Microhabitat mechanisms induced by cationic amino-functionalized ionic liquid electrolytes on CO2 electroreduction

KL Peng and SJ Zeng and HY Zhang and HY Jiang and GL Li and L Yuan and X Li and M Wang and XP Zhang, SEPARATION AND PURIFICATION TECHNOLOGY, 362, 131672 (2025).

DOI: 10.1016/j.seppur.2025.131672

Cationic-Functionalized ionic liquids (ILs) exhibit great potentials for CO2 electroreduction (CO2RR) due to wide electrochemical window, high conductivity and CO2 solubility. However, how the functionalized cations influence the CO2RR performance from the viewpoint of microscopic mechanism remains unclear. Herein, the cationic amino-functionalized IL (NH2C2mimBF4) and conventional IL (BmimBF4) were selected and investigated their effects on CO2RR performance by combing molecular dynamics simulation and density functional theory calculations. Compared with Bmim+, the NH2C2mim+ cation exhibits stronger electrostatic and dipole interactions with CO2, which could promote CO2 accumulation and activation, leading to higher current density and lower overpotential than that of Bmim+. However, the functionalized site of NH2C2mim+ shows an insufficient interaction with *COOH, strongly interacts with H2O and facilitate the occurrence of hydrogen evolution side reaction with a higher barrier of 0.074 eV than Bmim+, resulting in a low Faraday Efficiency (FE) of CO. Overall, the results not only demonstrated NH2C2mim+ enhances CO2 distribution and activization, but also emphasized that the interaction between ILs and *COOH, H2O should be considered, which is dominates the product FE. This work provides theoretical guidance for the design of new IL electrolytes.

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