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Ph.D. 1984, University of Michigan
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| Current Research Interests |
| Dynamics
of Small Particles - Sintering in Heterogeneous Catalysts This research is supported by NSF and by Industry. The research is aimed at understanding phenomena that lead to loss of metal surface area in heterogeneous catalysts. While most supported catalysts start out with metal particles in the nanometer size range, the particles grow in size during use as catalysts. Under demanding conditions such as in automotive exhaust, the catalyst is subjected to temperatures exceeding 900 C. This leads to agglomeration of metal particles and loss of metal surface area. We use a combination of experiment and theory to shed light on this age-old problem. Experiments in collaboration with the industry partner allow us to use realistic catalyst formulations and treatment conditions to examine ageing phenomena. We are also developing model catalysts that allow us to gain mechanistic insight into sintering phenomena. The work will use Monte Carlo simulation to understand the dynamics of these particles. In collaboration with Sandia National Laboratories, we are using the atom tracking STM to follow the motion of individual metal particles on oxide surfaces. The understanding of metal particle dynamics has broad applications, in thin film synthesis, CVD, all sorts of coating applications, as well as heterogeneous catalysis. |
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| Synthesis
of Nanostructured Catalysts This research is supported by CCMC (Center for Ceramic and Composite Materials) and the Materials Corridor Council. In this research, we are exploring novel approaches for the synthesis of catalytic materials. The discovery of self-assembly via surfactants, and the ability to shape inorganic materials has opened up a new frontier for materials synthesis. These self assembly processes allow us to make high surface area materials with controlled nanoscale pore structures. |
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| Restructuring
of Heterogeneous Catalysts This research is supported by DOE-Office of Science, Basic Energy Science program and by Industry. Supported catalysts undergo restructuring during use, often irreversibly altering their properties and performance. High temperature treatment, the gas atmosphere and support chemistry all play a role. Addition of promoters modifies the properties of the supported catalysts and is often critical to maintaining the performance of a supported catalyst. There is a paucity of fundamental information on the role of adsorbates, promoters and the support on metal restructuring, making the design and operation of these catalysts a 'black art.' An understanding of the structure of the noble metal particles, and the role of restructuring in the reaction is important to further development of improved industrial catalysts. |
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|
MicroReformers
for Fuel Cells |
