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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
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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

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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