“…This is based on the fact that the photogenerated electrons can flow from one semiconductor with a higher to a lower conduction band minimum. Under such conditions, the separation of electron-hole pairs was promoted while keeping reduction and oxidation reactions at two different sites (Peng, Xie, Lu, Fan, & Wang, 2010;Shang et al, 2009;Wang et al, 2009). As a result, the efficiency of semiconductors improved (Jing, Xu, Sun, Jing, & Cai, 2001;Lin, Wu, Zhang, & Pan, 2009;Liu, Ye, Xiong, & Liu, 2010;Vaezi, 2008;Zheng et al, 2009).…”