Micrometer-scale macroporous silica–alumina composites with spheric and lathy MFI-type crystals via seed-induced in-situ and layer-by-layer synthetic methods

Macroporous silica–alumina composites with continuous micrometer-scale pores were synthesized by seed-induced vapor-phase transport treatment. The parent silica–alumina monolith was employed as the silica and alumina source as well as the template for the three-dimensional interconnected structure. The silicalite-1 precursor solution with dispersed zeolite seeds was drawn into the pore channels of the parent monolith for modification by in-situ and layer-by-layer methods before the hydrothermal crystallization, which was believed to play a significant inducing role in the zeolite growing process. The composites synthesized are expected to display high catalytic performance on the bulky molecules since they incorporate the strong acidic advantages of the microporous zeolite and the macroporous pathways of the monolithic skeletons for mass transport.