Robert R. McCormick School of Engineering and Applied Science
Kung Include File
Catalysis for Sustainability

New Catalytic Materials
Understanding Catalysis by supported Au catalysts
Removal of atmospheric pollutant

Ideally, catalytic reactions to produce products that enhance the quality of life can be conducted with desirable activity and perfect selectivity. The latter is particularly important because a reaction conducted with perfect selectivity would produce no undesirable byproducts and would utilize only the planned reactants. Ideally, the material utilization will be minimum required for the products and the energy consumed will be close to what is dictated by thermodynamics. The reaction will be conducted with minimal, or no impact on the environment and nature. In order to achieve these, there needs to be techniques to synthesize the desired catalysts in a controlled manner, understanding of every chemical transformation in the reaction sequence so as to identify limitations and opportunities to overcome them, and methods to analyze the global impact of the entire, life-cycle impact of the processes.

New Catalytic Materials



In general, biological organisms utilize materials and energy rather efficiently, and many cellular reactions are catalyzed by enzymes. In general, enzymes operate by cooperative effect of binding sites to orientate the reactant molecules with respect to the catalytic active sites. One method to achieve high selectivity in other chemical catalytic reactions is to design catalysts that possess binding and active sites at the desired orientations with respect to each other, which are located in a cavity with controllable access windows. We have been developing synthetic techniques to accomplish this. We have synthesized a net-like, spherical structure of 2 nm in diameter that exhibits molecular-size selectivity for access to the interior amine functional groups. We have also completed the first synthesis of an asymmetric bicyclic siloxane with potential functional groups at designated positions.

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Understanding catalysis by supported Au catalysts


When prepared properly, particles of Au, about 2-3 nm in size, are extremely active for low temperature CO oxidation. When free of impurities and in a wet atmosphere, the activity depends relatively mildly on the nature of the support. Yet the dependence of the support increases markedly in a dry atmosphere. Understanding these phenomena and what makes Au catalysts active could lead to development of new and much more active catalysts for destruction of pollutants. We have been investigating the nature of the active sites on Au catalysts and the reaction mechanism using a combination of in-situ spectroscopic techniques, such as FTIR, X-ray absorption (EXAFS and XANES), poisoning, and transient measurements.

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Removal of atmospheric pollutant

Nitrogen oxides (NOx) is an atmospheric pollutant generated by combustion of fossil fuel. At present, there is no satisfactory method to remove NOx from the exhaust of Diesel engines. We are investigating various catalytic methods to reduce NOx using hydrocarbon-based reductants. The emphasis is to understand the interaction of the various chemical species with the catalytic surface and to elucidate the reaction mechanism.

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