Synergistic Electrochemical CO₂ Reduction and Water Oxidation with a Bipolar Membrane

The electrochemical conversion of CO2 and water to value-added products still suffers from low efficiency, high costs, and high sensitivity to electrolyte, pH, and contaminants. Here, we present a strategy for this reaction using a silver catalyst for CO2 reduction in a neutral catholyte, separated by a bipolar membrane from a nickel iron hydroxide oxygen evolution catalyst in a basic anolyte. This combination of electrolytes provides a favorable environment for both catalysts and shows the effective use of bicarbonate and KOH to obtain low cell voltages. This architecture brings down the total cell voltage by more than 1 V compared to that with conventional use of a Pt counter electrode and monopolar membranes, and at the same time, it reduces contamination and improves stability at the cathode.