Engineering Heteronuclear Dual‐Metal Active Sites in Ordered Macroporous Architectures for Enhanced C₂H₄ Production from CO₂ Photoreduction

Abstract Photocatalytic C 2 H 4 synthesis from CO 2 and H 2 O by utilizing solar energy represents a promising sustainable process, yet its efficiency remains significantly limited. Herein, we proposed a dual‐engineered strategy integrating 3D ordered macroporous (3DOM) architectures with heteronuclear dual‐metal active sites to synergistically promote the photocatalytic C 2 H 4 production. As an example, the Cu/3DOM‐In 2 O 3 photocatalyst was synthesized by in situ incorporating Cu single atoms (Cu SAs) into 3DOM In 2 O 3 through a template‐assisted pyrolysis process. The strong interaction between Cu SAs and In 2 O 3 resulted in the formation of charge‐polarized Cu─In active sites along with abundant oxygen vacancies (O V s). 3DOM architectures serving as special nanoreactors displayed significant advantages in promoting CO 2 enrichment and confining key intermediates, thereby increasing *CO coverage. Meanwhile, the charge‐polarized Cu─In active sites effectively mitigated electrostatic repulsion and promoted the formation of *CO + *CHO intermediates, resulting in a thermodynamically spontaneous C─C coupling step. Therefore, the Cu/3DOM‐In 2 O 3 photocatalyst exhibited robust CO 2 reduction to C 2 H 4 , achieving high C 2 H 4 evolution rates under various CO 2 concentrations, including pure CO 2 , 10% CO 2 in Ar (simulated flue gas), and 0.04% CO 2 in Ar (simulated air). This work offers a novel strategy for the construction of photocatalysts with tailored microstructures and specific active sites to promote the conversion of CO 2 and H 2 O into multicarbon products.