Two-Dimensional Crystalline Nanoporous Layers
Speaker: Michael Tsapatsis, University of Minnesota
Department: Chemical & Biological Engineering
Location: Engineering Quadrangle A224
Date/Time: Wednesday, April 2, 2014, 4:00 p.m. - 5:00 p.m.
It is only recently that single-unit-cell thick zeolite nanosheets (e.g., Science, 334, 72-75, 2011 and Science, 336, 1684-1687, 2012) with intact crystal and micropore structure were shown to be possible. The structural integrity and unprecedented purity and uniformity of these microporous nanosheets, open exciting possibilities for technological breakthroughs in molecular sieve membrane fabrication, synthesis of hierarchical catalysts and polymer-zeolite nanocomposites. Moreover, zeolite nanosheets enable for the first time zeolite pore mouth adsorption and catalysis to be studied by traditional uptake methods as well as surface science techniques. However, along with the exciting possibilities, challenges abound. For example, the in-plane dimensions of the existing nanosheets are in the sub-micrometer range limiting potential applications and processability as thin films. Moreover, the two exfoliated zeolites currently available are only a small fraction of zeolite topologies one would like to have available for a representative set. Earlier attempts to exfoliate other layered zeolites, including certain layered silicates and aluminophosphates with microporous layers, did not preserve the crystallographic order of the layers. Synthesis of high aspect ratio zeolite and other crystalline nanoporous nanosheets, methods to characterize their structure and properties, along with their processing and assembly to create functional devices will be the focus of this talk.