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS) were conducted to characterize the synthesized materials. The photocatalytic efficiency of the semiconductors was determined in a batch reactor irradiated with simulated solar light. Residual and mineralized DCF were quantified by high-performance liquid chromatography, total organic carbon analysis and ion exchange chromatography. The results indicated that the tungsten atoms were dispersed on the surface of TiO2 as WO3. The partial substitution of oxygen by nitrogen atoms into the lattice of TiO2 was an important factor to improve the photocatalytic efficiency of WO3/TiO2. Therefore, the best photocatalytic activity was obtained with the WO3/TiO2-N0.18 catalyst, reaching 100% DCF transformation at 250 kJ m(-2) and complete mineralization at 400 kJ m(-2) of solar-accumulated energy.

  17. Synergistic effects of graphene quantum dot sensitization and nitrogen doping of ordered mesoporous TiO2 thin films for water splitting photocatalysis(Conference Presentation)

    Science.gov (United States)

    Islam, Syed Z.; Wanninayake, Namal; Reed, Allen D.; Kim, Doo-Young; Rankin, Stephen E.

    2016-10-01

    The optical and electronic properties of TiO2 thin films provide tremendous opportunities in several applications including photocatalysis, photovoltaics and photoconductors for energy production. Despite many attractive features of TiO2, critical challenges include the innate inability of TiO2 to absorb visible light and the fast recombination of photoexcited charge carriers. In this study, we prepared ordered mesoporous TiO2 films co-modified by graphene quantum dot sensitization and nitrogen doping (GQD-N-TiO2) for hydrogen production from photoelectrochemical water splitting under visible light irradiation. First, cubic ordered mesoporous TiO2 films were prepared by a surfactant templated sol-gel method. Then, TiO2 films were treated with N2/Ar plasma for the incorporation of substitutional N atoms into the lattice of TiO2. GQDs were prepared by chemically oxidizing carbon nano-onions. The immobilization of GQDs was accomplished by reacting carboxyl groups of GQDs with amine groups of N-TiO2 developed by the prior immobilization of (3-aminopropyl)triethoxysilane (APTES). Successful immobilization of GQDs onto N-TiO2 was probed by UV-Vis, FT-IR, and scanning electron microscopy. Further, zeta potential and contact angle measurements showed enhanced surface charge and hydrophilicity, confirming the successful immobilization of GQDs. The GQD-N-TiO2, N-TiO2 and GQD-TiO2 films showed 400 times, 130 times and 8 times photocurrent enhancement, respectively, compared to TiO2 films for water splitting with a halogen bulb light source. This outstanding enhancement is attributed to the high surface area of mesoporous films and synergistic effects of nitrogen doping and GQD sensitization resulting in enhanced visible light absorption, efficient charge separation and transport.

  18. Liquid phase deposition of TiO2 nanolayer affords CH3NH3PbI3/nanocarbon solar cells with high open-circuit voltage.

    Science.gov (United States)

    Chen, Haining; Wei, Zhanhua; Yan, Keyou; Yi, Ya; Wang, Jiannong; Yang, Shihe

    2014-01-01

    Hybrid organic/inorganic perovskite solar cells are attracting intense attention and further developments largely hinge on understanding the fundamental issues involved in the cell operation. In this paper, a liquid phase deposition (LPD) method is developed to design and grow a TiO(2) nanolayer at room temperature for carbon-based perovskite solar cells. The TiO(2) nanolayer grown on FTO glass is compact but polycrystalline consisting of tiny anatase TiO(2) nanocrystals intimately stacked together. By directly exploiting this TiO(2) nanolayer in a solar cell of TiO(2) nanolayer/CH(3)NH(3)PbI(3)/nanocarbon, we have achieved a Voc as high as 1.07 V, the highest value reported so far for hole transporter-free CH(3)NH(3)PbI(3) solar cells. This is rationalized by the slower electron injection and longer electron lifetime due to the TiO(2) nanolayer, which enhances the electron accumulation in CH(3)NH(3)PbI(3) and consequently the Voc. By employing a rutile TiO(2) nanorod (NR) array as a base structure for the LPD-TiO(2) nanolayer to support the CH(3)NH(3)PbI(3) layer, the photocurrent density is considerably increased without obviously compromising the Voc (1.01 V). As a result, the power conversion efficiency is boosted from 3.67% to 8.61%. More elaborate engineering of the TiO(2) nanolayer by LPD in conjunction with judicious interfacing with other components has the potential to achieve higher performances for this type of solar cell.

  19. Fluoropolymer - TiO2 coatings and their superhydrophilicity

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob; Jepsen, Henrik

    In this work the superhydrophilicity of coatings on fluoropolymer were investigated. The different coatings were prepared by help of P25 Degussa TiO2 powder, titaniumisopropoxide, Lumiflon® and two different curing agents (BL 3175 and Cymel 303). The investigations were performed by help...

  20. Low temperature electroreflectance of TiO2

    NARCIS (Netherlands)

    Vos, K.; Krusemeyer, H.J.

    1974-01-01

    Franz-Keldysh type electroreflectance finestructure has been observed on single crystals of TiO2 between 3.0 and 3.7 eV at LNT. Critical points have been designated to two sets of oscillations which are dependent on the direction of polarization of the light and of the applied field.

  1. Synthesis and characterization of monoclinic TiO2 nanosheets

    Institute of Scientific and Technical Information of China (English)

    WU Yu; XU Boqing

    2005-01-01

    A novel two-step method for the synthesis of monoclinic titanium oxide (i.e. TiO2(B)) nanosheets is presented in this report. The method is featured by two steps: 1) synthesis of hydrogen titanate nanosheets, followed by 2) calcination of the titanate nanosheets at elevated temperatures. The hydrogen titanate nanosheets were prepared first by autoclaving anatase TiO2 powders, obtained by air calcining an ethanol-gel of Ti(OH)4 at 500℃, in aqueous NaOH (10 mol/L) at 150―200℃, and then by washing with hydrochloric acid under supersonic irradiation. While sizes of the nanosheets were found to increase with increasing the temperature of the hydrothermal treatment, the calcination at 400―500℃ of the hydrogen titanate nanosheets that were synthesized at higher autoclaving temperatures (180―200℃) produced monoclinic TiO2 nanosheets with a uniform morphology. By contrast, the same calcination of the titanate nanosheets synthesized at the autoclaving temperature 180℃ led to anatase TiO2 nanoparticles.

  2. Photocatalytic bacterial inactivation by TiO2-coated surfaces.

    Science.gov (United States)

    Bonetta, Silvia; Bonetta, Sara; Motta, Francesca; Strini, Alberto; Carraro, Elisabetta

    2013-10-04

    The aim of this study was the evaluation of the photoactivated antibacterial activity of titanium dioxide (TiO2)-coated surfaces. Bacterial inactivation was evaluated using TiO2-coated Petri dishes. The experimental conditions optimized with Petri dishes were used to test the antibacterial effect of TiO2-coated ceramic tiles. The best antibacterial effect with Petri dishes was observed at 180, 60, 30 and 20 min of exposure for Escherichia coli, Staphylococcus aureus, Pseudomonas putida and Listeria innocua, respectively. The ceramic tiles demonstrated a photoactivated bactericidal effect at the same exposure time. In general, no differences were observed between the antibacterial effect obtained with Petri dishes and tiles. However, the photochemical activity of Petri dishes was greater than the activity of the tiles.Results obtained indicates that the TiO2-coated surfaces showed a photoactivated bactericidal effect with all bacteria tested highlighting that the titania could be used in the ceramic and building industry for the production of coated surfaces to be placed in microbiologically sensitive environments, such as the hospital and food industry.

  3. Light scattering characteristicof TiO2 nanocrystalline porous films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    TiO2 nanocrystalline porous films consisting of binary particles mixture (mean diameters of 12 and 100 nm) are capable of increasing the light absorption due to the possession of large specific surface area and light scattering property. The simultaneous reduction of the film thickness leads to a decrease of the recombination loss during electron transport and an increase of the photocurrent efficiency.

  4. Spinodal equation of state for rutile TiO2

    DEFF Research Database (Denmark)

    Francisco, E.; Bermejo, M.; Baonza, V. Garcia

    2003-01-01

    )-temperature (T) data of the rutile phase of TiO2. We show that results of ab initio perturbed ion calculations and very recent x-ray-diffraction experiments of isothermal compression on this system closely follow the spinodal conduct. The computational scheme permits the incorporation of temperature effects...

  5. Low temperature electroreflectance of TiO2

    NARCIS (Netherlands)

    Vos, K.; Krusemeyer, H.J.

    1974-01-01

    Franz-Keldysh type electroreflectance finestructure has been observed on single crystals of TiO2 between 3.0 and 3.7 eV at LNT. Critical points have been designated to two sets of oscillations which are dependent on the direction of polarization of the light and of the applied field.

  6. High-pressure polymorphs of anatase TiO2

    DEFF Research Database (Denmark)

    Arlt, T.; Bermejo, M.; Blanco, M. A.

    2000-01-01

    The equation of state of anatase TiO2 has been determined experimentally-using polycrystalline as well as single-crystal material-and compared with theoretical calculations using the ab initio perturbed ion model. The results are highly consistent, the zero-pressure bulk modulus being 179(2) GPa...

  7. Fluoropolymer - TiO2 coatings and their superhydrophilicity

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob; Jepsen, Henrik

    In this work the superhydrophilicity of coatings on fluoropolymer were investigated. The different coatings were prepared by help of P25 Degussa TiO2 powder, titaniumisopropoxide, Lumiflon® and two different curing agents (BL 3175 and Cymel 303). The investigations were performed by help...

  8. Protein Corona Prevents TiO2 Phototoxicity.

    Directory of Open Access Journals (Sweden)

    Maja Garvas

    Full Text Available TiO2 nanoparticles have generally low toxicity in the in vitro systems although some toxicity is expected to originate in the TiO2-associated photo-generated radical production, which can however be modulated by the radical trapping ability of the serum proteins. To explore the role of serum proteins in the phototoxicity of the TiO2 nanoparticles we measure viability of the exposed cells depending on the nanoparticle and serum protein concentrations.Fluorescence and spin trapping EPR spectroscopy reveal that the ratio between the nanoparticle and protein concentrations determines the amount of the nanoparticles' surface which is not covered by the serum proteins and is proportional to the amount of photo-induced radicals. Phototoxicity thus becomes substantial only at the protein concentration being too low to completely coat the nanotubes' surface.These results imply that TiO2 nanoparticles should be applied with ligands such as proteins when phototoxic effects are not desired - for example in cosmetics industry. On the other hand, the nanoparticles should be used in serum free medium or any other ligand free medium, when phototoxic effects are desired - as for efficient photodynamic cancer therapy.

  9. Influence of TiO2 nanofiber additives for high efficient dye-sensitized solar cells.

    Science.gov (United States)

    Hwang, Kyung-Jun; Lee, Jae-Wook; Park, Ju-Young; Kim, Sun-Il

    2011-02-01

    TiO2 nanofibers were prepared from a mixture of titanium-tetra-isopropoxide and poly vinyl pyrrolidone by applying the electrospinning method. The samples were characterized by XRD, FE-SEM, TEM and BET analyses. The diameter of electrospun TiO2 nanofibers is in the range of 70 approximately 160 nm. To improve the short-circuit photocurrent, we added the TiO2 nanofibers in the TiO2 electrode of dye-sensitized solar cells (DSSCs). TiO2 nanofibers added in DSSCs can make up to 20% more conversion energy than the conventional DSSC with only TiO2 films only.

  10. Preparation and Photocatalytic Property of Porous TiO2 Film with Net-like Framework

    Institute of Scientific and Technical Information of China (English)

    XU Rong-guo; YAO Jian-xi; LAI Xiao-yong; MAO Dan; XING Chao-jian; WANG Dan

    2009-01-01

    By the UV-curing method, a porous TiO2 film with net-like framework has been prepared. The characte-rization results of the porous TiO2 film by means of SEM, TEM, XRD, and N2 adsorption-desorption analysis show that the net-like framework of the porous TiO2 film is composed of TiO2 nanoparticles, forming three dimensional porous structure. The porous TiO2 film exhibits higher photocatalytic activity for the degradation of methylene blue(MB) dye compared with the conventional dense TiO2 film.

  11. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    OpenAIRE

    Ming-Jer Jeng; Yi-Lun Wung; Liann-Be Chang; Lee Chow

    2013-01-01

    The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films ...

  12. A floating macro/mesoporous crystalline anatase TiO2 ceramic with enhanced photocatalytic performance for recalcitrant wastewater degradation.

    Science.gov (United States)

    Xing, Zipeng; Zhou, Wei; Du, Fan; Qu, Yang; Tian, Guohui; Pan, Kai; Tian, Chungui; Fu, Honggang

    2014-01-14

    A macro/mesoporous anatase TiO2 ceramic floating photocatalyst has been successfully synthesized using highly thermally stable mesoporous TiO2 powder as a precursor, followed by a camphene-based freeze-casting process and high-temperature calcinations. The ceramics are characterized in detail by X-ray diffraction, Raman spectra, scanning electron microscopy, transmission electron microscopy and N2 adsorption-desorption isotherms. The results indicate that the TiO2 ceramics present hierarchical macro/mesoporous structures, which maintain high porosity and high compressive strength at the optimal sintering temperature of 800 °C. The ordered mesoporous TiO2 network still possesses high thermal stability and inhibits the anatase-to-rutile phase transformation during calcinations. The obtained ceramics exhibit good adsorptive and photocatalytic activity for the degradation of octane and rhodamine B, and the total organic carbon removal ratio is up to 98.8% and 98.6% after photodegradation for 3 h, respectively. The roles of active species in the photocatalytic process are compared using different types of active species scavengers, and the degradation mechanism is also proposed. Furthermore, the ceramics are recyclable, and no clear changes are observed after ten cycles. In addition, the ceramics are also active in the photodegradation of phenol, thiobencarb, and atrazine. Therefore, these novel floating photocatalysts will have wide applications, including the removal of floating organic pollutants from the wastewater surfaces or the removal of soluble organic pollutants from wastewater.

