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Identifying Spinel Phases in Nearly Monodisperse Iron Oxide Colloidal Nanocrystal

Corrias, Anna, Mountjoy, Gavin, Loche, Danilo, Puntes, Victor, Falqui, Andrea, Zanella, Marco, Parak, Wolfgang J, Casula, Maria Francesca (2009) Identifying Spinel Phases in Nearly Monodisperse Iron Oxide Colloidal Nanocrystal. Journal of Physical Chemistry C, 113 (43). pp. 18667-18675. ISSN 1932-7447. (doi:10.1021/jp9047677) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://dx.doi.org/10.1021/jp9047677

Abstract

Nearly monodisperse iron oxide colloidal nanocrystals prepared by nonhydrolytic high-temperature solution method were obtained with two different sizes and degrees of oxidation. The characterization of the structural features of the nanocrystals was performed by a multitechnique approach including transmission electron microscopy, X-ray diffraction and X-ray absorption spectroscopy, energy filtered electron microscopy imaging, and SQUID magnetometry. The different techniques provided complementary information on the local oxidation state of iron in the iron oxide nanoparticles, the stability of the phases, the exact crystal structure, and the compositional homogeneity. X-ray diffraction, transmission electron microscopy, and extended X-ray absorption spectroscopy show that the addition of oxidizer to the iron precursor gives rise to monodisperse polycrystalline nanoparticles made out of FeO plus a spinel phase. X-ray absorption near-edge structure, which is very sensitive to the oxidation state and local environment of iron in the different iron oxides, was used to distinguish among isostructural spinel phases of iron (II,III) oxide (magnetite) and iron(III) oxide (maghemite). Single-crystalline spinel nanoparticles are obtained upon sequential oxidation: in smaller nanoparticles a mixture of mainly Fe3O4 and ?-Fe2O3 is present, whereas the larger nanoparticles are made out of ?-Fe2O3, as also supported by SQUID magnetization measurements. The importance of a multitechnique approach for the elucidation of the compositional and structural details in addition to geometrical parameters in the characterization of nanocrystalline iron oxides is pointed out.

Item Type: Article
DOI/Identification number: 10.1021/jp9047677
Additional information: number of additional authors: 7; article number: 060301;
Subjects: Q Science > QC Physics
Divisions: Faculties > Sciences > School of Physical Sciences
Depositing User: Anna Corrias
Date Deposited: 07 Mar 2014 00:05 UTC
Last Modified: 27 Jan 2020 04:05 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/40483 (The current URI for this page, for reference purposes)
Corrias, Anna: https://orcid.org/0000-0002-5190-8196
Mountjoy, Gavin: https://orcid.org/0000-0002-6495-2006
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