Corrigendum to “Magnetic iron oxide nanoparticles decorated graphene for chemoresistive gas sensing: The particle size effects” [J. Colloid Interface Sci. 539 (2019) 315–325]

Nanoparticles have gained large interest in a number of different fields due to their unique properties. In medical applications, for example, magnetic nanoparticles can be used for targeting, imaging, magnetically induced thermotherapy, or for any combination of the three. However, it is still a challenge to obtain narrowly dispersed, reproducible particles through a typical lab-scale synthesis when researching these materials. Here, we present a droplet capillary reactor that can be used for the synthesis of magnetic iron oxide nanoparticles. Compared to conventional batch synthesis, the particles synthesized in our droplet reactor have a narrower size distribution and a higher reproducibility. Furthermore, we demonstrate how the particle size can be changed from 5.2 ± 0.9 nm to 11.8 ± 1.7 nm by changing the reaction temperature and droplet residence time in the droplet capillary reactor.

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Controlled Synthesis of Magnetic Iron Oxide Nanoparticles: Magnetite or Maghemite?

Crystals ◽

10.3390/cryst10030214 ◽

2020 ◽

Vol 10 (3) ◽

pp. 214 ◽

Cited By ~ 4

Author(s):

Sebastian P. Schwaminger ◽

Christopher Syhr ◽

Sonja Berensmeier

Keyword(s):

Particle Size ◽

Iron Oxide ◽

Magnetic Nanoparticles ◽

Iron Oxide Nanoparticles ◽

Ion Concentration ◽

Oxide Nanoparticles ◽

Magnetic Iron Oxide Nanoparticles ◽

Magnetic Iron Oxide ◽

Synthesis Conditions ◽

Synthesis Parameters

Today, magnetic nanoparticles are present in multiple medical and industrial applications. We take a closer look at the synthesis of magnetic iron oxide nanoparticles through the co-precipitation of iron salts in an alkaline environment. The variation of the synthesis parameters (ion concentration, temperature, stirring rate, reaction time and dosing rate) change the structure and diameter of the nanoparticles. Magnetic iron oxide nanoparticles are characterized by X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM). Magnetic nanoparticles ranging from 5 to 16 nm in diameter were synthesized and their chemical structure was identified. Due to the evaluation of Raman spectra, TEM and XRD, the magnetite and maghemite nanoparticles can be observed and the proportion of phases and the particle size can be related to the synthesis conditions. We want to highlight the use of Raman active modes A1g of spinel structured iron oxides to determine the content of magnetite and maghemite in our samples. Magnetite nanoparticles can be derived from highly alkaline conditions even without establishing an inert atmosphere during the synthesis. The correlation between the particle properties and the various parameters of the synthesis was modelled with linear mixture models. The two models can predict the particle size and the oxidation state of the synthesized nanoparticles, respectively. The modeling of synthesis parameters not only helps to improve synthesis conditions for iron oxide nanoparticles but to understand crystallization of nanomaterials.

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