Precisely Constructing Orbital Coupling-Modulated Dual-Atom Fe Pair Sites for Synergistic CO₂ Electroreduction

Abstract

Electrochemical reduction of CO2 (CO2RR) provides an attractive pathway to achieve a carbon-neutral energy cycle. Single-atom catalysts (SAC) have shown unique potential in heterogeneous catalysis, but their structural simplicity prevents them from breaking linear scaling relationships. In this study, we develop a feasible strategy to precisely construct a series of electrocatalysts featuring well-defined single-atom and dual-site iron anchored on nitrogen-doped carbon matrix (Fe1–N–C and Fe2–N–C). The Fe2–N–C dual-atom electrocatalyst (DAC) achieves enhanced CO Faradaic efficiency above 80% in wider applied potential ranges along with higher turnover frequency (26,637 h–1) and better durability compared to SAC counterparts. Furthermore, based on in-depth experimental and theoretical analysis, the orbital coupling between the iron dual sites decreases the energy gap between antibonding and bonding states in *CO adsorption. This research presents new insights into the structure–performance relationship on CO2RR electrocatalysts at the atomic scale and extends the application of DACs for heterogeneous electrocatalysis and beyond.