Studying the surface reaction between NiO and Al2O3via total reflection EXAFS (ReflEXAFS)

The reaction between NiO and (0001)‐ and ()‐oriented Al2O3 single crystals has been investigated on model experimental systems by using the ReflEXAFS technique. Depth‐sensitive information is obtained by collecting data above and below the critical angle for total reflection. A systematic protocol f...

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Bibliographic Details
Published in:Journal of synchrotron radiation 2014-03, Vol.21 (2), p.395-400
Main Authors: Costanzo, Tommaso, Benzi, Federico, Ghigna, Paolo, Pin, Sonia, Spinolo, Giorgio, d'Acapito, Francesco
Format: Article
Language:English
Subjects:
epitaxy
non-equilibrium compounds
ReflEXAFS
spinel-forming reactions
topochemistry
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Summary:The reaction between NiO and (0001)‐ and ()‐oriented Al2O3 single crystals has been investigated on model experimental systems by using the ReflEXAFS technique. Depth‐sensitive information is obtained by collecting data above and below the critical angle for total reflection. A systematic protocol for data analysis, based on the recently developed CARD code, was implemented, and a detailed description of the reactive systems was obtained. In particular, for ()‐oriented Al2O3, the reaction with NiO is almost complete after heating for 6 h at 1273 K, and an almost uniform layer of spinel is found below a mixed (NiO + spinel) layer at the very upmost part of the sample. In the case of the (0001)‐oriented Al2O3, for the same temperature and heating time, the reaction shows a lower advancement degree and a residual fraction of at least 30% NiO is detected in the ReflEXAFS spectra.
ISSN:1600-5775
0909-0495
1600-5775
DOI:10.1107/S1600577513031299