Constructing Ag/Cu2O interface for efficient neutral CO2 electroreduction to C2H4.

Neutral CO2 electroreduction to multi-carbons (C2+) offers a promising pathway to reduce the CO2 and energy losses originating from the carbonate formation. However, the sluggish kinetics of C-C coupling brings a significant challenge of achieving high selectivity of a single product (such as ethylene), especially at industrial-relevant current densities (> 300 mA cm-2). Here, we reported an optimized Ag-Cu2O interfacial catalyst that exhibited C2+ Faradaic efficiency (FE) of 73.6% at 650 mA cm-2 in a flow cell. Remarkably, it obtained FEC2H4 of 66.0% with a partial current density of 429.1 mA cm-2, making it stand out among the reported Cu-based electrocatalysts. In situ Raman spectra uncovered that the Ag/Cu2O interfaces enabled a high coverage of *CO around the partially reduced Cu+/Cu0 active sites. Furthermore, theoretical calculations demonstrated the enhanced CO formation and C-C coupling at the Ag/Cu2O interface. This work reported an unprecedented neutral CO2 electroreduction to C2H4 performance and provided an in-depth comprehension of the role of the bimetallic interface.