Publication
Title
Chemistry of shape-controlled iron oxide nanocrystal formation
Author
Abstract
Herein, we demonstrate that meticulous and in-depth analysis of the reaction mechanisms of nanoparticle formation is rewarded by full control of the size, shape, and crystal structure of superparamagnetic iron oxide nanocrystals during synthesis. Starting from two iron sources, iron(II) and iron(III) carbonate, a strict separation of oleate formation from the generation of reactive pyrolysis products and concomitant nucleation of iron oxide nanoparticles was achieved. This protocol enabled us to analyze each step of nanoparticle formation independently in depth. The progress of the entire reaction was monitored via matrix-assisted laser desorption ionization time-of-flight mass spectrometry and gas chromatography, thus providing insight into the formation of various iron oleate species prior to nucleation. Interestingly, due to the intrinsic strongly reductive pyrolysis conditions of the oleate intermediates and redox process in early stages of the synthesis, pristine iron oxide nuclei were composed exclusively from wüstite irrespective of the oxidation state of the iron source. Controlling the reaction conditions provided a very broad range of size- and shape-defined monodispersed iron oxide nanoparticles. Curiously, after nucleation, star-shaped nanocrystals were obtained that underwent metamorphism toward cubic-shaped particles. Electron energy loss spectroscopy tomography revealed ex post oxidation of the primary wustite nanocrystal, providing a full 3D image of Fe2+ and Fe3+ distribution within. Overall, we developed a highly flexible synthesis, yielding multi-gram amounts of well-defined iron oxide nanocrystals of different sizes and morphologies.
Language
English
Source (journal)
ACS nano. - -
Publication
2019
ISSN
1936-0851
Volume/pages
13 :1 (2019) , p. 152-162
ISI
000456749900017
Pubmed ID
30540436
Full text (Publisher's DOI)
Full text (open access)
UAntwerpen
Faculty/Department
Research group
Project info
Colouring Atoms in 3 Dimensions (COLOURATOM).
Spectral electron tomography as a quantitative technique to investigate functional nanomaterials.
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 18.12.2018
Last edited 16.09.2021
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