Chinese Journal of Catalysis ›› 2026, Vol. 85: 96-105.DOI: 10.1016/S1872-2067(26)64963-7

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Anion surfactant-tailored electric double-layer: Toward higher faradaic efficiency in acidic CO2 electrolysis

Zheng Zhanga,b, Lei Tanga, Yihua Zhub, Wangxin Gea(), Hongliang Jianga(), Chunzhong Lia,b()   

  1. a Key Laboratory for Ultrafine Materials of Ministry of Education, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China
    b Shanghai Engineering Research Center of Hierarchical Nanomaterials, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
  • Received:2025-09-08 Accepted:2025-11-10 Online:2026-06-18 Published:2026-05-18
  • Contact: *E-mail: gwx@ecust.edu.cn (W. Ge),
    jhlworld@ecust.edu.cn (H. Jiang),
    czli@ecust.edu.cn/czlilab@sjtu.edu.cn (C. Li).
  • Supported by:
    National Natural Science Foundation of China(22222804);National Natural Science Foundation of China(U22B20143);National Key R&D program(2022YFB3808400);Science and Technology Commission of Shanghai Municipality(22dz1205900);and the Shanghai Municipal Science and Technology Major Project

Abstract:

Electric double-layer (EDL) structure critically influences electrocatalytic kinetics and performance, yet mechanistic understanding of anion-mediated EDL modulation remains limited, particularly in acidic CO2 electrolysis. Here, we demonstrate that the prototypical anionic surfactant sodium dodecyl sulfate (SDS) induces EDL expansion and reconstruct interfacial hydrogen-bonding (H-bond) networks, thereby suppressing the competitive hydrogen evolution reaction (HER) in acidic electrolytes, while achieving 94.1% CO Faradaic efficiency at 250 mA cm-2. Electrochemical kinetics analysis identifies that SDS-induced disruption of interfacial H-bond networks impedes proton transport kinetics, thereby suppressing HER in acid. Integrative electrolyte characterizations combined with in situ spectroscopic analysis revealed that the widening of the EDL stems from Lewis acid-base interactions between SDS and K+. Further, the introduction of SDS modulates interfacial water dissociation activity, thereby facilitating the hydrogenation pathway from CO2 to *COOH. These findings establish a rational electrolyte design strategy for manipulating EDL to enhance acidic CO2 electrolysis performance.

Key words: Acidic CO2 electrolysis, Anionic surfactants, Electrolyte regulation, Electric double-layer microenvironment, In-situ spectroscopy