title: Studying the surface reaction between NiO and Al2O3 via total reflection EXAFS (ReflEXAFS).
abstract: The reaction between NiO and (0001)- and (1102)-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 (1102)-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.
authors.affiliation: INSTM and Department of Chemistry, University of Pavia, I27100 Pavia, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Costanzo
authors.affiliation: School of Science and Technology, Geology Division, University of Camerino, I-62032 Camerino, Italy.
authors.forename: Federico
authors.initials: F
authors.lastname: Benzi
authors.affiliation: INSTM and Department of Chemistry, University of Pavia, I27100 Pavia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Ghigna
authors.affiliation: General Energy Research (ENE), Laboratory for Bioenergy and Catalysis, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland.
authors.forename: Sonia
authors.initials: S
authors.lastname: Pin
authors.affiliation: INSTM and Department of Chemistry, University of Pavia, I27100 Pavia, Italy.
authors.forename: Giorgio
authors.initials: G
authors.lastname: Spinolo
authors.affiliation: CNR-IOM-OGG, c/o ESRF, GILDA-CRG, BP 220, F-38043 Grenoble Cedex, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: d'Acapito
keywords: ReflEXAFS; epitaxy; non-equilibrium compounds; spinel-forming reactions; topochemistry