1. Institute of New Energy Technology Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 Zhejiang P. R. China
2. University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Beijing University of Chemical Technology Beijing 100029 P. R. China
4. Institute of Fuel Cells Interdisciplinary Science Research Centre School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 P. R. China