Direct in situ crystallization of highly oriented silicalite-1 thin films on a surface sol-gel process modified substrate

A new method for the fabrication of highly b-oriented silicalite-1 films is presented. With this method, the surface of the substrate of glass slides was modified with different surface coverage of Ti-OH groups by a surface sol-gel process, which enables layer-by-layer coating of a selected metal oxide on a hydroxyl-terminated surface. The modification of the glass substrate by the TiO₂ layers greatly increased the density and the reactivity of the surface hydroxyl groups. After the in situ growth under normal synthetic conditions, highly b-oriented zeolite thin films were obtained. The resulting highly b-oriented zeolite thin films were further characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM). This method offers a general, facile, and straightforward approach to the preparation of various zeolite films under normal synthetic conditions.