1. School of Chemistry and Materials Engineering, Huainan Normal University, Huainan 232038, P. R. China
2. Anhui Provincial Institute of Modern Coal Processing Technology, Anhui University of Science and Technology, Huainan 232038, P. R. China
3. Key Laboratory of Structure and Functional Regulation of Hybrid Materials, Ministry of Education, Anhui University, Hefei, Anhui 230601, P. R. China