1. Guangzhou Institute of Energy ConversionChinese Academy of Sciences Guangzhou 510640 P.R. China
2. CAS Key Laboratory of Renewable Energy Guangzhou 510640 P.R. China
3. Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou 510640 P.R. China
4. Dalian National Laboratory for Clean Energy Dalian 116023 P.R. China
5. University of Chinese Academy of Sciences Beijing 100049 P.R. China
6. Institute of Coal ChemistryChinese Academy of Sciences Taiyuan 030001 P. R. China
7. Department of Chemical and Biological EngineeringUniversity of Wisconsin 1415 Engineering Drive Madison Wisconsin 53706 USA