Water on Rutile TiO₂(110) and Au/TiO₂(110): Effects on Au Mobility and the Isotope Exchange Reaction

The behavior of adsorbed water on rutile TiO 2 (110) and 0.05 ML-equivalent Au/TiO 2 (110) have been probed over the temperature range from 110 to 800 K using a combination of temperature-programmed desorption (TPD), ion scattering spectroscopy (ISS), and X-ray photoelectron spectroscopy (XPS). Water, either predosed in order to hydroxylate vacancy sites on the surface prior to Au deposition, or dosed after Au deposition onto clean vacuum-annealed TiO 2, results in more facile agglomeration of the initially dispersed Au atoms compared to Au deposited on vacuum-annealed TiO 2 . TPD indicates that the presence of Au binding at oxygen vacancy sites blocks dissociative chemisorption of water.