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 °C. It was found that the oxidation starts at 200 °C, when the main products─methyl formate and dimethoxymethane─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 °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.