1. State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences Lanzhou 730000 P. R. China
2. University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. College of Petrochemical Technology Lanzhou University of Technology 730050 Lanzhou P. R. China
4. School of Chemical Engineering The University of New South Wales Sydney Kensington NSW 2052 Australia
5. National Synchrotron Radiation Research Center Hsinchu 30076 Taiwan
6. State Key Laboratory of Coal Conversion Institute of Coal Chemistry, Chinese Academy of Sciences Taiyuan 030001 P. R. China
7. School of Chemical Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China