Stabilizing *COOH on Ni Single-Atom Sites by Dual-Phase Ni₃ZnC_0.7 and Ni for Enhanced Electrocatalytic CO₂ Reduction

Metal-based nanoparticle-modulated single-atom catalysts have garnered significant attention in the field of electrocatalytic CO₂ reduction reaction. However, the scaling relationships between the intermediates and their binding energies lead to unsatisfactory selectivity for specific products. Herein, Ni₃ZnC_0.7-Ni nanoparticles (NPs)-modulated Ni single-atoms (SAs) supported on N-doped carbon (Ni_SAs/Ni₃ZnC_0.7-Ni_NPs@NC) were constructed using a metal-organic framework as a template. Experiments and theoretical calculations reveal that the charge transfer from Ni₃ZnC_0.7 and Ni NPs to Ni SAs results in the formation of electron-enriched Ni SAs sites, which is conducive to stabilize the key *COOH intermediate. The catalyst shows a partial current density for CO of -345 mA cm^-2 and a Faradaic efficiency for CO (FE_CO) of 99.3% at -0.8 V versus a reversible hydrogen electrode in a flow cell. Furthermore, the catalyst maintains FE_CO of above 94% after continuous electrolysis for 18 h, showcasing its remarkable long-term stability.