共查询到20条相似文献,搜索用时 78 毫秒
1.
E. P. Lokshin T. A. Sedneva A. T. Belyaevskii V. T. Kalinnikov 《Theoretical Foundations of Chemical Engineering》2008,42(5):590-594
Fluorine-doped anatase has a higher photocatalytic activity compared to undoped anatase obtained under identical conditions and retains this activity after thermal treatment in a temperature range of 400–700°C. The photocatalytic activity of the evaluated fluorine-doped titanium oxohydroxide with an allowance for its titanium content is insignificantly lower than the photocatalytic activity of fluorine-doped anatase. 相似文献
2.
二氧化钛凭借优异的光催化性能,越来越受到人们的广泛关注和重视。以钛酸四丁酯为原料,利用水解-水热-干燥/煅烧工艺制备得到未掺杂TiO2光催化剂和掺钒TiO2光催化剂,利用其对甲基橙溶液的降解率做了比较分析。结果表明,以钛酸四丁酯为原料,采用溶胶-凝胶法制备钒掺杂TiO2光催化剂是可行的。制备V/TiO2产品的最佳工艺条件:钒钛质量比为6∶100、水热温度为160 ℃、水热时间为12 h,120 ℃下干燥14 h。紫外光照射条件下,甲基橙光催化降解效率达到99.10%,降解时间小于45 min。 相似文献
3.
The extraction-pyrolytic method of applying a TiO2 film coating has been considered. The coating is suitable for various applications, in particular as a coating for self-cleaning glass, photocatalytic sterilization for medical and microbiological purposes, solar energy, and automotive and construction industries. Advantages of this method are its low cost and the possibility of coating large surfaces. The processes of extraction of titanium(IV), application of films of organic extracts to substrates, and pyrolytic treatment of precursors have been described. The phase composition and microstructure of the coatings obtained have been studied. It has been shown that the application of solutions of organic extracts to glass and metal substrates contributes to the formation of nanostructured continuous films, which possess photocatalytic activity. 相似文献
4.
将微反应器技术应用于光催化反应是一项新兴且极具潜力的技术创新.采用金属蚀刻技术制造了板式微反应器,并通过溶胶-凝胶法在微反应器中负载了铜离子掺杂改性的TiO2光催化剂涂层.使用X射线衍射分析、扫描电子显微镜以及紫外-可见漫反射吸收光谱对催化剂进行表征,并以甲基橙的降解反应来评价微反应器的光催化效果.结果表明,铜离子掺杂能够有效提高微反应器的光催化性能,掺杂浓度为0.04%(摩尔比于Ti)时效果最优,能够在90 s的停留时间内使初始浓度为10 mg·L-1的甲基橙溶液降解45%;光催化微反应器中甲基橙的降解过程为不完全氧化的动力学一级反应,其反应速率常数(k)远高于常规反应器体系,并随着甲基橙溶液初始浓度(C0)的减小而增大,且lnk-lnC0具有良好的线性关系. 相似文献
5.
Jian‐Hua Xu Fumihide Shiraishi 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1999,74(11):1096-1100
The photocatalytic decomposition of acetaldehyde in air at initial concentrations ranging from 3 to 200 mg m−3 has been studied in a semitransparent closed box with an inlet volume of 0.056 m3. The photocatalytic reactors consisted of a glass tube, 250 mm long with inside diameters of 28, 35, or 45 mm, whose inner surface was coated with a thin film of titanium dioxide, and a 6‐W blacklight fluorescent lamp located at the axis of the glass tube. The decomposition of acetaldehyde was almost complete within 1–3 h and its main product was carbon dioxide. A kinetic study showed that the photocatalytic reaction obeys a Langmuir adsorption isotherm. Although the light intensity was certainly decreased with the distance from the light source, the degree of this decrease was much smaller than the degree of the decrease in the kinetic constants, which suggests that the light intensity is not simply proportional to the degree of the photo‐excitation of TiO2 and the rate of the resulting photocatalytic decomposition of acetaldehyde. © 1999 Society of Chemical Industry 相似文献
6.
