CuO@TiO2 Hollow Cubes Enable Highly Selective and Stable Photocatalytic Non‐Oxidative Methane Coupling to Ethylene

Photocatalytic non‐oxidative coupling of methane (PNOCM) provides a green and sustainable route to the synthesis of ethylene (C2H4). TiO2 intrinsically can activate CH4 through photogenerated holes. However, taking advantage of this property for highly selective C2H4 production remains a significant challenge. Herein, CuO nanoparticles loaded hollow cubic TiO2 (CuO@hcTiO2) nanoparticles are synthesized via hydrolytic‐crystallization constrained morphology engineering combined with a chemical precipitation method. It exhibited an outstanding C2H4 selectivity of 97.7% and a production efficiency of 3937.2 µmol g−1CuO h−1, with excellent stability reaching 30 h. Compared with reported TiO2 based photocatalysts, the selectivity of C2H4 from CuO@TiO2 increased by 2~20 fold. Mechanistic investigations suggest that CuO nanoparticles loaded on TiO2 act as active sites for *CH3 capture due to the partially filled d orbitals. And the type‐I heterojunction between CuO and TiO2 promotes photogenerated holes migration from TiO2 to the CuO, facilitating the dehydrogenation of adsorbed *CH3 to *CH2 and subsequent coupling to C2H4. This work provides a promising strategy for designing photocatalysts to efficiently synthesis C2H4 via PNOCM.