Reactivity of the V2O5-TiO2-anatase catalyst:: role of the oxygen sites

A theoretical DFT-based study combining cluster and periodic models has been performed to elucidate the role of the oxygen sites in the reactivity of the vanadia/titania catalyst. We have focused on the coordination of the oxygen sites that has been directly related to reactivity. First, the reactivity of the active phase vanadia is studied by means of a V2O5 cluster model. The support TiO2-anatase is then modeled by periodic conditions. Finally, a complex model containing vanadia units dispersed on anatase surfaces (100) and (001) is explored. According to our results, reactivity of the catalyst is associated to the presence of V-O-Ti bonds, the vanadyl V = O bonds being too stable to react.