  13. A Photocatalytic Rotating Disc Reactor with TiO2 Nanowire Arrays Deposited for Industrial Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    Fang Li

    2017-02-01

    Full Text Available A photocatalytic rotating disc reactor (PRD-reactor with TiO2 nanowire arrays deposited on a thin Ti plate is fabricated and tested for industrial wastewater treatment. Results indicate that the PRD-reactor shows excellent decolorization capability when tested with methyl orange (>97.5%. Advanced oxidation processes (AOP, including photocatalytic oxidation and photolytic reaction, occurred during the processing. Efficiency of the AOP increases with reduction in light absorption pathlength, which enhanced the photocatalytic reaction, as well as by increasing oxygen exposure of the wastewater thin film due to the rotating disc design. It is found that, with a small dosage of hydrogen peroxide, the mineralization efficiency of industrial biodegraded wastewater can be enhanced, with a superior mineralization of >75% total organic carbon (TOC removal. This is due to the fact that the TiO2 photocatalysis and hydrogen peroxide processes generate powerful oxidants (hydroxyl radicals that can strongly improve photocatalytic oxidation efficiency. Application of this industrial wastewater treatment system is benefited from the TiO2 nanowire arrays, which can be fabricated by a mild solvothermal method at 80 °C and under atmospheric pressure. Similar morphologies and microstructures are found for the TiO2 nanowire arrays deposited on a large metal Ti disc, which makes the wastewater treatment process more practical and economical.

  14. TiO2 photocatalysis of naproxen: effect of the water matrix, anions and diclofenac on degradation rates.

    Science.gov (United States)

    Kanakaraju, Devagi; Motti, Cherie A; Glass, Beverley D; Oelgemöller, Michael

    2015-11-01

    The TiO2 photocatalytic degradation of the active pharmaceutical ingredient (API) naproxen (NPX) has been studied using a laboratory-scale photoreactor equipped with a medium pressure mercury lamp. UV/TiO2 photocatalysis proved highly efficient in the elimination of NPX from a variety of water matrices, including distilled water, unfiltered river water and drinking water, although the rate of reaction was not always proportional to TiO2 concentration. However, the NPX degradation rate, which follows first-order kinetics, was appreciably reduced in river water spiked with phosphate and chloride ions, a dual anion system. Addition of chloride into drinking water enhanced the TiO2-photocatalysed degradation rate. Competitive degradation studies also revealed that the NPX degradation was greatly reduced in the presence of increased concentrations of another API, diclofenac (DCF). This was established by (i) the extent of mineralization, as determined by dissolved organic carbon (DOC) content, and (ii) the formation of intermediate NPX by-products, identified using liquid chromatography and electrospray ionization (positive and negative mode) mass spectrometry techniques. This study demonstrates that competition for active sites (anions or DCF) and formation of multiple photoproducts resulting from synergistic interactions (between both APIs) are key to the TiO2-photocatalysed NPX degradation.

  15. CO2 dissociation activated through electron attachment on reduced rutile TiO2(110)-1x1 surface

    CERN Document Server

    Tan, Shijing; Zhao, Jin; Wang, Zhuo; Ma, Chuanxu; Zhao, Aidi; Wang, Bing; Luo, Yi; Yang, Jinlong; Hou, Jianguo

    2011-01-01

    Converting CO$_2$ to useful compounds through the solar photocatalytic reduction has been one of the most promising strategies for artificial carbon recycling. The highly relevant photocatalytic substrate for CO$_2$ conversion has been the popular TiO$_2$ surfaces. However, the lack of accurate fundamental parameters that determine the CO$_2$ reduction on TiO$_2$ has limited our ability to control these complicated photocatalysis processes. We have systematically studied the reduction of CO2 at specific sites of the rutile TiO$_2$(110)-1x1 surface using scanning tunneling microscopy at 80 K. The dissociation of CO2 molecules is found to be activated by one electron attachment process and its energy threshold, corresponding to the CO$_2^{\\dot-}$/CO$_2$ redox potential, is unambiguously determined to be 2.3 eV higher than the onset of the TiO$_2$ conduction band. The dissociation rate as a function of electron injection energy is also provided. Such information can be used as practical guidelines for the design...

  16. Alternative natural dyes in water purification: Anthocyanin as TiO 2-sensitizer in methyl orange photo-degradation

    Science.gov (United States)

    Zyoud, Ahed; Zaatar, Nidal; Saadeddin, Iyad; Helal, Muath H.; Campet, Guy; Hakim, Moulki; Park, DaeHoon; Hilal, Hikmat S.

    2011-06-01

    Natural molecular dye, anthocyanin, is described here as safe sensitizer for TiO 2 particles in photo-degradation of organic contaminants in water. The dye is a promising replacement for the more costly and hazardous heavy metal based systems, such as CdS particles and Ru-compounds. TiO 2/anthocyanin effectively catalyzed the photo-degradation of methyl orange contaminant under solar simulator radiation. The new TiO 2/anthocyanin catalyst showed comparable efficiency to earlier systems, while avoiding their hazardous nature. When supported onto activated carbon (AC) particles, the resulting AC/TiO 2/anthocyanin system showed enhanced efficiency and ease of recovery from the catalytic reaction mixture. The natural dye molecules showed the tendency to degrade under photo-degradation conditions, just like earlier hazardous sensitizers. However, complete mineralization of anthocyanin occurred leaving no traces of organic species in solution. Sensitizer degradation caused deactivation of the supported catalyst on recovery. Such a shortcoming was overcome by re-treatment of the recovered catalysts with fresh dye. Effects of different reaction parameters on the catalyst efficiency were studied. A mechanism, similar to earlier CdS-sensitized catalyst systems, is proposed for the TiO 2/anthocyanin catalyst.

  17. Photocatalytic degradation of MO by complex nanometer particles WO3/TiO2

    Institute of Scientific and Technical Information of China (English)

    CUI Yumin

    2006-01-01

    Complex nanometer particles WO3/TiO2 were prepared using a sol-gel process and characterized using XRD spectra. The photocatalytic activity of TiO2 can be increased by doping W6+ with TiO2 because the doped W6+ that entered into the crystal lattices of TiO2 led to the formation of defects in the crystal lattices of TiO2 and thereby improved the photocatalytic activity of TiO2.When WO3 doped in TiO2 exceeded 3%, the excess W6+ did not enter into the crystal lattices of TiO2 but were uniformly dispersed in TiO2 or they covered the surface of TiO2, which reduced the effective illumination area of TiO2 and thereby lowered the photocatalytic activity of TiO2.The relationship among the composition of the catalyst,the amount of photocatalyst, the illumination time, and the decolorizing rate of methyl orange (MO) were discussed. The results show that the decolorizing rate of MO can reach 82.3% using WO3/TiO2 as the photocatalyst, with the composition tion time = 7 h.

  18. Optimization of Solar Photocatalytic Degradation of Chloroxylenol Using TiO2, Er3+/TiO2, and Ni2+/TiO2 via the Taguchi Orthogonal Array Technique

    Directory of Open Access Journals (Sweden)

    Ahmed J. Mohammed

    2016-10-01

    Full Text Available In this study, the optical properties of a TiO2 photocatalyst were enhanced with various impregnations of Er3+ and Ni2+ separately, using the impregnation method as photocatalysts for the direct solar photolysis degradation of chloroxylenol. The synthesized Er3+/TiO2 and Ni2+/TiO2 catalysts were characterized using X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, energy dispersive X-ray (EDX, metal mapping, and ultraviolet visible (UV–Vis spectroscopy. The results showed that the Er3+/TiO2 and Ni2+/TiO2 nano-particles have the same structures of TiO2 nano-particles with little difference in particle size. The Er3+ and Ni2+ ions were well-distributed on the TiO2 surface, and it was found that the maximum band gap decreased from 3.13 eV for intrinsic TiO2 to 2.63 eV at 1.8 wt % Er3+/TiO2 and to 2.47 eV at 0.6 wt % for Ni2+/TiO2. The initial concentration of chloroxylenol, catalyst loading, and pH of the solution are the most important factors affecting the solar photocatalytic degradation efficiency that were optimized using Design Expert software (version 6.0.10, Minneapolis, MN, USA, 2003. The results showed that the optimal conditions for chloroxylenol degradation include a pH of 4, TiO2 loading at 3 g/L, and a chloroxylenol concentration of 50 mg/L. These conditions resulted in a degradation efficiency of 90.40% after 60 min of direct solar irradiation, wherein the solar energy recorded during a clear sunny day is 1000 W/m2. However, some experiments were conducted on a semi-cloudy day to cover all weather stated and to study the degradation kinetics. During semi-cloudy day experiments, using Er3+/TiO2 and Ni2+/TiO2 with a solar irradiation activity of 600 W/m2 for a 60 min exposure at optimal conditions increased the degradation efficiency from 68.28% for intrinsic TiO2 to 82.38% for Er3+/TiO2 and 80.70% for Ni2+/TiO2.

  19. Use Of Cu-C-Tio2 In Dye Sensitized Solar Cell

    Directory of Open Access Journals (Sweden)

    Monika Trivedi

    2015-07-01

    Full Text Available Abstract A novel and simple strategy has been used for the preparation of TiO2 nanoparticles co-doped with carbon non-metal and copper transition metal by sol-gel method. The dye sensitized solar cell was fabricated with Cu-C-TiO2 nanocrystalline layer on FTO conductive glass sensitized with rhodamine B dye. Iamp8722 I3 amp8722 redox couple was used as liquid electrolyte and carbon graphite as counter electrode. The experimental results of rhodamine B sensitized Cu-C-doped TiO2 showed Voc 101.2 mV isc 0.0545 mA Vpp 55.9 mV andipp 0.0496 mA and FF 0.50. The photo-to-electric power conversion efficiency was 0.004 under 66.0 mWcm-2 light intensity. The undoped andCu-C-TiO2 nanoparticles were analyzed by X-ray diffraction XRD scanning electron microscopySEM and Fourier transform infrared FT-IR techniques.

  20. Synthesis and enhanced visible-light responsive of C,N,S-tridoped TiO2 hollow spheres.

    Science.gov (United States)

    Lin, Xiaoxia; Fu, Degang; Hao, Lingyun; Ding, Zhen

    2013-10-01

    C,N,S-tridoped TiO2 hollow spheres (labeled as C,N,S-THs) were synthesized using carbon spheres as template and C,N,S-tridoped TiO2 nanoparticles as building blocks. The structure and physicochemical properties of the catalysts were characterized by Xray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectrum (DRS), N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Photoluminescence emission spectroscopy (PL). The results showed that the hollow spheres had average diameter of about 200 nm and the shell thickness was about 20 nm. The tridoped TiO2 hollow spheres exhibited strong absorption in the visible-light region. C,N,S-tridoped could narrow the band gap of the THs by mixing the orbit O 2p with C 2p, N 2p and S 3p orbits and shift its optical response from ultraviolet (UV) to the visible-light region. PL analysis indicated that the electron-hole recombination rate of TiO2 hollow spheres had been effectively inhibited when doped with C, N and S elements. The photocatalytic activities of the samples were evaluated for the degradation of X-3B (Reactive Brilliant Red dye, C.I. Reactive Red 2) aqueous solution under visible-light (lambda > 420 nm) irradiation. It was found that the C,N,S-tridoped TiO2 hollow spheres indicated higher photocatalytic activity than commercial P25 and the undoped counterpart photocatalyst.

  1. TiO2 Thin Film UV Detectors Deposited by DC Reactive Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    ZHANG Li-wei; YAO Ning; ZHANG Bing-lin; FAN Zhi-qin; YANG Shi-e; LU Zhan-ling

    2004-01-01

    Crystalline TiO2 thin films were prepared by DC reactive magnetron sputtering on indium-tin oxide(ITO) thin film deposited on quartz substrate, the photoconductive UV detector on TiO2 thin films was based on a sandwich structure of C/ TiO2/ITO. The measurement of the I-V characteristics for these devices shows good ohmic contact. The photoresponse of TiO2 thin films was analyzed at different bias voltage. Voltage.

  2. Photonic crystal coupled TiO(2)/polymer hybrid for efficient photocatalysis under visible light irradiation.

    Science.gov (United States)

    Liao, Gaozu; Chen, Shuo; Quan, Xie; Chen, Huan; Zhang, Yaobin

    2010-05-01

    Inverse TiO(2) opal photonic crystal coupled TiO(2)/poly(3-hexylthiophene) (bilayer TiO(2)/P3HT) was structured on FTO substrate for efficient photocatalysis under visible light irradiation (lambda > 400 nm). We expected that the photocatalytic capability of this hybrid photocatalyst could be enhanced by the efficient visible light absorption owing to the photonic crystal structure and effective charge separation owing to the unique heterojunction built between TiO(2) and P3HT. The bilayer TiO(2)/P3HT photocatalyst was prepared first by depositing inverse TiO(2) opal on FTO substrate via replicating polystyrene opal, followed by spin coating a layer of TiO(2) nanoparticles on the inverse TiO(2) opal. The as prepared bilayer TiO(2) was modified by P3HT via dipping method. Environmental scanning electron microscopy (ESEM) images demonstrated that the as prepared photocatalyst was composed of inverse TiO(2) opal layer and TiO(2) nanoparticles layer. The UV-vis diffuse reflectance spectra showed that the optical absorption for bilayer TiO(2)/P3HT was more intensive than for pristine TiO(2) nanoparticle/P3HT (NP-TiO(2)/P3HT) in the range of 400-650 nm. The enhanced generation of photocurrent under visible light irradiation (lambda > 400 nm) was observed using the bilayer TiO(2)/P3HT. The results of photocatalytic experiments under visible light irradiation revealed that the pseudofirst-order kinetic constant of photocatalytic degradation of methylene blue using the bilayer TiO(2)/P3HT was 2.08 times as great as that using NP-TiO(2)/P3HT, showing the advantage of the unique structure in the bilayer TiO(2)/P3HT for efficient photocatalysis.

  3. Study on the Formation Mechanism of Nanotube TiO2

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Nanotube TiO2 is a novel kind of nanomaterials. In 1998, Kasuga et al. first found that the nanotube TiO2 can be obtained through the treatment of the powered polycrystalline TiO2 in concentrated NaOH solution1. Then, we studied its morphological structure and physicochemical properties, and the results reported elsewhere2(Fig. 1, cover of Chinese Science Bulletin). In this paper the formation mechanism of nanotube TiO2 will be discussed.

