Strategies to Enhance CO₂ Electrochemical Reduction from Reactive Carbon Solutions

CO₂ electrochemical reduction (CO₂ ER) from (bi)carbonate feed presents an opportunity to efficiently couple this process to alkaline-based carbon capture systems. Likewise, while this method of reducing CO₂ currently lags behind CO₂ gas-fed electrolysers in certain performance metrics, it offers a significant improvement in CO₂ utilization which makes the method worth exploring. This paper presents two simple modifications to a bicarbonate-fed CO₂ ER system that enhance the selectivity towards CO. Specifically, a modified hydrophilic cathode with Ag catalyst loaded through electrodeposition and the addition of dodecyltrimethylammonium bromide (DTAB), a low-cost surfactant, to the catholyte enabled the system to achieve a FE_CO of 85% and 73% at 100 and 200 mA·cm^-2, respectively. The modifications were tested in 4 h long experiments where DTAB helped maintain FE_CO stable even when the pH of the catholyte became more alkaline, and it improved the CO² utilization compared to a system without DTAB.