Synergetic Bimetallic Nanopetal MOF(Cu,Fe)-CdS for Efficient Photocatalytic Oxidation of Methane into Methanol

Efficient conversion of methane into storable fuels with higher versatility, such as methanol, remains a significant challenge under ambient conditions. Solar-driven catalytic systems are regarded as promising strategies; however, their conversion efficiency and product selectivity remain relatively low. Focusing on developing high-efficiency metal–organic framework (MOF) photocatalysts, we report a novel MOF(Cu,Fe)-CdS composite for photocatalytic oxidation of methane to methanol under simulated sunlight. Methane photocatalytic oxidation activity was evaluated in a three-phase (gas–liquid–solid) reaction system under ambient conditions, achieving a methanol conversion rate of 30.04 μmol g–1 h–1, 1.57 times higher than that of pristine MOF(Cu,Fe). The enhanced photocatalytic activity of MOF(Cu,Fe)-CdS arises from the synergistic effect of bimetallic active centers(Cu,Fe) and the heterojunction between the MOF and CdS. The Cu–Fe bimetallic centers enable dynamic regeneration of Fe(III)/Fe(II) via an efficient redox cycle coupled with an optimized electron transport pathway. Fe(II) and Cu(I), serving as key active sites, significantly enhance the hydroxyl radical (•OH) generation efficiency (confirmed by ESR spectroscopy), thereby enabling efficient methane C–H bond activation. The incorporation of CdS reduced the bandgap of MOF(Cu,Fe) from 2.65 to 2.38 eV, broadening its light absorption range. This work offers a novel strategy for photocatalytic methane conversion and provides critical theoretical and practical insights for designing high-performance catalysts.