  4. Nb-doped TiO2 cathode catalysts for oxygen reduction reaction of polymer electrolyte fuel cells

    KAUST Repository

    Arashi, Takuya

    2014-09-01

    Nb-doped TiO2 particles were studied as electrocatalysts for the oxygen reduction reaction (ORR) under acidic conditions. The Nb-doped TiN nanoparticles were first synthesized by meso-porous C3N4 and then fully oxidized to Nb-doped TiO2 by immersing in 0.1 M H 2SO4 at 353 K for 24 h. Although the ORR activity of the as-obtained sample was low, a H2 treatment at relatively high temperature (1173 K) dramatically improved the ORR performance. An onset potential as high as 0.82 VRHE was measured. No degradation of the catalysts was observed during the oxidation-reduction cycles under the ORR condition for over 127 h. H2 treatment at temperatures above 1173 K caused the formation of a Ti4O7 phase, resulting in a decrease in ORR current. Elemental analysis indicated that the Nb-doped TiO 2 contained 25 wt% residual carbon. Calcination in air at 673 or 973 K eliminated the residual carbon in the catalyst, which was accompanied by a dramatic decrease in ORR activity. This post-calcination process may reduce the conductivity of the sample by filling the oxygen vacancies, and the carbon residue in the particle aggregates may enhance the electrocatalytic activity for ORR. The feasibility of using conductive oxide materials as electrocatalysts is discussed. © 2013 Elsevier B.V.

  5. Preparation of Photocatalytic TiO2 and TiO2-SiO2 Particles and Application to Degradation of Trace Organics in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    周亚松

    2003-01-01

    TiO2 and TiO2-SiO2 photocatalysts were prepared by sol-gel and supercritical CO2 fluid drying method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), etc. Their catalytic properties were tested through the photocatalytic degradation of phenol and aniline in wastewater. The results show that the developed fluidized photocatalytic reactor (FPR) and TiO2 catalyst had better performance in degrading pollutants as compared with slurry photocatalytic reactor (SPR) and commercial TiO2 catalyst. The composition and crystal form of TiO2-SiO2 composite oxide had obvious influence on catalytic effect and TiO2-SiO2 photocatalysts showed better catalytic activity and stability.

  6. 负载金属对WO3-TiO2光催化剂结构与催化性能的影响%Effects of Loaded Metal on Structure and Photocatalytic Performance of Photocatalyst for Synthesis of MAA from Propylene with Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    梅长松; 钟顺和

    2005-01-01

    用溶胶-凝胶和浸渍-还原相结合的方法制得M/WO3-TiO2(M=Pd,Cu,Ni,Ag)光催化剂.利用X射线衍射(XRD)、程序升温还原(TPR)、红外(IR)、程序升温脱附(TPD)、紫外-可见漫反射光谱(UV-Vis-DRS)和光反应器等技术研究了复合半导体负载金属的物相结构、光吸收性能和光催化反应性能.结果表明:金属负载在复合半导体上延迟了TiO2由锐钛矿向金红石相转化,增强W与载体TiO2的相互作用,使TiO2光吸收限发生蓝移,对可见光部分的吸收明显增加;固体材料吸光性能强弱顺序Pd/WO3-TiO2 Cu/WO3-TiO2>Ag/WO3-TiO2>Ni/WO3-TiO2;金属Pd对CO2吸附能力过强,卧式吸附态脱附温度高,光催化效率不高;金属Cu对CO2吸附能力适中,CO2与C3H6脱附温度较接近,实现了"光-表面-热"协同作用,光量子效率最高,达到19.7%.

  7. Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

    Institute of Scientific and Technical Information of China (English)

    GAO Yu-zhou; ZHANG Hui-chen; WANG Liang; YAN Li

    2004-01-01

    TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.

  8. TiO2 Based Photocatalyst: From Synthesis and Characterization to Optimization and Design

    DEFF Research Database (Denmark)

    Su, Ren

    2012-01-01

    TiO2 based photocatalyst has attracted gerat attentions from both fundamental and an applied aspects in water/air purifications and energy production. In this thesis, series of well-defined TiO2 photocatalyst with various parameters (i.e., polymorph composition, shape, impurity concentration...... the importance of fine tunning the properties of TiO2 photocatalyst materials....

  9. Dye-Sensitized Solar Cells with Anatase TiO2 Nanorods Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Ming-Jer Jeng

    2013-01-01

    Full Text Available The hydrothermal method provides an effective reaction environment for the synthesis of nanocrystalline materials with high purity and well-controlled crystallinity. In this work, we started with various sizes of commercial TiO2 powders and used the hydrothermal method to prepare TiO2 thin films. We found that the synthesized TiO2 nanorods were thin and long when smaller TiO2 particles were used, while larger TiO2 particles produced thicker and shorter nanorods. We also found that TiO2 films prepared by TiO2 nanorods exhibited larger surface roughness than those prepared by the commercial TiO2 particles. It was found that a pure anatase phase of TiO2 nanorods can be obtained from the hydrothermal method. The dye-sensitized solar cells fabricated with TiO2 nanorods exhibited a higher solar efficiency than those fabricated with commercial TiO2 nanoparticles directly. Further, triple-layer structures of TiO2 thin films with different particle sizes were investigated to improve the solar efficiency.

  10. Efficient CO2 capture and photoreduction by amine-functionalized TiO2.

    Science.gov (United States)

    Liao, Yusen; Cao, Shao-Wen; Yuan, Yupeng; Gu, Quan; Zhang, Zhenyi; Xue, Can

    2014-08-11

    Amine-functionalization of TiO2 nanoparticles, through a solvothermal approach, substantially increases the affinity of CO2 on TiO2 surfaces through chemisorption. This chemisorption allows for more effective activation of CO2 and charge transfer from excited TiO2 , and significantly enhances the photocatalytic rate of CO2 reduction into methane and CO.

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

    Science.gov (United States)

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

    2012-07-25

    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.

  12. TiO2 Based Photocatalyst: From Synthesis and Characterization to Optimization and Design

    DEFF Research Database (Denmark)

    Su, Ren

    2012-01-01

    TiO2 based photocatalyst has attracted gerat attentions from both fundamental and an applied aspects in water/air purifications and energy production. In this thesis, series of well-defined TiO2 photocatalyst with various parameters (i.e., polymorph composition, shape, impurity concentration...... the importance of fine tunning the properties of TiO2 photocatalyst materials....

  13. PREPARATION OF MACROPOROUS TIO2 BY STARCH MICROSPHERES TEMPLATE WITH ASSISTANCE OF SUPERCRITICAL CO2

    Directory of Open Access Journals (Sweden)

    Lin-Qi Tang

    2009-02-01

    Full Text Available In this work a green route is reported to prepare a TiO2 macroporous network using corn starch microspheres flake as a bio-template. The starch microspheres prepared by emulsion technology were used as a template into which precursor tetrabutyl titanate (TBOT was permeated using supercritical carbon dioxide (scCO2 as a forceful carrier or infiltration media, resulting in the formation of an organic/inorganic hybrid material; then the coated template was gelled and dried during the scCO2-coating and the depressurization processes, followed by removal of the template by calcination at 700°C; finally, TiO2 inverse-opals-like material reversely replicating the starch microspheres template was obtained. Scanning electron microscopy (SEM, nitrogen sorption measurements, and X-ray diffraction (XRD indicated that the products were the inverse replicas from their templates. The obtained TiO2 inverse opals-like material showed a wide dispersion of pore sizes from mesopores to macropores – a few nanometers to several micrometers –with the BET surface area up to 103 m2/g, and a predominantly anatase crystalline phase. In addition, the wall thickness of the macropores varied with tunable pressure for closed cells or open-cell foams. So this facile and environmentally friendly process for the preparation of high-surface area, thermally-stable, metal-oxide catalysts and supports by a starch microsphere templating approach may have widespread potential applications in catalysis, absorbents, photoelectric materials, and so on.

  14. Thermal catalytic oxidation of octachloronaphthalene over anatase TiO2 nanomaterial and its hypothesized mechanism

    Science.gov (United States)

    Su, Guijin; Li, Qianqian; Lu, Huijie; Zhang, Lixia; Huang, Linyan; Yan, Li; Zheng, Minghui

    2015-12-01

    As an environmentally-green technology, thermal catalytic oxidation of octachloronaphthalene (CN-75) over anatase TiO2 nanomaterials was investigated at 300 °C. A wide range of oxidation intermediates, which were investigated using various techniques, could be of three types: naphthalene-ring, single-benzene-ring, and completely ring-opened products. Reactive oxygen species on anatase TiO2 surface, such as O2-• and O2-, contributed to oxidative degradation. Based on these findings, a novel oxidation degradation mechanism was proposed. The reaction at (101) surface of anatase TiO2 was used as a model. The naphthalene-ring oxidative products with chloronaphthols and hydroxyl-pentachloronaphthalene-dione, could be formed via attacking the carbon of naphthalene ring at one or more positions by nucleophilic O2-. Lateral cleavage of the naphthalene ring at different C1-C10 and C4-C9, C1-C2 and C4-C9, C1-C2 or and C3-C4 bond positions by electrophilic O2-• could occur. This will lead to the formation of tetrachlorophenol, tetrachloro-benzoic acid, tetrachloro-phthalaldehyde, and tetrachloro-acrolein-benzoic acid, partially with further transformation into tetrachlorobenzene-dihydrodiol and tetrachloro-salicylic acid. Unexpectedly, the symmetric half section of CN-75 could be completely remained with generating the intricate oxidative intermediates characteristically containing tetrachlorobenzene structure. Complete cleavage of naphthalene ring could produce the ring-opened products, such as formic and acetic acids.

  15. Pengaruh Penggunaan Fotokatalis TiO2/Resin, TiO2/Zeolit Dan TiO2/Karbon Aktif dalam Proses Fotoreduksi Ion Hg(II dengan Metode SODIS (Solar Desinfection Water

    Directory of Open Access Journals (Sweden)

    Rosyid Ridho

    2016-06-01

    Full Text Available Pada penelitian ini telah dilakukan proses pembuatan fotokatalis TiO2/resin, TiO2/zeolit dan TiO2/karbon aktif yang selanjutnya dikarakterisasi dengan XRD dan Energi Band Gap (Eg. Karakterisasi XRD bertujuan untuk mengetahui telah terbentuknya fotokatalis. Sedangkan karaktererisasi Energi Band Gap (Eg bertujuan untuk mengetahui tingkat celah energi pada masing-masing fotokatalis dimana semakin tinggi harga Energi Band Gap maka efektivitas fotoreduksi akan semakin tinggi. Hasil dari karakterisasi XRD menunjukkan bahwa fotokatalis TiO2-resin, TiO2-zeolit, dan TiO2/karbon aktif telah terbentuk, sedangkan hasil energi band gap untuk TiO2/zeolit sebesar 3,608 eV, TiO2/resin sebesar 3,38 eV, sedangkan TiO2/karbon aktif adalah 3,48 eV. Didasarkan pada harga Eg tersebut diharapkan aktivitas fotokatalis TiO2/zeolit lebih tinggi daripada fotokatalis yang lain. Pengujian aktivitas fotokatalis dilakukan dengan mereaksikan 50 mg masing-masing fotokatalis untuk mereduksi 50 mL larutan Hg (II 5 ppm yang disinari oleh sinar matahari sebagai sumber cahaya dengan variasi waktu penyinaran (1,2,3,4,5 dan 6 jam. Dari hasil penyinaran menunjukkan bahwa semakin tinggi waktu penyinaran semakin tinggi % Hg tereduksi, dalam penelitian ini efektivitas fotokatalis terbaik adalah TiO2/zeolit dengan efektivitas fotoreduksi pada penyinaran 6 jam sebesar 98,5%. Pada tahap ini juga dipelajari pengaruh konsentrasi Ion Hg (II (0; 2,5; 5; 10; 20; dan 25 dengan waktu penyinaran 6 jam. Data yang diperoleh menunjukkan semakin tinggi konsentrasi awal ion Hg, semakin rendah efektivitas fotoreduksinya.

  16. Robust superamphiphobic film from electrospun TiO2 nanostructures.

    Science.gov (United States)

    Ganesh, V Anand; Dinachali, Saman Safari; Nair, A Sreekumaran; Ramakrishna, Seeram

    2013-03-13

    Rice-shaped TiO2 nanostructures are fabricated by electrospinning for creating a robust superamphiphobic coating on glass substrates. The as-fabricated TiO2 nanostructures (sintered at 500 °C) are superhydrophilic in nature which upon silanization turn into superamphiphobic surface with surface contact angle (SCA) values achieved using water (surface tension, γ = 72.1 mN/m) and hexadecane (surface tension, γ = 27.5 mN/m) being 166° and 138.5°, respectively. The contact angle hysteresis for the droplet of water and hexadecane are measured to be 2 and 12°, respectively. Thus, we have successfully fabricated superior self-cleaning coatings that possess exceptional superamphiphobic property by employing a simple, cost-effective, and scalable technique called electrospinning. Furthermore, the coating showed good mechanical and thermal stability with strong adherence to glass surface, thus revealing the potential for real applications.

  17. KARAKTERISTIK FILM TIPIS TiO2 DOPING NIOBIUM

    Directory of Open Access Journals (Sweden)

    Bilalodin

    2010-05-01

    Full Text Available Niobium (Nb doped Titanium dioxide (TiO2 thin films have been successfully grown using spin coating method. Characterizations of thin films was carried out using EDAX (Energy Dispersion Analysis for X-Ray, XRD (X-Ray Diffaction and SEM (Scanning Electron Microscope to determine the microstructure of thin films. Determination microstructure, particularly of crystal structure was examined using ICDD data, whereas porosity calculation was done using the toolbox application on Matlab 6.1 software. EDAX, XRD and SEM characterization show that the thin films grown well at the Si substrates with the (002 field orientation is dominant and the thin film has the rutile structure. The TiO2 : Nb thin films product have granules round, uniform grain size and porosity value of about 41%.

  18. Hydroxyapatite growth on anodic TiO2 nanotubes.

    Science.gov (United States)

    Tsuchiya, Hiroaki; Macak, Jan M; Müller, Lenka; Kunze, Julia; Müller, Frank; Greil, Peter; Virtanen, Sannakaisa; Schmuki, Patrik

    2006-06-01

    In the present work, we study the growth of hydroxyapatite formation on different TiO(2) nanotube layers. The nanotube layers were fabricated by electrochemical anodization of titanium in fluoride-containing electrolytes. To study various nanotube lengths, layers with an individual tube diameter of 100 nm were grown to a thickness of approximately 2 mum or 500 nm. The ability to form apatite on the nanotube layers was examined by immersion tests combined with SEM, XRD and FT-IR investigations. For reference, experiments were also carried out on compact anodic TiO(2) layers. The results clearly show that the presence of the nanotubes on a titanium surface enhances the apatite formation and that the 2-mum thick nanotube layer triggers deposition faster than the thinner layers. Tubes annealed to anatase, or a mixture of anatase and rutile are clearly more efficient in promoting apatite formation than the tubes in their "as-formed" amorphous state.

