Solubility‐Boosted Molecular Sieving‐Based Separation for Purification of Acetylene in Core–Shell IL@MOF Composites

Abstract Considering the small amount of CO 2 as a contaminant in industrial gas mixtures, developing CO 2 ‐selective adsorbents exhibit advantages in directly obtaining pure C 2 H 2 in one‐step to reduce the energy consumption. However, it is still a great challenge due to the essential molecular feature of C 2 H 2 , including the triple bond and high polarizability. Herein, a simple but effective CO 2 ‐facilitated transport strategy is presented to realize the overwhelming adsorption of CO 2 over C 2 H 2 by constructing core–shell composite structures using ionic liquid (IL) and metal‐organic framework (MOF). With the aid of excellent solubility of CO 2 in IL and almost total exclusion of C 2 H 2 , the obtained materials boost molecular sieving‐based separation of CO 2 /C 2 H 2 . Density functional theory calculations combining molecular dynamic simulations revealed the solution‐diffusion mechanism for CO 2 , which is rarely reported in solid adsorbents. Ideal adsorbed solution theory selectivity for CO 2 /C 2 H 2 with 1/1 and 1/3 volume ratios can reach over 10 4 and 4000 at 100 kPa with a high CO 2 uptake of 40.3 cm 3 g −1 , superior to those of the reported materials so far. More importantly, this solution‐based separation strategy can avoid the difficulty for precise control of the regulation of adsorbent structure, which may be beneficial to practical production.