An O-Bridged Fe–Cu Dual-Atom Catalyst Enabling the Breaking of the Linear Scaling Relationship for Electrocatalytic CO ₂ to CO

Electrochemical reduction of CO₂ (ECR) to CO on single-atom catalysts is often constrained by CO selectivity and insufficient current density due to the relatively low intrinsic activity and inherent scaling relationship governing the adsorption strength of intermediates. Herein, an FeCuN₅O dual-atom catalyst was developed by incorporating an O atom into a N bridge site on carbon black, achieving a Faradaic efficiency (FE_CO) of 96.7% alongside a current density of -11.3 mA cm^-2 at -0.8 V (vs reversible hydrogen electrode, RHE). Furthermore, the FeCuN₅O catalyst attained a current density of -162.4 mA cm^-2 and the highest FE_CO of 93.5% at -0.9 V (vs RHE) in a flow cell. Combined experimental analyses and density functional theory (DFT) computations indicated that the O bridge induces more electron transfer between Fe and Cu atoms on FeCuN₅O, which can activate the synergistic effect of Fe and Cu atoms. Consequently, the O-bridged Fe-Cu dual-atom configuration successfully circumvents the conventional scaling relationship, resulting in superior ECR to CO performance.