NiFe2O4 Nanoparticles Dispersed in an Aerogel Silica Matrix: An X-ray Absorption Study

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• 作者：Daniela Carta ; Danilo Loche ; Gavin Mountjoy ; Gabriele Navarra ; Anna Corrias
• 刊名：Journal of Physical Chemistry C
• 出版年：2008
• 出版时间：October 9, 2008
• 年：2008
• 卷：112
• 期：40
• 页码：15623-15630
• 全文大小：191K
• 年卷期：v.112,no.40(October 9, 2008)
• ISSN：1932-7455

文摘

The formation of NiFe₂O₄ nanoparticles dispersed in an aerogel silica matrix was investigated as a function of calcination temperature by X-ray absorption fine structure and X-ray absorption near edge structure at both the Fe and Ni K-edges. In particular, nanocomposite aerogels containing a relative NiFe₂O₄ amount of 10 wt % and calcined at 450, 750 (1 h and 20 h), and 900 °C were studied. A quantitative determination of the relative occupancy of iron and nickel cations in the octahedral and tetrahedral sites of the spinel structure was obtained. It has been found that nickel ferrite prepared by sol−gel has the classical inverted spinel structure found in bulk materials with nickel(II) cations fully occupying the octahedra sites and iron(III) equally distributed between octahedra and tetrahedra sites.