Aerogels are highly porous materials composed of 90-99% air by volume. This allows them to have special properties, such as high surface area, low density, and low thermal conductivity. These properties make aerogels interesting materials for different applications, including catalysis. Specifically, aerogels have the potential to be used in catalytic converters. Catalytic converters are placed in most cars today to facilitate the conversion of exhaust gases from the engine into less harmful gases. These devices, however, use precious noble metals such as platinum and palladium, which are both economically and environmentally expensive. Aerogels fabricated from various metal oxides have the capacity of converting the gases, thus potentially replacing the noble metals.
Aerogel fabrication starts with the hydrolysis and polymerization of precursors into a gel, in a process called the sol-gel method. Through its implementation, the sol-gel method allows for the incorporation of metal oxides, and control of aerogel properties. Following the synthesis of the gel, extraction of the solvent used is possible through Union College’s Rapid Supercritical Extraction (RSCE) technique, where the solvent is brought above its supercritical point, allowing it to leave the gel without causing matrix collapse. Currently, cerium oxide (ceria)-containing aerogels are being fabricated due to cerium’s ability to undergo rapid changes in oxidation state, making it a good oxygen storage component for automotive catalysis. Fabrication is then followed by heat-treatment, and characterization through bulk density and surface area measurements, and spectroscopy techniques such as IR and XRD. The aerogels' catalytic behavior is evaluated through the use of the Union’s Catalytic Aerogel Testbed, which mimics the environment inside catalytic converters. Preliminary results demonstrate favorable properties of the ceria-containing aerogels for applications in catalytic converters.