用溶胶-凝胶法制得Cu/Fe2O3-TiO2光催化材料。用XRD、Ram an、TPR、IR、TEM、UV-V is DRS测试技术和光催化反应等对固体材料的结构和性能进行了表征。结果表明,Fe2O3的质量分数为10%时,在TiO2表面以单分子层分散,Fe2O3的引入使TiO2吸光...用溶胶-凝胶法制得Cu/Fe2O3-TiO2光催化材料。用XRD、Ram an、TPR、IR、TEM、UV-V is DRS测试技术和光催化反应等对固体材料的结构和性能进行了表征。结果表明,Fe2O3的质量分数为10%时,在TiO2表面以单分子层分散,Fe2O3的引入使TiO2吸光限蓝移。Fe2O3含量超过单分子层分散时,有晶相Fe2O3生成,光吸收性能下降。Fe—O—Ti键的形成加强了半导体之间的相互作用,有利于光生载流子在半导体间的输送。少量Cu的引入,使复合材料的吸光域向可见光范围扩展。光催化反应性能与材料的光响应能力密切相关。在光催化CO2和CH3NH2直接合成NH2CH2COOH的反应中,负载质量分数为10%Fe2O3的光催化反应性能最优。在120℃、常压、空速200 h-1、CO2与CH3NH2摩尔比为1∶1和6.5×10-4W/cm2的紫外灯照射下,CH3NH2转化率为1.35%,NH2CH2COOH选择性达92.0%。展开更多
V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for N...V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for NOx conversion using NH3 as the reductant. Hydrothermal ageing decreased the NOx conversion of V2O5/WO3‐TiO2 catalyst severely over the entire measured tem‐perature range. Interestingly, the NH3‐SCR activity of the silica‐modified catalyst at 220–480℃ is enhanced after ageing. The catalysts were characterized by X‐ray diffraction, nitrogen adsorption, X‐ray fluorescence, Raman spectroscopy, H2 temperature‐programmed reduction, and NH3 temper‐ature‐programmed desorption. The addition of silica inhibited the phase transition from anatase to rutile titania, growth of TiO2 crystallite size and shrinkage of catalyst surface area. Consequently, the vanadia species remained highly dispersed and the hydrothermal stability of the V2O5/WO3‐TiO2 catalyst was significantly improved.展开更多
文摘用溶胶-凝胶法制得Cu/Fe2O3-TiO2光催化材料。用XRD、Ram an、TPR、IR、TEM、UV-V is DRS测试技术和光催化反应等对固体材料的结构和性能进行了表征。结果表明,Fe2O3的质量分数为10%时,在TiO2表面以单分子层分散,Fe2O3的引入使TiO2吸光限蓝移。Fe2O3含量超过单分子层分散时,有晶相Fe2O3生成,光吸收性能下降。Fe—O—Ti键的形成加强了半导体之间的相互作用,有利于光生载流子在半导体间的输送。少量Cu的引入,使复合材料的吸光域向可见光范围扩展。光催化反应性能与材料的光响应能力密切相关。在光催化CO2和CH3NH2直接合成NH2CH2COOH的反应中,负载质量分数为10%Fe2O3的光催化反应性能最优。在120℃、常压、空速200 h-1、CO2与CH3NH2摩尔比为1∶1和6.5×10-4W/cm2的紫外灯照射下,CH3NH2转化率为1.35%,NH2CH2COOH选择性达92.0%。
基金supported by the National Natural Science Foundation of China (51372137)the National High Technology Research and Development Program of China (863 Program,2015AA034603)~~
文摘V2O5/WO3‐TiO2 and V2O5/WO3‐TiO2‐SiO2 catalysts were prepared by a wetness impregnation method, and both the catalysts were hydrothermally aged at 750℃ in 10 vol%H2O/air for 24 h. The catalysts were evaluated for NOx conversion using NH3 as the reductant. Hydrothermal ageing decreased the NOx conversion of V2O5/WO3‐TiO2 catalyst severely over the entire measured tem‐perature range. Interestingly, the NH3‐SCR activity of the silica‐modified catalyst at 220–480℃ is enhanced after ageing. The catalysts were characterized by X‐ray diffraction, nitrogen adsorption, X‐ray fluorescence, Raman spectroscopy, H2 temperature‐programmed reduction, and NH3 temper‐ature‐programmed desorption. The addition of silica inhibited the phase transition from anatase to rutile titania, growth of TiO2 crystallite size and shrinkage of catalyst surface area. Consequently, the vanadia species remained highly dispersed and the hydrothermal stability of the V2O5/WO3‐TiO2 catalyst was significantly improved.
