Ultrathin oxide films on metal supports: structure-reactivity relations.

Well-ordered, thin oxide films have drawn some attention in recent years as suitable oxide supports for modeling highly dispersed metal catalysts at the atomic scale. It turned out, however, that ultrathin oxide films may exhibit interesting catalytic properties in their own right. In this review, we discuss phenomena specifically connected to ultrathin oxide films to explain and understand the physicochemical basis of their reactivity in oxidation reactions. Two sets of systems are discussed, i.e., transition metal oxide films grown on metal substrates and native oxide films formed upon oxidation of metal surfaces.