Abstract
Understanding how solvent composition governs competitive CO2 chemisorption within solvents is essential for the rational design of solvents for CO2 capture. In this work, we combine density functional theory (DFT), classical molecular dynamics (cMD), and microkinetic modeling to investigate CO2 chemisorption in choline-imidazolate based systems containing different alkanolamine hydrogen bond donors (HBDs): monoethanolamine (MEA), diethanolamine (DEA), and methyldiethanolamine (MDEA). By systematically characterizing the thermodynamics, kinetics and liquid structure influence, our results show that within these systems, choline is the preferred CO2-binding site unless a HBD is present. Accordingly, the MEA system shifts almost entirely to amine-centered carbamate formation, the DEA system retains carbamate dominance but with stronger competition from choline-centered capture, and the MDEA system which additionally includes water shifts back toward choline-centered carbonate together with a competitive water-assisted bicarbonate pathway. The findings illustrate how CO2 chemisorption in multicomponent liquids is controlled by a combination of intrinsic reaction thermodynamics, liquid-structure, and CO2 concentration. More broadly, this work provides insights that will facilitate molecular-level design of solvents for CO2 uptake and regeneration.