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 (Au0.5/VOx-HC400) was synthesized via a sol-immobilization method followed by H2 reduction. Structural characterizations confirmed the deposition of Au nanoparticles on VOx. 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/gcat 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.