Molecular Adsorption of H2O on TiO2 and TiO2:Y Surfaces

Abstract

In this work, using theoretical calculations within the framework of the density functional theory, taking into account the dispersive VDW interaction, the processes of adsorption and interaction of a water molecule with a TiO2 surface in various configurations are investigated. At the atomic/molecular level, the interactions of a water molecule with a TiO2 surface have been studied for various orientations. The results of calculations within the framework of DFT+ VDW show that the adsorption energies of single water molecules in different initial positions on the substrate surface vary from-0.72 to-0.84 eV, and the most stable adsorbate structure is the TiO2+ H2O system upon adsorption of a molecule of water, parallel to the Y axis, because during the adsorption of H2O parallel to the Y axis, some favorable effects are observed in the band structure of titanium dioxide. On the one hand, the band gap decreases to 2.59 eV, and on the other hand, a new energy state appears in the band gap with an energy contribution of 0.17 eV, when water is physisorbed and interacts with a titanium atom at a distance of 2.12 {\AA} and occupies a perpendicular position relative to the surface.