Composition effects of electrodeposited Cu-Ag nanostructured electrocatalysts for CO reduction.

The electrochemical carbon dioxide reduction (CORR) on Cu-based catalysts is a promising strategy to store renewable electricity and produce valuable C chemicals. We investigate the CORR on Cu-Ag nanostructures that have been electrodeposited in a green choline chloride and urea deep eutectic solvent (DES). We determine the electrochemically active surface area (ECSA) using lead underpotential deposition (UPD) to investigate the CORR intrinsic activity and selectivity. We show that the addition of Ag on electrodeposited Cu primarily suppresses the production of hydrogen and methane. While the production of carbon monoxide slightly increases, the partial current of the total C products does not considerably increase. Despite that the production rate of C is similar on Cu and Cu-Ag, the addition of Ag enhances the formation of alcohols and oxygenates over ethylene. We highlight the potential of metal electrodeposition from DES as a sustainable strategy to develop bimetallic Cu-based nanocatalysts for CORR.