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Full-Text Articles in Physical Sciences and Mathematics
Development Of Catalytic Chromia-Based Aerogels, Fiona Fitzgerald
Development Of Catalytic Chromia-Based Aerogels, Fiona Fitzgerald
Honors Theses
Over one billion automobiles are in use around the world, the majority of which employ internal combustion engines. Catalytic converters are used to convert the toxic compounds found in car exhaust -- carbon monoxide, nitrogen oxides (NOx) and hydrocarbons -- to less harmful gases. The typical catalytic converter employs as catalysts expensive raw materials (platinum, palladium and/or rhodium) wash-coated onto an alumina-based ceramic substrate. Aerogel materials have high surface area and thermal stability, properties that make them attractive for catalysis applications. Aerogels made with transition metal oxides are candidates to replace platinum in the catalytic converter. Chromium oxide (chromia) materials …
Optimization Of Superhydrophobic Surface Production Using Ambient-Dried Silica-Based Aerogels, Elizabeth Donlon
Optimization Of Superhydrophobic Surface Production Using Ambient-Dried Silica-Based Aerogels, Elizabeth Donlon
Honors Theses
Superhydrophobic surfaces exhibit particular properties that make them functional in various anti-sticking, anti-contamination, self-cleaning and drag reduction applications. Though such surfaces are found in nature - most notably the lotus leaf - they are difficult to produce. There are numerous methods and techniques for fabricating superhydrophobic surfaces. One such method is the sol-gel method, in which aerogel, a highly porous and lightweight material that can be made hydrophobic or superhydrophobic, is coated onto a surface. The purpose of this project is to devise a simple and repeatable procedure for making hydrophobic silica aerogel coatings that can be used for drag …
Alumina-Based Aerogels By Rapid Supercritical Extraction For Use In Green Automotive Catalysis, Nicholas J. Dunn
Alumina-Based Aerogels By Rapid Supercritical Extraction For Use In Green Automotive Catalysis, Nicholas J. Dunn
Honors Theses
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 …
Fabrication And Analysis Of Teos- And Mtes-Based Aerogels Prepared Via Rapid Supercritical Extraction, Suzanne K. Estok
Fabrication And Analysis Of Teos- And Mtes-Based Aerogels Prepared Via Rapid Supercritical Extraction, Suzanne K. Estok
Honors Theses
Silica aerogels were prepared using the precursor tetraethylorthosilicate (TEOS) and an organically modified TEOS derivative (methyltriethoxysilane, MTES) via a rapid supercritical extraction (RSCE) method. Multiple consistent batches of monolithic TEOS-based aerogels were fabricated via an eight-hour RSCE process. Fabricating TEOS-based aerogels with an RSCE method offers some distinct advantages. The main advantage is the relative simplicity of the RSCE approach: liquid precursors are mixed and poured into a mold in a hydraulic hot-press, where gelation, aging and extraction of liquid from the pores occur. The precursor recipe employs TEOS, ethanol, water, oxalic acid to catalyze hydrolysis, and ammonia to catalyze …