Papers by Keyword: Photocatalytic

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Authors: Yong Qian Wang, Xu Dong Jiang, Chun Xu Pan
Abstract: In this paper, a micro-arc oxidation (MAO) approach is introduced for “in-situ” preparing TiO2 composite layer upon the surface of titanium alloy (Ti-6Al-4V) substrate. The surface morphologies, chemical compositions, crystal microstructure and photocatalytic properties of the layers were investigated by using a field emission scanning electron microscope (FE-SEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), electro-chemical workstation and UV-Vis spectrophotometer. The experimental results revealed that photocatalytic performance of the TiO2 composite layers was much higher than that of the pure TiO2 layer and also exhibited absorption under the visible light irradiation.
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Authors: Yong Gang Luo, Linda Zou, Eric Hu
Abstract: The porous TiO2 pellets were prepared based on pigment grade titaina, P25 titania powder and titanium(IV) butoxide. The characterization was done with X-Ray diffraction, scanning electron microscopy and BET measurements. The result shows that TiO2 pellets by using titanium(IV) butoxide with some addictive have the best surface porosity, with specific surface area of 196.9m2/g. For pigment grade titania and P25 titania powder, it is still effective to enhance the surface area after reassembling. The surface area increased from 11.6 to 29.2 m2/g for pigment grade titania and from 50 to 84.4 m2/g for P25 titania powder. Furthermore, it has been investigated on how to optimize and get the highest surface area by controlling the sintering temperature, reaction temperature, pH of solution, and the amount of alcohol and addictive of surfactant during preparation. The experimental photocatalytic degradation of acetone and toluene was performed using titania pellets made from P25 titania powder.
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Authors: Yuet Lee Ying, Swee Yong Pung, Ming Thong Ong, Yuk Fen Pung
Abstract: This work studied the photocatalytic performance of ZnO nanorods and WO3/ZnO nanorods in bromocresol green (BCG). The ZnO nanorods were pre-synthesized via solution precipitation method. Subsequently, the nanorods were kept in sodium tungstate solution for the deposition of WO3. The present of WO3 was confirmed by XRD and EDX analysis. ZnO nanorods (64.34%) showed a higher photodegradation efficiency of BCG removal than WO3/ZnO nanorods (60.03%) under 75 minutes of UV irradiation. This could be attributed to the formation of WO3/ZnO shell-core nanostructure which limited the generation of holes and hydroxyl free radicals that needed for the photodegradation of BCG dyes.
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Authors: Xiao Ping Wu
Abstract: Because of the unique optical properties, titanium dioxide (TiO2) has been widely used as a white pigment over several decades. The numerous and diverse applications of TiO2 can be found in many common products such as paints, plastics, paper, sunscreens, etc. In the past decades, the emergence of nanotechnology and the discovery of some of the key application potentials of TiO2 have spurred the enormous interests to study TiO2, particularly, nano-structured TiO2, as the functional materials. Since then, substantial advances have been made in the fabrication, characterization, fundamental understanding of TiO2 nano-materials, and their promising applications in a number of areas such as energy and environment. This review will discuss the properties of nano-structured TiO2 and highlight the recent development of their applications.
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Authors: Xin Ping Lin, Fu Qiang Huang, Wen Deng Wang, Zhi Chao Shan, Jian Lin Shi
Abstract: A series of layered-structure Bi-based oxychlorides such as BiOCl, Bi3O4Cl, Na0.5Bi1.5O2Cl, Bi4NbO8Cl and MBiO2Cl (M = Ca, Sr, Ba, Cd, Pb) used as efficient photocatalysts. Among them, Bi3O4Cl (Eg = 2.79 eV), Na0.5Bi1.5O2Cl (Eg = 3.03 eV), Bi4NbO8Cl (Eg = 2.38 eV) and PbBiO2Cl (Eg = 2.45 eV) are visible-light-responsive. The powders synthesized by solid state reactions were characterized by X-ray diffraction (XRD) and UV-Vis diffuse reflection spectrum. Their photocatalytic activities were evaluated by the degradation of methyl orange. The results generally show that the UV-induced photocatalytic performances of the novel oxychloride catalysts are better than or comparable to that of anatase TiO2. The high photocatalytic performance of Bi-based oxychlorides is mainly ascribed to the presence of strong internal static electric fields between layers.
