Scalable synthesis of coordinatively unsaturated metal-nitrogen sites for large-scale CO2 electrolysis
Ji Wei Sun, Xuefeng Wu, Peng Fei Liu, Jiacheng Chen, Yuanwei Liu, Zhen Xin Lou, Jia Zhao, Hai Yang Yuan, Aiping Chen, Xue Lu Wang, Minghui Zhu, Sheng Dai, Hua Gui Yang
Abstract
Abstract Practical electrochemical CO 2 -to-CO conversion requires a non-precious catalyst to react at high selectivity and high rate. Atomically dispersed, coordinatively unsaturated metal-nitrogen sites have shown great performance in CO 2 electroreduction; however, their controllable and large-scale fabrication still remains a challenge. Herein, we report a general method to fabricate coordinatively unsaturated metal-nitrogen sites doped within carbon nanotubes, among which cobalt single-atom catalysts can mediate efficient CO 2 -to-CO formation in a membrane flow configuration, achieving a current density of 200 mA cm −2 with CO selectivity of 95.4% and high full-cell energy efficiency of 54.1%, outperforming most of CO 2 -to-CO conversion electrolyzers. By expanding the cell area to 100 cm 2 , this catalyst sustains a high-current electrolysis at 10 A with 86.8% CO selectivity and the single-pass conversion can reach 40.4% at a high CO 2 flow rate of 150 sccm. This fabrication method can be scaled up with negligible decay in CO 2 -to-CO activity. In situ spectroscopy and theoretical results reveal the crucial role of coordinatively unsaturated metal-nitrogen sites, which facilitate CO 2 adsorption and key *COOH intermediate formation.