FeOx–Au Supported WO3-x for Selective Photocatalytic Methane Conversion to Methanol under Visible Light

Abstract

Solar-driven direct oxidation of methane to methanol with WO3 offers a promising avenue for methane utilization, yet the activation of O2 remains a challenge. Here, a FeOx–Au co-modified urchin-like WO3-x with surface oxygen vacancies is fabricated by a one-step redox co-deposition protocol for selective methane conversion to methanol. An impressive CH3OH production rate of 5.4 mmol g–1 h–1 (apparent quantum efficiency of 12.1% at the plasmonic wavelength of 660 nm) with a near unity selectivity (ca. 95%) is achieved, ranking among the top in the WO3-based photocatalysts reported to date under comparable reaction conditions. Experimental results unravel that the excited electrons especially for plasmonic hot ones on WO3-x could be rapidly extracted by the Au and then transferred to FeOx for activating O2 to generate •O2– radicals. In parallel, the generated holes participate in attacking methane for producing methyl radicals. This work proposes a strategy for the rational design of plasmonic photocatalysts for selective CH4 photo-oxidation.