1. Department of Chemistry, College of Science, China University of Petroleum (East China), Qingdao, 266580, P. R. China
2. College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China
3. State Key Laboratory of Heavy Oil, China University of Petroleum (East China), Qingdao, 266580, P. R. China