Distinct Pathways in Visible-Light Driven Thermo-Photo Catalytic Methane Conversion.

Abstract

The utilization of visible light for direct photocatalytic methane conversion remains a huge challenge. Here, we developed a thermo-photo catalytic process with a visible-light-responsive Pt/WO3 catalyst and realized highly efficient visible-light driven methane conversion for the first time. The conversion efficiency was enhanced by 4.6 and 14.7 times compared to room-temperature photocatalysis and thermal catalysis at 150 °C, respectively. Furthermore, the production of liquid oxygenates (mainly CH3OH) was found to proceed via photocatalysis with high apparent quantum efficiencies of 5.9%, 4.5%, and 1.9% at 350, 420, and 450 nm, respectively, while CO2 evolution was contributed by photoassisted thermal catalysis. Solid isotope evidence further confirmed that CH3OH, HCHO, and CO2 were produced via parallel rather than sequential reactions. These observations provide a valuable guide for designing a visible-light driven system for methane conversion with high efficiency and controllable selectivity.