1. Beijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion Materials; Key Laboratory of Cluster Science; Ministry of Education School of Chemistry and Chemical Engineering; Beijing Institute of Technology; Beijing 100081 P. R. China
2. Research Institute of Petroleum Exploration & Development; China National Petroleum Corporation; No. 20 Xueyuan Rd., Haidian District Beijing 100083 P. R. China