LAUSR

Abstract Density functional theory calculations have been employed to investigate the adsorption and dissociation of H2O, as well as the aggregation of H2O over the clean and pre-adsorbed oxygen Cu(111) surface at different coverage. As the coverage increases, the adsorption ability of H2O, OH, H and O species becomes gradually weaker, H2O dissociation becomes more unfavorable on both the clean and pre-adsorbed oxygen Cu(111) surface. H2O desorption is more favorable than its dissociation on the clean Cu(111) surface at the different coverage due to the weakly physical interaction between H2O molecule and Cu surface. However, on the pre-adsorbed oxygen Cu(111) surface, the adsorbed oxygen atom promotes H2O dissociation at different coverage, and H2O prefers to be dissociated instead of its desorption at the coverage below 0.50 ML. For H2O aggregation over Cu(111) surface, as the number of H2O molecule increases, the aggregation becomes easier due to the stronger hydrogen-bond interaction among different adsorbed H2O molecules, while the interaction between (H2O)n and Cu surface becomes weaker.