Asymmetric Cu(I)─W Dual-Atomic Sites Enable C─C Coupling for Selective Photocatalytic CO 2 Reduction to C 2 H 4 .

Solar-driven CO 2 reduction into value-added C 2+ chemical fuels, such as C 2 H 4 , 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 W 18 O 49 nanowires (Cu 1 /W 18 O 49 ) photocatalyst with asymmetric Cu─W dual sites is reported for selective photocatalytic CO 2 reduction to C 2 H 4 . The interconversion between W(V) and W(VI) in W 18 O 49 ensures the stability of Cu(I) during the photocatalytic process. Under light irradiation, the optimal Cu 1 /W 18 O 49 (3.6-Cu 1 /W 18 O 49 ) catalyst exhibits concurrent high activity and selectivity toward C 2 H 4 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 C 2 H 4 generation from CO 2 photoreduction. This work demonstrates leveraging stabilized atomically-dispersed Cu(I) in asymmetric dual-sites for selective CO 2 -to-C 2 H 4 conversion and can provide new insight into photocatalytic CO 2 reduction to other targeted C 2+ products through rational construction of active sites for C─C coupling.