Ag Stabilized Cu⁺/Cu⁰ Interface Catalysts for Enhanced CO₂ Electroreduction to C₂₊ Products at Ampere Level Current Density

Electrochemical carbon dioxide reduction reaction (CO₂RR) to yield multicarbon (C₂₊) products still suffers from a great hardship, which requires high current density and Faradaic efficiency (FE) accompanied by favorable stability for the purpose of industrial applications. Herein, we display 5.6 atom % Ag/Cu₂O–Cu catalyst with abundant and steady Ag/Cu⁺/Cu⁰ interfaces for the efficient conversion of CO₂-to-C₂₊ at ampere level current density. 5.6 atom % Ag/Cu₂O–Cu catalyst attains a desirable FE of 76.5 ± 1.2% toward C₂₊ products at 1.0 A/cm² in 1 M KOH electrolyte and remains stable CO₂ electrolysis at 0.50 A/cm² for 20 h using a flow cell apparatus. <i>In situ</i> Raman spectrometry and density functional theory calculations indicate that a steady Ag/Cu⁺/Cu⁰ interface can promote CO₂-to-C₂₊ conversion through adjusting the energy barrier for the formation and dimerization of *CO intermediates. The synergistically heterogeneous interfaces promote the activity, selectivity, and stability of CO₂ electroreduction to C₂₊ products via a tandem route of *COOH, *CO, and *OCCO intermediates over Ag/Cu⁺/Cu⁰ cooperative sites.