The present thesis deals with the preparation and the mechanism of formation of core-shell zeolite micro-composites comprising a single crystal core and a polycrystalline shell. Several framework types (BEA, FAU, LTA, MFI, MOR, SOD) covering a broad range of chemical compositions were combined in the course of this study in order to determine the factors controlling the formation of the composites. Two approaches, a direct synthesis and a secondary growth after seeding of the core surface, were employed. The reactivity of the core surface and structural similarities of the zeolites building the composite were found to be of paramount importance for the direct unseeded synthesis. The factors controlling the composite formation via secondary growth were found to be: (i) the composition of the two counterparts; (ii) the stability of the core crystals in the synthesis media; and (iii) the rapid crystal growth kinetics of the shell. The synthesized core-shell composites are expected to show improved performance in the existing petrochemical processes and to open routes for new applications for zeolite materials.
