Selective Photocatalytic Oxidation of Low Concentration Methane over Graphitic Carbon Nitride-Decorated Tungsten Bronze Cesium

Although traditional thermal catalysis is usually used to convert methane into value-added products, its high reaction temperature results in a low performance–price ratio in conversion of low concentration methane. In this regard, we synthesized a series of mace-like g-C3N4-decorated Cs0.33WO3 nanocomposites for photocatalytic conversion of low concentration methane under mild conditions. The optimized g-C3N4@Cs0.33WO3 (weight ratio = 3:7) photocatalyst selectively converted low concentration methane (1000 ppm) into methanol with a yield of 4.38 μmol/h/g under light irradiation and at room temperature. Both performance experiments and trapping experiments verified that methane activation and methyl oxidation were involved in the photocatalytic conversion process of methane. The •O2– first activated the methane to methyl on the surface of g-C3N4 in the composite and then the photogenerated electrons from the Cs0.33WO3 in the composite inhibited the peroxidation and increased the generation of methanol. This research provides a new route to design and synthesize photocatalysts for converting methane into value-added chemicals.