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Metal alloy electrocatalysts are commonly used in electrochemical (EC) CO 2 reduction. In this study, we demonstrate the application of a ternary CuNiZn alloy as an electrocatalyst for both CO 2 and CO reductions. Our results show that formate, CO, CH 4 , and C 2−7 hydrocarbons were produced through the process of initial CO 2 adsorption followed by subsequent stepwise reactions. Interestingly, we also observed the production of CH 4 and C 2−7 hydrocarbons (C n H 2n+2 and C n H 2n ) through EC CO reduction, which occurred via direct CO adsorption, followed by hydrogenation reactions. Furthermore, we discovered an electrochemically-induced surface reaction that mimics the Fischer−Tropsch (F−T) synthesis, resulting in the formation of long-chain hydrocarbons through C−C coupling/polymerization. We utilized X-ray photoelectron spectroscopy with Ar + ion sputtering depth to investigate the interfacial electronic structures and surface elemental composition distributions of Cu, Ni, and Zn. Our results indicate that these properties are highly dependent on both the applied potential and the depth at which they are measured. These unique observation provides significant insights into the EC F−T synthesis process, C−C coupling mechanism, the design of efficient metal alloy electrodes, and the theoretical modeling of alloys in both electrochemical CO 2 reduction and CO reduction.

Converting CO2 into C n>2 hydrocarbons has been a significant challenge, but recent research has shown that cadmium (Cd) can be used to produce C2–7 hydrocarbons (C n H2n and C n H2n+2) directly through electrochemical CO2 reduction in a K2HPO4/KH2PO4 buffer. The production of hydrocarbons was found to be enhanced by engineering the interface of the Cd surface with other transition metals. This process imitates the Fischer–Tropsch (F–T) synthesis, which involves surface polymerization reactions that couple carbon atoms together, resulting in the formation of long-chain hydrocarbons via the insertion of CO and CH x molecules. While the formate path was almost completely suppressed, the CO path remained. While the current Faradaic efficiency may be low, this study highlights the potential of electrochemical CO reduction for Cd. The study demonstrates that CO and H can directly participate in F–T synthesis through electrochemistry. Furthermore, Cd was observed to recrystallize into stacked wall structures resembling flowers after the electrochemical process. As a result, this research provides crucial insights that can aid in a better understanding of C–C coupling paths via electrochemistry.

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