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91.
Andreas Mattsson Christian Lejon Vclav tengl Snejana Bakardjieva Frantiek Oplutil Per Ola Andersson Lars
sterlund 《Applied catalysis. B, Environmental》2009,92(3-4):401-410
The structure and photocatalytic activity of Zr doped TiO2 nanocrystallites with a varying Zr content between 0 and 15 wt% prepared by an efficient and environmentally benign method has been studied by vibrational spectroscopy, TEM and XRD. It is shown that the presence of Zr4+ ions stabilizes the anatase structure and delays phase transformation to rutile upon annealing as well as retarding grain coarsening. All TiO2 samples up to 13 wt% Zr doping concentration show better or similar photoreactivity compared to P25 (Degussa) for decomposition of adsorbed 2-chloroethyl ethyl sulphide (CEES) and dimethyl methylphosphonate (DMMP) in synthetic air at room temperature. The most efficient sample for photodegradation of both CEES and DMMP is shown to be titania doped with 6.8 wt% Zr. The photodegradation of CEES is faster than DMMP under the same experimental conditions. On the undoped TiO2 sample urea residues are detected spectroscopically. Much less is detected on the Zr doped samples. Mode resolved in situ FTIR surface spectroscopy enables distinction of CEES or DMMP, decomposition products as well as the influence of residues from the particle synthesis. This facilitates extraction of intra-comparable reaction rates. Possible explanations for the improved reactivity of the Zr doped titania are discussed. 相似文献
92.
Teresa Lana Villarreal Peter Bogdanoff Pedro Salvador N.Nicols Alonso-Vante 《Solar Energy Materials & Solar Cells》2004,83(4):347-362
Surface mesoscopic titanium dioxide (P25) films deposited onto conducting glass plates (SnO2:F) were modified by colloidal RuxSey nanoparticles (2 nm diameter). A decrease of the photocurrent was found upon modification of TiO2 films. However, interfacial electron transfer kinetics to oxygen was favored. The increase of the catalyst surface concentration onto TiO2, shifts the onset of the photocurrent under UV-illumination, to 0.6 V/RHE in presence of oxygen dissolved in the electrolyte. Concomitant to this, the cathodic current becomes important and shifts to more positive potentials. This phenomenon allows the system to work catalytically under open circuit conditions. On non-modified TiO2, the application of a 0.3 V/RHE potential leads to an enhancement of the photooxidation of formic acid. Photocurrent images revealed a non-homogeneous distribution of the catalyst on the titanium dioxide films. 相似文献
93.
利用锐钛矿晶型的纳米TiO2 胶体溶液 ,将硅胶作为粘结剂按不同配比加入TiO2 胶体 ,用提拉法在陶瓷表面形成均匀薄膜并在高温下烘烤成膜。研究TiO2 和硅胶在不同比例情况下的薄膜特性 ,讨论了退火温度对亲水性及光催化活性的影响 ,利用分光光度计测量了TiO2 薄膜对亚甲基蓝的分解活性 ,测定了薄膜对洗涤剂、消毒剂、3 %NaOH和沸水的抗腐蚀能力。结果表明 ,利用这种方法制备的薄膜具有较好的光致亲水性和光催化性 ,并具有良好的抗腐蚀能力。 相似文献
94.
Anhuai Lu Juan Liu Donggao Zhao Yanjun Guo Qiaorong Li Ning Li 《Catalysis Today》2004,90(3-4):337-materials
Natural rutile TiO2 shows photocatalysis on degrading trichloroethylene and tetrachloroethylene. In natural rutile, V, Fe, Cu, etc. substitute for Ti, resulting in lattice distortions and defects. We found that rutile, after heating, quenching and electron irradiation, changes its surface characteristics and photoactivity. The quenched rutile has the highest concentrations of adsorbed water and V on its surface, resulting in high photoactivity. For example, quenching at 1273 and 1373 K significantly improved photoactivity of rutile. The heated rutile also increased the concentration of adsorption water on the surface, e.g., rutile heated to 1273 K improved degradation rate of halohydrocarbons. On the contrary, electron irradiation decreased the concentration of adsorbed water on the rutile’s surface, which results in lower degradation rate for trichloroethylene. Therefore, heating and quenching over 1237 K improve the photocatalytic efficiency of the natural V-bearing rutile on degrading halohydrocarbons. The XRD spectra of the rutile samples showed that heating, quenching and electron irradiation did not result in formation of new phases or phase transitions. 相似文献
95.
