Fe-(μ-O)-Zn dual-atom boosting C-C coupling for direct oxidation of methane to acetic acid using O2

Direct oxidation of methane (DOM) into high-value C2+ products using molecular oxygen (O2) is essential for the sustainable production of clean energy and bulk chemicals, but is still challenging due to the difficult C-H activation and uncontrollable C-C coupling process. Herein, we design and construct the Fe-(μ-O)-Zn dual-atom sites by supporting Fe and Zn atoms on ZSM-5 (Fe1-Zn1/ZSM-5), which achieves the DOM by O2 to acetic acid under ambient temperature and pressure. The Fe-(μ-O)-Zn dual-atom sites yield an acetic acid productivity of 3006 μmol•gcat−1•h−1 with 86.8% selectivity (total C2+ products selectivity of 93.0%) for at least 20 hours at 25 oC and atmospheric pressure. The mutual electronic modulation between Fe and Zn shifts the d-band center of Fe 3d in Fe-(μ-O)-Zn dual-atom sites upwards, which promotes the formation and stabilization of highly reactive Fe=O species through O2 photodissociation and thereby enhances the C-H bond activation of CH4. The Fe-(μ-O)-Zn dual-atom reaction sites (spatial distance of 2.7 Å) boost the C-C coupling of key CH3 and HCHO intermediate species, which steadily produce acetic acid and other C2+ oxygenates. This work would broaden the avenue towards the sustainable conversion of methane to value-added C2+ products under ambient temperature and pressure. Direct methane oxidation to C2+ with O2 is impeded by tough C–H activation and uncontrolled coupling. Here, Fe-(μ-O)-Zn dual-atom sites on ZSM-5 enable efficient photocatalytic acetic acid production at ambient temperature and pressure.