Oxygen promoter on copper-silver coupling for electrochemical carbon dioxide reduction catalysts

The CO₂-to-CO conversion catalyst is a key component in the design of an eco-friendly and energy-efficient process for the conversion of CO₂ into useful chemicals. Ag and Cu are representative electrochemical catalytic materials for CO₂ reduction, and coupling the two metals is an extensively used approach to increase the catalytic activity and selectivity. Through a series of first-principles calculations, we identify novel structure–activity correlations resulting from the various interfaces between the Ag surface and Cu oxide subsurface. We find that the oxygen atoms incorporated into Cu play a pivotal role in promoting Cu-Ag alloy catalysts. Our calculation results highlight that the sigma-type interaction between subsurface oxygen and surface Ag aligned perpendicular to the surface breaks the linear scaling relationship between key reaction intermediates and leads to subsequent activity enhancement for CO production. Given that Cu is susceptible to oxidation, the unraveled oxygen-induced activity promotion effect is anticipated to be taken as a practically applicable reference to ongoing efforts for the development of high-performance electrochemical CO₂-to-CO conversion catalysts.