1. Contributions from the Department of Chemistry, Surface Science Center, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, Department of Chemical Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, Oldenburg Institut fur Reine und Angewandte Chemie, Carl von Ossietzky Universität, Carl-von-Ossietzky Str. 9-11, 26129 Oldenburg, Germany, and National Energy Technology Laboratory, Pittsburgh, Pennsylvania 15236