TiO_2/SnO_2复合薄膜的低温制备及其光催化性能  

Low-temperature Preparation of TiO_2/SnO_2 Composite Film and Its Photocatalytic Activity

作　　者：蔡振钱[1] 申乾宏[1] 高基伟[1] 杨辉[1] 

机构地区：[1]浙江大学纳米科学与技术中心硅材料国家重点实验室,杭州310027

出　　处：《无机材料学报》2007年第4期733-736,共4页Journal of Inorganic Materials

基　　金：浙江省科技计划(2005C24005)

摘　　要：采用溶胶-凝胶法合成了TiO_2溶胶和SnO_2溶胶,使用浸渍提拉法在低温下制备出底层为金红石型SnO_2,表层为锐钛矿型TiO_2的复合膜.考察了不同SnO_2薄膜层数对TiO_2/SnO_2复合膜光催化活性的影响,并对其光催化活性提高的机理进行了探讨.结果表明,SnO_2层的加入能有效提高TiO_2薄膜的光催化活性,随着SnO_2薄膜层数的增加,光催化活性先增大后减小,但始终高于单一的TiO_2薄膜.这是由于SnO_2的导带电位低于TiO_2的导带电位,SnO_2的价带电位高于TiO_2的价带电位,紫外光照下,TiO_2中产生的光生电子注入到SnO_2层,SnO_2中空穴注入到TiO_2层,有效抑制了薄膜内电子-空穴对的复合,增加了复合薄膜表面空穴的浓度,因而光催化活性得到了显著的提高.TiO2/SnO2 composite films were prepared on a slide glass with a sol-gel method at low temperature. The influence of different dip-coating times of SnO2 layers on the photocatalytic activity of TiO2/SnO2 composite films was investigated. In addition, the mechanism of the photocatalytic activity enhancement of TiO2/SnO2 composite film was also analyzed. The results show that the photocatalytic efficiency of TiO2 film is enhanced by using SnO2 layer as a substrate. Since the conduction band （CB） of SnO2 is lower than that of TiO2, and the valence band（VB） of SnO2 is higher than that of TiO2, electrons transfer from WiO2 to SnO2, while holes oppositely diffuse into the SnO2 layer . Thus, the charge recombination is suppressed more efficiently, and more holes can reach the TiO2 surface to cause oxidation reaction. This is believed to be the main reason for the photocatalytic activity enhancement of the TiO2 film photocatalyst.

关 键 词：二氧化钛 二氧化锡 复合膜 光催化 

分 类 号：O643[理学—物理化学]