1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing), Beijing 102249, China
2. Petrochemical Research Institute, PetroChina Company Limited, Beijing 102206, China
3. Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
4. Department of Chemistry, University of Tennessee−Knoxville, Knoxville, Tennessee 37996-1600, United States