A CO2 adsorption dominated carbon defect-based electrocatalyst for efficient carbon dioxide reduction

Abstract

Controlling interface gas adsorption properties of carbon materials is a prerequisite for exploiting efficient metal-free electrocatalysts but it is usually ignored. Herein, we fabricate a hierarchical porous carbon electrocatalyst with defect (DHPC) by carbon thermal reaction, which shows good CO₂RR selectivity and stability. The experimental results indicated that the carbon defect might be the active center for efficient CO₂RR performance because it can serve as a Lewis base center and provide an appropriate CO₂-chemisorption energy. Moreover, X-ray absorption spectroscopy (XAS) results demonstrated that the carbon defect can induce a reversible carbon–carbon interface with CO₂ gas molecule, which would be further strengthened under an applied bias. Besides, the ¹³CO₂ isotope labelling experiment and density functional theory calculations further confirmed that the high CO₂RR performance of DHPC comes from its intrinsic defect sites. This study not only provides a new avenue and concept to design CO₂RR electrocatalysts but also, to some extent, indicates a possible catalytic mechanism for carbon defect-based electrocatalysts.