Controlled Photocatalytic Oxidation of Methane to Methanol through Surface Modification of Beta Zeolites

The selective oxidation of methane to methanol is achieved by means of a photocatalytic process. For this purpose, designed Bi- and V-containing beta zeolites prepared by incipient wetness impregnation have been used under different test conditions. While the zeolite proves to be photoactive under UVC irradiation toward the total oxidation process, the formation of V2O5 on the surface is an effective alternative for modifying the acid–base surface properties, thus significantly decreasing the undesired CO2 formation. At the same time the zeolite framework serves as a scaffold for increasing the surface area and distribution of the metal oxide. Additionally, the addition of low Bi amount favors the formation of a BiVO4/V2O5 heterojunction, which acts as a visible light photocatalyst while at the same leading to total selectivity to methanol at the expense of ethylene formation.