Efficient electrochemical reduction of CO2 to CO by soft functional materials

TL;DR

This paper demonstrates a new ionic liquid that significantly enhances the electrochemical reduction of CO2 to CO, achieving high current density and efficiency on a commercial Ag electrode, supported by theoretical insights.

Contribution

The study introduces a novel ionic liquid that improves CO2 reduction efficiency and current density, supported by theoretical analysis of IL-CO2 interactions.

Findings

Current density up to 50.8 mA cm-2 with 90.6% Faradaic efficiency.

IL interacts with CO2 to lower activation energy via orbital interactions.

Theoretical calculations confirm IL-CO2 complex formation facilitates reduction.

Abstract

Electrochemical reduction of CO2 to CO is a promising strategy. However, achieving high Faradaic efficiency with high current density using ILs electrolyte remains a challenge. In this study, the IL N octyltrimethyl 1,2,4 triazole ammonium shows outstanding performance for electrochemical reduction of CO2 to CO on the commercial Ag electrode, and the current density can be up to 50.8 mA cm-2 with a Faradaic efficiency of 90.6%. The current density of CO is much higher than those reported in the ILs electrolyte. In addition, the density functional theory calculation further proved that IL interacts with CO2 to form IL CO2 complex which played a key role in reducing the activation energy of CO2. According to the molecular orbital theory, the electrons obtained from ILs was filled in the anti bonding orbit of the CO2, resulting in reducing the C=O bond energy. This work provides a new strategy to design novel ILs for high efficiency electrochemical reduction of CO2 to CO.