Catalytic Peculiarity of Electrode/Polyelectrolyte Interfaces Toward CO

A prominent feature of modern electrochemical technologies, such as fuel cells, water electrolysis, and CO 2 electrolysis, is to employ polyelectrolytes instead of liquid electrolytes.This shift not only mitigates risks like corrosion and leaks associated with liquid electrolytes, but also facilitates the construction of zero-gap membrane electrode assembly (MEA) devices.In the MEA setups, the anode and cathode are tightly pressed against a micron-thick polyelectrolyte membrane, which can significantly reduce internal resistance and enhance energy conversion efficiency.Electrocatalysis forms the scientific bedrock underpinning these electrochemical technologies.Currently, electrocatalysis studies are primarily conducted in traditional liquid electrolytes.However, disparities between electrolyte types induce that insights from fundamental research may not directly apply to practical MEA devices.Therefore, there is a pressing need to investigate the structural and catalytic properties of the electrode/polyelectrolyte interface directly.Yet, the zero-gap configuration of MEA devices restricts the use of conventional research methods like three-electrode testing and in-situ spectroscopies, hindering exploration of catalytic behaviors and reaction details at the electrode/polyelectrolyte interface.Despite efforts in the literature [1,2] , investigating electrocatalytic behavior and mechanisms at the pure electrode/polyelectrolyte interface remains challenging.To address these issues, Zhuangs group proposed a versatile approach for studying electrode/polyelectrolyte interfacial catalysis [3] (J. Am.Chem.Soc.2024, 146, 17377) .Their method involves using a working electrode coated with a thin layer of anion-exchange membrane together with a liquid electrolyte containing large-sized organic cations (Fig. 1(a)).This setup allows gas reactants like CO 2 to diffuse through the polyelectrolyte ad-layer while preventing liquid electrolyte crossover, enabling both regular three-electrode testing and attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) measurements.To validate their approach, they examined Au-catalyzed