1. Key Laboratory on Fuel Cell Technology of Guangdong Province; School of Chemistry and Chemical Engineering; South China University of Technology; Guangzhou 510641 P. R. China
2. Institute of Chemistry; The Hebrew University of Jerusalem; Jerusalem 9190401 Israel
3. Laboratoire d'Electrochimie Physique et Analytique; École Polytechnique Fédérale de Lausanne (EPFL Valais Wallis); Rue de I'Industrie, 17 1951 Sion Switzerland
4. Fuel Cell & Battery Division; Dalian National Laboratory for Clean Energy; Dalian Institute of Chemical Physics; Chinese Academy of Sciences; Dalian 116023 P. R. China