Preparation and characterization of porous alumina-titania aerogel via co2 supercritical extraction
Porous aerogel of titania-alumina were prepared by hydrolysis of metal alkoxides and supercritical extraction of the solvent. Monolithic wet-gel of 0.2Ti02-0.8Al203, prepared by hydrolysis of metal alkoxides in alcoholic solutions, and the solvent in wet gel was supercritically extracted in CO2 at 6...
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| Format: | Article NonPeerReviewed |
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[Yogyakarta] : Universitas Gadjah Mada
2004
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| Online Access: | https://repository.ugm.ac.id/17683/ http://i-lib.ugm.ac.id/jurnal/download.php?dataId=445 |
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| Institution: | Universitas Gadjah Mada |
| Summary: | Porous aerogel of titania-alumina were prepared by hydrolysis of metal alkoxides and supercritical extraction of the solvent. Monolithic wet-gel of 0.2Ti02-0.8Al203, prepared by hydrolysis of metal alkoxides in alcoholic solutions, and the solvent in wet gel was supercritically extracted in CO2 at 60°C and 24Mpa for 2h. Thermal evolutions of the microstructure of the gel were evaluated by differential thermal analysis (TGDTA), N2 adsorption, scanning electron microscopy and X-ray diffractometer. After calcination at 500°C, the specific surface area of the gel was more than 400m2e. The average pore radius of aerogel, about 8nm, was about 50% of that for alumina aerogel, but about 4 times larger than that of the xerogel. The specific surface area of the aerogel was more than 200m2g-1 after calcination at 800°C. The pore size and pore volume of aerogel hardly decreased after calcinations at 800°C, although those values of the xerogel remarkably decreased after calcination up to 800°C. The thermal stability of the microstructure of porous titania-alumina is improved by supercritical extraction.rnrnKeywords: Oxides, Sol-gel chemistry, X-ray diffraction, Infrared pectroscopy |
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