Intrinsic Electron Transfer in Heteronuclear Dual-Atom Sites Facilitates Selective Electrocatalytic Carbon Dioxide Reduction

The metal–metal (M₁–M₂) interactions in heteronuclear dual-atom catalysts (HNDACs) significantly optimize the electronic properties of the active sites, resulting in the promotion of the reaction kinetics in electrocatalysis. However, the regulation mechanisms in these M₁–M₂ dual-atom sites still remain unclear. Herein, the intrinsic electron transfer in Fe–Zn dual-atom sites are revealed for facilitating electrocatalytic carbon dioxide reduction (ECO₂R) to carbon monoxide (CO). The electronegativity difference between the Fe and Zn centers induces the specific electron transfer from Zn to Fe, which regulates the electron structures of the active Zn sites, leading to the optimized reaction pathway of CO₂-to-CO conversion on these sites. The Fe–Zn HNDAC (FeZnNC) exhibits superior ECO₂R performances than the single-atom Fe/Zn catalysts (FeNC and ZnNC) in the typical H-cell system, the maximum CO partial current density on FeZnNC reaches more than 3.3 and 1.8 folds of those on FeNC and ZnNC, respectively. More importantly, in a strongly acidic medium (pH = 1), FeZnNC achieves CO Faradaic efficiencies greater than 94% in the current density range of 100–400 mA cm⁻². This work uncovers the intrinsic electron transfer at the heteronuclear diatomic sites, providing new insights for the rational design of high-performance HNDACs toward industrial electrocatalysis.