Authors: Qiyou Wang, Yuxiang Liu, Yao Tan, Yusen Xiao, Liling Liao, Junwei Fu, Shilin Zhao, Hongmei Li, Cheng‐Wei Kao, Ting‐Shan Chan, Haiqing Zhou, Feng Li, Liyuan Chai, Zhang Lin, Kang Liu, Min Liu
Published: 2025-03-11
Source: Full article
AbstractAcidic CO2 electroreduction reaction (CO2RR) garners significant attention as a promising approach for cutting carbon density, as it effectively mitigates CO2 loss by suppressing carbonate species formation. Unfortunately, achieving efficient multi‐carbon products (C2+) production in acidic media remains challenging due to two main limitations: weak CO adsorption on Cu sites and competitive H* adsorption caused by the high concentration protons (H+). To overcome these challenges, a cation‐anion‐modification strategy is proposed using an ionic liquid layer—1‐Propyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([PMIM][NTf2])—on Cu surface. Density functional theory calculations predict that PMIM+ cation strengthens *CO adsorption through quasi‐hydrogen bonding, while NTf2− anion creates a hydrophobic environment, effectively reducing H* coverage and promoting *CO adsorption. Resistance tests demonstrate that [PMIM][NTf2] modification effectively reduced proton diffusion. Attenuated total reflection infrared spectroscopy (ATR‐IR) confirmed the reinforcement of *CO adsorption on the modified Cu surface. As a result, the [PMIM][NTf2] modified Cu catalyst achieved a remarkable partial current density of ≈640 mA cm−2 for C2+ products, with exceptional faradaic efficiency of 80.1% and durability of ≈20 h at a partial current density exceeding 500 mA cm−2 in a flow cell. This study highlights the potential of cation‐anion modification strategies for significantly enhancing CO2RR in acidic media.