LAUSR

Abstract The interactions of H2O, O2 and H2O + O2 with TiO2 (1 0 1) surface was studied using density functional theory (DFT). The adsorption energy of H2O + O2 on the TiO2 surface is the largest, followed by O2, and H2O. H2O molecule and O2 molecule adsorbed respectively on TiO2 surface are not dissociated, while the coadsorption of H2O and O2 results in the dissociation of H2O molecule and O2 molecule. H2O and O2 molecules not only interact respectively with TiO2 surface, but also interact with each other when H2O and O2 molecules adsorb simultaneously on the TiO2 surface. The interaction of H2O + O2 with TiO2 surface is more complex than those of single H2O or O2, including the formations of five new bonds and the cleavages of four bonds, which suggests the strong interaction between H2O + O2 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 O2 molecule. Another oxygen atom of O2 molecule is bonded to another titanium atom of TiO2 surface.