Date of Award
Bachelor of Science
aerogel, gas, exhaust, remediation, catalyst, processing reactions
Aerogels are highly porous solids with low bulk density, high specific surface area, high thermal stability and tunable chemical composition. These properties make aerogels interesting for use as catalysts in automotive exhaust remediation. Noble metals such as platinum are currently used for this function, but are costly and harmful to the environment. Aerogels offer a potential alternative to noble metals that could reduce both the cost and environmental impact associated with catalytic converter production. Alumina and nickel-alumina aerogels have shown activity in catalyzing exhaust processing reactions. The environmental impact of the production of aerogel catalysts could be further reduced by using a rapid supercritical extraction (RSCE) technique, which reduces the time and solvent waste associated with aerogel preparation. Alumina, nickel-alumina and copper alumina aerogels were prepared using an epoxide-assisted gelation technique followed by a solvent rinse, then RSCE on a hydraulic hot press. Samples were characterized by FTIR, XRD, SEM, EDX, nitrogen adsorption porosimetry and pycnometry. Alumina aerogels with surface areas of up to 790 m2/g and bulk densities as low as 0.05 g/mL were prepared, while nickel-alumina aerogels with surface areas of up to 580 m2/g and bulk densities as low as 0.06 g/mL were produced. In the nickel-alumina and copper-alumina samples, the nickel and copper were evenly distributed throughout the material. Alumina aerogels exhibit catalytic activity for the conversion of ethanol to diethyl ether under hot press conditions. Preliminary characterization of the aerogels' exhaust-processing ability has begun, utilizing a catalytic test bed and a simulated emissions gas blend.
Dunn, Nicholas J., "Alumina-based aerogels by rapid supercritical extraction for use in green automotive catalysis" (2011). Honors Theses. 970.