1. Electrochemistry Laboratory, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
2. Fuel Cell Nanomaterials Center, University of Yamanashi, 4 Takeda, Kofu 400-8510, Japan
3. Nano-science Center, Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark
4. SP2M, ICMMO, Université de Paris-Sud XI, 91405 Orsay, France
5. Instituto de Ciencia de Materiales de Aragón and Institut Laue-Langevin, 38000 Grenoble, France
6. Laboratory of Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland