Effects of electron transfer between TiO2 films and conducting substrates on the photocatalytic oxidation of organic pollutants

被引:86
作者
Dai, Wenxin [1 ]
Wang, Xuxu [1 ]
Liu, Ping [1 ]
Xu, Yiming [1 ]
Li, Guangshe [1 ]
Fu, Xianzhi [1 ]
机构
[1] Fuzhou Univ, Chem & Chem Engn Coll, Res Int Photocatalysis, Fuzhou 350002, Peoples R China
关键词
D O I
10.1021/jp061483h
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
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.
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页码:13470 / 13476
页数:7
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