Adsorbate coverage effects on the electroreduction of CO to acetate

Abstract

CO electroreduction (COR), powered by renewable electricity, shows promise for producing green chemicals at the industrial scale. Here, we aim to understand why amongst C2 products, acetate is formed with relatively greater selectivity on Cu catalysts mounted in flow cells, as compared to in H-cells. We attribute this to improved CO transport in flow cells, which increases local pH and *CO coverage (θ*CO). The effect of local pH was verified through COR in different electrolytes, which shows a significant increase in the Faradaic efficiency (FE) of acetate as local pH rose. Higher CO concentrations in flow cells under similar local pH also substantially increased the FEacetate, as compared to FEethylene and FEethanol. This suggests that acetate formation is most sensitive to θ*CO. DFT calculations emphasize the importance of θ*CO in favoring acetate formation from the *CHCO intermediate, and reveals the role of lateral interactions in the production of C2 molecules.