Atomic Level In Situ and Modeling Studies of Redox Processes in Ceria and Ceria Zirconia

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Clear air is vital for our health, and milestone achievements have been made in reducing pollution by using catalytic converters in automobile exhaust systems which incorporate ceria-zirconia materials. The catalysts are composed of nanometer-sized particles, and this research will investigate the structural and chemical changes that occur when these materials are in use. Recent advances in environmental transmission electron microscopy have made it possible to make atomic level observations of the structural and chemical changes under in situ [close to reactor or application] conditions. Unique capabilities exist at the Center for High Resolution Electron Microscopy which allow the chemistry of individual particles that are no larger than 5-50 nanometers to be examined. A complementary combination of computational techniques will be used to understand how temperature and oxidizing/reducing conditions affect the particles, including the effect on crystal structure, surface energy, surface segregations, surface diffusion, and sintering behavior. Experiments will be performed in various environments to identify the reasons for enhanced low temperature reduction and oxygen storage capacity for ceria-zirconia systems. The information obtained from this research will be used to develop improved catalysts leading to potential reductions in automobile pollution. Several excellent educational programs are in place, including an Industrial Associates Program. Educational modules on pollution abatement will be developed and targeted to elementary and high school students from less advantaged schools. Summer internships will be available.