Constructing Ag/Cu2O Interface for Efficient Neutral CO2 Electroreduction to C2H4.

Abstract

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 FE_C2H4 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.