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Science 9 October 1998:
Vol. 282. no. 5387, pp. 265 - 268
DOI: 10.1126/science.282.5387.265
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Reports

The Chemistry of Water on Alumina Surfaces: Reaction Dynamics from First Principles

Kenneth C. Hass, William F. Schneider, Alessandro Curioni, Wanda Andreoni *

Aluminas and their surface chemistry play a vital role in many areas of modern technology. The behavior of adsorbed water is particularly important and poorly understood. Simulations of hydrated alpha -alumina (0001) surfaces with ab initio molecular dynamics elucidate many aspects of this problem, especially the complex dynamics of water dissociation and related surface reactions. At low water coverage, free energy profiles established that molecularly adsorbed water is metastable and dissociates readily, even in the absence of defects, by a kinetically preferred pathway. Observations at higher water coverage revealed rapid dissociation and unanticipated collective effects, including water-catalyzed dissociation and proton transfer reactions between adsorbed water and hydroxide. The results provide a consistent interpretation of the measured coverage dependence of water heats of adsorption, hydroxyl vibrational spectra, and other experiments.

K. C. Hass and W. F. Schneider, Ford Research Laboratory, Dearborn, MI 48121-2053, USA. A. Curioni and W. Andreoni, IBM Research Division, Zurich Research Laboratory, 8803 Rüschlikon, Switzerland.
*   To whom correspondence should be addressed. E-mail: and{at}zurich.ibm.com

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
SURFACE ENTHALPY OF BOEHMITE.
J. Majzlan, J. Majzlan, A. Navrotsky, and W. H. Casey (2000)
Clays and Clay Minerals 48, 699-707
   Abstract »    Full Text »    PDF »
Structure of the Hydrated -Al2O3 (0001) Surface.
P. J. Eng, T. P. Trainor, G. E. Brown Jr., G. A. Waychunas, M. Newville, S. R. Sutton, and M. L. Rivers (2000)
Science 288, 1029-1033
   Abstract »    Full Text »


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Science. ISSN 0036-8075 (print), 1095-9203 (online)