Asymmetric Cu(I)─W Dual‐Atomic Sites Enable C─C Coupling for Selective Photocatalytic CO2 Reduction to C2H4

Solar-driven CO₂ reduction into value-added C₂₊ chemical fuels, such as C₂H₄, is promising in meeting the carbon-neutral future, yet the performance is usually hindered by the high energy barrier of the C─C coupling process. Here, an efficient and stabilized Cu(I) single atoms-modified W₁₈O₄₉ nanowires (Cu₁/W₁₈O₄₉) photocatalyst with asymmetric Cu─W dual sites is reported for selective photocatalytic CO₂ reduction to C₂H₄. The interconversion between W(V) and W(VI) in W₁₈O₄₉ ensures the stability of Cu(I) during the photocatalytic process. Under light irradiation, the optimal Cu₁/W₁₈O₄₉ (3.6-Cu₁/W₁₈O₄₉) catalyst exhibits concurrent high activity and selectivity toward C₂H₄ production, reaching a corresponding yield rate of 4.9 µmol g^-1 h^-1 and selectivity as high as 72.8%, respectively. Combined in situ spectroscopies and computational calculations reveal that Cu(I) single atoms stabilize the *CO intermediate, and the asymmetric Cu─W dual sites effectively reduce the energy barrier for the C─C coupling of two neighboring CO intermediates, enabling the highly selective C₂H₄ generation from CO₂ photoreduction. This work demonstrates leveraging stabilized atomically-dispersed Cu(I) in asymmetric dual-sites for selective CO₂-to-C₂H₄ conversion and can provide new insight into photocatalytic CO₂ reduction to other targeted C₂₊ products through rational construction of active sites for C─C coupling.