Benchmarking anion-exchange membranes for electrocatalytic carbon monoxide reduction

Performing carbon monoxide reduction in membrane electrode assembly configuration (MEA) is critical to achieving a high reaction rate while reducing cell resistance. Most studies examine the role of the cathode on product selectivity and cell stability, and comparatively little attention has been given to the membrane impact on cell performance. This study demonstrates that membrane properties such as water uptake, ion-exchange capacity, and functional groups alter the liquid product selectivity. Interestingly, we show that high ethanol crossover in conjunction with a suitable anode (NiFeO x ) tunes the acetate selectivity. Overall, membrane properties significantly affect cell stability and product selectivity in a membrane electrode assembly configuration. • Insights on product crossover through polymer membranes during CO electroreduction • The synergy between the membrane and anode tunes the selectivity of liquid products • Acetate Faradaic efficiency increased from 20% to 35% in a single pass conversion As a key component of carbon capture, utilization, and storage (CCUS), CO 2 utilization technologies are crucial for the circular carbon economy. Among all technologies being developed, CO2 electrolysis is particularly attractive because of its ability to convert CO 2 into various value-added products. Currently, research in CO 2 electrolysis primarily focuses on electrocatalyst development, whereas an ion-conductive polymer membrane did not receive sufficient attention despite the fact that it has a strong impact on full-cell performance. Here, we report the correlation between membrane properties and CO electroreduction performance. We present a new strategy to tune product selectivity by choosing a suitable membrane material and an electrochemically active anode. The understanding of membrane-electrode assembly performance presented in this study provides important insights for the future rational design of better membranes for CO 2 /CO electrolyzers. Suitable membrane properties and an active anode catalyst can tune the Faradaic efficiency of liquid products during CO electroreduction. Acetate Faradaic efficiency increased from 20% to 35% in single pass conversion using membranes with high ion-exchange capacity and active anode electrode for partial ethanol oxidation.