Yunfeng Zhu Giovanna G. Buonocore Marino Lavorgna Luigi Ambrosio 《Polymer Composites》2011,32(4):519-528
Poly(lactic acid)/titanium dioxide (TiO2) composite films were prepared by direct melt processing using three different procedures (i.e., compression molding, twin‐screw melt extrusion, and melt extrusion and thermoforming). The effect of TiO2 loading and processing procedures on the phase morphology and on the thermal, mechanical, and barrier properties of the obtained nanocomposites were analyzed respectively by field‐emission scanning electron microscopy‐energy dispersive spectrometry, differential scanning calorimetry, universal testing machine, and water vapor and oxygen permeability measurements. The incorporation of TiO2 nanoparticles into the poly(lactic acid) matrix increased the crystallinity and improved the barrier properties of the composites. The maximum tensile strength was achieved at the 2% content of TiO2 for the films produced by compression molding and twin‐screw melt extrusion, whereas the tensile strength for films produced by melt extrusion and thermoforming decreases markedly with an increasing TiO2 content. The photocatalytic activities of the obtained nanocomposites were investigated by analyzing the degradation of methyl orange. Results confirmed that the processing procedures and the distribution of TiO2 in the polymer matrix are the key parameters, which rule the photocatalytic behavior of composite films. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers 相似文献
7.
8.
R. Nirmala Hak Yong Kim R. Navamathavan Chaun Yi Jeong Jin Won Kyungsoo Jeon Ayman Yousef R. Afeesh Mohamed El-Newehy 《Ceramics International》2012,38(6):4533-4540
SnO2 doped TiO2 electropsun nanofiber photocatalysts were successfully prepared by means of electrospinning process. The surface morphology, structure and optical properties of the resultant products were characterized by field-emission electron microscopy (FE-SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), UV–vis spectroscopy, photoluminescence (PL) and cathodoluminescence (CL) techniques. The utilized physiochemical analyses indicated that the introduced SnO2 doped TiO2 nanofibers have a smooth surface and uniform diameters along their lengths. The photocatalytic performance of the composite nanofibers was tested for degradation of methylene blue (MB) and methyl orange (MO) dye solution under ultraviolet (UV) irradiation. Under the UV irradiation, the photocatalytic reaction rate in case of utilizing SnO2-doped TiO2 nanofibers was rapidly increased than that of the pristine TiO2 nanofibers. Overall, this study demonstrates cheap, stable and effective material for photocatalytic degradation at room temperature. 相似文献
9.
A set of metal nanoparticle-decorated titanium dioxide(M_x/TiO_2; where x is the percent by mass, %)photocatalysts was prepared via the sol-immobilization in order to enhance the simultaneous hydrogen(H_2)production and pollutant reduction from real biodiesel wastewater. Effect of the metal nanoparticle(NP) type(M = Ni, Au, Pt or Pd) and, for Pd, the amount(1 %–4 %) decorated on the surface of thermal treated commercial TiO_2(T_(400)) was evaluated. The obtained results demonstrated that both the type and amount of decorated metal NPs did not significantly affect the pollutant reduction, measured in terms of the reduction of chemical oxygen demand(COD), biological oxygen demand(BOD) and oil grease levels, but they affected the H_2 production rate from both deionized water and biodiesel wastewater, which can be ranked in the order of Pt_1/T_(400) Pd_1/T_(400) Au_1/T_(400) Ni_1/T_(400). This was attributed to the high difference in work function between Pt and the parent T_(400). However, the difference between Pt_1/T_(400) and Pd_1/T_(400) was not great and so from an economic consideration, Pd/TiO_2 was selected as appropriate for further evaluation. Among the four different Pd x/TiO_2 photocatalysts, the Pd_3/TiO_2 demonstrated the highest activity and gave a high rate of H_2 production(up to135 mmol·h_(-1)) with a COD, BOD and oil grease reduction of 30.3%, 73.7% and 58.0%, respectively. 相似文献
10.
Photocatalytic reduction of nitrobenzene over titanium dioxide: by-product identification and possible pathways 总被引:1,自引:0,他引:1
The photocatalytic reduction of nitrobenzene (ethanol + TiO2 + UV-light) in non-aqueous suspension yielded aniline and acetaldehyde as main products. However, various by-products as
intermediates of nitrobenzene photoreduction (i.e. nitrosobenzene and hydroxyaniline) and others (i.e. indoles and quinolines)
were also detected. These last results were explained in terms of reactions between aniline and oxidation products of ethanol. 相似文献
11.
12.
