1. School of Chemical & Biomolecular Engineering; Georgia Institute of Technology; Atlanta Georgia 30332-0100 USA
2. State Key Laboratory of Materials-Oriented Chemical Engineering; Nanjing Tech University; Nanjing 210009 P. R. China
3. State Key Laboratory of Coal Conversion; Institute of Coal Chemistry; Chinese Academy of Sciences; Taiyuan 030001 P. R. China
4. Chevron Energy Technology Company; 100 Chevron Way Richmond California 94802-0627 USA