Dai Wenxin, Wang Xuxu, Liu Ping, Xu Yiming, Li Guangshe, Fu Xianzhi
Research Institute of Photocatalysis, Chemistry and Chemical Engineering College, Fuzhou University, Fuzhou 350002, P. R. China.
J Phys Chem B. 2006 Jul 13;110(27):13470-6. doi: 10.1021/jp061483h.
TiO2 films on Al alloy (Al), indium-tin oxide glass (ITO/glass), and glass were prepared by a dip-coating method. ITO is found to have a higher work function, while the work function for Al is lower than that of TiO2 films. An electron transfer is indicated to occur in the interfaces between TiO2 films and conducting substrate Al or ITO, which results in an Ohm contact or Schottky barrier under the transient equilibrium UV radiation conditions. Photocatalytic measurements showed that the TiO2 films on Al have a higher activity for photocatalytic oxidation of C2H4, but the activity for photocatalytic degradation of oleic acid is lower as compared with TiO2 films on glass. Alternatively, TiO2 films on ITO give completely contrary photocatalytic performance to those on Al. These observations could be associated with the electron transfer, in which Al acts as an electron donor and offers electrons to TiO2, allowing photocatalytic oxidation of ethylene to proceed by the photogenerated electrons, while ITO could be an acceptor for the photogenerated electrons, which is beneficial to photocatalytic degradation of oleic acid by the photogenerated holes. This electron-transfer model could be extended to other photocatalytic systems.
采用浸涂法在铝合金（Al）、氧化铟锡玻璃（ITO/玻璃）和玻璃上制备了TiO₂薄膜。发现ITO具有较高的功函数，而Al的功函数低于TiO₂薄膜。表明在TiO₂薄膜与导电基底Al或ITO的界面处发生了电子转移，这在瞬态平衡紫外辐射条件下导致了欧姆接触或肖特基势垒。光催化测量表明，Al上的TiO₂薄膜对C₂H₄的光催化氧化具有较高的活性，但与玻璃上的TiO₂薄膜相比，其对油酸的光催化降解活性较低。另外，ITO上的TiO₂薄膜的光催化性能与Al上的完全相反。这些观察结果可能与电子转移有关，其中Al作为电子供体向TiO₂提供电子，使光生电子能够进行乙烯的光催化氧化，而ITO可能是光生电子的受体，这有利于光生空穴对油酸的光催化降解。这种电子转移模型可以扩展到其他光催化体系。
