EXAFS study of Fe(3+) interaction with ZrO2 and TiO2 oxides

Abstract

The forms of Fe(3+) ions stabilization on TiO2, ZrO2 oxide nanoparticles and their composition were studied by EXAFS spectroscopy. The structure of the iron local surrounding was investigated with respect to: preparation method, coverage, support crystal modification, acidity of oxide surface and way of iron introduction into oxide matrix. For all oxides, it was shown that Fe(3+) ions stabilized mainly on the nanoparticle surfaces as isolated ions at low coverage. The location of these ions on the oxide surface depends on the correlation between Fe-O bond length and Me-O (Me = Ti, Zr) interatomic distances of oxide carriers. The increase of surface coverage results in formation of two-dimension layer structures. For the ZrO 2-TiO2 composition, it should be noted that the iron cations interact mainly with zirconia. A few structural models of different iron locations were discussed. © Physica Scripta 2005.