Preparation of regular macroporous structures built of intergrown silicalite-1 nanocrystals

Organized silicalite-1 bodies with a regular system of macropores were prepared. The procedure includes two stages. In the first, self-assembly of monodisperse polystyrene spheres and silicalite-1 nanocrystals is induced by the slow evaporation of the solvent. In the second stage a hydrothermal treatment of the self-assembled composite in a silicalite-1 precursor solution leads to intergrowth and closing of the mesopores between the nanocrystals building the walls of the macroporous structure. The mechanical properties of the macroporous zeolite structures obtained after removal of the polystyrene were substantially improved by this secondary growth of the zeolite crystals. The characteristic features of the self-assembled and hydrothermally treated macroporous structures were studied by XRD, FTIR, SEM, TG-DTA and nitrogen adsorption measurements.