Selective Photoconversion of CO ₂ to C ₂ H ₄ on Asymmetrical CeO ₂ ─Cu ₂ O Interfaces Driven by Oxygen Vacancies

Abstract Photocatalytic conversion of CO ₂ into valuable C ₂ H ₄ is desirable for achieving a carbon‐neutral future, yet faces sluggish kinetics of C─C dimerization and insufficient electron deliverability. Herein, an effective top‐down etching route is presented to construct interfacial asymmetric oxygen vacancies (Ov) in CeO ₂ ─Cu ₂ O supported on the copper foam (CeO ₂ ─Cu ₂ O/CF). In situ characterizations and theoretical calculations demonstrate that the nanointerface‐based CeO ₂ ─Cu ₂ O heterojunctions serve as rapid electron‐transfer pathways, promoting efficiency without the need for sacrificial agents. Moreover, the asymmetric sites (Ce‐Ov‐Cu) with different charge distributions can effectuate C─C coupling reaction through the stabilization of the key ^* COCO intermediates, thus making CO ₂ reduction to C ₂ H ₄ become a more favorable process. Accordingly, the optimized CeO ₂ ─Cu ₂ O/CF demonstrates remarkable performance with 93% electron selectivity toward C ₂ H ₄ generation and an impressive production rate of 26.1 µmol g ⁻¹ h ⁻¹ . Such strongly coupled heterogeneous catalysts with finely tailored structure and interaction, containing asymmetric charge polarized metal sites at the interface, will provide some inspiration for constructing efficient photocatalysts to convert CO ₂ into high value‐added multi‐carbon products with solar energy.