1. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, P. R. China
2. Department of Chemical and Petroleum Engineering, University of Wyoming, 1000 E University Ave, Laramie, WY 82071, USA
3. State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, P. R. China