1. School of Materials and Chemical Engineering, Bengbu University, Bengbu, Anhui Province 233030, P. R. China
2. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi Province 030001, P. R. China
3. State Key Laboratory of Chemical Recourse Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China