1. Department of Chemistry Tsinghua University Beijing 100084 China
2. State Key Laboratory of Heavy Oil Processing China University of Petroleum (East China) Qingdao 266580 China
3. College of Chemistry and Materials Science Anhui Normal University Wuhu 241000 China
4. Department of Chemistry University of Science and Technology Beijing Beijing 100083 China
5. Department of Chemical Engineering Tsinghua University Beijing 100084 China
6. Beijing Synchrotron Radiation Facility Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China
7. Center for Electron Microscopy Tianjin University of Technology Tianjin 300384 China