Tailoring Product Selectivity in Electrochemical CO2 Reduction with Polyampholyte Ionomers

Electrochemical CO₂ reduction (CO₂R) is a promising method for producing sustainable chemicals in energy conversion. In CO₂R, ionomers have been regarded as supplementary components for binding catalysts. However, recent studies show that ionomers influence product selectivity by modifying the electrode microenvironment. Nevertheless, commercial ionomers exhibit significant differences in the structure of their backbone and functional groups, making it difficult to explain selectivity based on structure. This study uses a polyampholyte ionomer to investigate selectivity variations based on structure. Polyampholytes are polymers that contain both cationic and anionic monomers, where the cationic part was designed with an imidazolium group to enhance CO₂ solubility, and the anionic part contained a functional group to modulate hydrophobicity. Additionally, adjusting the monomer ratio regulated the overall charge of the ionomer, and the resulting selectivity changes were examined.