Internal architecture and molecular transport barriers of large zeolite crystals

Abstract

In this PhD thesis a new experimental approach has been introduced to shed fundamental insight in the architecture and molecular transport barriers of large zeolite crystals. More specifically, we have investigated diffusion limitation in large as-prepared and dealuminated zeolite crystals of AFI and MFI topology by using a combination of the template removal method with UV-Vis, confocal fluorescence and synchrotron-based IR micro-spectroscopy. Furthermore, a thorough comprehension of the internal architecture and related intergrowth phenomena was obtained through employment of focused ion beam milling - electron backscattered diffraction and electron tomography, atomic force microscopy and X-ray absorption spectroscopy. The goal of this correlative characterization approach was threefold: (1) resolving the intergrowth structure; (2) relating the examined structures to the crystal growth mechanism and (3) understanding the diffusion limiting behavior of the related intracrystalline and external transport barriers in AFI- and MFI-type zeolite crystals.