1. State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, 27 South Taoyuan Road, Taiyuan, Shanxi 030001, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
3. Department of Chemistry, Centre for Materials and Nanoscience (SMN), University of Oslo, P.O.
Box 1033, Blindern, Oslo NO-0315, Norway