Composition effects of electrodeposited Cu-Ag nanostructured electrocatalysts for CO2 reduction

18 January 2024, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The electrochemical reduction of carbon dioxide (CO2RR) to valuable C2+ liquid fuels and oxygenates, such as ethanol and propanol, is a promising strategy to minimize the carbon footprint and store renewable electricity. In this study, we investigate the CO2RR on electrodeposited Cu-Ag nanostructures obtained using a green choline chloride and urea deep eutectic solvent (DES). We show that Cu-Ag nanostructured electrocatalysts with tunable composition, loadings, and size can be simply prepared in one step, without adding other additives or surfactant agents. We investigate the intrinsic activity and selectivity of the CO2RR by determining the electrochemically active surface area (ECSA) using lead underpotential deposition (UPD). The analysis of the partial current densities normalized by the ECSA shows that the addition of Ag on electrodeposited Cu primarily suppresses the production of hydrogen and methane with respect to Cu nanostructures. At the same time, the production of carbon monoxide (CO) slightly increases but, the partial current of the total C2+ products does not considerably increase. Despite that the production rate of C2+ is similar on Cu and CuAg, the addition of Ag enhances the formation of alcohols and oxygenates over ethylene, in line with previous reports. We highlight the potential of metal electrodeposition from DES as a sustainable and inexpensive strategy for the development of bimetallic Cu-based nanocatalysts towards CO2RR.


CO2 reduction
deep eutectic solvent
copper-silver nanostructures

Supplementary materials

Supporting Information Composition effects of electrodeposited Cu-Ag nanostructured electrocatalysts for CO2 reduction
A detailed electrochemical characterization of the Cu-Ag electrodeposition from DES by CV and CA analysis is included. The three-electrode glass cell setups for the electrodeposition are also shown. Ex-situ characterization of the Cu and the Cu-Ag nanostructures with SEM images and XPS analysis of the Cu-Ag nanostructures are added. The calculations to determine the mass loadings of all nanostructures by Faraday law are also explained. Additional product distribution analysis after one hour of CO2RR on the 3Cu:1Ag and 6Cu:1Ag are included. Lead UPD voltammograms of the Cu and the 6Cu:1Ag nanostructures have been exhibited together with a table which summarizes all ECSA and R. Finally, a summary of faradic efficiencies and partial currents of the CO2RR products on different Cu and Cu-Ag nanostructures are included.


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