Selective Photocatalytic Oxidative Coupling of Methane via Regulating Methyl Intermediates over Metal/ZnO Nanoparticles
Pu Wang, Run Shi, Yunxuan Zhao, Zhenhua Li, Jiaqing Zhao, Jiaqi Zhao, Geoffrey I. N. Waterhouse, Li‐Zhu Wu, Tierui Zhang
Abstract
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.