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Authors: Mao Lin Zhang, Long Feng Li, Xiang Dong Meng
Abstract: Cu-doped TiO2 photocatalysts were synthesized by a homogeneous hydrolysis and low temperature crystallization method using tetrabutyl titanate as the titanium source and cupric acetate as the doping agent. The phase structure, composition and morphology of the product were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS) and Brunauer-Emmett-Teller surface area analysis (BET). The XRD results confirmed that the crystalline phase of all prepared samples was anatase-type TiO2. SEM results showed that the Cu-doped TiO2 were composed of spherical particles with particle diameter smaller than 20 nm. Furthermore, the photocatalytic activity of the Cu-doped TiO2 catalysts were evaluated based on the photocatalytic degradation of methyl orange (MO) in aqueous solution. The results showed that Cu-doped TiO2 had the higher visible-light-induced catalytic activity than the commercial P25 TiO2 powder. The copper content in Cu-doped TiO2 had obvious effect on the visible-light-induced catalytic activity, and the degradation rate of MO could reach 33.7% using Cu-doped TiO2 with a doping level of 1.0 mol% Cu as a photocatalyst under the visible light irradiation for 3 hours.
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Authors: Long Hui Nie, Hong Tao Xu, Song Dong Yuan
Abstract: A visible-light-active C-doped TiO2 photocatalyst was prepared by a simple wet process. The XPS analysis results showed that carbon was doped into TiO2 particles and one kind of carbonate species with Ti-O-C structure was formed. The obtained sample showed obvious absorption in the 400-800 nm range in UV-vis spectra. By degrading of methyl orange (MO) solution under visible light irradiation (l>420 nm), the apparent rate constant (kapp) of S170 was about 10 times larger than that of P25. The preparation procedure of such C-doped catalyst can be easily scaled up for industrial production due to its simplicity.
1175
Authors: Chul Hee Han
Abstract: In our study of organic molecules for OLED, we have paid attention to 4,4'-bis(N-carbazolyl)biphenyl (CBP), an arylamine commonly used as phosphorescent host or hole transport material in OLED, and performed photochemical and photocatalytic experiments. For the photocatalytic experiment, heterogeneous mixture of CBP and TiO2 powder (Degussa P25) in tetrahydrofuran solution has been placed under UV radiation. Both photochemical and photocatalytic experiments have resulted in degradation of CBP, however, with widely different rates and degradation products. With ever increasing demand for high performance OLEDs, higher stability and longer lifetime of their organic components are essential. In this respect, current informations are sure to be valuable in the design and operation of OLEDs as well as arylamine-based OLED.
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Authors: Ching Song Jwo, Chien Chih Chen, Ho Chang, Sih Li Chen, Chi Hsiang Lin
Abstract: This research carries out an inexpensive, rapid and novel exercise, which is applied to perform the photocatalyst decomposition effectiveness of Methanol and Ethanol in gaseous form. The major devices of this applicable measurement developed by this practice are only utilizing ultraviolet-visible spectrophotometer and quartz cuvette, and the experimental procedures are straightforward and speedy. In the conduct experiments, Methanol and Ethanol with a specific concentration is initially injected into an enclosed quartz cuvette. Then the cuvette is put in ultraviolet- visible spectrophotometer to measure the Methanol and Ethanol concentration, so as to obtain an unique UV absorbance spectrum at its particular concentration. In the conduct experiments of measuring photocatalyst decomposition efficiency, the self-made (SANSS) nanocatalyst TiO2 is initially coated in the quartz plate, and put into the quartz. Then a specific concentration of methanol alcohol and ethanol is injected into the quartz cuvette under the UV irradiation exposure, so as to carry out photodecomposition of Methanol and Ethanol experiment. After that, the cuvettes are then put into the ultraviolet-visible spectrophotometer for measuring the absorbance intensity of UV spectrums in order to produce degradation chart. The preliminary results point out that the self-made nanocatalyst TiO2 has exceptionally outstanding decomposition efficiency which further points out the fact that, when UV irradiation for 60minutes, the gaseous Methanol can be reduced to 3.8% of the original sample, and the gaseous Ethanol can be reduced to 6% of the original sample. But when exercising with commercial nanocatalyst TiO2 to undergo the same process exactly under the same circumstances, the residue gaseous concentration can only be reduced to 17% and 16% of the gaseous Methanol and Ethanol original sample.
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Authors: H.J. Oh, J.H. Lee, Y. Jeong, Su Jeong Suh, C.-S. Chi
Abstract: The microstructure and photocatalytic characteristics of anodic TiO2 film have been investigated for applications in waste water treatment. The major structure of the fabricated anodic TiO2 film consisted of porous cell structure, of which the main crystal structure bas been found to be anatase type. The photocatalytic efficiencies of anodized TiO2 were evaluated by the degradation rate of aniline blue and the chemical states of anodic film were estimated by P2P spectrum. The reaction order and the rate constant for degradation of dye have been determined to be first dimension and 1.608410-4s. Due to the high bonding strength between TiO2 film, and the substrate and the high specific surface area, the anodized TiO2 can be used as efficient photocatalyst with high reactivity for waste water treatment and water purification.
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