First-Principles Study of C–C Coupling Pathways for CO2 Electrochemical Reduction Catalyzed by Cu(110)

To build a carbon-neutral energy cycle, the development of electrocatalysts that can reduce CO2 into products containing at least two carbon atoms (C2+) is crucial. This process would require at least one C–C coupling of two C1 intermediates. The (110) facet of copper is known for its ability to reduce CO2 to C2+ products in high quantities (Faradaic efficiency ≥65%). In this study, we used constant electrode potential density functional theory calculations to determine the dominant C–C coupling pathways for CO2 electrochemical reduction (CO2ER) on Cu(110). By studying the mechanism of CO2ER to methane, we identified *CO and *CH as high-concentration C1 species due to their high ΔG ‡ for further hydrogenation. Based on this result, 26 C–C coupling reactions that contain at least one high-concentration C1 intermediate were selected for investigation. The most important ones responsible for C2+ formation on Cu(110) were identified, and the influence of strain on the rates of these reactions was also investigated.