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Full-Text Articles in Physical Sciences and Mathematics
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 …
Fabrication And Preliminary Characterization Of Hydrophobic Silica Aerogel Films For Oil Remediation Studies, Ellen Yang
Fabrication And Preliminary Characterization Of Hydrophobic Silica Aerogel Films For Oil Remediation Studies, Ellen Yang
Pomona Senior Theses
Due to the potential of oil sorbents for oil spill clean-up, hydrophobic silica-based aerogel thin films have been synthesized and characterized by various methods. Aerogels were prepared using a two-step acid/base sol-gel process and functionalized with trimethylchlorosilane in hexane, followed by drying in ambient conditions. After film deposition by spin-coating, samples were characterized by scanning electron microscopy, nitrogen adsorption analysis (BET surface area = 377.66 m2 /g), and variable-angle spectroscopic ellipsometry (thickness of 287.00 ± 0.85 nm, refractive index of 1.08, porosity of 80.9%). Unlike previous studies with aerogel films, quartz crystal microbalance with dissipation monitoring (QCM-D) was applied to …