Exploring C1-C3 variations and Fischer–Tropsch chemistry via electrochemical CO2 reduction on electrodeposited Cu/Ag and Ag/Cu electrodes

Abstract

Ag and Cu bimetallic electrodes are extensively studied for producing C-C coupled C2+ reduction products through electrochemical CO2 reduction. In this study, we prepared electrodes with Cu electrodeposited on Ag supports (CuED/Ag) and Ag electrodeposited on Cu supports (AgED/Cu) via electrodeposition, demonstrating behaviors for reduction products under various electrochemical conditions. The products were categorized as H2, C1 (CO, CH4, formate, methanol), C2 (C2H4, ethanol, acetate, acetaldehyde, glycolaldehyde, and ethylene glycol), C3 (propanol, isopropanol), and Fischer–Tropsch (F-T) synthesis products (CnH2n and CnH2n+2, n ≥ 2). Notably, ethylene glycol was only observed over AgED/Cu. The reduction products dynamically changed with applied potentials and electrolyte concentrations. The mechanism was understood to involve surface H* adsorption, CO2 adsorption, C-C coupling, hydrogenation, and dehydration. Minor F-T synthesis chemistry was observed, explained by *CO and *CH2 insertion chain growth. The distinct product behaviors over the CuED/Ag and AgED/Cu electrodes provide valuable insights into the development of electrodes for producing value-added carbon products via CO2 utilization.