Design of Prototype Monolithic Aerogel Catalytic Converter

Internal combustion engines utilize catalytic converters to combat the production of toxic compounds found in car exhaust, such as nitrogen oxides, carbon monoxide, and hydrocarbons, by converting them to more environmentally friendly gasses, such as carbon dioxide, water vapor, and nitrogen gas. Aerogels' high porosity and high surface area, as well as the ability to maintain textural stability at high temperatures, make them good candidates for heterogeneous catalysis applications. Past research in the Union College Aerogel Lab has shown that the catalytic performance of granular or powdered aerogels can be augmented by adding metal salts in the synthesis process. Unfortunately, free-standing granular aerogels would be an unaccommodating substitute for traditional catalytic converters as they are difficult to contain. While the low-difficulty, low-cost pathway into the commercialization of aerogel catalytic converters is through the introduction of aerogels into the conventional wash-coating process used to coat the catalytic converter substrate with a catalyst material, monolithic models may prove to be more feasible to produce and more effective at improving the catalysis of automotive emissions. Aerogels have high surface areas and are very porous, however, the rate of diffusion of gases through a monolithic aerogel is not suitable for use in a catalytic converter. The purpose of this research is to develop an aerogel catalytic converter prototype, and by doing so accomplish three things: 1) create multiple monolithic aerogel substrate models; 2) quantitatively compare the substrate models against each other to prescribe the most effective model; 3) and lastly, test the catalytic performance of the model when doped with catalytic metals. Five inert substrate models were created, and the model with the most reproducibility and mechanical stability under flow conditions was the laser cut two sides lined up model. This model was then doped with heat treated copper alumina aerogel granules and catalytically tested. While the catalytic testing showed that the first monolithic catalytic aerogel substrate iteration was inert when compared to previous union college granular catalytic aerogels, promising future iterations arose that could make monolithic catalytic converter substrates feasible.

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Union College (Schenectady, N.Y.). Department of Mechanical Engineering