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 H2 using the model clusters (Au10 and Au13) on ZnO(101) surface and find that H2 prefers to adsorb on the bottom layer of Au clusters on the ZnO surface. The interaction energies of H2 are exponentially correlated with the H–H and H–Au bond parameters. The dissociation of H2 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 H2 activation and dissociation.