Structure and activity of Sn-Mo-O catalysts: partial oxidation of methanol

This work deals with the catalytic behavior of a series of Sn-Mo-O catalyst s in the partial oxidation of methanol. The catalysts of different Sn:Mo ra tios, were prepared by co-precipitation and they were investigated by means of dynamic experiments, test reactions (methanol-formaldehyde partial oxid ation. isopropyl alcohol decomposition) and physico-chemical characterizati on (XRD, BET, TPD of NH3. TPR, XPS and EPR). It was observed that interdispersion between MoO3 and SnO2 favors a superfi cial architecture in which the Sn-Mo interaction plays a major role modifyi ng the reactivity of the lattice oxygens and the reducibility of Mo ions an d, therefore, the catalytic behavior. The partial oxidation of methanol ind uces a reordering of the catalyst structural organization leading to a Mo s urface enrichment. The absence of chemical shifts for Sn (XPS) suggests tha t the O-Mo bond is mainly responsible fur the methanol reaction. (C) 2001 E lsevier Science B.V. All rights reserved.