Paper SS+AS+EN-WeA11
Pd-Au Single Atom Alloys for the Activation of Diatomic Molecules

Wednesday, October 21, 2015, 5:40 pm, Room 113

Pd-Au alloys are known to catalyze a wide range of hydrogenation and oxidation reactions; however, the size of Pd ensembles in Au required for small molecule activation is not well understood. On the atomic scale, we investigate size effects of Pd atoms in Au for the catalytic activation of H₂ and O₂. We show that isolated Pd atoms are capable of catalyzing the dissociative adsorption of H₂, a process which was previously thought to require contiguous Pd sites. H spillover from active Pd sites to the Au surface can be induced the adsorption of CO. Conversely, single Pd atoms are not capable of O₂ dissociation. Small Pd clusters on Au enable O₂ activation and adsorption at Pd-Au interface sites. Since weakly bound H and O atoms are capable of enhancing reaction selectivity on Au substrates, this Pd-Au system serves as an ideal model system with which to probe selective hydrogenation and oxidation reactions at both single and ensemble active sites.