Electroreduction Of Carbon Dioxide Driven By The Intrinsic Defects In The Carbon Plane Of A Single Fe-N-4 Site

Manipulating the in-plane defects of metal-nitrogen-carbon catalysts to regulate the electroreduction reaction of CO2 (CO2RR) remains a challenging task. Here, it is demonstrated that the activity of the intrinsic carbon defects can be dramatically improved through coupling with single-atom Fe-N-4 sites. The resulting catalyst delivers a maximum CO Faradaic efficiency of 90% and a CO partial current density of 33 mA cm(-2) in 0.1 m KHCO3. The remarkable enhancements are maintained in concentrated electrolyte, endowing a rechargeable Zn-CO2 battery with a high CO selectivity of 86.5% at 5 mA cm(-2). Further analysis suggests that the intrinsic defect is the active sites for CO2RR, instead of the Fe-N-4 center. Density functional theory calculations reveal that the Fe-N-4 coupled intrinsic defect exhibits a reduced energy barrier for CO2RR and suppresses the hydrogen evolution activity. The high intrinsic activity, coupled with fast electron-transfer capability and abundant exposed active sites, induces excellent electrocatalytic performance.