DFT study of the interactions of H2O, O2 and H2O + O2 with TiO2 (101) surface

The interactions of H2O, O-2 and H2O + O-2 with TiO2 (101) surface was studied using density functional theory (DFT). The adsorption energy of H2O + O-2 on the TiO2 surface is the largest, followed by O-2, and H2O. H2O molecule and O-2 molecule adsorbed respectively on TiO2 surface are not dissociated, while the coadsorption of H2O and O-2 results in the dissociation of H2O molecule and O-2 molecule. H2O and O-2 molecules not only interact respectively with TiO2 surface, but also interact with each other when H2O and O-2 molecules adsorb simultaneously on the TiO2 surface. The interaction of H2O + O-2 with TiO2 surface is more complex than those of single H2O or O-2, including the formations of five new bonds and the cleavages of four bonds, which suggests the strong interaction between H2O + O-2 and TiO2 surface. Two hydrogen-oxygen bonds of H2O molecule are all broken, and two hydrogen atoms interact with two oxygen atoms of TiO2 surface, respectively, while oxygen atom of H2O interacts simultaneously with a titanium atom of TiO2 surface and an oxygen atom of O-2 molecule. Another oxygen atom of O-2 molecule is bonded to another titanium atom of TiO2 surface. (C) 2017 Elsevier B.V. All rights reserved.