Water‐stable imidazole‐based ionic liquid‐functionalized metal–organic framework for efficient C 2 H 2 / CO 2 separation

Abstract Efficiently sieving C 2 H 2 from CO 2 remains a significant challenge due to their similar molecular sizes and physical properties. To address this issue, we developed a novel strategy for selectively sieving C 2 H 2 from CO 2 by functionalizing metal–organic frameworks (MOFs) with imidazole‐based ionic liquids (ILs). The constructed model material, MIL‐101‐Cr‐EMImCl (EMImCl = 1‐ethyl‐3‐methylimidazolium chloride), exhibits both a high C 2 H 2 capacity (94.2 cm 3 g −1 at 298 K and 1.0 bar) and outstanding C 2 H 2 IAST selectivity over CO 2 (2.43), which are 1.7 and 1.5 times higher than those of the control (MIL‐101‐Cr), respectively. This highlights the critical role of IMIL functionalization in enhancing the C 2 H 2 /CO 2 separation performance of MOFs. This work not only positions the IL‐functionalized MIL‐101‐Cr‐EMImCl as a promising candidate for efficient C 2 H 2 /CO 2 separation, but also introduces a novel strategy for developing advanced C 2 H 2 /CO 2 separation adsorbents through the incorporation of ILs into porous materials.