Structural Insights into Ni–Fe Layered Double Hydroxides as Anode Catalysts for Pairing CO2 Reduction and Ethylene Glycol Oxidation

Harnessing renewable electricity for CO2 electroreduction is essential for the low-carbon production of chemicals and fuels. Traditional methods combine the CO2 reduction reaction (CO2RR) with the oxygen evolution reaction (OER), which has high energy consumption and low-value products. Here, we propose using anodic ethylene glycol oxidation reaction (EGOR) instead of OER, which has a lower oxidation potential and valuable product. Nickel–iron layered double hydroxide (NiFe-LDH) is identified as an efficient EGOR catalyst. Using systematic electrochemical measurements and both ex situ and operando spectroscopy revealed that NiFe-LDH undergoes distinct structural evolution under EGOR and the OER. We found that metal–oxygen hybridization enhances EGOR selectivity and reduces the OER selectivity. Pairing EGOR with CO2RR allowed achieving a low electrical consumption of 6.2 kWh Nm–3 at 300 mA cm–2 for CO production using Ag as the cathode. This strategy was successfully applied to the conversion of CO2 to multicarbon products, demonstrating a partial current density of 364 mA cm–2 for C2+ production using Cu2O as the cathode.