Defective ZnO Nanoplates Supported AuPd Nanoparticles for Efficient Photocatalytic Methane Oxidation to Oxygenates

Direct photocatalytic methane oxidation into value-added oxygenates under mild conditions enables the sustainable chemical production but suffers from the lack of active photocatalysts and the overoxidation issue. Herein, defective ZnO nanoplates supported AuPd nanoparticles for efficient methane oxidation with O₂ as the oxidant at room temperature are reported. A maximum liquid oxygenates productivity of 152.2 mm g⁻¹ h⁻¹ and a selectivity of 86.7%, more than half of which is CH₃OH, are achieved over the optimized AuPd/ZnO photocatalyst, resulting in a 16.5% apparent quantum efficiency at 380 nm. The superior photocatalytic performance is benefited from the synergistic effect between defective ZnO substrate and AuPd cocatalyst, wherein the former facilitates CH₄ adsorption, and the latter promotes light absorption, charge separation, as well as O₂ activation into the reactive oxygen species. This work provides new guidance for regulating the activity and selectivity of the photocatalyst toward methane oxidation.