Well-defined Fe–Cu diatomic sites for efficient catalysis of CO2 electroreduction

The diatomic catalysts (DACs) provide a new strategy for efficient catalysis of CO2 reduction reaction (CO2RR) owing to their maximum atomic utility and more flexible active sites. However, it is still challenging to precisely design heteronuclear diatomic active centers and understand the coordination mechanism of binary sites at the atomic level. Herein, a nitrogen-doped carbon matrix with precisely controlled Fe–Cu diatom sites is synthesized through a metal–organic framework. The as-obtained Fe/Cu–N–C catalyst exhibits an excellent CO faradaic efficiency (>95% over a wide potential range of −0.4 to −1.1 V vs. RHE, 99.2% at −0.8 V vs. RHE), a high turnover frequency (5047 h−1 at −1.1 V vs. RHE), and a low overpotential (50 mV), thus outperforming most reported atomically dispersed catalysts. Further density functional theory calculations indicate that the synergy between Fe–Cu diatoms causes rapid charge transfer and effectively adjusts the position of the d-band center, which reduces the energy barriers for *COOH formation and *CO desorption. This work provides a new approach for advancing universal synthesis strategies to construct heteronuclear diatomic catalysts and explore synergistic effects.