Controllable surfactant-directed zeolitic-imidazolate-8 growth on swollen 2D zeolites

Abstract

To meet society’s need for more and more specialized materials, this work focuses on the preparation of porous metal–organic framework (MOF)–zeolite hybrid materials based on two 2D zeolites, namely, IPC-1P (Institute of Physical Chemistry - 1 Precursor) and the metal–organic framework ZIF-8 (Zeolitic Imidazolate Framework-8). Using the previously well-established assembly–disassembly–organization–reassembly method, the zeolite was (i) synthesized, (ii) hydrolyzed to a layered zeolite, (iii) the interlayer distance was increased using the swelling agent cetyltrimethylammonium chloride, and (iv) nanocrystals of ZIF-8 were grown stepwise on the zeolite surface but predominantly at the edges of the crystallites where the openings to the interlayer region are located. This selective MOF growth and attachment was facilitated by a combination of intercalation of the metal ions and the swelling agent between the zeolite layers. The influence of the solvent and the number of additional steps on the ZIF-8 growth on the zeolite was systematically investigated, and the synthesis protocol was successfully adapted to a further two-dimensional silicate RUB-18 (Ruhr-Universität Bochum - 18). This paves the way toward the controlled preparation of more MOF–zeolite hybrid materials, which might provide interesting properties for future applications.