  19. Properties of Electrospun TiO2 Nanofibers

    Directory of Open Access Journals (Sweden)

    Bianca Caratão

    2014-01-01

    Full Text Available Titanium oxide filled polyvinylpyrrolidone (PVP composite nanofibers have been prepared via a simple electrospinning technique. The combination of good TiO2 properties with its high surface area leads these nanofibers into having a vast applicability such as cosmetics, scaffolds for tissue engineering, catalytic devices, sensors, solar cells, and optoelectronic devices. The structural and chemical properties of the prepared samples have been studied. The presence of the TiO2 phase on the nanofibers was confirmed. An anatase to rutile transformation was observed at 600°C. Regarding the thermogravimetric and differential thermal analysis (TGA/DTA, the TIP decomposition and the PVP evaporation at 225°C were verified.

  20. Nanometer TiO2 Modified Polyacrylic Copolymer Sizing Agent

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of new-type nanometer TiO2 modified polyacrylic copolymer sizing agent were synthesized from acrylic acid, ethyl acrylate, nanometer TiO2, oleic acid etc.by orthogonal design method. Results of the studies show that the synthetic method used in this paper was a new way and had never been found in the synthesis of acrylate sizing agent, and that the properties of those new-type size-agent were be improved, which had potential for substituting PVA (polyvinyl alcohol) sizing agent. The technology for solving the problem of nano-scale powder agglomeration and dispersion were also studied. The transmission electron microscope (TEM) observation showed that nano-TiO2 had good dispersion and stability in aqueous solution and in sizing agent solution.

  1. Photocorrosion Mechanism of TiO2-Coated Photoanodes

    Directory of Open Access Journals (Sweden)

    Arjen Didden

    2015-01-01

    Full Text Available Atomic layer deposition was used to coat CdS photoanodes with 7 nm thick TiO2 films to protect them from photocorrosion during photoelectrochemical water splitting. Photoelectrochemical measurements indicate that the TiO2 coating does not provide full protection against photocorrosion. The degradation of the film initiates from small pinholes and shows oscillatory behavior that can be explained by an Avrami-type model for photocorrosion that is halfway between 2D and 3D etching. XPS analysis of corroded films indicates that a thin layer of CdS remains present on the surface of the corroded photoanode that is more resilient towards photocorrosion.

  2. Comparison study on photocatalytic oxidation of pharmaceuticals by TiO2-Fe and TiO2-reduced graphene oxide nanocomposites immobilized on optical fibers.

    Science.gov (United States)

    Lin, Lu; Wang, Huiyao; Jiang, Wenbin; Mkaouar, Ahmed Radhi; Xu, Pei

    2017-03-08

    Incorporating reduced graphene oxide (rGO) or Fe(3+) ions in TiO2 photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO2-Fe and TiO2-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO2-rGO and TiO2-Fe nanocomposites. Doping Fe into TiO2 particles (2.40eV) could reduce more band gap energy than incorporating rGO (2.85eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO2 decreased significantly the intensity of TiO2 photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO2-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO2-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO2-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO2-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic activity.

  3. Photocatalytic antibacterial performance of TiO2 and Ag-doped TiO2 against S. aureus. P. aeruginosa and E. coli.

    Science.gov (United States)

    Gupta, Kiran; Singh, R P; Pandey, Ashutosh; Pandey, Anjana

    2013-01-01

    This paper reports the structural and optical properties and comparative photocatalytic activity of TiO2 and Ag-doped TiO2 nanoparticles against different bacterial strains under visible-light irradiation. The TiO2 and Ag-doped TiO2 photocatalysts were synthesized by acid catalyzed sol-gel technique and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis spectroscopy and photoluminescence (PL). The XRD pattern revealed that the annealed sample of TiO2 has both anatase and rutile phases while only an anatase phase was found in Ag-doped TiO2 nanoparticles. The decreased band-gap energy of Ag-doped TiO2 nanoparticles in comparison to TiO2 nanoparticles was investigated by UV-vis spectroscopy. The rate of recombination and transfer behaviour of the photoexcited electron-hole pairs in the semiconductors was recorded by photoluminescence. The antimicrobial activity of TiO2 and Ag-doped TiO2 nanoparticles (3% and 7%) was investigated against both gram positive (Staphylococcus aureus) and gram negative (Pseudomonas aeruginosa, Escherichia coli) bacteria. As a result, the viability of all three microorganisms was reduced to zero at 60 mg/30 mL culture in the case of both (3% and 7% doping) concentrations of Ag-doped TiO2 nanoparticles. Annealed TiO2 showed zero viability at 80 mg/30 mL whereas doped Ag-TiO2 7% showed zero viability at 40 mg/30 mL culture in the case of P. aeruginosa only.

  4. Photocatalytic antibacterial performance of TiO2 and Ag-doped TiO2 against S. aureus. P. aeruginosa and E. coli

    Directory of Open Access Journals (Sweden)

    Kiran Gupta

    2013-06-01

    Full Text Available This paper reports the structural and optical properties and comparative photocatalytic activity of TiO2 and Ag-doped TiO2 nanoparticles against different bacterial strains under visible-light irradiation. The TiO2 and Ag-doped TiO2 photocatalysts were synthesized by acid catalyzed sol–gel technique and characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, UV–vis spectroscopy and photoluminescence (PL. The XRD pattern revealed that the annealed sample of TiO2 has both anatase and rutile phases while only an anatase phase was found in Ag-doped TiO2 nanoparticles. The decreased band-gap energy of Ag-doped TiO2 nanoparticles in comparison to TiO2 nanoparticles was investigated by UV–vis spectroscopy. The rate of recombination and transfer behaviour of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. The antimicrobial activity of TiO2 and Ag-doped TiO2 nanoparticles (3% and 7% was investigated against both gram positive (Staphylococcus aureus and gram negative (Pseudomonas aeruginosa, Escherichia coli bacteria. As a result, the viability of all three microorganisms was reduced to zero at 60 mg/30 mL culture in the case of both (3% and 7% doping concentrations of Ag-doped TiO2 nanoparticles. Annealed TiO2 showed zero viability at 80 mg/30 mL whereas doped Ag-TiO2 7% showed zero viability at 40 mg/30 mL culture in the case of P. aeruginosa only.

  5. Atomic Layer Deposition TiO2 Films and TiO2/SiNx Stacks Applied for Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Zu-Po Yang

    2016-08-01

    Full Text Available Titanium oxide (TiO2 films and TiO2/SiNx stacks have potential in surface passivation, anti-reflection coatings and carrier-selective contact layers for crystalline Si solar cells. A Si wafer, deposited with 8-nm-thick TiO2 film by atomic layer deposition, has a surface recombination velocity as low as 14.93 cm/s at the injection level of 1.0 × 1015 cm−3. However, the performance of silicon surface passivation of the deposited TiO2 film declines as its thickness increases, probably because of the stress effects, phase transformation, atomic hydrogen and thermal stability of amorphous TiO2 films. For the characterization of 66-nm-thick TiO2 film, the results of transmission electron microscopy show that the anatase TiO2 crystallinity forms close to the surface of the Si. Secondary ion mass spectrometry shows the atomic hydrogen at the interface of TiO2 and Si which serves for chemical passivation. The crystal size of anatase TiO2 and the homogeneity of TiO2 film can be deduced by the measurements of Raman spectroscopy and spectroscopic ellipsometry, respectively. For the passivating contacts of solar cells, in addition, a stack composed of 8-nm-thick TiO2 film and a plasma-enhanced chemical-vapor-deposited 72-nm-thick SiNx layer has been investigated. From the results of the measurement of the reflectivity and effective carrier lifetime, TiO2/SiNx stacks on Si wafers perform with low reflectivity and some degree of surface passivation for the Si wafer.

  6. Photocatalytic Activity of Immobilized Geometries of TiO2

    Science.gov (United States)

    Koohestani, Hassan; Sadrnezhaad, Sayed Khatiboleslam

    2015-07-01

    Photocatalysts that are used for waste water treatment are often suspended in the waste water during processing and then must be removed from the water after treatment. To reduce the post-degradation expenses and time, separation is facilitated by an immobilization process. The effect of immobilized TiO2 geometries on the photocatalytic behavior of the photocatalyst is investigated in this work. Powder, fiber, film, and network-shaped TiO2 nanocatalysts were produced by using different templates. The cellulose fiber and ceramic templates were used as substrates for fiber and film/network geometry production. The products were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area measurement. The photocatalytic performance was determined by methyl orange degradation and cyanide photo-oxidation under ultraviolet irradiation. From the SEM images, the size range of the TiO2 particles in the film and in the network geometries were 20-60 nm. The nanoparticles had covered the surface of the substrate, uniformly. Removal of the cellulose substrate by heat treatment yielded hollow TiO2 fibers with diameters of 0.5-1 µm and lengths of 30 µm. The efficiencies of both photocatalytic reactions were obtained in the following order: powder > network > film > fiber geometry. The rate constant of the dye degradation reaction using powder catalyst was 0.0118 min-1. For network catalyst, it was 0.0083 min-1. Corresponding results for cyanide disinfection were 0.0055 and 0.0046 min-1. Although powder samples had higher rate constants, network geometry was preferred due to its higher immobility.

  7. Band alignment of rutile and anatase TiO2

    Science.gov (United States)

    Scanlon, David O.; Dunnill, Charles W.; Buckeridge, John; Shevlin, Stephen A.; Logsdail, Andrew J.; Woodley, Scott M.; Catlow, C. Richard A.; Powell, Michael. J.; Palgrave, Robert G.; Parkin, Ivan P.; Watson, Graeme W.; Keal, Thomas W.; Sherwood, Paul; Walsh, Aron; Sokol, Alexey A.

    2013-09-01

    The most widely used oxide for photocatalytic applications owing to its low cost and high activity is TiO2. The discovery of the photolysis of water on the surface of TiO2 in 1972 launched four decades of intensive research into the underlying chemical and physical processes involved. Despite much collected evidence, a thoroughly convincing explanation of why mixed-phase samples of anatase and rutile outperform the individual polymorphs has remained elusive. One long-standing controversy is the energetic alignment of the band edges of the rutile and anatase polymorphs of TiO2 (ref. ). We demonstrate, through a combination of state-of-the-art materials simulation techniques and X-ray photoemission experiments, that a type-II, staggered, band alignment of ~ 0.4 eV exists between anatase and rutile with anatase possessing the higher electron affinity, or work function. Our results help to explain the robust separation of photoexcited charge carriers between the two phases and highlight a route to improved photocatalysts.

  8. Photocatalytic TiO2/glass nanoflake array films.

    Science.gov (United States)

    Ho, Wingkei; Yu, Jimmy C; Yu, Jiaguo

    2005-04-12

    A new approach for the fabrication of oriented TiO2/glass nanoflake arrays has been developed. The ceramic nanoflake array was formed on a glass substrate via a simple, low temperature, and one-step hydrothermally induced phase separation approach without using any templates or additives. The factors affecting the formation of ceramic nanoflakes were examined by various characterization techniques. The results showed that the leaching of the soluble phase from the glass surface through hydrothermal processes resulted in oriented uniform ceramic nanoflake arrays. Electron microscope observations revealed that the nanoflakes formed a continuous porous three-dimensional-network array with a large surface-to-volume ratio. In addition, an anatase TiO2 film was successfully coated onto the nanoflake array by the sol-gel method. The TiO2/glass nanoflake array exhibited high activity for the photocatalytic degradation of acetone and for photoinduced hydrophilic conversion. Such enhancements were attributed to the beneficial effects of the new continuous porous three-dimensional-interconnected nanoflake network and its surface geometrical nanostructure. The present approach provides a convenient route to modify a photocatalytic coating with a porous nano-architectured substrate. This opens extensive new opportunities in the design of semiconductor/ceramic nanostructural array thin films with unusual properties for future optical and electronic applications.

  9. Fe-doped TiO 2 thin films

    Science.gov (United States)

    Mardare, Diana; Nica, Valentin; Teodorescu, Cristian-Mihail; Macovei, Dan

    2007-09-01

    The reactive sputtering technique was used to obtain undoped and Fe-doped TiO 2 thin films deposited on glass substrates. At 250 °C substrate temperature, undoped TiO 2 films crystallize in a mixed rutile/anatase phase, while Fe-doped films exhibit the rutile phase only. Presence of Fe 3+ ions into the TiO 2 lattice is suggested by the intensity variation of forbidden 1s → 3d transitions between the Ti and Fe K-edges. Ti K-edge EXAFS data are assessed to a mixture of the two kinds of surroundings, a rutile-like crystalline phase, identified also by X-ray diffraction, and a nanosized or amorphous anatase-like surrounding. The local atomic order about Fe atoms is quite different and could be related also to an amorphous phase. The Swanepoel method is used to obtain the dispersion of the refractive index below the interband absorption edge. The dispersion energy, the single-oscillator energy and the coordination number of the Ti atoms are evaluated using the single-oscillator model (Wemple-DiDomenico).

  10. Photodecomposition of methylene blue by amorphous TiO2, CdS and TiO2-CdS films

    OpenAIRE

    F.G. Nieto-Caballero; E. Sánchez-Mora; J. M. Gracia-Jiménez; N.R. Silva-González; A.G. Rodríguez

    2007-01-01

    TiO2is one of the most widely studied oxide materials for applications related to photocatalytic processes. It has been reported that TiO2combined with CdS produces an improvement in the photocatalytic efficiency. This work focuses on the obtainment of TiO2, CdS and TiO2-CdSin situthin films by the sol-gel/dip coating method. After deposition on glass, each film was calcined at 300oC in an argon atmospherefor 30 min. The films were characterized by SEM, UV-Vis, XRD and micro-Raman. The TiO...

