Bulk and surface structures of iron doped zirconium oxide systems: influence of preparation method. - Archive ouverte HAL
Article Dans Une Revue Journal of Materials Science Année : 2005

Bulk and surface structures of iron doped zirconium oxide systems: influence of preparation method.

Résumé

Three different Fe-Zr oxide systems were prepd. using, firstly, classical impregnation of iron nitrates on calcined ZrO2 (Fex/ZrO2, x represents Fe/Zr ratio = 0.01 and 0.11), secondly, impregnation of iron nitrates on dried zirconium hydroxide ZrO(OH)2 (Fex/ZrO(OH)2) and, finally, hydrolysis of aq. suspension of iron and zirconium salts to coppt. iron and zirconium hydroxides (Fex-Zr). Thermal decompn. study of dried samples evidenced a delay in the temp. of crystn. of zirconia for Fex-Zr and Fex/ZrO(OH)2; the higher the iron content in the sample, the more important the delay. For these samples, the formation and the stabilization of different phases were evidenced by several characterization techniques: X-Ray Diffraction (XRD), Raman spectroscopy and ESR (EPR). The interaction of iron species with zirconia was different in accordance with different prepn. methods. A bulk dispersion of the copptd. sample was obsd. and, as a consequence, Zr3+ defects in the solid were not produced. In the case of Fex/ZrO2 sample, prodn. of surface Zr3+ ions was established at low temp. of calcination (up to 600°C) and explained by the reaction of NO3- with Zr4+ on the zirconia surface. However such interaction did not occur for Fex/ZrO(OH)2 since a low dispersion of iron species was obsd. by XPS, deposited phase (Fe2O3) forming preferentially blocks. Temp. Programmed Redn. (TPR) showed that the redn. of small particles of Fe2O3 and bulk Fe2O3 present in the impregnated samples was easier than that of iron species well dispersed in the bulk of the copptd. solid.

Domaines

Catalyse

Dates et versions

hal-00105447 , version 1 (11-10-2006)

Identifiants

Citer

Leon Gengembre, Antoine Aboukaïs, Jean-François Lamonier, Stéphane Siffert, Frederic Wyrwalski, et al.. Bulk and surface structures of iron doped zirconium oxide systems: influence of preparation method.. Journal of Materials Science, 2005, 40(4), pp.933. ⟨10.1007/s10853-005-6512-5⟩. ⟨hal-00105447⟩
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