Effect of Carbon Doping on CO<sub>2</sub>‐Reduction Activity of Single Cobalt Sites in Graphitic Carbon Nitride
Peipei Huang, Jiahao Huang, Junying Li, Lei Zhang, Jie He, Christine A. Caputo, Anatoly I. Frenkel, Gonghu Li
Abstract
Abstract Single‐atom catalysts have demonstrated interesting activity in a variety of applications. In this study, we prepared single Co 2+ sites on graphitic carbon nitride (C 3 N 4 ), which was doped with carbon for enhanced activity in visible‐light CO 2 reduction. The synthesized materials were characterized with a variety of techniques, including microscopy, X‐ray powder diffraction, UV‐vis spectroscopy, infrared spectroscopy, photoluminescence spectroscopy, and X‐ray absorption spectroscopy. Doping C 3 N 4 with carbon was found to have profound effect on the photocatalytic activity of the single Co 2+ sites. At relatively low levels, carbon doping enhanced the photoresponse of C 3 N 4 in the visible region and improved charge separation upon photoactivation, thereby enhancing the photocatalytic activity. High levels of carbon doping were found to be detrimental to the photocatalytic activity of the single Co 2+ sites by altering the structure of C 3 N 4 and generating defect sites responsible for charge recombination.