A study was conducted on the properties of structural defects on the rutile TiO2(110) surface and their interaction with molecular oxygen showing a fairly complex behavior. A simple pair-wise interaction model was applied using interaction parameters derived from the results, working reasonably well as a rough first approximation. As such, the adsorption of molecular oxygen was found to be possible only in the presence of bridging oxygen vacancies.

Adsorption, Diffusion, and Dissociation of Molecular Oxygen at Defected TiO2(110): a Density Functional Theory Study. Rasmussen, M.D., Molina, L.M., Hammer, B.: Journal of Chemical Physics, 2004, 120[2], 988-97