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Structural and Acidic Properties of Niobia-Silica and Niobia-Alumina Aerogels
Final rept. 1 Jun 1988-6 May 1991
CARNEGIE INST OF TECH PITTSBURGH PA DEPT OF CHEMISTRY
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This study used a variety of techniques to establish the structural- chemical property relationships over niobia, niobia-silica, and niobia-alumina binary oxide aerogels. The objective is to develop a comparative set of samples of known structure for chemical characterization. Bulk oxide aerogels of niobia, alumina, and silica were prepared as base oxides by the sol-gel method followed by supercritical extraction to dry the solvent-ladened gel. The synthesis of the bulk niobia aerogel was followed by a 500 C calcination and yielded the highest surface area, 190 m2g, ever reported for bulk niobia. Other physical properties of the aerogel of niobia such as total pore volume and average pore diameter were significantly higher than found previously for conventionally prepared niobia. Laser Raman Spectroscopy LRS and pyridine adsorption experiments were used to investigate the structural and chemical properties of the niobia aerogel as a function of heat treatment.
APPROVED FOR PUBLIC RELEASE