Zeolitic Imidazolate Frameworks (ZIFs) Porous Liquids for CO 2 /N 2 Sorption

Porous liquids (PLs), as a new type of liquid porous material that combines the permanent pores of porous solid adsorbents and the continuous flowing ability of liquid absorbents, have shown great application prospects in the field of gas capture and separation. At present, PLs still have many disadvantages in stability, viscosity, melting point, and CO 2 /N 2 separation performance, which have become limitations on further industrial application. In this study, Zeolitic Imidazolate Frameworks ZIF‐67 and ZIF‐8 were prepared as pore generators, respectively. Eight different sterically hindered solvents were selected to prepare Type III ZIFs PLs. Five PLs with better stability were optimized and screened, and the capture and separation performance of CO 2 and N 2 was evaluated in detail. ZIF‐67%–1%‐PL with 1‐ethyl‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIm][NTf 2 ]) as the sterically hindered solvent has the highest CO 2 sorption capacity of 0.83 mmol/g at 10.24 bar and 298 K, demonstrating good CO 2 /N 2 separation performance, and has the advantages of low viscosity (25°C, 0.034 Pa s), low melting point (−15.67°C), and high thermal stability (25 ∼ 350°C). The idea of this work provides a new perspective for the design of PLs and the application of CO 2 /N 2 sorption separation.