1. Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1, Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1, and Ballard Power Systems Inc., 9000 Glenlyon Parkway, Burnaby, British Columbia, Canada V5J 5J8