1. School of Chemistry and Chemical Engineering, North Minzu University, Yinchuan 750021, P. R. China
2. Ningxia Key Laboratory of Solar Chemical Conversion Technology, North Minzu University, Yinchuan 750021, P. R. China
3. Key Laboratory of Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, P. R. China