Synthesis of Reduced Vanadium Oxide-Supported Au Catalysts for Methane Selective Oxidation

Methane selective oxidation is essential but challenging due to the difficulty in activating the C-H bond under mild conditions and the ease of overoxidation of the organic products. In this study, a reduced vanadium oxide-supported Au catalyst (Au_0.5/VO_x-HC400) was synthesized via a sol-immobilization method followed by H₂ reduction. Structural characterizations confirmed the deposition of Au nanoparticles on VO_x. The catalyst efficiently promoted the selective oxidation of methane to methanol, formic acid, and acetic acid using O₂ as the oxidant without a coreductant, achieving a total organic productivity of 782 μmol/g_cat at 200 °C. The catalyst activity was optimized by tuning reaction parameters. Further investigation revealed that the catalyst effectively activated the C-H bond of methane by Au, and the reduced V oxides also promoted the reaction. Quenching experiments indicated that hydroxyl radicals were the key active oxidation species.