Confinement of Ionic Liquids in Nanocages: Tailoring the Molecular Sieving Properties of ZIF‐8 for Membrane‐Based CO2 Capture. Issue 51 (30th October 2015)

• Record Type: Journal Article
• Authors: Ban, Yujie; Li, Zhengjie; Li, Yanshuo; Peng, Yuan; Jin, Hua; Jiao, Wenmei; Guo, Ang; Wang, Po; Yang, Qingyuan; Zhong, Chongli; Yang, Weishen
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 51(2015)
• Page Start: 15483
• Page End: 15487
• Publication Date: 2015-10-30
• Subjects: CO2 capture -- confinement -- ionic liquids -- molecular sieving -- ZIF‐8; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201505508
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Fine‐tuning of effective pore size of microporous materials is necessary to achieve precise molecular sieving properties. Herein, we demonstrate that room temperature ionic liquids can be used as cavity occupants for modification of the microenvironment of MOF nanocages. Targeting CO2 capture applications, we tailored the effective cage size of ZIF‐8 to be between CO2 and N2 by confining an imidazolium‐based ionic liquid [bmim][Tf2 N] into ZIF‐8's SOD cages by in‐situ ionothermal synthesis. Mixed matrix membranes derived from ionic liquid‐modified ZIF‐8 exhibited remarkable combinations of permeability and selectivity that transcend the upper bound of polymer membranes for CO2 /N2 and CO2 /CH4 separation. We observed an unusual response of the membranes to varying pressure, that is, an increase in the CO2 /CH4 separation factor with pressure, which is highly desirable for practical applications in natural gas upgrading. Abstract : Filling the cavity : A room temperature ionic liquid (IL) was incorporated into ZIF‐8 nanocages by ionothermal synthesis, reducing the effective cage size of ZIF‐8 and enabling molecular sieving of CO2 over bulky N2 and CH4 .