Localized electronic states induced by oxygen vacancies on anatase TiO2 (101) surface

Abstract A theoretical study about the influence of surface oxygen vacancies on the structural and electronic properties of anatase TiO 2 (101) surface is presented. Calculations were performed within the density functional theory using the self-consistent Hubbard U correction to take into account the electron repulsion increase and the localization of additional electrons in the reduced anatase. The oxygen vacancies yield surface Ti 3 + species, producing localized electronic states in the energy gap of the anatase TiO 2 (101). By increasing the oxygen vacancies, the electron concentration also increases in the energy gap region and some of the localized electronic states approaching the conduction band minimum. Thus reduced anatase TiO 2 (101) behaves as an n -type semiconductor, and the surface Ti 3 + species presence improves its photocatalytic properties.