Support effects on the dissociation of hydrogen over gold clusters on ZnO(101) surface: Theoretical insights

We perform density functional studies of the support effects on the gold-catalyzed dissociation of H(2) using the model clusters (Au(10) and Au(13)) on ZnO(101) surface and find that H(2) prefers to adsorb on the bottom layer of Au clusters on the ZnO surface. The interaction energies of H(2) are exponentially correlated with the H-H and H-Au bond parameters. The dissociation of H(2) easily occurs on the bottom layer with the energy barriers no more than 0.44 eV. The support effects on the dissociation barriers are greatly dependent on the H-H bond distance in the transition state (TS), i.e., the early TSs with small barriers have larger support effects than the late TSs with large barriers. We find that the charge transfer from the gold clusters to the oxide support creates the localized charging states of the interface gold with the high feasibility for H(2) activation and dissociation.