Synthesis and Characterization of Nanocrystalline Zeolites and Zeolite Structures

Typically, zeolites, which are crystalline porous aluminosilicates, are industrially manufactured with micron-sized crystals or crystal aggregates. Recently, we have synthesized nanocrystalline zeolites, zeolites with crystal sizes of less than 100 nm. The scaling down of zeolite crystals from the micrometer to the nanometer scale leads to enhanced zeolite properties, such as increased surface area and decreased diffusion path lengths. As the crystal size is decreased below 100 nm, the zeolite external surface area, which is distinct from the internal pore surface and is negligible for micron-sized zeolites, increases dramatically, resulting in zeolites with over 25% of the total surface area on the external surface. If active sites are incorporated onto the external surface, high surface reactivity results, leading to zeolites with improved catalytic properties. We have developed strategies for spectroscopic characterization of the external surface and for tailoring the properties of the external surface through functionalization. Nanocrystalline zeolites have also been used as porous building blocks for hollow zeolite structures that can encapsulate transition metals and organic functional groups. The improved properties of nanocrystalline zeolites for adsorption and intracrystalline diffusion afford many potential opportunities for their application in environmental applications, decontamination, and drug delivery.

The synthesis of the nanocrystalline zeolites and hollow zeolite structures and magnetic resonance studies of the materials were conducted in my laboratory and the FTIR studies (structural and in-situ) of the nanocrystalline zeolites were in collaboration with Prof. Vicki Grassian (UI Chemistry). This work was initially funded by the Environmental Protection Agency and they subsequently changed the focus of the program to Implications of Nanoscience and Nanotechnology (eliminating renewal EPA funding opportunities for this project). Subsequent sources of funding have focused on applications of nanocrystalline zeolites as described in the section II: Environmental Applications (Department of Energy, Petroleum Research Fund), Decontamination (Army Research Office) and Drug Delivery (National Science Foundation).