Ionomer-directed reaction pathway for CO₂ electroreduction

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Electrochemical CO2 reduction reaction (CO2RR) converts emissions into fuels/chemicals.
• Catalyst and local microenvironment dictate CO2RR selectivity and stability.
• Ionomers, previously passive binders, are now key microenvironment regulators.

Purpose of the Study:

• Address the underappreciated role of low ionomer content in CO2RR catalyst layers.
• Elucidate the structure-property-function relationships of ionomers in CO2RR.
• Provide design principles for next-generation CO2 conversion electrodes.

Main Methods:

• Review of structural diversity and physicochemical properties of proton- and anion-exchange ionomers.
• Analysis of solvent-controlled dispersion and film formation effects on ionomer morphology.
• Discussion of ionomer configuration control over CO2RR pathways.

Main Results:

• Ionomer structure critically influences ion transport and interfacial reactions.
• Dispersion and morphology impact mass transport and local hydration.
• Ionomer configuration affects reactant diffusion, intermediate adsorption, and hydrogen bonding.

Conclusions:

• Ionomers are vital for efficient, selective, and durable CO2RR.
• Future work should focus on nanoscale characterization, ionomer durability, and co-design.
• Principles are applicable to various electrocatalytic reactions beyond CO2RR.