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.

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Molybdenum disulfide (MoS 2 ) is a promising material for energy and environmental applications. In this paper, we report the direct hydrothermal growth of MoS 2 on a Mo support and its application in the rarely explored electrochemical CO 2 reduction (EC CO 2 R) process. To investigate the effects of metal overlayers and the MoS 2 support, Au, Ag, and Cu were sputter-deposited on a MoS 2 electrode. Large amounts of CH 4 , C 2−3 hydrocarbons, and formate were produced via EC CO 2 R on bare MoS 2 . The introduction of a Au overlayer on MoS 2 enhanced the production of CO, methanol, and formate. Furthermore, the alkanes (C 𝑛 H 2𝑛+2 , 𝑛 = 2, 3) to alkenes (C 𝑛 H 2𝑛 , 𝑛 = 2, 3) ratio was dependent on the applied potential and overlayer metals. Notably, photoirradiation remarkably increased the CO and C 2 H 4 concentrations by 28-fold and 10-fold, respectively. These findings provide valuable insights for the development of MoS 2 -based materials for CO 2 recycling.