S. Bals

Catalytic and molecular separation properties of Zeogrids and Zeotiles

J.A. Martens, J.W. Thybaut, J.F.M. Denayer, S. Pulinthanathu Sree, A. Aerts, M-F. Reyniers, V. Van Speybroeck, M. Waroquier, A. Buekenhoudt, I. Vankelecom, W. Buijs, J. Persoons, G.V. Baron, S. Bals, G. Van Tendeloo, G.B. Marin, P.A. Jacobs, C. Kirschhock
Catalysis Today
168, 17-27
2011
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Abstract 

Zeogrids and Zeotiles are hierarchical materials built from assembled MFI zeolite precursor units. Permanent secondary porosity in these materials is obtained through self assembly of nanoparticles encountered in MFI zeolite synthesis in the presence of supramolecular templates. Hereon, the aggregated species are termed nanoslabs. Zeogrids are layered materials with lateral spacings between nanoslabs creating galleries qualifying as supermicropores. Zeotiles present a diversity of tridimensional nanoslab assemblies with mesopores. Zeotile-1, -4 and -6 are hexagonal mesostructures. Zeotile-1 has triangular and hexagonal channels; Zeotile-4 has hexagonal channels interconnected via slits. Zeotile-2 has a cubic structure with gyroid type mesoporosity. The behavior of Zeogrids and Zeotiles in adsorption, membrane and chromatographic separation and catalysis has been characterized and compared with zeolites and mesoporous materials derived from unstructured silica sources. Shape selectivity was detected via adsorption of n- and iso-alkanes. The mesoporosity of Zeotiles can be exploited in chromatographic separation of biomolecules. Zeotiles present attractive separation properties relevant to CO2 sequestration. Because of its facile synthesis procedure without hydrothermal steps Zeogrid is convenient for membrane synthesis. The performance of Zeogrid membrane in gas separation, nanofiltration and pervaporation is reported. In the Beckmann rearrangement of cyclohexanone oxime Zeogrids and Zeotiles display a catalytic activity characteristic of silicalite-1 zeolites. Introduction of acidity and redox catalytic activity can be achieved via incorporation of Al and Ti atoms in the nanoslabs during synthesis. Zeogrids are active in hydrocracking, catalytic cracking, alkylation and epoxidation reactions. Zeogrids and Zeotiles often behave differently from ordered mesoporous materials as well as from zeolites and present a valuable extension of the family of hierarchical silicate based materials.

Design of zeolite by inverse sigma transformation

E. Verheyen, L. Joos, K. Van Havenbergh, N. Kasian, E. Gobechiya, K. Houthoofd, M. Hinterstein, E. Breynaerts, V. Van Speybroeck, M. Waroquier, S. Bals, G. Van Tendeloo, C. Kirschhock, J.A. Martens
Nature Materials
11 (12), 1059-1064
2012
A1

Abstract 

Zeolites are silicon materials, that have channels and pores on the nanoscale. This paper reports the synthesis of a new zeolite, in which the pores were widened using a revolutionary synthesis method. The final material has a series of unique and special properties, useful for industrial processes. Molecular modeling was used to determine the structure of the material.

Zeolieten zijn materialen opgebouwd uit silicium, die op nanoschaal kanalen en poriën bevatten. Deze paper rapporteert de synthese van een nieuw type zeoliet, waarbij de kanalen op een revolutionaire manier werden vergroot. Het eindmateriaal heeft daarom een hele reeks aan unieke en bijzonder interessante eigenschappen voor een aantal industriële processen. Moleculaire modelering werd gebruikt om de structuur van het materiaal te bepalen.

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