Regulated Cu Diatomic Distance Promoting Carbon−Carbon Coupling During CO<sub>2</sub> Electroreduction
Hongxin Guan, Yu-Xiang Zhang, Wenjun Fan, Kang Yang, Guang Li, Sheng Chen, Laiquan Li, Jingjing Duan
Abstract
Abstract To address the bottle‐neck carbon‐carbon coupling issue during electrochemical carbon dioxide reduction (eCO 2 RR) to multicarbon (C 2+ ) products, this work develops an anion‐directed strategy (Cl − , NO 3 − , and SO 4 2− ) to regulate interatomic distance of Cu diatoms. In comparison to pristine Cu (with a typical Cu‐Cu distance of 2.53 Å), Cu‐boroimidazole frameworks (BIF)/SO 4 , NO 3 , and Cl material shows elongated diatomic distance of 3.90 Å, 4.21 Å, and 3.30 Å, respectively. Among them, the Cu‐BIF/Cl exhibits an outstanding eCO 2 RR performance with a Faradaic efficiency of 72.12% for C 2+ products and an industrial‐level current density of 539.0 mA cm −2 at −1.75 V versus RHE. Significantly, according to theoretical and in situ experimental investigation, the highly electronegative Cl − ion lifts d‐band center of Cu sites of Cu‐BIF/Cl, facilitating *CO adsorption with a low Gibbs free energy and its later dimerization overcoming a small energy barrier. In addition, this strategy to manipulate interatomic distance for diatomic catalysts, can also be adaptable to other reactions involving intermediate coupling and following the Langmuir‐Hinshelwood mechanism, such as carbon‐nitrogen coupling, nitrogen‐nitrogen coupling, etc.