Interaction of oxygen with the surface of vanadia catalysts

Abstract Kinetics of the re-oxidation of the H 2 -reduced or vacuum treated VO x /TiO 2 catalyst was studied. It was found that oxygen does not adsorb in the form of ad-atoms on the fully oxidized surface of the catalyst but re-oxidizes oxygen vacancies. On the basis of the surface potential measurements it was concluded that nucleophillic oxygen O (s) 2− is almost exclusively present above 550 K on the catalyst surface. The quantum-chemical calculations were supported by the experimental results. The implications of these results for the reaction mechanism of the oxidative dehydrogenation of propane are discussed.