Zeolites are crystalline silica-based microporous materials with a pore size ranging from 0.25 to several nm. Until now, approximately 200 zeolite topologies have been reported (http://www.iza-online.org/) and for each topology, many varieties of framework composition are feasible. After isomorphic substitution of Si with other atoms, for example Al, Ti, Sn, Fe, B, Ga, and Ge, zeolites can provide catalytic sites including ones for oxidation as well as Brönsted and Lewis acid catalysis. They can also be functionalized with many synthetic and post synthetic strategies involving framework O atoms, including incorporation of carbon, nitrogen or grafted functional groups. Although there are numerous commercial applications where a single zeolite catalyst or adsorbent is used, there is an emerging need for synthesis of hybrid zeolitic materials, which combine different functions.
Despite some recent successes with microstructured catalysts, the challenge of creating zeolite catalysts by design remains elusive due to the following two limitations: (i) Active site localization. With very few exceptions, functionalization and isomorphous substitution are used currently in a statistical sense, i.e., without the ability to precisely localize the catalytic active sites within the zeolite frameworks. (ii) Nanoscale level control of zeolite structure and composition. The combination of different functions of a zeolite with other zeolites or functional materials, needed to accomplish, for example, product separation immediately after reaction cannot be achieved yet at the nanoscale level.
This collaborative seed proposal builds on recent developments in the co-PIs laboratories which enable us for the first time to address: (i) precise determination and manipulation of active site location in nanoscale zeolite building blocks and (ii) construction of hierarchical zeolite nanostructures by assembly of these building blocks.
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