Iodine‐Mediated C─C Coupling in Neutral Flow Cell for Electrochemical CO2 Reduction

Carbon utilization efficiency is of vital importance for electrochemical CO2 reduction systems. Proton exchange membrane (PEM) electrolyzers using nonalkaline electrolytes can prevent CO2 crossover and increase carbon utilization efficiency, yet they suffer from unfavored C & horbar;C coupling and severe hydrogen evolution. Herein, an iodine-mediated approach to facilitate C & horbar;C coupling on Cu-based catalysts toward multi-carbon products in a neutral PEM electrolyzer is reported. By in situ constructing an I-modified Cu surface, the hydrogenation of *CO is promoted and the C & horbar;C coupling process progresses through the *CO-*COH pathway with a low energy barrier. A high Faradaic efficiency of approximate to 72% and a high partial current density of 575 mA cm(-2) are achieved for multi-carbon products. The present study demonstrates an efficient approach to developing advanced CO2 electrolyzers for high-value products with high efficiency.