1. Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou 510640 P. R. China
2. University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Key Laboratory of Renewable Energy Chinese Academy of Sciences Guangzhou 510640 P. R. China
4. Institute of Carbon Materials Science Shanxi Datong University Datong Shanxi 037009 P. R. China
5. Department of Chemical Engineering Nagoya University Nagoya 464-8603 Japan
6. National Institute of Clean-and-Low-Carbon Energy China Energy Investment Corporation Ltd. Beijing 102211 P.R. China