Black nanostructured Bi OCl microspheres were directly synthesized by a hydrothermal method. The black balllike Bi OCl microspheres and black flower-like Bi OCl microspheres were obtained using different surfactant.The color of the Bi OCl microspheres turned from black to white when being annealed at 400℃ in air for 3 h and could be recovered to black by exposure to ultraviolet light for a few hours. The photocatalytic activity of both the black and the white Bi OCl microspheres was characterized by the photo-degradation of methyl orange dye under visible light irradiation. The black ball-like nanostructure Bi OCl displayed the best photocatalytic activity, compared with the white Bi OCl and the black flower-like Bi OCl. It can degrade the methyl orange dye to 20% within 70 min under visible light irradiation. The high activity of the Bi OCl ball-like sphere may own to its special morphology, strong absorption in visible light range and the existence of oxygen vacancies. 相似文献
96.
Enrique Snchez Mora Estela Gmez Barojas Esmeralda Rojas Rojas Rutilo Silva Gonzlez 《Solar Energy Materials & Solar Cells》2007,91(15-16):1412-1415
Morphological, optical and photocatalytic properties of TiO2, Fe2O3 and TiO2–Fe2O3 samples (formed by 1, 3 and 5 coatings) were studied. The layers were deposited on glass substrate by the sol–gel method. The catalytic activity of the samples was studied by the photodecomposition of methylene blue (MB) under visible light illumination. The FTIR results indicate that all samples present surface OH radicals that are bound either to the Ti or Fe atoms. This effect is better visualized at larger number of coatings in the TiO2–Fe2O3/glass systems. Also, two mechanisms are observed during the photodecomposition of the MB. 相似文献
97.
氢能是一种新型高效洁净能源。本文介绍了颇有应用前景的光分解水制氢技术的原理,重点介绍了半导体光催化分解水制氢反应机理和技术方法。 相似文献
98.
Mohamed N. Ghazzal N. ChaouiM. Genet Eric M. GaigneauxD. Robert 《Thin solid films》2011,520(3):1147-1154
TiO2 thin films grown on different kinds of substrates were obtained by sol-gel process. X-ray diffraction revealed that the TiO2 lattice parameter c decreased continuously, indicating a continuous variation in the compressive stress, a negligible compressive stress of the film grown onto Soda-Lime Glass (SLG), medium compressive stress of the film grown onto BoroSilicate Glass (BSG) and large compressive stress of the film deposited onto the Quartz Substrate (QS). UV-Vis absorbance spectra exhibited a red-shift of the absorbance edge of the TiO2 films suggesting a lowering of the band gap, which is a direct consequence of the increase of the compressive stress. X-ray photoelectron spectroscopy revealed that the surface composition of titania films was similar except for sodium-ion concentration. The rate observed during the photo-oxydation of the stearic acid on TiO2/QS was twice as high as that of TiO2/BSG and about 1000 times superior to that of TiO2/SLG. The photoinduced wettability shows an identical dependence of the compressive stress. According to these results, the compressive stress could be used to tune the band gap of the titanium oxide in order to enhance the photoinduced properties. 相似文献
99.
Nigel Van de Velde Melis ArinPetra Lommens Dirk PoelmanIsabel Van Driessche 《Thin solid films》2011,519(11):3475-3479
This article summarizes our progress made on an aqueous chemical solution deposition method used for the deposition of photocatalytically active TiO2 thin films. Starting from Titanium(IV)butoxide we achieved a stable titanium precursor solution containing titanium-peroxo compounds by reaction between Titanium(IV)butoxide and hydrogen peroxide. We were able to deposit anatase TiO2 films with good optical transparency and abrasion resistance. Dip-coating was used to deposit thin films on glass substrates from the solution. The occurring reaction mechanism was examined via thermal analysis, mass spectrometry and Raman spectroscopy. Decomposition of organic polluents was confirmed by the breakdown of ethanol. The obtained results show promising possibilities of this low-carbon containing synthesis method towards transparent, photocatalytic coatings. Presence of carbon was minimized by avoiding organic complexing agents. These materials are of great importance in the synthesis of self-cleaning materials. 相似文献
100.
Choong-Soo ChiJinwook Choi Yongsoo JeongOh Yeon Lee Han-Jun Oh 《Thin solid films》2011,519(15):4676-4680
Micro-arc oxidation method is a useful process for mesoporous titanium dioxide films. In order to improve the photocatalytic activity of the TiO2 film, N-Eu co-doped titania catalyst was synthesized by micro-arc oxidation in the H2SO4/Eu(NO3)3 mixture solution.The specific surface area and the roughness of the anodic titania film fabricated in the H2SO4/Eu(NO3)3 electrolyte, were increased compared to that of the anodic TiO2 film prepared in H2SO4 solution. The absorbance response of N-Eu titania film shows a higher adsorption onset toward visible light region, and the incorporated N and Eu ions during anodization as a dopant in the anodic TiO2 film significantly enhanced the photocatalytic activity for dye degradation. After dye decomposition test for 3 h, dye removal rates for the anodic TiO2 film were 60.7% and 90.1% for the N-Eu doped titania film. The improvement of the photocatalytic activity was ascribed to the synergistic effects of the surface enlargement and the new electronic state of the TiO2 band gap by N and Eu co-doping. 相似文献