1. Center of Hydrogen Science School of Materials Science and Engineering Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai 200240 P. R. China
2. The Instrumental Analysis Center Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai 200240 P. R. China
3. Department of Mechanical Engineering University of Colorado Boulder 1111 Engineering Drive Boulder CO 80309 USA