Hierarchical pore ZSM-5 zeolite structures: From micro- to macro-engineering of structured catalysts

Zeolite crystals coated on mesoporous glass materials with hierarchical tri-modal pore size distributions have been successfully prepared and characterized. Starting glass monoliths, having regular meso- and macro-pores, were partly re-constructed into zeolite material, thus introducing additional microporosity via the growth of these zeolite crystals. Hierarchical 3D porous glass scaffolds were prepared by a combination of sol-gel, double polymer templating, and rapid prototyping (RP) techniques. Structured zeolitic catalytic materials were produced by conventional self-assembly of template cations and silica species on the glass surface. Zeolite crystals are therefore in an intimate contact with the glass support, featuring micropores in addition to the mesopores. A higher catalytic performance and selectivity toward low alkenes were achieved in n-hexane cracking reaction over these zeolite/glass composites in comparison with purely microporous zeolite materials. (C) 2009 Elsevier B.V. All rights reserved.