Influence of Subsurface Defects on the Surface Reactivity of TiO2: Water on Anatase (101)

The adsorption of water on a reduced TiO2 anatase (101) surface is investigated with scanning tunneling microscopy and density functional theory calculations. The presence of subsurface defects, which are prevalent oil reduced anatase (101), leads to a higher desorption temperature of adsorbed water, indicating an enhanced binding due to the defects. Theoretical calculations of water adsorption oil anatase (101) surfaces containing Subsurface oxygen vacancies or titanium interstitials show a strong selectivity for water binding to sites in the vicinity of the subsurface defects. Moreover, (lie water adsorption energy at these sites is considerably higher that) that on the stoichiometric surface, thus giving all explanation for the experimental observations. The calculations also predict facile water dissociation at these sites, confirming the important role of defects in the Surface chemistry of TiO2.