A replacement strategy for regulating local environment of single-atom Co-SxN4−x catalysts to facilitate CO2 electroreduction
Jiajing Pei, Huishan Shang, Junjie Mao, Zhe Chen, Rui Sui, Xuejiang Zhang, Danni Zhou, Yu Wang, Fang Zhang, Wei Zhu, Tao Wang, Wenxing Chen, Zhongbin Zhuang
Abstract
Abstract The performances of single-atom catalysts are governed by their local coordination environments. Here, a thermal replacement strategy is developed for the synthesis of single-atom catalysts with precisely controlled and adjustable local coordination environments. A series of Co-S x N 4−x ( x = 0, 1, 2, 3) single-atom catalysts are successfully synthesized by thermally replacing coordinated N with S at elevated temperature, and a volcano relationship between coordinations and catalytic performances toward electrochemical CO 2 reduction is observed. The Co-S 1 N 3 catalyst has the balanced COOH*and CO* bindings, and thus locates at the apex of the volcano with the highest performance toward electrochemical CO 2 reduction to CO, with the maximum CO Faradaic efficiency of 98 ± 1.8% and high turnover frequency of 4564 h −1 at an overpotential of 410 mV tested in H-cell with CO 2 -saturated 0.5 M KHCO 3 , surpassing most of the reported single-atom catalysts. This work provides a rational approach to control the local coordination environment of the single-atom catalysts, which is important for further fine-tuning the catalytic performance.