Solar-Powered Asymmetric C-C Coupling toward Efficient CO2-to-C2+ Hydrocarbon Conversion at Ultralow Bias.

Electrochemical CO2 reduction to multicarbon (C2+) hydrocarbons offers a promising route for value-added fuels and chemical feedstocks, yet its selectivity is usually limited by the sluggish symmetric C-C coupling. Herein, we demonstrate the synthesis of phosphidated Cu-Ni-Cu triangular single-atom cones (Ni1PCu2) by decorating Cu nanowires with Ni single atoms and P. These Ni1PCu2 can deliver an impressive CO2-to-C2+ hydrocarbon (C2H4 43%, C2H6 48%) Faradaic efficiency of 91% under solar light at an ultralow bias of -0.3 VRHE, and a stable C2+ hydrocarbon production rate of 370 μmol h-1 cm-2 for 4 days at 100 mA cm-2, where the Cu nanowires harness solar light to generate plasmonic electrons for the CO2 activation and its subsequent conversion to *CO, while electronegative phosphidation induces the formation of Cu+ sites to well stabilize *CO across high coverages. Strategically positioned Ni single atoms generate and confine active hydrogen (•H) for efficient hydrogenation of adjacent Cu+-*CO into Cu+-*CHO. The resulting Cu+-*CHO displays a weakened C-O bond and enhanced C nucleophilicity, allowing for solar-powered asymmetric C-C coupling with neighboring *CO toward efficient and selective C2+ hydrocarbon synthesis.