  11. Fabrication of dye-sensitized solar cells with multilayer photoanodes of hydrothermally grown TiO$_2$ nanocrystals and P25 TiO$_2$ nanoparticles

    Indian Academy of Sciences (India)

    MAZIAR MARANDI; MAHBOUBEH NAEIMI SANI SABET; FARZANEH AHMADLOO

    2016-10-01

    TiO$_2$ nanocrystals (NCs) with sizes around 20 nm were synthesized by hydrothermal method in acidic autoclaving pH. The hydrothermally grown TiO$_2$ NCs and P25 TiO$_2$ nanoparticles (NPs) were used in the preparationof two different pastes using different procedures. These pastes with different characteristics were separately deposited on FTO glass plates to form multilayer photoanodes of the dye-sensitized solar cells. The aim of this study was to search how a thin sub-layer of the hydrothermally grown TiO2 NCs in the photoanodes could improve the efficiency of TiO$_2$ P25-based solar cells. The highest efficiency of 6.5% was achieved for a cell with a photoanodecomposed of one transparent sub-layer of hydrothermally grown TiO$_2$ NCs and two over-layers of P25 NPs. Higher energy conversion efficiencies were also attainable using two transparent sub-layers of hydrothermally grown TiO$_2$ NCs. In this case, an efficiency of 7.2% was achieved for a cell with a photoelectrode made of one over-layer of P25 TiO$_2$ NPs. This could show an increase of about 30% in the efficiency compared to the similar cell with a photoanode made of two layers of hydrothermally grown TiO2 NCs.

  12. Microwave-hydrothermal synthesis of TiO2 and zirconium doped TiO2 adsorbents for removal of As(III) and As(V)

    OpenAIRE

    Ivan Andjelkovic; Dalibor Stankovic; Milica Jovic; Marijana Markovic; Jugoslav Krstic; Dragan Manojlovic; Goran Roglic

    2015-01-01

    Microwave-hydrothermal method was used for the synthesis of TiO2 and TiO2 doped with zirconium. The method was fast and simple and adsorbents were used for removal of As(III) and As(V) from aqueous solutions. The adsorbents were characterized by BET surface area measurements and powder XRD. Experiments showed that TiO2 doped with 10% of Zr using the microwave-hydrothermal method have greater specific surface area and total pore volume in comparison with TiO2 synthesized using the same method....

  13. TiO2 nanowire and TiO2 nanowire doped Ag-PVP nanocomposite for antimicrobial and self-cleaning cotton textile.

    Science.gov (United States)

    Hebeish, A A; Abdelhady, M M; Youssef, A M

    2013-01-16

    The TiO(2) nanowire (TiO(2) Nw) was successfully prepared via hydrothermal method through TiO(2) nanoparticle (TiO(2) Np). TiO(2) Np doped silver and TiO(2) Nw doped silver were prepared via photo-reducing Ag(+) ions to Ag metal on the TiO(2) Np or TiO(2) Nw surfaces. The prepared nanomaterials were evaluated using X-ray (XRD) diffraction pattern, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Bleached untreated cotton fabric and PVP treated cotton fabrics were coated with the synthesized nanomaterials using pad-dry-cure method. Photocatalytic activity of untreated and coated cotton fabrics with TiO(2) nanomaterials was investigated through the fabric self cleaning of MB dye stains. Also, the PVP finished cotton fabric modified by nanomaterials demonstrated antimicrobial activity against Gram positive bacteria, Gram negative bacteria and fungi. The mechanical properties of coated cotton fabric (tear strength, surface roughness, tensile strength and elongation at break) were examined.

  14. Study of concentration-dependent cobalt ion doping of TiO2 and TiO(2-x)Nx at the nanoscale.

    Science.gov (United States)

    Gole, James L; Prokes, Sharka M; Glembocki, O J; Wang, Junwei; Qiu, Xiaofeng; Burda, Clemens

    2010-07-01

    Experiments with a porous sol-gel generated TiO(2) nanocolloid and its corresponding oxynitride TiO(2-x)N(x) are carried out to evaluate those transformations which accompany additional doping with transition metals. In this study, doping with cobalt (Co(ii)) ions is evaluated using a combination of core level and VB-photoelectron and optical spectroscopy, complementing data obtained from Raman spectroscopy. Raman spectroscopy suggests that cobalt doping of porous sol-gel generated anatase TiO(2) and nitridated TiO(2-x)N(x) introduces a spinel-like structure into the TiO(2) and TiO(2-x)N(x) lattices. TEM and XPS data complemented by valence band-photoelectron spectra demonstrate that metallic cobalt clusters are not formed even at high doping levels. As evidenced by Raman spectroscopy, the creation of a spinel-like structure is commensurate with the room temperature conversion of the oxide and its oxynitride from the anatase to the rutile form. The onset of this kinetically driven process correlates with the formation of spinel sites within the TiO(2) and TiO(2-x)N(x) particles. Despite their visible light absorption, the photocatalytic activity of these cobalt seeded systems is diminished relative to the oxynitride TiO(2-x)N(x).

  15. Hybrid matrices of TiO2 and TiO2–Ag nanofibers with silicone for high water flux photocatalytic degradation of dairy effluent

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmad; Alm, Martin; Thomsen, Peter

    2016-01-01

    TiO2 and TiO2–Ag nanofibers were produced by electrospinning technique and surface coated on silicone elastomer (diameter: 10.0 mm; thickness: 2.0 mm) by dipcoating method. These coated hybrid nanoporous matrices were characterized by various morphological and physicochemical techniques (like SEM......, TEM, XRD, FTIR, EDS and UV). These characterizations reveal that the surface morphology of electrospun nanofibers remain intact by the dipcoating technique. The produced hybrid matrices of TiO2 and TiO2–Ag silicone were utilized as photocatalysts to degrade dairy waste water with an efficient water...

  16. Removal of formaldehyde from aqueous solutions using TiO2 immobilized on bamboo activated carbon%竹活性炭负载二氧化钛光催化降解水溶液中甲醛的研究

    Institute of Scientific and Technical Information of China (English)

    崔丹丹; 蒋剑春; 孙康; 卢辛成

    2011-01-01

    A composite of TiO2 and bamboo activated carbon was achieved through sol-gel method and its remov-al of formaldehyde was evaluated. Removal rate of formaldehyde with different pre-adsorbing time, initial con-centrations and different catalyst dosages over the composite was investigated. It was shown that the prepared composite photocatalyst remove formaldehyde from aqueous solution distinctly- when the dosage is 1.0g, 800mL initial concentration of 5mg/L aqueous solution of formaldehyde, after 1h pre-adsorbing and then expo-sure in 17W UV-light, the formaldehyde removal rate is up to 95. 96% at 480min. The kinetic analysis showed that photocatalytic rates were well described by the Langmuir-Hinshelwood model. The apparent first-order re-action coefficient of photocatalysis with low concentration is higher than that with high concentration formalde-hyde. More composite showed higher reaction coefficient than the less one in certain extent, and too much com-posite hindered the photocatalysis owing to the lower light transmittance.%采用竹活性炭作为载体,通过溶胶-凝胶法制备二氧化钛/竹活性炭复合光催化剂,并考察其对水溶液中甲醛的去除效果.分别考察了预吸附时间、催化剂投加量、初始反应浓度等对去除效果的影响,结果表明预吸附1h,催化剂投加量为1g时,初始浓度为5mg/L甲醛溶液在17W紫外灯照射480min时,去除率达95.96%.同时,对制备所得的复合光催化剂去除水溶液中甲醛的动力学进行了初步研究,结果表明二氧化钛/竹活性炭复合光催化剂去除水溶液中甲醛的反应符合解格缪尔-欣伍(Langmuir-Hinshelwood )动力学方程,为一级反应.

  17. TiO_2-石墨烯-Nafion复合膜修饰玻碳电极同时测定多巴胺和尿酸%Simultaneous Determination of Dopamine and Uric Acid Based on TiOz-Graphene- Nation Composite Film Modified Glassy Carbon Electrode

    Institute of Scientific and Technical Information of China (English)

    刘雪; 王兰; 樊阳; 刘凤杰

    2012-01-01

    利用在玻碳电极上修饰了TiO2-石墨烯-Nafion复合膜制得的修饰电极进行多巴胺(DA)和尿酸(UA)的同时测定。用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了该修饰电极的电化学行为。在pH为7.0的磷酸盐缓冲液(PBS)中,修饰电极对于DA和UA的电化学氧化具有良好的电催化性能。DA和UA的氧化峰电流分别在2~120和60~300μmol/L浓度范围内呈良好的线性关系,检出限分别为0.066和0.102μmol/L。实验结果表明,TiO2-石墨烯-Nafion复合膜修饰电极显著提高了检测的灵敏度,并表现出良好的选择性和重现性。%A modified electrode, which was fabricated by casting TiO2-graphene-Nafion composite film on glass carbon electrode surface and drying in room temperature, was used for determination of dopamine (DA) and uric acid (UA) simultaneously. The electrochemical behavior of DA and UA at the modified electrode was investigated by cyclic voltametry (CV) and different pulse vohametry ( DPV). In pH 7.0 phosphate buffer solution (PBS), the modified electrode showed excellent electro-catalytic activity for the oxidation of DA and UA. The oxidation peak current showed good linear relationships with the concentration of DA and UA in the range of 2 - 120 and 60 - 300p~mol/L, respectively. The limits of detection were 0. 066 and 0. 102μmol/L. The presented method exhibits high sensitivity, selectivity and reproducibility.

  18. Simultaneous Determination of Acetaminophen and Tryptophan Based on TiO2-graphene/poly(4-aminobenzoic acid)Modified Glassy Carbon Electrode%聚对氨基苯甲酸/TiO2-石墨烯修饰玻碳电极 同时测定扑热息痛和色氨酸

    Institute of Scientific and Technical Information of China (English)

    许春萱; 郭晓海; 孙双霞; 刘静

    2012-01-01

    采用滴涂法和电聚合法制备聚对氨基苯甲酸/Ti02-石墨烯修饰玻碳电极.用循环伏安法和差分脉冲伏安法研究扑热息痛和色氨酸在修饰电极上的电化学行为,据此建立一种扑热息痛和色氨酸同时测定的电化学方法.实验结果表明,该修饰电极对于扑热息痛和色氨酸的电化学反应具有良好的催化性能.利用差分脉冲伏安法测定,扑热息痛和色氨酸在1.0~530 μmol/L浓度范围内与氧化峰电流呈良好的线性关系,相关系数分别为0.990和0.993.信噪比为3时,扑热息痛和色氨酸检出限分别为0.4μmol/L和0.1μmol/L.将该方法用于实际样品分析,回收率为95.2% ~ 105.8%.%TiO2-graphene (TiO2-Gr) was coated on glassy carbon electrode (GCE) and 4-aminoben2oic acid was then electropolymerized on the modified electrode to fabricated electrochemical sensor. The electrochemical behaviors of acetaminophen and tryptophan on the modified electrode were investigated by cyclic voltammetry and differential pulse voltammelry. A novel electrochemical method for simultaneous determination of acetaminophen and tryptophan was developed. The results showed that the modified electrode has good electrocatalytic performance toward the electrochemical reaction of acetaminophen and tryptophan. Differential pulse voltammetry was used for the determination of acetaminophen and tryptophan. The concentration of acetaminophen and tryptophan showed good linear relationships with the oxidation peak current in the range of 1.0 -530 μmol/L, with correlation coefficients of 0.990 and 0.993, respectively. The limits of detection were 0.4 μmol/L and 0.1 μmol/L ( SSN = 3), respectively. The developed method was used to determine real samples with recoveries of 95.2% ~ 105. 8%.

  19. Synergetic Effect of Ti(3+) and Oxygen Doping on Enhancing Photoelectrochemical and Photocatalytic Properties of TiO2/g-C3N4 Heterojunctions.

    Science.gov (United States)

    Li, Kai; Huang, Zhenyu; Zeng, Xiaoqiao; Huang, Baibiao; Gao, Shanmin; Lu, Jun

    2017-04-05

    To improve the utilization of visible light and reduce photogenerated electron/hole recombination, Ti(3+) self-doped TiO2/oxygen-doped graphitic carbon nitride (Ti(3+)-TiO2/O-g-C3N4) heterojunctions were prepared via hydrothermal treatment of a mixture of g-C3N4 and titanium oxohydride sol obtained from the reaction of TiH2 with H2O2. In this way, exfoliated O-g-C3N4 and Ti(3+)-TiO2 nanoparticles were obtained. Simultaneously, strong bonding was formed between Ti(3+)-TiO2 nanoparticles and exfoliated O-g-C3N4 during the hydrothermal process. Charge transfer and recombination processes were characterized by transient photocurrent responses, electrochemical impedance test, and photoluminescence spectroscopy. The photocatalytic performances were investigated through rhodamine B degradation test under an irradiation source based on 30 W cold visible-light-emitting diode. The highest visible-light photoelectrochemical and photocatalytic activities were observed from the heterojunction with 1:2 mass ratio of Ti(3+)-TiO2 to O-g-C3N4. The photodegradation reaction rate constant based on this heterojuction is 0.0356 min(-1), which is 3.87 and 4.56 times higher than those of pristine Ti(3+)-TiO2 and pure g-C3N4, respectively. The remarkably high photoelectrochemical and photocatalytic performances of the heterojunctions are mainly attributed to the synergetic effect of efficient photogenerated electron-hole separation, decreased electron transfer resistance from interfacial chemical hydroxy residue bonds, and oxidizing groups originating from Ti(3+)-TiO2 and O-g-C3N4.

  20. Graphene oxide nanosheets as an effective template for the synthesis of porous TiO2 film in dye-sensitized solar cells

    Science.gov (United States)

    Wang, Ping; He, Fenglong; Wang, Jin; Yu, Huogen; Zhao, Li

    2015-12-01

    Template method by using various organic components as the pore-forming agent is an effective strategy for the preparation of various porous inorganic materials. After high-temperature calcination in air, the organic components can be in situ decomposed into the gaseous CO2, resulting in the formation of porous structures in inorganic materials. In addition to the well-known organic components, it is highly required to develop new and simple carbon-containing template to prepare porous inorganic nanostructures. In this study, graphene oxide (GO) nanosheets were used as a new template for the preparation of porous TiO2 film photoelectrode, which can be applied in dye-sensitized solar cells (DSSCs). The porous TiO2 film was fabricated via a three-step method, including the initially homogeneous grafting of GO nanosheets on the TiO2 surface (TiO2-GO), the preparation of TiO2-GO film using blade method and final formation of porous structure after the in situ removal of GO by high-temperature calcination. The effect of GO content on photoelectric conversion performance of the as-fabricated DSSCs was investigated. It was found that the conversion efficiency of DSSC based on porous TiO2-GO (0.75%) film reached up to a maximum value (4.65%), which was much higher than that of DSSC based on nonporous TiO2 film (4.01%). The enhanced conversion efficiency can be attributed to the formation of more porous structures caused by the GO nanosheets after high-temperature calcination. This work may provide a new insight for preparing other porous structured materials.

