Engineering Heterogeneous Catalysts Using Novel Nanotechnology Synthesis

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Selectivity in catalysis requires the use of materials with well-defined active sites. Those sites also need to be robust, to survive all of the conditions used for their preparation and activation and for the process of catalysis. The manufacturing of such materials with well-defined active sites has been difficult to achieve in the past, but has recently received some help from the field of nanotechnology. Professor Francisco Zaera of the University of California at Riverside believes preparation of catalyst sites with extreme specificity in physicochemistry is now possible, and the results will be extremely useful. New colloidal and other self-assembly synthetic methodologies can now be used to make nanoparticles with specific sizes and shapes. This proposal describes research to develop general synthetic approaches for the preparation of metal-based catalysts with well-defined structural and/or chemical characteristics. Two interconnected directions of research are proposed: (1) the use of nanoparticles of Pt, Ni, and Pd will be made with exclusive (111) or (100) facets exposed with narrow distributions of sizes and well-defined shapes for the preparation of heterogeneous catalysts; and (2) the encapsulation of those metal nanoparticles by several approaches as a way to increase their stability and isolate their functionality. Desirable catalytic behavior will be targeted in terms of selectivity and/or stability, in particular for mild reactions involving hydrocarbon conversions such as hydrogenations and isomerizations in olefins and other unsaturated molecules. The aim is to combine the use of novel synthetic methods with the understanding achieved from studies using model systems to design selective and robust metal catalysts for mild catalytic processes. The value of this approach is that it combines knowledge developed by three separate communities: self-assembly chemists, catalyst developers, and surface scientists. Success will have repercussions on the design of new industrialprocesses that rely on catalysis of mild reactions such as in the food industry, where selectivity for the production of cis olefins is desired because of the adverse health effects of trans fats. The general synthetic methodology generated by the work is also likely to apply to the preparation of materials for other uses such as absorbents, sensors, and paints. The knowledge deriving from this work will be used for educational purposes to illustrate basic solid-state synthesis and catalysis principles in undergraduate and graduate classes. Collaborations with Latin American research groups will be forged, and student participation from underrepresented groups in research (Hispanics in particular) will be strongly pursued. This is characteristic for this group and university.