1. State Key Laboratory of Coal Conversion; Institute of Coal Chemistry; Chinese Academy of Sciences; 27 South Taoyuan Road Taiyuan 030001 P. R. China
2. University of Chinese Academy of Sciences; Beijing 100049 P. R. China
3. Department of Chemistry; inGAP Centre of Research-based Innovation; University of Oslo; P.O. Box 1033 Blindern 0315 Oslo Norway