▎ 摘　　要

CO2 capture and sequestration is an energy-intensive industry to deal with the global greenhouse effect. Membrane separation is considered a cost-effective method to mitigate the emission of CO2. Though good separation performance and stability have been reported, supported ionic liquid membranes are still not widely applied for CO2 separation due to the high cost. As a novel analogous solvent to ionic liquid, deep eutectic solvent retains the excellent merits of ionic liquid and is cheap with facile preparation. Herein, a highly CO2-philic separation membrane is constructed by nanoconfining choline chloride/ethylene glycol (ChCl/EG) deep eutectic solvent into graphene oxide nanoslits. Molecular dynamic simulation results indicate that the confinement makes a difference to the structure of the nanoconfined ChCl/EG liquid from their bulk, which remarkably facilitates CO2 transport. By tuning the molar ratio of ChCl/EG and thickness of the membrane, the resultant membrane exhibits outstanding separation performance for CO2 with excellent selectivity over other light gases, good long-term durability, and thermal stability. This makes it a promising membrane for selective CO2 separation.