Synergistic Effects of the Electric Field Induced by Imidazolium Rotation and Hydrogen Bonding in Electrocatalysis of CO.

The roles of the ionic liquid (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF]), and water in controlling the mechanism, energetics, and electrocatalytic activity of CO reduction to CO on silver in nonaqueous electrolytes were investigated. The first electron transfer occurs to CO at reduced overpotentials when it is trapped between the planes of the [EMIM] ring and the electrode surface due to cation reorientation as determined from voltammetry, in situ surface-enhanced Raman spectroscopy, and density functional theory calculations. Within this interface, water up to 0.

Key Experimental Considerations When Evaluating Functional Ionic Liquids for Combined Capture and Electrochemical Conversion of CO.

Ionic liquids (ILs) are considered functional electrolytes for the electrocatalytic reduction of CO (ECOR) due to their role in the double-layer structure formation and increased CO availability at the electrode surface, which reduces the voltage requirement. However, not all ILs are the same, considering the purity and degree of the functionality of the IL. Further, there are critical experimental factors that impact the evaluation of ILs for ECOR including the reference electrode, working electrode construction, cosolvent selection, cell geometry, and whether the electrochemical cell is a single compartment or a divided cell.

Understanding the Electrode-Electrolyte Interfaces of Ionic Liquids and Deep Eutectic Solvents.

Developing unconventional electrolytes such as ionic liquids (ILs) and deep eutectic solvents (DESs) has led to remarkable advances in electrochemical energy storage and conversion devices. However, the understanding of the electrode-electrolyte interfaces of these electrolytes, specifically the liquid structure and the charge/electron transfer mechanism and rates, is lacking due to the complexity of molecular interactions, the difficulty in studying the buried interfaces with nanometer-scale resolution, and the distribution of the time scales for the various interfacial events. This Feature Article outlines the standing questions in the field, summarizes some of the exciting approaches and results, and discusses our contributions to probing the electrified interfaces by electrochemical impedance spectroscopy (EIS), surface-enhanced Raman spectroscopy (SERS), and neutron reflectivity (NR).

Tailoring Electrochemical CO Reduction on Copper by Reactive Ionic Liquid and Native Hydrogen Bond Donors.

Electrochemical CO reduction (CO RR) on copper (Cu) shows promise for higher-value products beyond CO. However, challenges such as the limited CO solubility, high overpotentials, and the competing hydrogen evolution reaction (HER) in aqueous electrolytes hinder the practical realization. We propose a functionalized ionic liquid (IL) which generates ion-CO adducts and a hydrogen bond donor (HBD) upon CO absorption to modulate CO RR on Cu in a non-aqueous electrolyte.

A Bifunctional Ionic Liquid for Capture and Electrochemical Conversion of CO to CO over Silver.

Electrochemical conversion of CO requires selective catalysts and high solubility of CO in the electrolyte to reduce the energy requirement and increase the current efficiency. In this study, the CO reduction reaction (CORR) over Ag electrodes in acetonitrile-based electrolytes containing 0.1 M [EMIM][2-CNpyr] (1-ethyl-3-methylimidazolium 2-cyanopyrolide), a reactive ionic liquid (IL), is shown to selectively (>94%) convert CO to CO with a stable current density (6 mA·cm) for at least 12 h.