1. Department
of Chemistry, Tsinghua University, Beijing 100084, China
2. Beijing
Guyue New Materials Research Institute, Beijing University of Technology, Beijing 100124, China
3. Materials
Characterization and Preparation Center, South University of Science and Technology of China, Shenzhen 518055, China
4. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
5. State
Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China