Mechanistic Study of Selective Oxidation of Methanol over a Monolayer V2O5/CeO2 Catalyst

An operando Fourier transform infrared spectroscopy (FTIRS) study of the oxidation of methanol over a monolayer V2O5/CeO2 catalyst was carried out at atmospheric pressure in a temperature range of 150-300 degrees C. It was found that the oxidation starts at 200 degrees C, when the main products & horbar;methyl formate and dimethoxymethane & horbar;are formed with a selectivity of 62 and 38%, respectively. An increase in the reaction temperature initiates the formation of formaldehyde, CO, and CO2, and at 300 degrees C, CO becomes the main reaction product. The main reaction intermediates are methoxy groups, formates, dioxymethylene species, and adsorbed formaldehyde. According to X-ray photoelectron spectroscopy (XPS) studies, the reaction involves a reversible reduction of V5+ and Ce4+ cations, indicating that both vanadia and ceria are involved in the oxidation of methanol. A reaction mechanism of the oxidation of methanol over supported vanadium oxide catalysts is discussed.