A density functional theory study on water adsorption on TiO₂-terminated SrTiO₃ (001) surface

Water adsorptions on TiO₂-terminated SrTiO₃ (001) surfaces at four kinds of coverages (0.25 monolayer (ML), 0.5 ML, 0.75 ML and 1 ML) are investigated by using density functional theory calculations. Molecular and dissociative adsorptions of water are comparatively investigated. The nudged elastic band method is employed to calculate the dissociative energy barrier. The obtained results showed that dissociative adsorptions were energetically more favorable at low coverages (0.25 ML and 0.5 ML), whereas molecular adsorption was more favorable at high coverage (1 ML), and particularly a special mixed adsorption was more favorable at 0.75 ML. Based on these results, the influence of adsorption coverage on water dissociation is analyzed.