Insight intoH2O-ice adsorption and dissociation on metal surfaces from first-principles simulations

Abstract

Density-functional theory has been used to perform a systematic study of (intact) ${\mathrm{H}}_2\mathrm{O}$ bilayer and (dissociated) ${\mathrm{H}}_2\mathrm{O}-\mathrm{O}\mathrm{H}-\mathrm{H}$ overlayer adsorption on hexagonal $3d,$ $4d,$ and $5d$ transition- and noble-metal surfaces. Through careful decompositions of the ${\mathrm{H}}_2\mathrm{O}$ adsorption energies, we find that variations in the relative stability of intact bilayers and dissociated overlayers depend mainly on variations in adsorbate-substrate bonding, and not on variations in H bonding as previously assumed. Further, we show that the ${\mathrm{H}}_2\mathrm{O}$ dissociation energy in the bilayers is controlled by the OH-metal bond strength in the dissociated overlayers.