Research Interests

In the Larsen group, we are interested in the synthesis, spectroscopic characterization and application of novel zeolite materials. Zeolites are crystalline, aluminosilicate molecular sieves which are widely used in applications such as separations, ion exchange and catalysis. Zeolites can be synthesized with a wide range of pore sizes and topologies. The zeolite chemical composition, framework topology and pore size can be varied to control selectivity and reactivity. Although the pore dimensions of these materials are in the nanometer-size range, the zeolite crystals prepared through conventional syntheses are typically on the order of micrometers in diameter. We are interested in the new properties and applications of zeolites with crystal sizes of less than 100 nm. Ongoing projects in the group include 1) synthesis, characterization and application of nanocrystalline zeolites, 2) magnetic resonance (EPR and solid state NMR) studies of zeolite materials , 3) DFT calculations to complement experimental studies and 4) development of undergraduate chemistry laboratory experiments related to nanoscience and nanotechnology.

Nanocrystalline Zeolites

The main focus of our research is on the synthesis, spectroscopic characterization and application of nanocrystalline zeolites, which are zeolites with discrete, uniform crystals with dimensions of less than 100 nm. Nanocrystalline zeolites are promising catalytic materials that have higher external surface areas and reduced diffusion path lengths relative to conventional micrometer-sized zeolites. In addition, nanometer-sized zeolites can be assembled into optically transparent thin films and other porous nanostructures for use as separation membranes, chemical sensors and photochemical hosts. These new nanocrystalline zeolites have potential applications in environmental protection, decontamination, catalysis and drug delivery. The nanocrystalline zeolite materials can also be used as building blocks for hierarchical zeolite structures, which can be tailored for specific applications. Recently, hollow zeolite structures have been prepared in our lab (see SEM images below) and are being investigated for applications in water purification and drug delivery.

Hollow Zeolite Sphere	Hollow Zeolite Tube

Magnetic Resonance Spectroscopy

We are also interested in magnetic resonance spectroscopy of novel zeolite materials. Electron paramagnetic resonance (EPR) spectroscopy is used to investigate the electronic environment of transition metal-exchanged zeolites. Experimental studies are combined with computational methods to enhance the interpretation of the EPR spectra. Amsterdam Density Functional theory (ADF) methods are used to calculate the EPR parameters. Solid state nuclear magnetic resonance (NMR) techniques are used to study reactions of chemical species that form in the zeolite pores during catalytic reactions. Line-narrowing techniques, such as MAS (magic angle spinning) NMR are routinely employed in these studies.