Surface Engineering of Copper Catalyst through CO* Adsorbate

The electrochemical reduction of CO2 with Cu based catalysts depends intimately on the instantaneous local chemical environment of the catalyst-electrolyte interface. This microenvironment fluctuates according to the concentration of surface-adsorbed competing reaction intermediates and the applied electrode potential. In practice, disentangling these factors is exceedingly challenging, yet they critically determine the electrocatalyst efficiency and selectivity. Using grand canonical quantum classical hybrid calculations, we quantify the complex interdependence between electrode potential, CO* coverage, and the interfacial field strength. We show that the often overlooked CO* coverage effect in fact strongly influences the field strength, with a magnitude change exceeding 1 V/angstrom at certain potentials; among other effects, this change should lower the CO* dimerization barrier that dictates selectivity toward multicarbon products. Beyond showcasing the importance of surface coverage for CO2 reduction, our results highlight the power of surface additives to modulate interfacial fields toward tailored electrochemical pathways.

Automated summary

The electrochemical reduction of CO2 with Cu based catalysts is closely related to the instantaneous local chemical environment of the catalyst-electrolyte interface. This microenvironment fluctuates depending on the concentration of surface-adsorbed competing reaction intermediates and the applied electrode potential. Quantifying the complex interdependence between electrode potential, CO* coverage, and the interfacial field strength, our study reveals the strong influence of CO* coverage on the field strength, suggesting its significance in determining the selectivity towards multicarbon products. Additionally, our results demonstrate the potential of surface additives to modulate interfacial fields for tailored electrochemical pathways.