Potential-regulated dominant pathways of acetate and ethanol in electrochemical CO reduction

Electrochemical reduction of carbon monoxide to acetate and ethanol represents a promising strategy for sustainable chemical synthesis. Nevertheless, achieving precise control over product selectivity remains a critical challenge as these compounds originate from complex and closely coupled reaction pathways. In this study, a generalized potential-dependent switch in the dominant pathway for carbon monoxide to C 2 oxygenates on Cu-based electrodes is revealed. At applied potentials above −0.6 V versus the reversible hydrogen electrode, acetate and ethanol are primarily generated via electrode-mediated acetaldehyde disproportionation reaction; at more negative applied potentials, acetate production proceeds predominantly via a ketene-mediated route. Theoretical simulations corroborate the potential-dependent pathway divergence at key intermediates, offering a clear rationale for the observed selectivity trends. These findings establish a comprehensive and unified framework for understanding and guiding product distribution in carbon oxide electroreduction processes. Potential-driven bifurcation controls C 2 oxygenate selectivity in CO electroreduction on copper: low overpotentials favor acetaldehyde disproportionation, while higher potentials promote acetate formation via a ketene intermediate. Download: Download high-res image (171KB) Download: Download full-size image