Selective Photocatalytic Oxidative Coupling of Methane via Regulating Methyl Intermediates over Metal/ZnO Nanoparticles

Abstract Methane conversion to higher hydrocarbons requires harsh reaction conditions due to high energy barriers associated with C−H bond activation. Herein, we report a systematic investigation of photocatalytic oxidative coupling of methane (OCM) over transition‐metal‐loaded ZnO photocatalysts. A 1 wt % Au/ZnO delivered a remarkable C 2 ‐C 4 hydrocarbon production rate of 683 μmol g −1 h −1 (83 % C 2 ‐C 4 selectivity) under light irradiation with excellent photostability over two days. The metal type and its interaction with ZnO strongly influence the selectivity toward C−C coupling products. Photogenerated Zn + ‐O − sites enable CH 4 activation to methyl intermediates (*CH 3 ) migrating onto adjacent metal nanoparticles. The nature of the *CH 3 ‐metal interaction controls the OCM products. In the case of Au, strong d‐σ orbital hybridization reduces metal‐C−H bond angles and steric hindrance, thereby enabling efficient methyl coupling. Findings indicate the d‐σ center may be a suitable descriptor for predicting product selectivity during OCM over metal/ZnO photocatalysts.