Accelerating the Reaction Kinetics of CO<sub>2</sub> Reduction to Multi‐Carbon Products by Synergistic Effect between Cation and Aprotic Solvent on Copper Electrodes
Xiaowan Bai, Chaojie Chen, Xunhua Zhao, Yehui Zhang, Yao Zheng, Yan Jiao
Abstract
Abstract Improving the selectivity of electrochemical CO 2 reduction to multi‐carbon products (C 2+ ) is an important and highly challenging topic. In this work, we propose and validate an effective strategy to improve C 2+ selectivity on Cu electrodes, by introducing a synergistic effect between cation (Na + ) and aprotic solvent (DMSO) to the electrolyte. Based on constant potential ab initio molecular dynamics simulations, we first revealed that Na + facilitates C−C coupling while inhibits CH 3 OH/CH 4 products via reducing the water network connectivity near the electrode. Furthermore, the water network connectivity was further decreased by introducing an aprotic solvent DMSO, leading to suppression of both C 1 production and hydrogen evolution reaction with minimal effect on *OCCO* hydrogenation. The synergistic effect enhancing C 2 selectivity was also experimentally verified through electrochemical measurements. The results showed that the Faradaic efficiency of C 2 increases from 9.3 % to 57 % at 50 mA/cm 2 under a mixed electrolyte of NaHCO 3 and DMSO compared to a pure NaHCO 3 , which can significantly enhance the selectivity of the C 2 product. Therefore, our discovery provides an effective electrolyte‐based strategy for tuning CO 2 RR selectivity through modulating the microenvironment at the electrode‐electrolyte interface.