A core-shell IL@MOF composite with ultra-high selectivity in multiple CO2 purification systems

Porous adsorbents are widely used for the adsorptive separation of carbon dioxide (CO 2 ) from gas mixtures, offering a promising solution to address both the energy crisis and environmental issues. However, developing highly efficient CO 2 selective adsorbents has been challenging due to the similar physicochemical properties of CO 2 and other gases. To overcome this challenge, we herein have developed a core–shell composite utilizing ionic liquids (ILs) and metal–organic frameworks (MOFs) based on the dissolution-diffusion mechanism. The unique solubility differences of ILs for various gas molecules, particularly their strong solubility for CO 2 , allow only CO 2 to be adsorbed while excluding other gases. As a result, the composite exhibits a remarkable separation selectivity for CO 2 /C 2 H 2 , CO 2 /CH 4 and CO 2 /N 2 . Breakthrough experiments have verified the outstanding performance of this core–shell composite in separating gas mixtures containing CO 2 impurities. Remarkably, this composite can be synthesized by a simple method, which is more practical for large-scale production.