How is CO absorbed into a deep eutectic solvent?

Deep eutectic solvents show great potential as CO absorbents, which is highly desirable for the sustainable development of CO reduction and prevention of global climate changes. Ab initio molecular dynamics simulations in the isothermal-isobaric ensemble at pressures of 1 MPa and 5 MPa and at the corresponding experimental density are carried out to investigate the CO absorption in choline chloride: ethylene glycol deep eutectic solvent. Based on the structural analysis, there is a strong anion and hydrogen bond donor effect and a minor cation effect on CO solvation in the solvent. Instead of cooperation, a competition between the anion and the hydrogen bond donor (ethylene glycol) for the interaction with CO is indicated. While at a lower pressure, the ethylene glycol-CO interaction dominates, at a higher pressure, it is the chloride-CO interaction. Thus, it is possible to use the same advantages within the deep eutectic solvent as the CO absorbent as in ionic liquids, but in the hydrogen bond, a donor can be exploited.