Alumina-silica aerogel catalysts prepared by two supercritical drying methods for methane combustion
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Palladium-supported alumina-silica (10 mol%) aerogels were prepared by two different supercritical drying methods. In one method, an alumina-silica wet gel was dried under supercritical conditions of ethanol in an autoclave at a temperature of 270‡C and pressure of 26.5 MPa. In the other, ethanol was supercritically extracted by carbon dioxide in an extractor at 80‡C and 15.7 MPa. Their catalytic properties for methane combustion were measured after being fired at 1200‡C for 5 h. The palladium-supported alumina-silica aerogels prepared in the autoclave showed higher activity (methane conversion) than the one prepared in the extractor. This was attributed to the autoclave-dried aerogel having a larger pore size and better palladium dispersion.
KeywordsPolymer Combustion Methane Dioxide Carbon Dioxide
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- 3.Idem, J. Mater. Res., in press.Google Scholar
- 4.D. L. Trimm, Appl. Catal. 7 (1983).Google Scholar
- 9.A. Wheeler, Adv. Catal. 3 (1951) 266.Google Scholar
- 10.E. E. Perterson, “Chemical Reaction Analysis” (Prentice-Hall, New York, 1965) p. 106.Google Scholar
- 11.K. Hashimoto, “Reaction engineering” (Baifukan, Tokyo 1976) p. 182.Google Scholar
- 12.K. Kawazoe and T. Kawai, in “Zeolite, Basis and Application”, edited by N. Hara and H. Takahashi (Koudansha, Tokyo, 1974) p. 105.Google Scholar