1. Institute of Crystalline Materials Shanxi University Wucheng Rd., No. 92 Taiyuan 030006 P. R. China
2. Institute of Molecular Science Shanxi University Wucheng Rd., No. 92 Taiyuan 030006 P. R. China
3. State key laboratory of Coal Conversion Institute of Coal Chemistry Chinese Academy of Science 19 Kangle Street Taiyuan 030001 P. R. China
4. School of Chemistry & Material Science Shanxi Normal University 1 Gongyuan Street Linfen 041004 P. R. China