Oxygen vacancy related distortions in rutile Ti O2 nanoparticles: A combined experimental and theoretical study

The effects of doubly ionized oxygen vacancies (VO2+) on the electronic structure and charge distribution in rutile TiO2 are studied by combining first-principles calculations based on density functional theory and experimental results from x-ray photoelectron and x-ray absorption measurements carried out in synchrotron facilities on rutile TiO2 nanoparticles. The generalized gradient approximation of the Perdew-Burke-Ernzerhof functional has demonstrated its suitability for the analysis of the VO2+ defects in rutile TiO2. It has been found that the presence of empty electronic states at the conduction band shifted ∼1eV from t2g and eg states can be associated with local distortions induced by VO2+ defects, in good agreement with Gauss-Lorentzian band deconvolution of experimental O K-edge spectra. The asymmetry of t2g and eg bands at the O-K edge has been associated with VO2+, which can enrich the understanding of studies where the presence of these defects plays a key role, as in the case of doped TiO2.