Insight into the Microenvironments of the Metal–Ionic Liquid Interface during Electrochemical CO₂ Reduction

Abstract

Recently, many experimental and theoretical efforts are being intensified to develop high-performance catalysts for electrochemical CO 2 conversion. Beyond the catalyst material screening, it is also critical to optimize the surrounding reaction medium. From vast experiments, inclusion of room-temperature ionic liquid (RTIL) in the electrolyte is found to be beneficial for CO 2 conversion; however, there is no unified picture of the role of RTIL, prohibiting further optimization of the reaction medium. Using a state-of-the-art multiscale simulation, we here unveil the atomic origin of the catalytic promotion effect of RTIL during CO 2 conversion. Unlike the conventional belief, which assumes a specific intermolecular coordination by the RTIL component, we find that the promotion effect is collectively manifested by tuning the reaction microenvironment. This mechanism suggests the critical importance of the bulk properties (e.g., resistance, gas solubility and diffusivity, viscosity, etc.) over the detailed chemical variations of the RTIL components in designing the optimal electrolyte components, which is further supported by our experiments. This fundamental understanding of complex electrochemical interfaces will help in the development of more advanced electrochemical CO 2 conversion catalytic systems in the future.

Specific Cation Adsorption: Exploring Synergistic Effects on CO2 Electroreduction in Ionic Liquids

“…The majority of the studies published in this field have utilized Ag materials of varying morphology (planar surfaces, nanoparticles, nanowires, metal foams, etc.) as primary CO 2 RR catalysts in ILs, whereas other electrode materials have scarcely been studied …”

Insights into Carbon Dioxide Electroreduction in Ionic Liquids: Carbon Dioxide Activation and Selectivity Tailored by Ionic Microhabitat

“…This meanst hat electron transfer to the electrode surface in [Bmim][124Triz] is more facile, which can enhance the current density. [23] Additionally,p revious works presumed that the monolayer formed by ILs on the electrode surfacep layed ak ey role in CO 2 reduction and inhibiting H 2 formation on the cathode surface. We found that the resistance of the absorbed film on the cathode surface (R f )w as only 0.7 W cm À2 ,w hichs uggested that the reaction species could be easily transferred through the IL monolayer.T hese results provide sufficient support to the excellent performance of CO 2 electroreduction in the superbasicI L.…”

Electrolyte Effects on the Electrochemical Reduction of CO2

“…Rosen et al [92] investigated the limitations of water addition to ionic liquids and show that additions of up to 30 mol/liter of water to EMIm-BF 4 do not significantly influence amount of hydrogen Catal., 2018, 8, 2420-2427. [90] Copyright 2018 American Chemical Society. [97] produced.…”