  1. TiO2 nanotube arrays and TiO2-nanotube-array based dye-sensitized solar Cell

    Institute of Scientific and Technical Information of China (English)

    LIU YanBiao; ZHOU BaoXue; XIONG BiTao; BAI Jing; LI LongHai

    2007-01-01

    To substitute the non-regular nano-crystalline semiconductor for a novel kind of ordered microstructure is a very important aspect in the domain of dye-sensitized solar cell.One of the researching hotspots is the highly-ordered TiO2 nanotube architecture.As a new type of titania nano-material,titania nanotube arrays have drawn extraordinary attention due to its distinctive morphology,notable photoelectrical and hydro-sensitive performance.At 100% sun the new kind of TiO2 nanotube arrays solar cell exhibits an overall conversion efficiency of 5.44%.This paper introduces the preparation methods of titania nanotube arrays,the existing problems and recent progress in titania nanotube arrays solar cell.

  2. Reason for the loss of hydrophilicity of TiO2 film and its photocatalytic regeneration

    Institute of Scientific and Technical Information of China (English)

    殷好勇; 金振声; 张顺利; 王守斌; 张治军

    2002-01-01

    TiO2 film was prepared on soda-lime glass by sol-gel method. The water contact angle (θw) of the fresh TiO2 film is 0o. During storage in air, the surface of TiO2 film is gradually converted to the hydrophobic state. XPS and ITD results reveal that it is due to the adsorption of organic contaminants on TiO2 surface in air ambience. The lost hydrophilicity of TiO2 film can be regenerated by UV illumination.

  3. Fabrication and characterization of perovskite photovoltaic devices with TiO2 nanoparticle layers

    Science.gov (United States)

    Oku, Takeo; Ueoka, Naoki; Suzuki, Kohei; Suzuki, Atsushi; Yamada, Masahiro; Sakamoto, Hiroki; Minami, Satoshi; Fukunishi, Sakiko; Kohno, Kazufumi; Miyauchi, Shinsuke

    2017-01-01

    TiO2/CH3NH3PbI3-based photovoltaic devices were fabricated by a spin-coating method using mixture solutions with TiO2 nanoparticles. Compact TiO2 layers were prepared from titanium diisopropoxide bis(acetyl acetonate) and TiO2 nanoparticles with different particle sizes. The performance of the photovoltaic devices was improved by sequential deposition of the TiO2 layers, which resulted in microstructural change of the perovskite layers.

  4. Fabrication and characterization of photovoltaic devices based on perovskite compounds with TiO2 nanoparticles

    Science.gov (United States)

    Kanayama, Masato; Oku, Takeo; Suzuki, Atsushi; Yamada, Masahiro; Fukunishi, Sakiko; Kohno, Kazufumi; Sakamoto, Hiroki

    2015-02-01

    Perovskite-type photovoltaic devices were fabricated by a spin-coating method using a mixture solution. The compact and meso-porous TiO2 of the solar cells were fabricated from TiO2 nanoparticles and sol, and the photovoltaic properties and microstructures were characterized. The conversion efficiencies were improved by the combination of TiO2 nanoparticles and sol. Current density was also improved by increasing numbers of spin-coatings of meso-porous TiO2. Thick meso-porous TiO2 layers would assist the construction of perovskite layers and block of the leak current.

  5. Composite Electrode SnO2/TiO2 for Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Jiang Bin XIA; Fu You LI; Shu Ming YANG; Chun Hui HUANG

    2004-01-01

    Composite nanoporous electrode SnO2/TiO2 was fabricated for the dye sensitized solar cell (DSSC) with N3 (Cis-Ru). After introducing of TiO2, the open-circuit photovoltage (Voc) was higher than that of the pure SnO2 electrode, while short-circuit photocurrent (Isc) was varied with the ratio of the TiO2. Appropriate content of the TiO2 can be beneficial to the efficiency of the solar cell, and it gives negative impact on the composite electrode when the content of TiO2 is higher.

  6. Characteristics of dye-sensitized solar cell with TiO2 anode under UV irradiation

    Science.gov (United States)

    Lee, Ming-Kwei; Hsiao, Chih-Chen; Weng, Hao-Wei

    2016-03-01

    The anatase phase crystalline quality of commercial TiO2 (P25) nanoparticle sintered in air and N2 is improved. Compared DSSC with air-sintered TiO2 anode, DSSC with N2-sintered TiO2 anode has better performance mainly from high optical absorption efficiency. Under UV irradiation, organic contaminants adsorbed on TiO2 are dissociated by the photocatalysis, and the dye adsorption is enhanced. The DSSC performance with UV-treated/N2-sintered TiO2 anode is further improved.

  7. STUDY OF METHYL ORANGE PHOTODEGRADATION USING TiO2-MONTMORILLONITE COMPOSITE

    OpenAIRE

    2015-01-01

    Composite TiO2-montmorillonite (Ti-MMT) has been synthesized with the aim to improve the ability of TiO2 photocatalysts degrade methyl orange. Synthesis of composite made by mixing TiO2 and montmorillonite in ethanol solution, then heated using the furnace at a temperature of 450 °C for 5 hours. TiO2-MMT composites were characterized by FT-IR, XRD and SAA. Test photodegradation activity of TiO2-MMT composites made to dye Methyl Orange 8 mg / L with UV light irradiation time variation and mass...

  8. Enhanced photocatalytic performance of TiO2-ZnO hybrid nanostructures

    OpenAIRE

    Chun Cheng; Abbas Amini; Chao Zhu; Zuli Xu; Haisheng Song; Ning Wang

    2014-01-01

    We studied the photocatalytic properties of rational designed TiO2-ZnO hybrid nanostructures, which were fabricated by the site-specific deposition of amorphous TiO2 on the tips of ZnO nanorods. Compared with the pure components of ZnO nanorods and amorphous TiO2 nanoparticles, these TiO2-ZnO hybrid nanostructures demonstrated a higher catalytic activity. The strong green emission quenching observed from photoluminescence of TiO2-ZnO hybrid nanostructures implied an enhanced charge transfer/s...

  9. Combination of TiO2-Film Photocatalysis and Ultrafiltration to Treat Wastewater

    OpenAIRE

    Shu-Hai You; Ming-Hua Guo

    2013-01-01

    In this study, a combination of TiO2-film photocatalysis reactor and ultrafiltration was used treat the secondary effluent from the manufacturing of thin film transistor-liquid crystal display (TFT-LCD). TiO2 particles, as a photocatalyst, were immobilized on silica glass to form TiO2-film by the sol-gel and dip coating methods. TiO2-film photocatalysis was done within three parameters, including number of coating times of TiO2-film, wavelengths of UV light source, and operating time. During...

  10. Enhanced Photocatalytic Activity of Pure Anatase Tio2 and Pt-Tio2 Nanoparticles Synthesized by Green Microwave Assisted Route

    OpenAIRE

    Filippo, Emanuela; Carlucci, Claudia; Capodilupo,Agostina Lina; Perulli,Patrizia; Conciauro,Francesca; Corrente, Giuseppina Anna; Gigli, Giuseppe; Ciccarella, Giuseppe

    2015-01-01

    High-yield, rapid and facile synthesis of elongated pure anatase titania nanoparticles has been achieved through a nonaqueous microwave-based approach. The residual organics onto nanoparticles surfaces were completely removed through a new treatment under ozone flow, at room temperature in air. Such an ozone cleaning method revealed an effective inexpensive dry process of removing organic contaminants from nanoparticles surfaces. The TiO2 elongated nanoparticles having a length of 13.8 ±...

  11. Structural analysis of TiO2 and TiO2-Ag thin films and their antibacterial behaviors

    Science.gov (United States)

    Hsieh, J. H.; Yu, R. B.; Chang, Y. K.; Li, C.

    2012-01-01

    TiO2 (rutile and anatase) thin films was first prepared using reactive sputtering, in an Ar+O2 plasma. In the 2nd stage of the experiment, various amounts (3, 7, and 10 at. %) of Ag was doped into the rutile film in order to form TiO2-Ag thin films. These films were annealed for one hour in Ar atmosphere, at 300, 400, and 500 °C. The films' structures were then examined using X-ray diffractometry. FESEM (field-emission scaning electron microscopy) was used to investigate the surface emergence of Ag particles. As for the examination of optical band gaps and absorption of these films, UV-Vis-NIR photometer was used. The results show that, in as-deposited condition, the addition of Ag might disrupt the growth of crystalline structure and cause the formation of amorphous films. After annealing, it is found that the structure tends to become anatase phase which is a metastable phase between amorphous titanium oxide and rutile. More importantly, the absorption of the Ag-doped films would be enhanced in the visible-light range. Some of the enhancement is clearly due to plasmon resonance effect. The Ag-doped samples have shown some antibacterial effect in dark. When irradiated with light, the samples show a synergistic behavior combining the bactericidal effect of Ag ions and photocatalytic effect of TiO2.

  12. 4-Nitroaniline Degradation by TiO2 Catalyst Doping with Manganese

    Directory of Open Access Journals (Sweden)

    Kai Zheng

    2015-01-01

    Full Text Available Stainless steel anode covered with layer film of TiO2 doped with manganese was utilized to decompose 4-nitroaniline in rectangular borosilicate glass reactor, while stainless steel mesh was chosen as cathode; the anode and cathode were connected to the direct-current power; meantime two 60 W (λmax = 365 nm UV lamps were used as light source. The microstructures on TiO2 before and after being doped with manganese were analyzed by energy disperse X-ray (EDX and X-ray diffraction (XRD. The performance of degradation of 4-nitroaniline was evaluated by analyzing cracking ratio of 4-nitroaniline ring, the chemical oxygen demand (COD, and total organic carbon (TOC in remaining solution. Monitored parameters during all the photocatalytic reaction including dissolved oxygen, direct voltage, and radiation dosage of ultraviolet rays were investigated. When dissolved oxygen concentration, direct voltage, and radiation dosage of ultraviolet rays were, respectively, equivalent to 9 mg/L, 24 V, and 1200 μW/cm2, the degradation ratio of 4-nitroaniline reached maximum. The experimental results indicated that cracking ratio of 4-nitroaniline ring and the removal ratio of COD and TOC were, respectively, more than 99%, 85%, and 80% when reaction was run for 10 hours. The values of COD and TOC were, respectively, less than 16 mg/L and 8 mg/L while the experiment was finished.

  13. Principal component analysis of Raman spectra for TiO2 nanoparticle characterization

    Science.gov (United States)

    Ilie, Alina Georgiana; Scarisoareanu, Monica; Morjan, Ion; Dutu, Elena; Badiceanu, Maria; Mihailescu, Ion

    2017-09-01

    The Raman spectra of anatase/rutile mixed phases of Sn doped TiO2 nanoparticles and undoped TiO2 nanoparticles, synthesised by laser pyrolysis, with nanocrystallite dimensions varying from 8 to 28 nm, was simultaneously processed with a self-written software that applies Principal Component Analysis (PCA) on the measured spectrum to verify the possibility of objective auto-characterization of nanoparticles from their vibrational modes. The photo-excited process of Raman scattering is very sensible to the material characteristics, especially in the case of nanomaterials, where more properties become relevant for the vibrational behaviour. We used PCA, a statistical procedure that performs eigenvalue decomposition of descriptive data covariance, to automatically analyse the sample's measured Raman spectrum, and to interfere the correlation between nanoparticle dimensions, tin and carbon concentration, and their Principal Component values (PCs). This type of application can allow an approximation of the crystallite size, or tin concentration, only by measuring the Raman spectrum of the sample. The study of loadings of the principal components provides information of the way the vibrational modes are affected by the nanoparticle features and the spectral area relevant for the classification.

  14. Impact and mechanism of TiO2 nanoparticles on DNA synthesis in vitro

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The impact of TiO2 nanoparticles on DNA synthesis in vitro in the dark and the molecular mechanism of such impact were studied. The impact of TiO2 nanoparticles on DNA synthesis was investigated by adding TiO2 nanoparticles in different sizes and at various concentrations into the polymerase chain reaction (PCR) system. TiO2 nanoparticles were premixed with the DNA polymerase, the primer or the template, respectively and then the supernatant and the precipitation of each mixture were added into the PCR system separately to observe the impact on DNA synthesis. Sequentially the interaction be- tween TiO2 nanoparticles and the DNA polymerase, the primer or the template was further analyzed by using UV-visible spectroscopy and polyacrylamide gel electrophoresis (PAGE). The results suggest that TiO2 nanoparticles inhibit DNA synthesis in the PCR system in the dark more severely than mi- croscale TiO2 particles at the equivalent concentration and the inhibition effect of TiO2 nanoparticles is concentration dependent. The molecular mechanism of such inhibition is that in the dark, TiO2 nanoparticles interact with the DNA polymerase through physical adsorption while TiO2 nanoparticles do with the primer or the template in a chemical adsorption manner. The disfunction levels of the bio-molecules under the impact of TiO2 nanoparticles are in the following order: the primer > the tem- plate > the DNA polymerase.

  15. Doped-TiO2 Photocatalysts and Synthesis Methods to Prepare TiO2 Films

    Institute of Scientific and Technical Information of China (English)

    Ying CUI; Hao DU; Lishi WEN

    2008-01-01

    TiO2 is a promising photocatalyst. However, the low photocatalytic efficiency calls for the modification of TiO2. Metal- and nonmetal-doping of TiO2 have been proved to be effective ways to enhance photocatalytic properties. This review provides a deep insight into the understanding of the metal- and nonmetal-doped TiO2 photocatalysts. This article begins with the introduction of the crystal structures of TiO2 and applications of TiO2 materials. We then reviewed the doped-TiO2 system in two categories: (1) metal-doped TiO2photocatalysts system, and (2) nonmetal-doped TiO2 photocatalysts system. Both experimental results and theoretical analyses are elaborated in this section. In the following part, for the advantages of TiO2 thin films over particles, various preparation methods to obtain TiO2 thin films are briefly discussed. Finally, this review ends with a concise conclusion and outlook of new trends in the development of TiO2-based photocatalysts.

