Cu/SnO_2-TiO_2催化剂的结构、光吸收性能和催化反应性能

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

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%.

The solid material of coupled semiconductor SnO2-TiO2 was prepared by sol-gel method. The Photoeatalyst SnO2-TiO2 supported metallic Cu was prepared by an isovolumie impregnation method. The surface structure, particle size, photo absorption performance and photoeatalysis 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 Mierophotoreaetor. The experiment results show that 10% SnO2 disperses on the surface of TiO2 support with one monolayer of non-crystalline phase, and the average particle size of 1% Cu/10% SnO2-TiO2 is about 22 nm. Blue shifting of photo absorption edges is observed clearly after addition of SnO2 on the surface of TiO2. The crystalline phase SnO2 forms and photo absorption performance decreases when supporting amount of SnO2 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 TiO2 and SnO2. 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 l%Cu/10%SnO2-TiO2 are the best among the others, and the quantum efficiency reaches 13.9%.