Effect of silica capping on the oxidation of Fe 3 O 4 nanoparticles in dispersion revealed by x-ray absorption spectroscopy
Effect of silica capping on the oxidation of Fe 3 O 4 nanoparticles in dispersion revealed by x-ray absorption spectroscopy
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DOI：
10.1103/physrevb.85.235113
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发表时间：
2012-06
影响因子：
3.7
通讯作者：
A. Warland;C. Antoniak;M. Darbandi;C. Weis;J. Landers;W. Keune;H. Wende
中科院分区：
文献类型：
--
作者：
A. Warland;C. Antoniak;M. Darbandi;C. Weis;J. Landers;W. Keune;H. Wende
Fe${}_{3}$O${}_{4}$ nanoparticles have been investigated as they are biocompatible and their surface can be functionalized. We synthesized iron oxide nanoparticles using a water-in-oil microemulsion method. Bare and silica-coated iron oxide nanoparticles of a core size of 6 nm dispersed in ethanol have been investigated by means of x-ray absorption spectroscopy (XAS). Due to a dedicated experimental setup the particles can be measured directly in dispersion. XAS allows us to disentangle the contributions of the Fe${}^{2+}$ and Fe${}^{3+}$ ions and therefore to estimate the amount of Fe${}_{3}$O${}_{4}$ in the particles. In case of the silica coated particles a high amount of magnetite was obtained. In contrast, the bare nanoparticles showed indications of a further oxidation into $\ensuremath{\gamma}$-Fe${}_{2}$O${}_{3}$ even in dispersion.
Fe${}_{3}$O${}_{4}$ nanoparticles have been investigated as they are biocompatible and their surface can be functionalized. We synthesized iron oxide nanoparticles using a water-in-oil microemulsion method. Bare and silica-coated iron oxide nanoparticles of a core size of 6 nm dispersed in ethanol have been investigated by means of x-ray absorption spectroscopy (XAS). Due to a dedicated experimental setup the particles can be measured directly in dispersion. XAS allows us to disentangle the contributions of the Fe${}^{2+}$ and Fe${}^{3+}$ ions and therefore to estimate the amount of Fe${}_{3}$O${}_{4}$ in the particles. In case of the silica coated particles a high amount of magnetite was obtained. In contrast, the bare nanoparticles showed indications of a further oxidation into $\ensuremath{\gamma}$-Fe${}_{2}$O${}_{3}$ even in dispersion.