Tailoring Dual-Functional Ionomers for Efficient CO₂ Electroreduction to Ethanol

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrochemical CO2 reduction reaction (CO2RR) is a promising route for sustainable alcohol production and energy storage.
• Achieving high efficiency and long-term stability in CO2-to-ethanol conversion remains a significant challenge.

Purpose of the Study:

• To develop a functionalized ionomer that enhances the performance of CO2RR for efficient ethanol production.
• To engineer the ionomer microenvironment to improve CO2 and water adsorption and facilitate ethanol formation.

Main Methods:

• Synthesis of a novel poly[2-acrylamido-2-methylpropanesulfonic acid-co-(2-methyl-2-(trifluoromethylsulfonamido)propyl methacrylate)-co-(1-vinyl-3-butylimidazolium hexafluorophosphate)] ionomer (PAMV).
• Fabrication of PAMV-based gas diffusion electrodes using commercial copper nanoparticles.
• Electrochemical testing in bicarbonate electrolyte to evaluate ethanol faradaic efficiency (FE) and cathodic energy efficiency (CEE).
• Long-term electrolysis and theoretical studies to understand the mechanism.

Main Results:

• Achieved 57.3% ethanol FE and 29.3% CEE using PAMV-Cu electrodes, a ~4-fold improvement over commercial Nafion.
• Demonstrated long-term stability, inhibiting salt precipitation and hydrogen evolution.
• Experimental and theoretical data indicated that PAMV modulates interfacial mass transfer and promotes CO intermediate formation.

Conclusions:

• The developed ionomer microenvironment engineering strategy effectively boosts CO2RR to ethanol.
• PAMV offers a robust and convenient solution for efficient CO2 conversion to value-added products.
• This approach provides a novel pathway for modulating electrocatalytic reactions.