@conference{
author = "Jaćimović, Željko and Ognjanović, Miloš and Kosović-Perutović, Milica and Dojčinović, Biljana and Stanković, Dalibor and Antić, Bratislav",
year = "2022",
abstract = "Nanoferrites have been intensively studied because of the possibility of their use in the fields such as medicine, sensors, environmental, agriculture, weather, battery, etc. Often, they are used as modal systems in fundamental science to study physical and chemical phenomena at the nanoscale. Various pathways were applied for the synthesis of nanoferrites with the same composition were led to different microstructure and structure properties, which further influenced magnetic, electric, catalytic and other properties. Consequently, with a controlled synthesis, it is possible to tune the properties of nanoferrites important for applications. On the other side, properties can be controlled by changing chemical composition. In ternary nanoferrites often deviation of stoichiometry accompanied with cation polyvalence was found [1]. The main idea of our work was the application of the polyol-modified method developed for the synthesis of flower-structured iron oxides nanoparticles in the preparation of ternary ZnxMnyFezO4 samples to seek a correlation among chemical composition and microstructure with magnetic hyperthermia efficiency and electrochemical properties. A series of the samples ZnxMnyFezO4 was prepared by polyol process using a slightly modified procedure described in ref [2]. By elemental analysis performed using the ICP technique, the content of cations in the formula unit was determined as follow: Zn0.640Fe2.360O4, Zn0.394Mn0.138Fe2.468O4, Zn0.309Mn0.240Fe2.451O4, Zn0.182Mn0.344Fe2.474O4, Zn0.098Mn0.447Fe2.455O4, Mn0.624Fe2.376O4. The ICP results pointed to the presence of multivalent cations, Mn2+/Mn3+ and Fe3+/Fe2+. Zn has stable valence +2, while the oxidation state of +4 for Mn couldn’t be excluded. Different oxidation states of Mn and Fe and possible deviation of stoichiometry, can create physical effects [3] and make ZnxMnyFezO4 suitable material in practical applications, used for modification of working electrodesin electrochemical sensors. Consequently, we have performed basic electrochemical characterisation of nanoferrites. Cyclic voltammetry of 5 mM K3[Fe(CN)]6/K4[Fe(CN)]6 (1:1) in 0.1 M KCl at bare SPCE and ZnxMnyFezO4-modified SPCE showed that the highest peak current (Ip) was achieved using a Zn0.098Mn0.447Fe2.455O4/SPCE. The Ip was about 22% higher than the bare electrode. X-ray diffraction pattern showed the samples were single-phase crystallising in spinel structure type. Morphology and particle size of the samples were analysed from TEM micrographs. Particles (or crystallites) were agglomerated in a flower-like structure (Figure 1). The diameter of the flowers was around 50-60 nm. Superparamagnetic behaviour of the samples was found from magnetization versus field measurements (hysteresis loops). Prepared samples were in the form of stable colloids with hydrodynamic diameter in the range of 50-120 nm. The heating properties of the samples were analysed from the data of specific absorption rate (SAR), Figure 1b. The highest SAR value was found for Zn0.098Mn0.447Fe2.455O4. The best heating efficiency and electrochemical properties had the same sample. To correlate ZnxMnyFezO4 different efficiency in magnetic hyperthermia and electrochemical sensor applications with parameters like cation distribution in two non-equivalent spinel crystallographic sites (space group, Fd-3m), local distortion on cationic sites, crystallite size and defects, an integrated study of samples structure and microstructure is in progress.",
publisher = "Sociedade Portuguesa de Química",
journal = "ECC8 : 8th EuChemS Chemistry Congress : programme and the book of abstracts; Aug 28 - Sep 1, Lisbon, Portugal",
title = "Ternary flower-structured nanoferrites with polyvalent cations for potential applications in electrochemical sensors and magnetic hyperthermia",
pages = "850-850",
doi = "10.52590/E.ECC8"
}
