Efficient Photocatalytic Oxidation Methane to C1 Oxygenates Over Pt Nanoparticles Supported on TiO ₂ Mediated by Polyoxometalates

The photocatalytic conversion of methane and oxygen into C1 oxygenates with high activity and high selectivity under mild conditions has long been a sought-after goal in industrial production. This work proposes a polyoxometalate-mediated Pt-based catalyst prepared by treating MOF-derived TiO2 via impregnation and calcination. The optimal dual co-catalyst (Pt/TiO2-HPW) achieved C1 oxygenates with a yield of 28.06 mmol·gcat−1 and selectivity of 98.96%, where HCOOH selectivity accounted for 57.66% after 1 h of reaction at 80 °C. Furthermore, the apparent quantum efficiency at 365 nm reached 1.46%. Combined experimental characterization and DFT calculations reveal that the high-density PtOx species on rutile TiO2 (110) and anatase TiO2 (101) facilitate the reduction of O2 to ·OOH radicals, while the Lewis acid sites on TiO2 promote the dissociation of H2O into ·OH radicals. Simultaneously, the introduction of phosphotungstic acid (HPW) further optimizes the electronic structure of the catalytic center via synergy with Pt. The observed strong charge interactions indicate enhanced adsorption and more efficient C−H bond activation, thereby achieving efficient methane and oxygen photocatalytic conversion.