TY  - JOUR
AU  - Dojčinović, Milena
AU  - Vasiljević, Zorka Z
AU  - Pavlović, Vera P.
AU  - Barisic, Dario
AU  - Pajić, Damir
AU  - Tadić, Nenad B.
AU  - Nikolić, Maria Vesna
PY  - 2021
UR  - http://rimsi.imsi.bg.ac.rs/handle/123456789/1451
AB  - CoxMg1-xFe2O4 (where x was 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1) spinel ferrites were synthesized by the sol-gel combustion method using citric acid as fuel, following the rules of propellant chemistry. Amorphous powders were then calcined at 700 degrees C for 3 h. Structural analysis by X-Ray diffraction (XRD), FTIR and Raman spectroscopy confirmed the formation of a cubic spinel structure where the cation distribution and inversion degree depended on the Co2+ and Mg2+ ion content. Accordingly, the lattice parameter varied between 8.3703 angstrom (MgFe2O4) and 8.3919 A (Co-0.9 Mg0.1Fe2O4) as did the crystallite size, from 34 nm (Co0.1Mg0.9Fe2O4) to 48 nm (Co0.9Mg0.1Fe2O4). Scanning electron microscopy (SEM) showed the formation of multigrain agglomerates. Determined values of the maximal and remanent magnetization, as well as coercive field, depended on the Co2+ and Mg2+ ion content and increased with substitution of diamagnetic Mg2+ ions with magnetic Co2+ ions. Most impressive is the increase of the coercive field from 74 Oe for MgFe2O4 to 1000 Oe for CoFe2O4, as well as an increase of magnetization in the field of 10 kOe from 27.4 emu g(-1) to 75.7 emu g(-1). The determined optical band gaps from UV/Vis DRS measurements showed a strong dependence on cation content, morphology, and crystallite size, decreasing from 2.09 eV for MgFe2O4 to 1.42 eV for CoFe2O4. The photocatalytic efficiency of as-synthesized ferrites was investigated by monitoring photocatalytic degradation of Methylene Blue (MB) under natural sunlight, and artificial light source emitting visible light. Different conditions of MB degradation such as photocatalyst loading, molar concentration of MB, and pH values were investigated. Results have shown that under both visible light and natural sunlight, excessive amounts of cobalt retarded the photocatalytic process. Co0.9Mg0.1Fe2O4 showed considerable activity (74.5% after 4 h) that is unexpected but possibly connected to structural anomalies. The best photocatalytic activity under natural sunlight was achieved by MgFe204 (82% after 4 h), while the best photocatalytic activity under visible light was achieved by Co0.1Mg0.9Fe2O4 (79% after 4 h).
PB  - Elsevier Science Sa, Lausanne
T2  - Journal of Alloys and Compounds
T1  - Mixed Mg-Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties
VL  - 855
DO  - 10.1016/j.jallcom.2020.157429
ER  - 

@article{
author = "Dojčinović, Milena and Vasiljević, Zorka Z and Pavlović, Vera P. and Barisic, Dario and Pajić, Damir and Tadić, Nenad B. and Nikolić, Maria Vesna",
year = "2021",
abstract = "CoxMg1-xFe2O4 (where x was 0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1) spinel ferrites were synthesized by the sol-gel combustion method using citric acid as fuel, following the rules of propellant chemistry. Amorphous powders were then calcined at 700 degrees C for 3 h. Structural analysis by X-Ray diffraction (XRD), FTIR and Raman spectroscopy confirmed the formation of a cubic spinel structure where the cation distribution and inversion degree depended on the Co2+ and Mg2+ ion content. Accordingly, the lattice parameter varied between 8.3703 angstrom (MgFe2O4) and 8.3919 A (Co-0.9 Mg0.1Fe2O4) as did the crystallite size, from 34 nm (Co0.1Mg0.9Fe2O4) to 48 nm (Co0.9Mg0.1Fe2O4). Scanning electron microscopy (SEM) showed the formation of multigrain agglomerates. Determined values of the maximal and remanent magnetization, as well as coercive field, depended on the Co2+ and Mg2+ ion content and increased with substitution of diamagnetic Mg2+ ions with magnetic Co2+ ions. Most impressive is the increase of the coercive field from 74 Oe for MgFe2O4 to 1000 Oe for CoFe2O4, as well as an increase of magnetization in the field of 10 kOe from 27.4 emu g(-1) to 75.7 emu g(-1). The determined optical band gaps from UV/Vis DRS measurements showed a strong dependence on cation content, morphology, and crystallite size, decreasing from 2.09 eV for MgFe2O4 to 1.42 eV for CoFe2O4. The photocatalytic efficiency of as-synthesized ferrites was investigated by monitoring photocatalytic degradation of Methylene Blue (MB) under natural sunlight, and artificial light source emitting visible light. Different conditions of MB degradation such as photocatalyst loading, molar concentration of MB, and pH values were investigated. Results have shown that under both visible light and natural sunlight, excessive amounts of cobalt retarded the photocatalytic process. Co0.9Mg0.1Fe2O4 showed considerable activity (74.5% after 4 h) that is unexpected but possibly connected to structural anomalies. The best photocatalytic activity under natural sunlight was achieved by MgFe204 (82% after 4 h), while the best photocatalytic activity under visible light was achieved by Co0.1Mg0.9Fe2O4 (79% after 4 h).",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Journal of Alloys and Compounds",
title = "Mixed Mg-Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties",
volume = "855",
doi = "10.1016/j.jallcom.2020.157429"
}

Dojčinović, M., Vasiljević, Z. Z., Pavlović, V. P., Barisic, D., Pajić, D., Tadić, N. B.,& Nikolić, M. V.. (2021). Mixed Mg-Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties. in Journal of Alloys and Compounds
Elsevier Science Sa, Lausanne., 855.
https://doi.org/10.1016/j.jallcom.2020.157429

Dojčinović M, Vasiljević ZZ, Pavlović VP, Barisic D, Pajić D, Tadić NB, Nikolić MV. Mixed Mg-Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties. in Journal of Alloys and Compounds. 2021;855.
doi:10.1016/j.jallcom.2020.157429 .

Dojčinović, Milena, Vasiljević, Zorka Z, Pavlović, Vera P., Barisic, Dario, Pajić, Damir, Tadić, Nenad B., Nikolić, Maria Vesna, "Mixed Mg-Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties" in Journal of Alloys and Compounds, 855 (2021),
https://doi.org/10.1016/j.jallcom.2020.157429 . .