1. Department of Physics, Simon Fraser University, Burnaby, BC V5A 1S6, Canada; Department of Chemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada; Institute for Fuel Cell Innovation, National Research Council Canada, 3250 East Mall, Vancouver, BC V6T 1W5, Canada; and UMR SPrAM 5819, CEA-Grenoble, 17 av. des Martyrs, 38054 Grenoble, Cedex 9, France