Intrinsic Carbon-Defect-Driven Electrocatalytic Reduction of Carbon Dioxide

Heteroatom-doped carbon catalysts are currently attracting enormous attention due to their excellent performance for the electrocatalytic carbon dioxide reduction reaction (ECRR). However, the origin of the high catalytic activities of doped-carbon materials remains obscure with the role of intrinsic carbon defects in promoting the ECRR receiving little attention despite the abundance of carbon defects in all carbon-based catalytic materials. Herein, a positive correlation is reported between the ECRR performance of carbon-based catalysts and the content of intrinsic carbon defects contained within these catalysts. Further, it is demonstrated that defective porous carbon catalysts containing no active heteroatom dopants also show excellent catalytic performance for ECRR. C K-edge near edge X-ray absorption fine structure measurements and density functional theory calculations reveal that sp² defects (octagonal and pentagonal) rather than edge defects are key to the excellent ECRR activity of the defective porous carbon catalysts. This work thus makes an important contribution to the understanding of the origin of the ECRR activity of carbon-based catalysts, with heteroatom doping perhaps being less important than previously envisaged for achieving a high ECRR performance.