Selective photocatalytic oxidation of methane by quantum-sized bismuth vanadate

Abstract

The direct oxidation of methane to more desirable, one-carbon oxygenated molecules such as methanol and formaldehyde offers a pathway towards a more sustainable chemical industry as the current commercial reforming process involving two steps features a high carbon footprint and energy consumption. Here, we report the selective photocatalytic oxidation of methane at room temperature using quantum-sized bismuth vanadate nanoparticles as the catalyst and oxygen as a mild oxidant. The reaction offers a high selectivity, of 96.6% for methanol or 86.7% for formaldehyde, under optimum wavelength and intensity of light, reaction time and amount of water solvent. Comprehensive characterizations disclose a multistep reaction mechanism in which the activation of methane by the hydroxyl radical determines the reaction rate. This work broadens the avenue towards the selective conversion of the greenhouse gas methane into desirable chemical products in a sustainable way.