SURFACE DYNAMICS IN TIN DIOXIDE-CONTAINING CATALYSTS .1. SURFACE DYNAMICS OF TIN DIOXIDE INTERACTION WITH PROPENE-CONTAINING FEED IN PRESENCE OF RESIDUAL WATER

Changes in AC electrical conductance were used to obtain information o n the peculiarities of propene interaction with the surface of polycry stalline tin dioxide. As results from in situ electrical conductivity data, adsorption of propene seems to prevail over oxygen adsorption, w hen both reactants are present. The influence of residual humidity sug gests the involvement of surface hydroxyl groups in the mechanism of a dsorption/oxidation as a possible source of oxygen. The strong adsorpt ion of propene is facilitated by the low mobility of the bulk lattice oxygen of tin dioxide up to 400 degrees C which in turn determines the surface proton mobility coupled with the ability of this material to catalyze dehydrogenation.