Efficient Electrocatalytic CO₂ Reduction Driven by Ionic Liquid Buffer-Like Solutions.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Electrocatalytic reduction of carbon dioxide (CO2) is crucial for sustainable energy solutions.
• Ionic liquids (ILs) offer unique properties for enhancing electrochemical reactions.
• Developing efficient CO2 reduction catalysts is an ongoing research challenge.

Purpose of the Study:

• To investigate the electrocatalytic performance of gold electrodes in an aqueous electrolyte containing an ionic liquid for CO2 reduction.
• To assess the selectivity and efficiency of CO production.
• To understand the role of the ionic liquid and bicarbonate in the electrocatalytic process.

Main Methods:

• Electrocatalysis experiments were conducted using commercially available gold electrodes.
• An electrolyte composed of an ionic liquid, 1-n-butyl-2,3-dimethylimidazolium acetate ([BMMIm][OAc]), and DMSO was employed.
• CO2 absorption, overpotential, and faradaic efficiency for CO production were measured.

Main Results:

• Electrocatalysis of CO2 reduction occurred at low overpotentials (-0.9 V vs. Ag/AgCl).
• High selectivity for CO production was achieved, with a 58% faradaic efficiency at -1.6 V vs. Ag/AgCl.
• The electrolyte absorbed a significant amount of CO2 (0.43 mol CO2 per mol IL) at atmospheric pressure, forming bicarbonate.

Conclusions:

• The ionic liquid ([BMMIm][OAc]) and bicarbonate in the electrolyte enhance CO2 electroreduction.
• Stabilization of CO2 radical anions by imidazolium cations and buffer-like effects of bicarbonate contribute to efficient catalysis.
• This system demonstrates a promising approach for selective CO production from CO2 electroreduction.