INFRARED INVESTIGATION OF THE ADSORPTION AND REACTIONS OF METHANOL ON V2O5/TiO2 CATALYSTS.

The oxidation of methanol on a V//2O//5/TiO//2 monolayer catalyst was studied by infrared spectroscopy using transmittance and diffuse-reflectance cells. Methanol was adsorbed on the catalyst surface at room temperature to form methoxy groups. Upon heating to 150 degree C, these groups were oxidized to oxymethylene species. The latter species were also formed by adsorption of formaldehyde. When nitrogen saturated with methanol vapor was passed over the catalyst continuously at 150 degree C, methoxy, oxymethane, and CO were detected simultaneously in the gas phase. When the gas stream was stopped, the formation of these products did not stop immediately; this indicates that the observed surface species are reaction intermediates. On the basis of these results, a mechanism is proposed for the reaction.