Cu/SnO2-TiO2催化剂的结构、光吸收性能和催化反应性能

用溶胶-凝胶法制得复合半导体SnO2-TiO2,用等体积浸渍法制得Cu/SnO2-TiO2光催化剂.利用X射线衍射、拉曼光谱、程序升温还原、红外光谱、透射电镜、紫外-可见漫反射光谱和光反应器等技术研究了Cu/SnO2-TiO2的物相结构、微粒尺寸、吸光性能和光催化反应性能.结果表明,质量分数为10%的SnO2单分子层分散在TiO2表面,固体材料平均粒径为22nm;SnO2的引入使TiO2吸收限发生明显蓝移,SnO2负载量超过单分子层分散(大于10%),有晶相SnO2生成,光吸收性能下降;Ti-O-Sn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;负载金属Cu使复合半导体可见光部分的吸收明显增加,拓宽了催化剂的光响应范围;不同Sn担载量的光催化剂光吸收性能与量子产率有良好的对应关系,担载10%SnO2光催化剂光吸收性能和催化活性优于其它含量的催化剂,其光量子效率达到13.9%.

Structure, Photo Absorption and Catalyze Reaction Performance of Cu/SnO_2-TiO_2 Catalyst

The solid material of coupled semiconductor SnO_2-TiO_2 was prepared by sol-gel method. The Photocatalyst SnO_2-TiO_2 supported metallic Cu was prepared by an isovolumic impregnation method. The surface structure, particle size, photo absorption performance and photocatalysis performance of the materials were characterized by X-ray diffraction, Laser Raman spectroscopy, Temperature-programmed reduction and Infrared spectroscopy, Transmission electron microscopy, Ultraviolet-visible diffuse reflectance spectroscopy and Micro-photoreactor. The experiment results show that 10%SnO_2 disperses on the surface of TiO_2 support with one monolayer of non-crystalline phase, and the average particle size of 1%Cu/10%SnO_2-TiO_2 is about (22 nm). Blue shifting of photo absorption edges is observed clearly after addition of SnO_2 on the surface of TiO_2. The crystalline phase SnO_2 forms and photo absorption performance decreases when supporting amount of SnO_2 is more than the monolayer phase(>10%). The formation of Ti-O-Sn bond in the solid systems promotes transfer of generating charge carriers between TiO_2 and SnO_2. Loaded metallic Cu increases the photo absorption capacity of the photocatalyst and enlarges photo absorption range to visible light. Photo absorption performance and quantum efficiency of the photocatalysts have a corresponding relationship with various Sn content. Both photo absorption performance and quantum efficiency of the reaction on 1%Cu/10%SnO_2-TiO_2 are the best among the others, and the quantum efficiency reaches 13.9%.