A density functional theory study of the interaction of oxygen with a reduced SnO2 (110) surface

Ab initio calculations using density functional theory within the generalized gradient approximation have been performed for the interaction of oxygen with a reduced SnO2 (110) surface. We found two species of chemisorbed O2 that can be described as a peroxo (O22−) species for side-on type adsorption and a superoxo (O2−) species for end-on type adsorption on the basis of their geometries and vibrational frequencies. We also found a low dissociation barrier of 2.0 kcal/mol for the peroxo species and high migration barriers of ∼13–18 kcal/mol for an oxygen atom produced by dissociation of O2 on the reduced SnO2 surface. An analysis of the electronic density of states indicates that an adsorbed oxygen atom coupled with the nearest-neighboring bridging oxygen vacant site is an O− species that displays catalytic activity on the surface.