Angulated Edge Intrinsic Defect in Carbon as Bridge-Adsorption Site of CO for Highly Efficient CO2 Electroreduction

Abstract

Pervasive intrinsic defects have a significant impact on the electrocatalytic activity of carbon materials, but previous research has focused on the effects of topological structures exclusively. Herein, a compelling demonstration of the pivotal role played by the positions and spatial arrangement of intrinsic defects in determining their efficacy for electrochemical CO2 reduction (ECR) is presented. Theoretical calculations reveal a substantial reduction in energy barriers for *COOH formation at intrinsic defects positioned along the edges while hindering the transformation of *COOH to *CO in the ECR process. To address this issue, a sea urchin-like nanocarbon (F1100) is designed, which provides adjacent intrinsic defects located in V-type arranged carbon nanorods. The angulated edge intrinsic defects facilitate the bridge adsorption of carbon monoxide (CO), as confirmed by in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy, thereby enhancing the specific activity of ECR on intrinsic carbon defects. In a 0.1 m potassium bicarbonate (KHCO3) solution, F1100 achieves a FECO of 95.0%, while in an ionic liquids-based electrolyte, a current density of 90.0 mA cm−2 is obtained with nearly complete conversion of CO2 to CO in an H-type cell.