Aerogels are one of the lightest materials known. They exhibit high surface area, high pore volume and low bulk density. These properties make aerogels attractive candidates for catalytic applications, including catalytic converters in automotive applications, for which aerogels might replace the expensive rare earth metals currently used as three-way catalysts. Aerogels are fabricated through the sol-gel process followed by removal of the liquid filling the pores of a wet gel without causing pore collapse. Here, a rapid supercritical extraction (RSCE) method is used to prepare aerogels based on different metal oxide networks. Alumina and silica can act both as catalysts and as supports for other metal and metal oxide species. The work presented here concerns the fabrication, physical characterization and catalytic testing of copper-alumina (Cu-Al), copper-silica (Cu-Si), alumina and silica aerogels. Surface area, bulk density, FT-IR, XRD, and SEM are employed to characterize the materials after preparation, following heat-treatment and following catalytic testing. For example, for Cu-Al aerogels, we observed color changes as temperatures increased, ranging from brick red to dark blue and green. Changes in bulk density (initially 0.10 -0.15 g/cm3) and surface area (initially 400-500 m2/g) of the Cu-Al aerogels occurred after heating to 600°C, at which point density increased to 0.30 g/cm3 and surface area decreased to ~200 m2/g. The catalytic activity of the aerogels when exposed to simulated automotive exhaust (containing a combination of CO, NO, and propane) in a testbed will also be presented. The goals of catalytic testing are to examine the overall catalytic performance of the materials and to determine which metal is responsible for catalysis of each of the exhaust gases.

Catalytically active copper-containing aerogels

251st National Meeting (2016)

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