Oxygen-Assisted Water Dissociation on Metal Surfaces: Kinetics and Quantum Effects

A model of oxygen-assisted water dissociation reaction (OWD, H2O + O (2) -> OH), based on a tunnel mechanism of H transfer, is presented and analyzed to show that the corresponding activation energies are much lower than those of water dissociation on a clean surface. The Morse and the Poschl-Teller potentials are used to describe the initial and final energy wells. The reaction probability is analyzed in the framework of the nonadiabatic theory that also allows considering the hydrogen transfer in the case of a strong electron coupling. It is shown that the main contribution to the rate constant is due to quantum transition between the ground vibrational levels of the H atom in the initial and final potential wells. Numerical analysis of the rate constants and kinetic isotope effects is performed for the OWD proceeding on platinum, copper, nickel, and rhodium metal surfaces.