Leveraging the Intermetal Distance in Dual-Atom Catalysts: Revealing Optimized Synergistic Interactions for CO₂ Electroreduction

Dual-atom catalysts (DACs) offer a potential to accelerate reaction kinetics and provide versatile active sites by the synergistic combination of two metal atoms. However, the effects of dual-atom configurations and interatomic distances on catalytic performance have yet to be thoroughly investigated. Herein, we report DACs composed of Cu/Ni species anchored on N-doped carbon (Cu/Ni-NC) for the electrochemical CO₂ reduction reaction (CO₂RR). The role of intermetal interactions as a function of atomic distance was systematically investigated through a combination of theoretical calculations and advanced experimental techniques, including aberration-corrected transmission electron microscopy (AC-HAADF-STEM) and X-ray absorption fine structure analysis (XAFS). Our findings reveal that a Cu-Ni atomic distance of ∼4.08 Å maximizes synergistic interactions between the two metals, significantly enhancing catalytic activity and CO selectivity. The resulting catalysts demonstrate a CO faradaic efficiency (FE_CO) of ∼100% at -0.9 V vs the reversible hydrogen electrode (RHE) in an H-type cell and 96.3% at -0.4 V vs RHE in the flow cell, outperforming other Cu/Ni configurations and single-metal counterparts.