Ionic Liquids as Interfacial Media for Metal-Free Electrochemical CO 2 Reduction in Water

High Resolution Image Download MS PowerPoint Slide The electrochemical carbon dioxide reduction reaction (CO 2 RR) in water offers a sustainable pathway to mitigate carbon emissions while generating value-added chemicals. Most conventional CO 2 RR systems rely heavily on metal-based catalysts. Beyond traditional metal-based catalyst design, attention has increasingly shifted to understanding how the electrochemical microenvironment and the electrode–electrolyte interface influence CO 2 RR. Ionic liquids (ILs), widely regarded as green solvents, have previously been employed as electrolytes or cocatalysts in metal-catalyzed systems. Yet, the ability of ILs to facilitate CO 2 RR at metal-free interfaces in aqueous media remains underexplored. Here, we demonstrate that ILs polarize CO 2 and facilitate CO 2 electrochemical response at a glassy carbon interface under aqueous conditions, while simultaneously functioning as electrolytes. Spectroscopic, electrochemical, and computational analyses reveal that ILs interact with CO 2, thereby increasing its dipole moment. This interaction suggests a favorable environment for CO 2 polarization that correlates with the observed electrochemical response. The response efficiency depends on the chemical identity of the ILs, highlighting the tunability of this IL-based system. These findings redefine the functional role of ILs in CO 2 RR, establishing IL-induced molecular polarization as a potential strategy for promoting the reactivity of otherwise inert molecules. More broadly, this work introduces IL-driven dipole modulation as a general approach for enabling reactivity of nonpolar small molecules, with implications for sustainable chemical synthesis.