How can the Dual-atom Catalyst FeCo–NC Surpass Single-atom Catalysts Fe–NC/Co–NC in CO2RR? – CO Intermediate Assisted Promotion via a Synergistic Effect

Abstract

Atomically dispersed catalysts are widely adopted in CO2 reduction reaction (CO2RR) due to maximal atomic utilization and high catalytic activity. Dual-atom catalysts (DACs), with more dispersed active sites and distinct electronic structures compared with single-atom catalysts (SACs), may exhibit diverse catalytic performance. Herein, the DAC FeCo–NC and SAC Fe–NC/Co–NC are employed as probes to explore DACs advantage in CO2RR. Results show that the moderate interaction between the dual-atom center and N coordination balances structural stability and catalytic activity. CO is the only product on Fe–NC/Co–NC, and the high limiting potentials from −1.22 to −1.67 V inhibit further reduction. FeCo–NC assisted with CO intermediate exhibits low limiting potentials of −0.64 V for both CH3OH and CH4, comparable to those on Cu-based catalysts. Under circumstance of applied potentials, CO2RR on FeCo–NC has greater advantages in yielding CH3OH and CH4 than that on Fe–NC/Co–NC, and hydrogen evolution reaction is severely inhibited. The intrinsic essence is that dual-atom center can provide large spin-polarization and multi-electron transfer capability, rendering CO intermediates as effective electronic and geometric modifiers in CO2RR. This work highlights FeCo–NC as a high-performance CO2RR catalyst toward deep-reduction C1 products and elucidates CO intermediate assisted promotion mechanism via a dual-atom synergistic effect.