1. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou, Guangdong Province 510640, P. R. China
2. Energy Science and Technology School, University of Science and Technology of China, Hefei, Anhui Province 230023, P. R. China
3. CAS Key Laboratory of Gas Hydrate, Guangzhou, Guangdong Province 510640, P. R. China