title: Theoretical study of adsorption of O((3)P) and H(2)O on the rutile TiO(2)(110) surface.
abstract: The adsorption of oxygen atoms O(3P) on both ideal and hydrated rutile TiO(2)(110) surfaces is investigated by periodic density functional theory (DFT) calculations within the revised Perdew-Burke-Ernzerhof (RPBE) generalized gradient approximation and a four Ti-layer slab, with (2 x 1) and (3 x 1) surface unit cells. It is shown that upon adsorption on the TiO(2) surface the spin of the O atom is completely lost, leading to stable surface peroxide species on both in-plane and bridging oxygen sites with O-binding energies of about 1.0-1.5 eV, rather than to the kinetically unstable terminal Ti-O and terminal O-O species with smaller binding energies of 0.1-0.7 eV. Changes in O-atom coverage ratios between 1/3 and 1 molecular layer (ML) and coadsorption of H(2)O have only minor effects on the O-binding energies of the stable peroxide configurations. High O-atom diffusion barriers of about 1 eV are found, suggesting a slow recombination rate of adsorbed O atoms on TiO(2)(110). Our results suggest that the TiOOTi peroxide intermediate experimentally observed in photoelectrolysis of water should be interpreted as a single spinless O adatom on TiO(2) surface rather than as two Ti-O* radicals coupled together.
authors.affiliation: Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Post Office Box 9502, 2300 RA Leiden, The Netherlands. z.qu@chem.leidenuniv.nl
authors.forename: Zheng-Wang
authors.initials: ZW
authors.lastname: Qu
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Kroes