Nitric acid-stabilized superparamagnetic iron oxide nanoparticles studied with X-rays

Mandel K, Szczerba W, Thuenemann AF, Riesemeier H, Girod M, Sextl G (2012)

Publication Type: Journal article

Publication year: 2012

Journal

Journal of Nanoparticle Research Springer Verlag (Germany)

Book Volume: 14

Article Number: 1066

Journal Issue: 8

DOI: 10.1007/s11051-012-1066-3

Abstract

Agglomerated superparamagnetic iron oxide nanoparticles can easily and in large scale be precipitated from iron salt solutions. Although the process is well known, it is ambiguously either assumed that magnetite or maghemite is obtained. The first part of our study clarifies this question using X-ray absorption spectroscopy. For further processing of the nanoparticles, i.e., for giving them a surface functionality or incorporating them into composites, it is important to break the agglomerates and individualize the particles at first. This can effectively be done with nitric acid treatment. The influence of this process on the particles chemistry and structure was analyzed in great detail using X-ray diffraction, X-ray absorption, and small-angle X-ray scattering. In contrast to our expectation, no oxidation from magnetite (Fe 3O 4) to maghemite (γ-Fe 2O 3) was found; the formal valence of the particles in any case is magnetite (Fe 3O 4). Instead, an increase in the particles' surface disorder was discovered from X-ray absorption analyses and high-resolution transmission electron microscopy. The acid treatment roughens and distorts the surface of the nanoparticles which is connected with an increased spin disorder. © 2012 Springer Science+Business Media B.V.

Authors with CRIS profile

Karl Mandel

Involved external institutions

Bundesanstalt für Materialforschung und -prüfung (BAM) DE Germany (DE) Fraunhofer Institut für Silicatforschung (ISC) DE Germany (DE)

How to cite

APA:

Mandel, K., Szczerba, W., Thuenemann, A.F., Riesemeier, H., Girod, M., & Sextl, G. (2012). Nitric acid-stabilized superparamagnetic iron oxide nanoparticles studied with X-rays. Journal of Nanoparticle Research, 14(8). https://dx.doi.org/10.1007/s11051-012-1066-3

MLA:

Mandel, Karl, et al. "Nitric acid-stabilized superparamagnetic iron oxide nanoparticles studied with X-rays." Journal of Nanoparticle Research 14.8 (2012).

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