1. Chemistry and Material Science, Langfang Normal University, 100 Aiminxi Road, Langfang 065000, Hebei Province, P. R. China
2. State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing), 18 Fuxue Road, Beijing 102249, P. R. China
3. College of Liberal Arts and Sciences, University of Illinois at Chicago, 1200 W. Harrison Street, Chicago, Illinois 60607, United States