Tunable CO 2 Adsorbents by Mixed-Linker Synthesis and Postsynthetic Modification of Zeolitic Imidazolate Frameworks

Joshua A. Thompson, Nicholas A. Brunelli, Ryan P. Lively, J. R. Johnson, Christopher W. Jones, Sankar Nair

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120 Scopus citations


The incorporation of accessible amine functionality in zeolitic imidazolate frameworks (ZIFs) is used to improve the adsorption selectivity for CO 2/CH4 gas separation applications. Two synthetic approaches are described in this work to introduce functionality into the ZIF: (i) mixed-linker ZIF synthesis with 2-aminobenzimidazole as a substitution linker and (ii) postsynthetic modification of a mixed-linker ZIF with ethylenediamine. Using 2-aminobenzimidazole, a linker with a primary amine functional group, substitution of the ZIF-8 linker during synthesis allows for control over the adsorption properties while maintaining the ZIF-8 structure with up to nearly 50% substitution in the mixed-linker ZIF framework, producing a material with tunable pore size and amine functionality. Alternatively, postsynthetic modification of a mixed-linker ZIF containing an aldehyde functional group produces a ZIF material with a primary amine without detrimental loss of micropore volume by controlling the amount of functional group sites for modification. Both approaches using mixed-linker ZIFs yield new materials that show improvement in adsorption selectivity for the CO 2/CH4 gas pair over ZIF-8 and commercially available adsorbents as well as an increase in the heat of adsorption for CO2 without significant changes to the crystal structure. These results indicate that tuning the surface properties of ZIFs by either mixed-linker synthesis and/or postsynthetic modification may generate new materials with improved gas separation properties, thereby providing a new method for tailoring metal-organic frameworks. © 2013 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)8198-8207
Number of pages10
JournalThe Journal of Physical Chemistry C
Issue number16
StatePublished - Apr 16 2013
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): KUS-Il-011-21
Acknowledgements: This work was supported by King Abdullah University of Science and Technology under Award KUS-Il-011-21.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


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