1. School of Materials Science & Engineering Xi'an Polytechnic University Jinhua South Road 19 Xi'an Shaanxi 710048 P. R. China
2. Laboratory of Solar Fuel Faculty of Materials Science and Chemistry China University of Geosciences 388 Lumo Road Wuhan 430074 P. R. China
3. College of Chemistry and Chemical Engineering Hubei Polytechnic University Huangshi 435003 P. R. China