Hostname: page-component-7bb8b95d7b-2h6rp Total loading time: 0 Render date: 2024-09-15T18:34:33.838Z Has data issue: false hasContentIssue false
  • English
  • Français

The Role of Hydrogen In The Structure of γ-Alumina

Published online by Cambridge University Press:  15 February 2011

Karl Sohlberg ,
Stephen J. Pennycook  and
Sokrates T. Pantelides
Karl Sohlberg
Affiliation:
Solid State Division, P.O. Box 2008, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6031
Stephen J. Pennycook
Affiliation:
Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235
Sokrates T. Pantelides
Affiliation:
Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235
Get access

Abstract

The structure of a-alumina (α-A12O3) is well known to be hexagonal close packed. In contrast, the structures of the so-called transition aluminas (-γ-alumina, η-alumina,…) are the subject of controversy. We report theoretical calculations which show that -γ-alumina is actually a sequence of compounds with the general formula H3mAl2−mO3. (0 ≤ m ≤ ⅓). m = ⅛ is a unique form, HAl5O8, with a perfect spinel structure. For m > 8, there are interstitial H atoms whereas for m < ⅛. there are vacancies. This picture is supported m > ⅛ by calculations of material density and proton vibrational frequencies. The results are in excellent agreement with measured values. The present new systematic approach accounts for a wide range of seemingly contradictory data and leads to the conclusion that γ-alumina behaves as a “reactive sponge” by storing and releasing water in a novel reactive way.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 549: Symposium FF – Advanced Catalytic Materials - 1998 , 1998 , 165
Copyright
Copyright © Materials Research Society 1999

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Satterfield, C. N., Heterogeneous Catalysis in Practice, §4.5 (McGraw Hill, New York, 1980).Google Scholar
[2] Henrich, V. E. and Cox, P. A., The Surface Science of Metal Oxides (Cambridge University Press, Cambridge 1994).Google Scholar
[3] Tsyganenko, A. A. and Mardilovich, P. P., J. Chem. Soc., Faraday Trans. 92, 4843–4852 (1996).Google Scholar
[4] Deboer, J. H. and Houben, G. M. M., Proceedings of the International Symposium on the Reactivity of Solids, I, 237 (1952).Google Scholar
[5] Soled, S., J. Catalysis 81, 252–257 (1983).Google Scholar
[6] Ushakov, V. A. and Moroz, E. M., React. Kinet. Catal. Lett. 24, 113–118 (1984).Google Scholar
[7] Zhou, R-S. and Snyder, R. L., Acta. Cryst. B47, 617–630 (1991).Google Scholar
[8] Hohenberg, P. and Kohn, W., Phys. Rev. 136B, 864 (1964); Kohn, W. and Sham, L. J., Phys. Rev. 140A, 1133 (1965).Google Scholar
[9] Perdew, J. P., Phys. Rev. B 33, 8822, (1986).Google Scholar
[10] Payne, M. C., Teter, M. P., Allen, D. C., Arias, T. A., and Joannopoulos, J. D., Rev. Mod. Phys. 64, 1045–1097, (1992).Google Scholar
[11] Kleinman, L. and Bylander, D. M., Phys Rev. Lett. 48, 1425 (1982).Google Scholar
[12] Monkhorst, H. J. and Pack, J. D., Phys. Rev. B 13, 5188 (1976).Google Scholar
[13] Califano, S., Vibrational States, (Wiley, London, 1976).Google Scholar
[14] Wefers, K. and Misra, C., Oxides and Hydroxides of Aluminum (Alcoa, 1987).Google Scholar
[15] Wyckoff, R. W. G., Crystal Structures (Interscience, NY 1963).Google Scholar
[16] Lippens, B. C. and Steggerda, J. J., in Linsen, B. G. (ed.) Physical and Chemical Aspects of Adsorbents and Catalysts (Academic Press, London 1970).Google Scholar
[17] Dowden, D. A., J. Chem. Soc. 1–2 242–265 (1950).Google Scholar
[18] Tsyganenko, A. A., Smirnov, K. S., Rzhevskij, A. M., and Mardilovich, P. P. Mat. Chem. and Phys. 26, 35–46 (1990).Google Scholar
[19] John, C. S., Alma, N. C. M., and Hays, G. R., Applied Catal. 6 341–346 (1983).Google Scholar
[20] Lee, M.-H., Cheng, C-F., Heine, V., and Klinowski, J., Chem. Phys. Lett. 265, 673–676 (1997).Google Scholar
[21] Mo, S-D., Xu, Y-N., and Ching, W-Y., J. Am. Ceram. Soc. 80 1193–1197 (1997).Google Scholar
[22] Tung, S. E. and Mcininch, E., J. Catalysis 3, 229–238 (1964).Google Scholar