Using first-principles density-functional calculations a study was made of the interactions of molecular oxygen with a partially reduced rutile (110) surface. In agreement with experiment, a number of different O2 adsorption states, both molecular and dissociated, was found. The kinetic barriers for conversion between these states were also calculated. Based upon these results, an analysis was made of the mechanism of oxygen vacancy diffusion, recently observed by scanning tunnelling microscopy, and a pathway was suggested which did not imply the high oxygen adatom reactivity assumed in the original model.

Oxygen Vacancy Mediated Adsorption and Reactions of Molecular Oxygen on the TiO2(110) Surface. Wu, X., Selloni, A., Lazzeri, M., Nayak, S.K.: Physical Review B, 2003, 68[24], 241402