1. School of Materials Science and Engineering Peking University Beijing 100871 P. R. China
2. Beijing Graphene Institute Beijing 100095 P. R. China
3. Center for Nanochemistry Beijing Science and Engineering Center for Nanocarbons Beijing National Laboratory for Molecular Science College of Chemistry and Molecular Engineering Peking University Beijing 100871 P. R. China
4. Academy for Advanced Interdisciplinary Studies Peking University Beijing 100871 P. R. China
5. National Center for Nanoscience and Technology Chinese Academy of Sciences Beijing 100190 P. R. China
6. CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics University of Science and Technology of China Hefei 230027 P. R. China
7. College of Science China University of Petroleum Beijing 102249 P. R. China
8. College of Chemistry and Chemical Engineering Qingdao University Qingdao 266000 P. R. China