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Theoretical Explanation of Pt Trimers Observed by Z-Contrast STEM

Published online by Cambridge University Press:  10 February 2011

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

First-principles quantum-mechanical calculations on γ-alumina have revealed a fascinating “reactive sponge” phenomenon. γ-alumina can store and release water, but in a unique, “reactive” way. This “reactive sponge process” facilitates the creation of aluminum and oxygen vacancies in the alumina surface. Earlier atomic-resolution Z-contrast STEM images of ultradispersed Pt atoms on a γ-alumina support showed the individual atoms to form dimers and trimers with preferred spacings and orientations that are apparently dictated by the underlying support[1]. In turn, the reactive sponge property of γ-alumina is the key to understanding the Pt clusters. Our calculations demonstrate that if three Pt atoms fill three vacancies created during the reactive sponge process, the resulting geometry precisely matches that of the Pt trimers observed in the Z-STEM images. Understanding the initial nucleation of small clusters on the complex gamma alumina surface is an essential first step in determining the origins of catalytic activity.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 589 , 1999 , 241
Copyright
Copyright © Materials Research Society 2001

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References

[1] Nellist, P. D. and Pennycook, S. J., Science, 274, 413 (1996).Google Scholar
[2] Satterfield, C. N., Heterogeneous Catalysis in Practice, §4.5 (McGraw Hill, New York, 1980).Google Scholar
[3] Shi, B. and Davis, B. H., J. Catal., 157, 359 (1995).Google Scholar
[4] Knözinger, H. and Ratnasamy, P., Catal. Rev. - Sci. Eng., 17, 31 (1978).Google Scholar
[5] Gates, B. C., Chem. Rev., 95, 511 (1995).Google Scholar
[6] Che, M. and Bennett, C. O., Adv. Catal., 36, 55 (1989).Google Scholar
[7] Shah, R., Payne, M. C., Lee, M.-H., and Gale, J. D., Science, 271, 1395 (1996).Google Scholar
[8] Xu, Z., Xiao, F.-S., Purnell, S. K., Alexeev, O., Kawi, S., Deutsch, S. E., and Gates, B. C., Nature, 372, 346 (1994).Google Scholar
[9] Pennycook, S. J., Howie, A., Shannon, M. D., and Whyman, R., J. Molec. Catal. 20, 345 (1983).Google Scholar
[10] Sohlberg, K., Pennycook, S. J., and Pantelides, S. T., J. Am. Chem. Soc., 121, 7493 (1999).Google Scholar
[11] Kohn, W. and Sham, L. J., Phys. Rev., 140A, 1133 (1965).Google Scholar
[12] Perdew, J. P., Phys. Rev. B, 33, 8822, (1986).Google Scholar
[13] Payne, M. C., Teter, M. P., Allan, D. C., Arias, T. A., and Joannopoulos, J. D., Rev. Mod. Phys., 64, 1045, (1992).Google Scholar
[14] Al pseudopotential: Winkler, B., Milman, V., Hennion, B., Payne, M. C., Lee, M. H., Lin, J. S., Phys. Chem. Min., 22, 461 (1995); H pseudopotential: CASTEP default reciprocal-space; O pseudopotential: B. Winkler, V. Milman, B. Hennion, M. C. Payne, M. H. Lee, J. S. Lin, Phys. Chem. Min., 22, 461 (1995); Pt pseudopotential: Troullier, N., and Martins J. L., Phys. Rev. B, 43, 1993 (1991).Google Scholar
[15] Kleinman, L. and Bylander, D. M., Phys Rev. Lett., 48, 1425 (1982).Google Scholar
[16] Sohlberg, K., Pennycook, S. J., and Pantelides, S. T., J. Am. Chem. Soc., 121, XXXX (1999).Google Scholar
[17] Monkhorst, H. J. and Pack, J. D., Phys. Rev., B 13, 5188 (1976).Google Scholar
[18] Wefers, K. and Misra, C., Oxides and Hydroxides of Aluminum (Alcoa, 1987).Google Scholar
[19] Tsyganenko, A. A. and Mardilovich, P. P., J. Chem. Soc., Faraday Trans. 92, 4843–4852 (1996).Google Scholar
[20] Henrich, V. E. and Cox, P. A., The Surface Science of Metal Oxides (Cambridge University Press, Cambridge 1994).Google Scholar
[21] Léonard, A. J., Semaille, P. N., and Fripiat, J. J., Proc. Br. Ceram. Soc., 103, 103 (1969).Google Scholar
[22] 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
[23] Mo, S-D., Xu, Y-N., and Ching, W-Y., J. Am. Ceram. Soc., 80 1193 (1997).Google Scholar
[24] Lee, M.-H., Cheng, C-F., Heine, V., and Klinowski, J., Chem. Phys. Lett., 265, 673 (1997).Google Scholar
[25] Dowden, D. A., J. Chem. Soc., 1–2 242 (1950).Google Scholar
[26] Boer, J. H. de and Houben, G. M. M., Proceedings of the International Symposium on the Reactivity of Solids, I, 237 (1952).Google Scholar
[27] Soled, S., J. Catalysis, 81, 252 (1983).Google Scholar
[28] Ushakov, V. A. and Moroz, E. M., React. Kinet. Catal. Lett., 24, 113 (1984).Google Scholar
[29] Pearson, R. M., J. Catal., 23, 388 (1971).Google Scholar
[30] Saniger, J. M., Mat. Lett., 22, 109 (1995).Google Scholar
[31] Tsyganenko, A. A., Smirnov, K. S., Rzhevskij, A. M., and Mardilovich, P. P. Mat. Chem. and Phys., 26, 35 (1990).Google Scholar
[32] Wilson, S. J., J. Solid State Chem., 30, 247 (1979).Google Scholar
[33] Zhou, R-S. and Snyder, R. L., Acta. Cryst., B47, 617 (1991).Google Scholar
[34] Hill, R. J., Clays Clay Min., 29, 435 (1981).Google Scholar
[35] John, C. S., Alma, N. C. M., and Hays, G. R., Applied Catal., 6 341 (1983).Google Scholar
[36] Sohlberg, K., Pennycook, S. J., and Pantelides, S. T., Recent Research Developments in Physical Chemistry, (submitted).Google Scholar
[37] For a detailed account of how H20 breaks up on an alumina surface, see Ref.[39].Google Scholar
[38] Nellist, P. D., private communication.Google Scholar
[39] Hass, K. C., Schneider, W. F., Curioni, A., and Andreoni, W., Science, 282, 265 (1998).Google Scholar