Polythiophene/titanium dioxide (PT/TiO2) composites were prepared via in situ chemical oxidative polymerization, and the obtained composites were characterized by X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy (DRS) and transmission electron microscopy (TEM). Using methyl orange (MeO) as a target pollutant, the adsorption capacities and the photocatalytic activities of the resulting composites were investigated. The results indicate that PT/TiO2 composites have good adsorption capacities due to the electrostatic attraction between the positively charged composite particles’ surfaces and MeO; the incorporation of PT into the composites enhances the photocatalytic degradation activity for MeO under both UV and visible light. 相似文献
13.
14.
Hawn‐Chung Chu Li‐Huei Lin Hsin‐Chi Liu Ho‐Fu Chen Hsin‐Jiant Liu Keng‐Ming Chen 《应用聚合物科学杂志》2009,114(1):413-419
This study uses titanium dioxide treated with calcium phosphate to prepare multilayer structure composites. These products are regarded as photocatalysts. Utilizing polyethylene glycol (PEG)–silicone polyester as an adhesive spread on matrix surfaces, this can provide these products with antifouling properties, good weather resistance, and antibacterial property. It has been observed that UV irradiation has caused changes in the film molecular structure of PEG–silicone polyesters, as well as changes in the surface morphology. These changes in molecular structure have been observed by FTIR and Raman analysis. PEG–silicone polyesters contain silicon atoms with both organic and inorganic characteristics. This makes fixation of photocatalysts possible and retards oxidation of organic materials in the polyesters. The results of FTIR and Raman spectrum analyses indicate films made of these polyesters effectively cover calcium phosphate–titanium dioxide photocatalysts, retard surface cracks, and slow down decomposition, caused by UV light. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
15.
16.
《Diamond and Related Materials》2000,9(11):1862-1866
A simple process has been perfected to deposit smooth fine-grained diamond coatings at 600°C on titanium alloys or titanium-coated surfaces. It consists of a two-step microwave plasma-assisted chemical vapor deposition (PACVD) procedure including first the deposition of a sacrificial sp2-carbon containing layer from a methane-rich CH4–H2 mixture and then the diamond growth from a CO2–CH4 inlet mixture. Scanning electron microscopy, X-ray diffraction, visible and UV Raman spectroscopy show that the coatings are smooth and mainly composed of crystalline diamond with a fine-grained morphology. The results are compared with the results obtained with classical rough polycrystalline coatings deposited from 8% CO–H2. Optical emission spectroscopy reveals important differences between the plasma species produced for the deposition of these smooth coatings and the plasma species produced for the deposition of both polycrystalline coatings from 1% CH4–H2 or 8% CO–H2 mixture and nanocrystalline films from Ar–CH4(–H2). 相似文献
17.
Shigeru Kohtani Eito Yoshioka Kenji Saito Akihiko Kudo Hideto Miyabe 《Catalysis communications》2010,11(13):1049-1053
In the absence of molecular oxygen, various aromatic ketones such as acetophenone derivatives and diaryl ketones were photocatalytically hydrogenated on polycrystalline titanium dioxide (Degussa P25) under UV light irradiation (> 340 nm). The desired secondary alcohols were obtained with excellent chemical efficiency (almost 100% yields for 10 examples) by choosing ethanol as a sacrificial hole scavenger, which was oxidized into acetaldehyde. 相似文献
18.
19.
M. Fassier N. Chouard C.S. Peyratout D.S. Smith H. Riegler D.G. Kurth C. Ducroquetz M.A. Bruneaux 《Journal of the European Ceramic Society》2009,29(4):565-570
The coating of fired clay substrates with various metal oxides, such as anatase, rutile, zinc oxide and tin oxide was achieved using a simple spraying technique followed by a thermal treatment. The photocatalytic activity of the layer was characterized through measurement of the absorption spectrum, in the range 400–800 nm, of methylene blue deposited on top of the coating. Results show that the presence of anatase enhances the degradation of methylene blue when it is exposed to ultraviolet light. Thermal treatment at 1050 °C transforms anatase crystals into thermodynamically stable rutile. This results in a decrease of the photocatalytic activity, which can be explained by increase of the grain size and by a difference in the crystal structure. Measurements of the photocatalytic activity of ZnO and SnO2 show that these two oxides also exhibit photocatalytic properties. In particular, ZnO is a promising alternative material to anatase. 相似文献