Cation Enrichment Promotes High‐rate CO Electroreduction to C2+ Liquid Products

Abstract Electrochemical reduction of CO into valuable multicarbon (C 2+ ) liquids is crucial for reducing CO 2 emissions and advancing clean energy, yet mastering efficiency and selectivity in this process remains a tough challenge. Herein, we employ a surface‐modification strategy using electrochemically active polymeric 1,4,5,8‐naphthalenete‐tracarboxylic dianhydride (PNTCDA)‐modified copper nanosheets (PM−Cu) to rearrange reactive species in the electric double layer, where the PNTCDA triggers a distinctive enolization that anchor potassium ions (K + ) onto the cathode surface under reduction condition. Electrochemical analysis and computational simulations revealed that this approach fine‐tunes K + distribution in the double layer, making the dehydration of hydrated K + more efficient and reducing active water molecules at the interface, thus inhibiting the hydrogen evolution reaction while concurrently promoting CO reduction via enhanced C−C coupling. For the first time, the PM−Cu catalyst demonstrates ampere‐scale current densities with the exclusive selectivity of a C 2+ liquid product yield exceeding 90 %. Thus, by tailoring the local microenvironment with electrochemically active organics, it is possible to modulate CO reduction, improve sustainable energy storage, and increase industrial carbon utilization.