Cascade Dual Sites Modulate Local CO Coverage and Hydrogen-Binding Strength to Boost CO2 Electroreduction to Ethylene

Rationally modulating the binding strength of reaction intermediates on surface sites of copper-based catalysts could facilitate C–C coupling to generate multicarbon products in an electrochemical CO2 reduction reaction. Herein, theoretical calculations reveal that cascade Ag–Cu dual sites could synergistically increase local CO coverage and lower the kinetic barrier for CO protonation, leading to enhanced asymmetric C–C coupling to generate C2H4. As a proof of concept, the Cu3N-Ag nanocubes (NCs) with Ag located in partial Cu sites and a Cu3N unit center are successfully synthesized. The Faraday efficiency and partial current density of C2H4 over Cu3N-Ag NCs are 7.8 and 9.0 times those of Cu3N NCs, respectively. In situ spectroscopies combined with theoretical calculations confirm that Ag sites produce CO and Cu sites promote asymmetric C–C coupling to *COCHO, significantly enhancing the generation of C2H4. Our work provides new insights into the cascade catalysis strategy at the atomic scale for boosting CO2 to multicarbon products.