1. College of Chemistry & Chemical Engineering, China University of Petroleum (East China), Qingdao, 266555 Shandong, P. R. China
2. Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Province, Liaoning Shihua University, Fushun, 113001 Liaoning, P. R. China
3. Lanzhou Petrochemical Research Center, Petrochemical Research Institute, PetroChina Company Limited, Lanzhou 730060, P. R. China
4. Department of Chemistry, Lanzhou University, Lanzhou 730000, P. R. China