Park, Jihyun Chae, Younghyun Lee, Chanwoo Kwon, Gyeongjin Lee, Woong Hee Jeon, Hyo Sang Cho Jinhan Won, Da hye Koh Jai Hyun 2025-07-29T02:00:39Z 2025-07-29T02:00:39Z 2025-07-28 2025-07 https://pubs.kist.re.kr/handle/201004/152860 This study investigates how the molecular structure of imidazolium ionomers with linear alkyl side chains (CnH2n+1 where n = 1, 4, 10, 16) modulates interfacial microenvironments in the Ag-catalyzed CO2 reduction reaction (CO2RR). Variations in side chain length and molecular weight establish structure-performance relationships that link hydrophobicity and ion transport to activity and selectivity. Longer side chains suppress hydrogen evolution and enhance the CO2RR, with the n-hexadecyl ionomer achieving the highest Faradaic efficiency for the CO2RR of 90.1% in a two-compartment cell. Incorporation of this ionomer in a cation-exchange membrane-based membrane electrode assembly achieves selective CO production with a partial current density exceeding 100 mA cm(-2), outperforming a commercial benchmark. Controlled studies under lean and acidic electrolytes reveal that the ionomer maintains local alkaline environments by restricting the interfacial water and proton transport. These findings provide molecular-level insights into ionomer function and design principles for selective CO2RR in practical electrolyzers. English American Chemical Society Ionomer Side Chains Modulate Interfacial Microenvironments for Selective CO2 Electrolysis Article 10.1021/acscatal.5c03583 1 ACS Catalysis, v.15, no.14, pp.12222 - 12230 ACS Catalysis 15 14 12222 12230 N scie scopus 001532597400001 2-s2.0-105009816431 Chemistry, Physical Chemistry CARBON-DIOXIDE REDUCTION ELECTROREDUCTION CO2 reduction Ag catalyst ionomer microenvironment MEA