  16. Reaction pathways of dimethyl phthalate degradation in TiO2-UV-O2 and TiO2-UV-Fe(VI) systems.

    Science.gov (United States)

    Yuan, Bao-ling; Li, Xiang-zhong; Graham, Nigel

    2008-05-01

    The photocatalytic degradation of dimethyl phthalate (DMP) in aqueous TiO2 suspension under UV illumination has been investigated using oxygen (O2) and ferrate (Fe(VI)) as electron acceptors. The experiments demonstrated that Fe(VI) was a more effective electron acceptor than O2 for scavenging the conduction band electrons from the surface of the catalyst. Some major intermediate products from DMP degradation were identified by HPLC and GC/MS analyses. The analytical results identified dimethyl 3-hydroxyphthalate and dimethyl 2-hydroxyphthalate as the two main intermediate products from the DMP degradation in the TiO2-UV-O2 system, while in contrast phthalic acid was found to be the main intermediate product in the TiO2-UV-Fe(VI) system. These findings indicate that DMP degradation in the TiO2-UV-O2 and TiO2-UV-Fe(VI) systems followed different reaction pathways. An electron spin resonance analysis confirmed that hydroxyl radicals existed in the TiO2-UV-O2 reaction system and an unknown radical species (most likely an iron-oxo species) is suspected to exist in the TiO2-UV-Fe(VI) reaction system. Two pathway schemes of DMP degradation in the TiO2-UV-O2 and TiO2-UV-Fe(VI) reaction systems are proposed. It is believed that the radicals formed in the TiO2-UV-O2 reaction system preferably attack the aromatic ring of the DMP, while in contrast the radicals formed in the TiO2-UV-Fe(VI) reaction systems attack the alkyl chain of DMP.

  17. Synthesis of a CNT-grafted TiO(2) nanocatalyst and its activity triggered by a DC voltage.

    Science.gov (United States)

    Kuo, Chien-Sheng; Tseng, Yao-Hsuan; Lin, Hong-Ying; Huang, Chia-Hung; Shen, Chih-Yen; Li, Yuan-Yao; Ismat Shah, S; Huang, Chin-Pao

    2007-11-21

    Carbon nanotube (CNT)-grafted TiO(2) (CNT/TiO(2)) was synthesized as an electrically conductive catalyst that exhibits redox ability under electrical excitation besides ultraviolet (UV) irradiation. The CNT/TiO(2) material was synthesized by a two-step process. Ni nanoparticles were photodeposited onto TiO(2) first. The Ni nanoparticles then served as seeds for the growth of CNTs using the chemical vapor deposition (CVD) of C(2)H(2). The CNT/TiO(2) nanocomposite exhibits strong oxidation activity toward NO gas molecules via both photocatalysis under UV irradiation and electrocatalysis under a DC voltage of 500 V in dark conditions.

  18. Treating dye wastewater by TiO2 coated on coal cinder

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-hua; WANG Hai-jun

    2009-01-01

    We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide (TiO2) coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the sol-gel method. Using the Congo red as the model pollutant for dye wastewater, we studied the decolorization efficiency, and effects of TiO2 film thickness and roasting temperature on the efficiency. We also evaluated the recycling and regeneration of the immobilized TiO2 (TiO2/cinder). Results show that the decolorization rate of Congo red solution was more than 98% after 2 h treatment when we used TiO2/cinder calcined at 500 °C for 2 h and coated four times as the photocatalyst. At the same time, the TiO2/cinder remained high catalytic activity after being reused and regenerated for many times.

  19. Surface hydroxyl groups direct cellular response on amorphous and anatase TiO2 nanodots.

    Science.gov (United States)

    Hong, Yi; Yu, Mengfei; Lin, Jun; Cheng, Kui; Weng, Wenjian; Wang, Huiming

    2014-11-01

    In this study, we investigated the differences between amorphous and anatase TiO2 at the biomolecular level which could explain differences in the osteoblast response on these surfaces. The number of surface hydroxyl groups in the TiOHT form on amorphous and anatase TiO2 was found to be the most important factor, resulting in adsorption of bovine serum albumin as a monolayer on amorphous TiO2 nanodots but as a multilayer on anatase TiO2 nanodots. The reason for this is that the presence of more TiOHT groups on amorphous TiO2 nanodots attracts more -NH3+ groups on BSA molecules, causing the conformation of surface-bound BSA molecules to differ from those adsorbed on anatase TiO2 nanodots. Fibronectin which is subsequently adsorbed on anatase TiO2 nanodots then retains a more active conformation for osteoblast adhesion and mineralization.

  20. Photocatalytic hydrogen generation over lanthanum doped TiO2 under UV light irradiation.

    Science.gov (United States)

    Liu, Y; Xie, L; Li, Y; Qu, J L; Zheng, J; Li, X G

    2009-02-01

    TiO2 nanoparticles doped with different amount of lanthanum were obtained by sol-gel approach and followed annealing at different temperature. The crystal size of TiO2 doped with lanthanum was smaller than that of pure TiO2. Photocatalytic activity of TiO2 doped with lanthanum for water splitting into H2 was investigated. The photocatalytic activity of TiO2 doped with lanthanum for water splitting into H2 is higher than that of pure TiO2. It was found that the optimal photocatalyst was TiO2 doped with 2 wt% lanthanum and calcined at 600 degrees C for 4 h which had hydrogen generation rate 700.6 micromol h(-1).

  1. Enhanced efficiency of dye-sensitized solar cells with novel synthesized TiO2.

    Science.gov (United States)

    Ju, Ki-Young; Cho, Jung-Min; Cho, Sung-June; Yun, Je-Jung; Mun, Soo-San; Han, Eun-Mi

    2010-05-01

    An anatase TiO2 and three kinds of novel TiO2 nanoparticles were prepared by a hydrothermal method for dye-sensitized solar cells (DSSCs), which were obtained by mixing NaOH (10 M), KOH (14 M) and LiOH (10 M) solution with an anatase TiO2 powder, respectively. The TiO2 working electrodes of DSSCs were prepared and the photoelectric properties of the cells were characterized. The influence of different poly(ethylene glycol) contents in TiO2 films with and without HNO3 treatment on the electron transfer in DSSCs were investigated. It is found that the DSSC with HNO3 (0.002 mol/l)-treated film containing 16.7 wt% PEG shows the higher power conversion efficiency of 6.0%, which was mainly depended on the degrees of TiO2 pore size and uniformity of TiO2 films.

  2. Photocatalytic antibacterial performance of Sn(4+)-doped TiO(2) thin films on glass substrate.

    Science.gov (United States)

    Sayilkan, Funda; Asiltürk, Meltem; Kiraz, Nadir; Burunkaya, Esin; Arpaç, Ertuğrul; Sayilkan, Hikmet

    2009-03-15

    Pure anatase, nanosized and Sn(4+) ion doped titanium dioxide (TiO(2)) particulates (TiO(2)-Sn(4+)) were synthesized by hydrothermal process. TiO(2)-Sn(4+) was used to coat glass surfaces to investigate the photocatalytic antibacterial effect of Sn(4+) doping to TiO(2) against gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus). Relationship between solid ratio of TiO(2)-Sn(4+) in coatings and antibacterial activity was reported. The particulates and the films were characterized using particle size analyzer, zeta potential analyzer, Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), SEM, AAS and UV/VIS/NIR techniques. The results showed that TiO(2)-Sn(4+) is fully anatase crystalline form and easily dispersed in water. Increasing the solid ratio of TiO(2)-Sn(4+) from 10 to 50% in the coating solution increased antibacterial effect.

  3. Enhanced photocatalytic performance of TiO2-ZnO hybrid nanostructures

    Science.gov (United States)

    Cheng, Chun; Amini, Abbas; Zhu, Chao; Xu, Zuli; Song, Haisheng; Wang, Ning

    2014-02-01

    We studied the photocatalytic properties of rational designed TiO2-ZnO hybrid nanostructures, which were fabricated by the site-specific deposition of amorphous TiO2 on the tips of ZnO nanorods. Compared with the pure components of ZnO nanorods and amorphous TiO2 nanoparticles, these TiO2-ZnO hybrid nanostructures demonstrated a higher catalytic activity. The strong green emission quenching observed from photoluminescence of TiO2-ZnO hybrid nanostructures implied an enhanced charge transfer/separation process resulting from the novel type II heterostructures with fine interfaces. The catalytic performance of annealing products with different TiO2 phase varied with the annealing temperatures. This is attributed to the combinational changes in Eg of the TiO2 phase, the specific surface area and the quantity of surface hydroxyl groups.

  4. Enhanced photocatalytic efficacy of hetropolyacid pillared TiO2 nanocomposites.

    Science.gov (United States)

    Nivea, R; Gunasekaran, V; Kannan, R; Sakthivel, T; Govindan, K

    2014-06-01

    The removal of dye from industrial effluents is prime important, photo-catalysis is a finest method to combat dye from effluents. This study concerns about the investigation of photocatalytic activity of TiO2-HPAs (Hetropolyacids) nanocomposite namely TiO2-Phosphomolybdic nanocomposite [TiO2-HMA] and TiO2-Phosphotungstic nanocomposite [TiO2-HWA] which were prepared by Sol-gel method and the same were characterized by using XRD, SEM-EDAX. The photocatalytic activity of prepared photo-catalysts were evaluated and compared by the degradation of Methylene Blue dye in water solution under UV irradiation. In that TiO2-HMA nanocomposite showed superior photocatalytic activity than TiO2-HWA.

  5. Influence of coating material on laser damage threshold of TiO2 films

    Institute of Scientific and Technical Information of China (English)

    Jianke Yao; Zhengxiu Fan; Hongbo He; Jianda Shao

    2007-01-01

    @@ The optical property, structure, surface properties (roughness and defect density) and laser-induced damage threshold (LIDT) of TiO2 films deposited by electronic beam (EB) evaporation of TiO2 (rutile), TiO2 (anatase) and TiO2 + Ta2O5 composite materials are comparatively studied. All films show the polycrystalline anatase TiO2 structure. The loose sintering state and phase transformation during evaporating TiO2 anatase slice lead to the high surface defect density, roughness and extinction coefficient, and low LIDT of films. The TiO2 + Ta2O5 composite films have the lowest extinction coefficient and the highest LIDT among all samples investigated. Guidance of selecting materials for high LIDT laser mirrors is given.OCIS codes: 310.3840, 140.3330.

  6. Photocatalytic degradation and mineralization of microcystin-LR under UV-A, solar and visible light using nanostructured nitrogen doped TiO2.

    Science.gov (United States)

    Triantis, T M; Fotiou, T; Kaloudis, T; Kontos, A G; Falaras, P; Dionysiou, D D; Pelaez, M; Hiskia, A

    2012-04-15

    In an attempt to face serious environmental hazards, the degradation of microcystin-LR (MC-LR), one of the most common and more toxic water soluble cyanotoxin compounds released by cyanobacteria blooms, was investigated using nitrogen doped TiO(2) (N-TiO(2)) photocatalyst, under UV-A, solar and visible light. Commercial Degussa P25 TiO(2), Kronos and reference TiO(2) nanopowders were used for comparison. It was found that under UV-A irradiation, all photocatalysts were effective in toxin elimination. The higher MC-LR degradation (99%) was observed with Degussa P25 TiO(2) followed by N-TiO(2) with 96% toxin destruction after 20 min of illumination. Under solar light illumination, N-TiO(2) nanocatalyst exhibits similar photocatalytic activity with that of commercially available materials such as Degussa P25 and Kronos TiO(2) for the destruction of MC-LR. Upon irradiation with visible light Degussa P25 practically did not show any response, while the N-TiO(2) displayed remarkable photocatalytic efficiency. In addition, it has been shown that photodegradation products did not present any significant protein phosphatase inhibition activity, proving that toxicity is proportional only to the remaining MC-LR in solution. Finally, total organic carbon (TOC) and inorganic ions (NO(2)(-), NO(3)(-) and NH(4)(+)) determinations confirmed that complete photocatalytic mineralization of MC-LR was achieved under both UV-A and solar light.

  7. Porous immobilized C coated N doped TiO2 containing in-situ generated polyenes for enhanced visible light photocatalytic activity

    Science.gov (United States)

    Sabri, N. A.; Nawi, M. A.; Nawawi, W. I.

    2015-10-01

    Carbon coated nitrogen-doped Degussa P25TiO2 (or C,N-P25TiO2) was successfully immobilized on a glass plate using epoxidized natural rubber (ENR-50) and polyvinyl chloride (PVC) as the organic binders. Photo-etching of the fabricated system for 10 h oxidized its PVC binder into polyenes as well as forming a highly porous surface. The band gap energy (Eg) of the photo-etched immobilized photocatalyst system (C,N-P25TiO2/ENR/PVC-10 h) was reduced from 2.91 to 2.86 eV. Its photocatalytic activity was studied via photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) under a 45 W visible light fluorescent lamp. C,N-P25TiO2/ENR/PVC-10 h with polyenes performed better than its slurry counterpart under visible light irradiation where the conjugated double bonds acted as photo sensitizers. The immobilized C,N-P25TiO2/ENR/PVC-10 h has excellent reusability and sustainable with an average k value of 0.056 ± 0.011 min-1 and average percent removal of 99.18 ± 0.54%.

  8. High Photocatalytic Activity of Fe3O4-SiO2-TiO2 Functional Particles with Core-Shell Structure

    Directory of Open Access Journals (Sweden)

    Chenyang Xue

    2013-01-01

    Full Text Available This paper describes a novel method of synthesizing Fe3O4-SiO2-TiO2 functional nanoparticles with the core-shell structure. The Fe3O4 cores which were mainly superparamagnetic were synthesized through a novel carbon reduction method. The Fe3O4 cores were then modified with SiO2 and finally encapsulated with TiO2 by the sol-gel method. The results of characterizations showed that the encapsulated 700 nm Fe3O4-SiO2-TiO2 particles have a relatively uniform size distribution, an anatase TiO2 shell, and suitable magnetic properties for allowing collection in a magnetic field. These magnetic properties, large area, relative high saturation intensity, and low retentive magnetism make the particles have high dispersibility in suspension and yet enable them to be recovered well using magnetic fields. The functionality of these particles was tested by measuring the photocatalytic activity of the decolouring of methyl orange (MO and methylene blue (MB under ultraviolet light and sunlight. The results showed that the introduction of the Fe3O4-SiO2-TiO2 functional nanoparticles significantly increased the decoloration rate so that an MO solution at a concentration of 10 mg/L could be decoloured completely within 180 minutes. The particles were recovered after utilization, washing, and drying and the primary recovery ratio was 87.5%.

