First-principles calculations of M10/graphene (M = Au, Pt) systems - Atomic structures and hydrogen adsorption

Abstract

The usage of Au nano-particles as a catalytic electrode may be effective for the CO-poisoning problem in the anode of a proton-exchange membrane fuel cell (PEMFC), because Au nano-particles supported on metal oxides have novel catalytic activity of low-temperature CO oxidation or water gas-shift reaction. As the first step to examine this possibility, we have performed first-principles calculations of a Au10 cluster on graphene as well as a Pt10 cluster on graphene, based on the density functional theory (DFT). There are no strong interactions between the cluster and graphene such as substantial charge transfer or orbital hybridization, although the interaction for Pt is stronger than that for Au. We have further examined the H-atom adsorption on the clusters on graphene, and found that the adsorption energy is much larger for the Pt cluster than for the Au cluster. However, we have observed that the energy gain in the dissociation and adsorption from a H2 molecule is indeed obtained tor the Au small cluster in spite of no energy gain for the Au(l 11) surface. © 2008 The Japan Institute of Metals.