By using first-principles density-functional calculations, the interactions of molecular O with a partially reduced rutile TiO2 (110) surface were studied. In agreement with experiment, a number of different O2 adsorption states, both molecular and dissociated, were found. The kinetic barriers for conversion between these states had also been calculated. Based upon these results, the mechanism of O vacancy diffusion (recently observed by scanning tunneling microscopy) was analyzed and a pathway was suggested which did not imply the high O adatom reactivity which was assumed in the original model.

Oxygen Vacancy Mediated Adsorption and Reactions of Molecular Oxygen on the TiO2 (110) Surface. X.Wu, A.Selloni, M.Lazzeri, S.K.Nayak: Physical Review B, 2003, 68[24], 241402 (4pp)