  9. Formation and photovoltaic performance of few-layered graphene-decorated TiO2 nanocrystals used in dye-sensitized solar cells.

    Science.gov (United States)

    Liu, Yueli; Cheng, Yuqing; Shu, Wei; Peng, Zhuoyin; Chen, Keqiang; Zhou, Jing; Chen, Wen; Zakharova, Galina S

    2014-06-21

    Few-layer graphene/TiO2 nanocrystal composites are successfully in situ synthesized at a low temperature of 400 °C using C28H16Br2 as the precursor. Raman mapping images show that the TiO2 nanocrystals are very uniformly dispersed in the composite films, and the in situ coating during the thermal decomposition process will favor the formation of a good interface combination between the few-layered graphene and the TiO2 nanocrystals. The few-layer graphene/TiO2 nanocrystal composites are used as photoanodes in dye-sensitized solar cells (DSSCs), and the conversion efficiency of 8.25% is obtained under full sun irradiation (AM 1.5), which increases by 65% compared with that of the pure TiO2 nanocrystal DSSCs (5.01%). It is found that the good interface combination between few-layered graphene and TiO2 nanocrystals may improve the electric conductivity and lifetime of photoinduced electrons in DSSCs. Moreover, some carbon atoms are doped into the crystal structure of the TiO2 nanocrystals during the thermal decomposition process, which will enhance the light absorption by narrowing the band gap and favor the improvement of the photovoltaic efficiency.

  10. Comparison of catalytic activities for photocatalytic and sonocatalytic degradation of methylene blue in present of anatase TiO2-CNT catalysts.

    Science.gov (United States)

    Zhang, Kan; Zhang, Feng Jun; Chen, Ming Liang; Oh, Won Chun

    2011-05-01

    Anatase TiO(2)-CNT catalysts with high specific surface areas were prepared by depositing TiO(2) particles on the surface of carbon nanotubes (CNTs) using a modified sol-gel technique. These catalysts prepared with different amounts of CNTs were characterized by nitrogen adsorption, Fourier Transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray (EDX) and ultraviolet-visible (UV-Vis) spectroscopy. The catalytic activity of the anatase TiO(2)-CNT catalysts was assessed by examining the degradation of methylene blue (MB) from model aqueous solutions as a probe reaction under visible light and ultrasonic irradiation. The synergistic effect of the greater surface area and catalytic activities of the composite catalysts was examined in terms of the strong adsorption ability and interphase interaction by comparing the different amounts and roles of CNTs in the catalysts.

  11. Photocatalytic oxidation of selected gas-phase VOCs using UV light, TiO2, and TiO2/Pd.

    Science.gov (United States)

    Fujimoto, Tânia M; Ponczek, Milena; Rochetto, Ursula L; Landers, Richard; Tomaz, Edson

    2017-03-01

    Heterogeneous photocatalytic oxidation systems using titanium dioxide (TiO2) have been extensively studied for the removal of several volatile organic compounds (VOCs). The addition of noble metals such as palladium on TiO2 may improve photocatalytic activity by increasing charge separation efficiency. In this work, palladium was impregnated on TiO2 and the efficiency of the new catalyst was tested and compared with that of pure TiO2. Pd was impregnated on TiO2 by the reduction method, using NaBH4, and was characterized by XRD, XPS, UV-Vis, and H2 chemisorption. The photocatalytic tests were performed in an annular coated-wall reactor using octane, isooctane, n-hexane, and cyclohexane at inlet concentrations varying from 100 to 120 ppmv. Compared with pure TiO2 film, the photocatalytic activity of TiO2 impregnated with 1 wt% of palladium was improved. All the aforementioned analytical techniques confirmed the presence of Pd incorporated into the structure of TiO2, and the conversion rates were studied in a broad range of residence times, yielding up to 90 % or higher rates in 40 s of residence time, thus underscoring the relevant contribution of the technology.

  12. Charge transfer between biogenic jarosite derived Fe(3+)and TiO2 enhances visible light photocatalytic activity of TiO2.

    Science.gov (United States)

    Chowdhury, Mahabubur; Shoko, Sipiwe; Cummings, Fransciuos; Fester, Veruscha; Ojumu, Tunde Victor

    2017-04-01

    In this work, we have shown that mining waste derived Fe(3+) can be used to enhance the photocatalytic activity of TiO2. This will allow us to harness a waste product from the mines, and utilize it to enhance TiO2 photocatalytic waste water treatment efficiency. An organic linker mediated route was utilized to create a composite of TiO2 and biogenic jarosite. Evidence of FeOTi bonding in the TiO2/jarosite composite was apparent from the FTIR, EFTEM, EELS and ELNEFS analysis. The as prepared material showed enhanced photocatalytic activity compared to pristine TiO2, biogenic jarosite and mechanically mixed sample of jarosite and TiO2 under both simulated and natural solar irradiation. The prepared material can reduce the electrical energy consumption by 4 times compared to pristine P25 for degradation of organic pollutant in water. The material also showed good recyclability. Results obtained from sedimentation experiments showed that the larger sized jarosite material provided the surface to TiO2 nanoparticles, which increases the settling rate of the materials. This allowed simple and efficient recovery of the catalyst from the reaction system after completion of photocatalysis. Enhanced photocatalytic activity of the composite material was due to effective charge transfer between TiO2 and jarosite derived Fe(3+) as was shown from the EELS and ELNEFS. Generation of OH was supported by photoluminesence (PL) experiments.

  13. Positive role of incorporating P-25 TiO2 to mesoporous-assembled TiO2 thin films for improving photocatalytic dye degradation efficiency.

    Science.gov (United States)

    Sreethawong, Thammanoon; Ngamsinlapasathian, Supachai; Yoshikawa, Susumu

    2014-09-15

    In this work, a simple and effective strategy to improve the photocatalytic dye degradation efficiency of the mesoporous-assembled TiO2 nanoparticle thin films by incorporating small contents of commercial P-25 TiO2 during the thin film preparation was developed. The mesoporous-assembled TiO2 nanoparticles were synthesized by a sol-gel method with the aid of a mesopore-directing surfactant, followed by homogeneously mixing with P-25 TiO2 prior to the thin film coating on glass substrate. The mesoporous-assembled TiO2 film with 5 wt.% P-25 TiO2 incorporation and calcined at 400°C provided an improved photocatalytic Acid Black (AB) dye degradation efficiency. The increase in number of coated layers to the optimum four layers of the aforementioned film was found to further improve the degradation efficiency. The recyclability test of this 5 wt.% P-25 TiO2-incorporated mesoporous-assembled TiO2 film with four coated layers revealed that it can be reused for multiple cycles without a requirement of post-treatment while the degradation efficiency was retained.

  14. Visible light catalysis of rhodamine B using nanostructured Fe(2)O(3), TiO(2) and TiO(2)/Fe(2)O(3) thin films.

    Science.gov (United States)

    Mahadik, M A; Shinde, S S; Mohite, V S; Kumbhar, S S; Moholkar, A V; Rajpure, K Y; Ganesan, V; Nayak, J; Barman, S R; Bhosale, C H

    2014-04-05

    The Fe(2)O(3), TiO(2) and TiO(2)/Fe(2)O(3) composite films are deposited using spray pyrolysis method onto glass and FTO coated substrates. The structural, morphological, optical and photocatalytic properties of Fe(2)O(3), TiO(2) and TiO(2)/Fe(2)O(3) thin films are studied. XRD analysis confirms that films are polycrystalline with rhombohedral and tetragonal crystal structures for Fe2O3 and TiO(2) respectively. The photocatalytic activity was tested for the degradation of Rhrodamine B (Rh B) in aqueous medium. The rate constant (-k) was evaluated as a function of the initial concentration of species. Substantial reduction in concentrations of organic species was observed from COD and TOC analysis. Photocatalytic degradation effect is relatively higher in case of the TiO(2)/Fe(2)O(3) than TiO(2) and Fe(2)O(3) thin film photoelectrodes in the degradation of Rh B and 98% removal efficiency of Rh B is obtained after 20min. The photocatalytic experimental results indicate that TiO(2)/α-Fe(2)O(3) photoelectrode is promising material for removing of water pollutants.

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

    Science.gov (United States)

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

    2012-09-26

    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 μm 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.

  16. Development of TiO2 and TiO2/Fe-based polymeric nanocomposites by single-step laser pyrolysis

    Science.gov (United States)

    Alexandrescu, R.; Morjan, I.; Dumitrache, F.; Scarisoreanu, M.; Fleaca, C. T.; Morjan, I. P.; Barbut, A. D.; Birjega, R.; Prodan, G.

    2013-08-01

    Polymer-based nanocomposites provided with inorganic cores were simultaneously manufactured by the single-step laser pyrolysis. A comparative study was performed on two types of nanocomposites, starting from two different systems: TiO2/methyl methacrylate (MMA) and TiO2/Fe/hexamethyl disiloxane (HMDSO) polymer. The reactive mixture contained TiCl4 as Ti precursor and alternatively, Fe(CO)5 (in case of TiO2/Fe mixture). The analytical techniques used for the characterization indicate distinct morphologies for the obtained nanostructures. Polyhedral and almost spherical nanoparticles in a coalescent matrix and very rare individual core-shell particles are noticed for the TiO2/MMA nanocomposites. Instead, nanoparticles presenting core-shell structures were often present in the TiO2/Fe/HMDSO polymeric nanocomposites.

  17. 负载金属对MoO3-TiO2光催化剂结构与催化性能的影响%Effects of loaded metal on structure and photocatalytic performance of photocatalyst for MAA synthesis from propylene and carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    梅长松; 钟顺和

    2005-01-01

    用溶胶-凝胶和浸渍-还原相结合的方法制得M/MoO3-TiO2(M=Pd, Cu, Ni和Ag)光催化剂.利用X-射线衍射(XRD)、程序升温还原(TPR)、红外光谱(IR)、程序升温脱附(TPD)、紫外-可见漫反射光谱(UV-VisDRS)和光反应等技术,研究了负载金属复合半导体的物相结构、吸附性能、吸光性能和光催化反应性能.结果表明,金属M(M=Pd, Cu)负载在复合半导体上,延迟了TiO2由锐钛矿向金红石相的转化,增强了Mo与载体TiO2的相互作用,促进Mo物种由四面体配位向八面体配位转化,使TiO2光吸收限发生蓝移,对可见光部分的吸收明显增加,拓宽了催化剂的光响应范围;固体材料吸光性能强弱顺序Pd/MoO3-TiO2 >Cu/MoO3-TiO2 >Ag/MoO3-TiO2>Ni/MoO3-TiO2;Pd对CO2吸附能力过强,卧式吸附态脱附温度高,光催化效率不高;金属Cu对CO2吸附能力适中,CO2与C3H6脱附温度较接近,实现了光-表面-热的协同作用,光量子效率最高.

  18. Electrical Conductivity of TiO2 Nanotubes

    OpenAIRE

    Tighineanu, Alexei

    2015-01-01

    Nanostructured TiO2 is a material with high potential in a wide range of applications (water splitting, solar cells, biomedical applications as implant coatings and drug-delivery, batteries, sensors, electro-chromic devices and membranes). Nano-TiO2 is a material which properties depend mostly on surface-related processes. Therefore, detailed analysis of electronic properties of such material is of crucial importance for most of applications of nano-TiO2. At the beginning of the study, a ...

  19. Adsorption of natural organic matter and disinfection byproduct precursors from surface water onto TiO2 nanoparticles: pH effects, isotherm modelling and implications for using TiO2 for drinking water treatment.

    Science.gov (United States)

    Gora, Stephanie L; Andrews, Susan A

    2017-05-01

    Titanium dioxide is a photocatalyst that can remove organic contaminants of interest to the drinking water treatment industry, including natural organic matter (NOM) and disinfection byproduct (DBP) precursors. The photocatalytic reaction occurs in two steps: adsorption of the contaminant followed by degradation of the adsorbed contaminant upon irradiation with UV light. The second part of this process can lead to the formation of reactive intermediates and negative impacts on treated water quality, such as increased DBP formation potential (DBPfp). Adsorption alone does not result in the formation of reactive intermediates and thus may prove to be a safe way to incorporate TiO2 into drinking water treatment processes. The goal of this study was to expand on the current understanding of NOM adsorption on TiO2 and examine it in a drinking water context by observing NOM adsorption from real water sources and evaluating the effects of the resulting reductions on the DBPfp of the treated water. Bottle point isotherm tests were conducted with raw water from two Canadian water treatment plants adjusted to pH 4, pH 6 and pH 8 and dosed with TiO2 nanoparticles. The DOC results were a good fit to a modified Freundlich isotherm. DBP precursors and liquid chromatography with organic carbon detection NOM fractions associated with DBP formation were removed to some extent at all pHs, but most effectively at pH 4. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Mechanism of Acetyl Salicylic Acid (Aspirin Degradation under Solar Light in Presence of a TiO2-Polymeric Film Photocatalyst

    Directory of Open Access Journals (Sweden)

    Debjani Mukherjee

    2016-04-01

    Full Text Available Application of titanium dioxide (TiO2 as a photocatalyst has presented a promising avenue for the safe photocatalytic degradation of pollutants. Increasing levels of the release of pharmaceuticals in the environment and formation of the intermediates during their degradation may impose health and environmental risks and therefore require more attention. Photocatalytic degradation of acetylsalicylic acid (aspirin was carried out in the presence of the TiO2-filled polymeric film as a photocatalyst under solar light irradiation. The polymeric film incorporates TiO2 in the matrix, which acts as a photocatalyst under solar illumination and degrades the acetyl salicylic acid (ASA into a range of organic compounds before complete demineralization (formation of carbon dioxide and water as final products. Among the intermediates, acetic acid was found to be present in a larger amount compared to other organic acids. The qualitative/quantitative analyses of the intermediates resulted in the determination of the most probable reaction’s mechanism in the degradation process. The mechanism of degradation of acetylsalicylic acid and its reaction pathway were developed from liquid chromatography/mass spectroscopy (LC/MS, Fourier Transform Infra Red (FTIR and UV spectrophotometric analysis. It was found that hydroxyl groups were dominant in the degradation process compared to electrons and holes generated by TiO2. The total organic carbon (TOC analysis was also carried out to analyze the organic carbon content of the intermediates formed during the course of degradation.