BUILDUP OF ACTIVE OXIDE SURFACE UNDER INFLUENCE OF THE REACTION MIXTURE

On studying the approach to steady state of oxide catalysts for oxidat ive coupling of methane and propylene as well as of catalysts for cros s-coupling between toluene and ammonia (toluene ammoxidation), three k inds of surface changes under the reaction conditions have been reveal ed. The formation of a two-dimensional phase, surface reduction and ge neration of adsorptive type active sites has been shown to be responsi ble for a build-up of more active and/or selective surface structures.