TY  - CONF
AU  - Dojčinović, Milena
AU  - Vasiljević, Zorka Ž.
AU  - Rakočević, Lazar
AU  - Pavlović, Vera P.
AU  - Ammar-Merah, Souad
AU  - Vujančević, Jelena
AU  - Nikolić, Maria Vesna
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7269
AB  - Mixed spinel ferrites MgxNi1-xFe2O4 were synthesized via sol-gel combustion synthesis with citric acid as fuel, followed by calcination at 700 °C for 3 hours. Obtained powders were characterized via X-ray diffraction analysis (XRD), X-ray photoelectron (XPS), FTIR and Raman spectroscopy and FESEM microscopy. Elemental composition was examined via energy dispersive spectroscopy (EDS). Humidity sensing properties were tested by measuring AC impedance in a climactic chamber at 25 °C and in the relative humidity range of 40–90%. Temperature sensing properties were tested by measuring DC resistance at 40% RH in the temperature range 40–90 °C. Synthesized powders were proven to be pure spinel Fd 3m phase with spherical, slightly agglomerated particles. Substitution of Mg with Ni results in structural changes such as a change in inversion parameter and particle agglomeration, which influences sensing properties of the material. Results show that the sensing properties of magnesium ferrite, which is already a well-established NTC sensor, can be improved by incorporating 10% of nickel in the spinel lattice structure. Mg0.9Ni0.1Fe2O4 exhibited higher temperature sensitivity and higher sensitivity towards humidity compared to MgFe2O4, while further substitution of Mg with Ni resulted in the decline of sensing properties, increase in particle size and agglomeration degree.
PB  - University of Novi Sad, Faculty of Technology, Novi Sad, Serbia
C3  - CYSC-2023 : 15th EcerS Conference for Young Scientists in Ceramics, Programme and Book of Abstracts; October 11-14, 2023, Novi Sad, Serbia
T1  - Magnesium substitution with nickel and its influence on the sensing properties of MgFe2O4
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7269
ER  - 

@conference{
author = "Dojčinović, Milena and Vasiljević, Zorka Ž. and Rakočević, Lazar and Pavlović, Vera P. and Ammar-Merah, Souad and Vujančević, Jelena and Nikolić, Maria Vesna",
year = "2023",
abstract = "Mixed spinel ferrites MgxNi1-xFe2O4 were synthesized via sol-gel combustion synthesis with citric acid as fuel, followed by calcination at 700 °C for 3 hours. Obtained powders were characterized via X-ray diffraction analysis (XRD), X-ray photoelectron (XPS), FTIR and Raman spectroscopy and FESEM microscopy. Elemental composition was examined via energy dispersive spectroscopy (EDS). Humidity sensing properties were tested by measuring AC impedance in a climactic chamber at 25 °C and in the relative humidity range of 40–90%. Temperature sensing properties were tested by measuring DC resistance at 40% RH in the temperature range 40–90 °C. Synthesized powders were proven to be pure spinel Fd 3m phase with spherical, slightly agglomerated particles. Substitution of Mg with Ni results in structural changes such as a change in inversion parameter and particle agglomeration, which influences sensing properties of the material. Results show that the sensing properties of magnesium ferrite, which is already a well-established NTC sensor, can be improved by incorporating 10% of nickel in the spinel lattice structure. Mg0.9Ni0.1Fe2O4 exhibited higher temperature sensitivity and higher sensitivity towards humidity compared to MgFe2O4, while further substitution of Mg with Ni resulted in the decline of sensing properties, increase in particle size and agglomeration degree.",
publisher = "University of Novi Sad, Faculty of Technology, Novi Sad, Serbia",
journal = "CYSC-2023 : 15th EcerS Conference for Young Scientists in Ceramics, Programme and Book of Abstracts; October 11-14, 2023, Novi Sad, Serbia",
title = "Magnesium substitution with nickel and its influence on the sensing properties of MgFe2O4",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7269"
}

Dojčinović, M., Vasiljević, Z. Ž., Rakočević, L., Pavlović, V. P., Ammar-Merah, S., Vujančević, J.,& Nikolić, M. V.. (2023). Magnesium substitution with nickel and its influence on the sensing properties of MgFe2O4. in CYSC-2023 : 15th EcerS Conference for Young Scientists in Ceramics, Programme and Book of Abstracts; October 11-14, 2023, Novi Sad, Serbia
University of Novi Sad, Faculty of Technology, Novi Sad, Serbia..
https://hdl.handle.net/21.15107/rcub_machinery_7269

Dojčinović M, Vasiljević ZŽ, Rakočević L, Pavlović VP, Ammar-Merah S, Vujančević J, Nikolić MV. Magnesium substitution with nickel and its influence on the sensing properties of MgFe2O4. in CYSC-2023 : 15th EcerS Conference for Young Scientists in Ceramics, Programme and Book of Abstracts; October 11-14, 2023, Novi Sad, Serbia. 2023;.
https://hdl.handle.net/21.15107/rcub_machinery_7269 .

Dojčinović, Milena, Vasiljević, Zorka Ž., Rakočević, Lazar, Pavlović, Vera P., Ammar-Merah, Souad, Vujančević, Jelena, Nikolić, Maria Vesna, "Magnesium substitution with nickel and its influence on the sensing properties of MgFe2O4" in CYSC-2023 : 15th EcerS Conference for Young Scientists in Ceramics, Programme and Book of Abstracts; October 11-14, 2023, Novi Sad, Serbia (2023),
https://hdl.handle.net/21.15107/rcub_machinery_7269 .

TY  - JOUR
AU  - Dojčinović, Milena 
AU  - Vasiljević, Zorka Ž.
AU  - Rakočević, Lazar
AU  - Pavlović, Vera P.
AU  - Ammar-Merah, Souad
AU  - Vujančević, Jelena 
AU  - Nikolić, Maria Vesna
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3982
AB  - Temperature- and humidity-sensing properties were evaluated of NixMg1-x spinel ferrites (0 ≤ x ≤ 1) synthesized by a sol-gel combustion method using citric acid as fuel and nitrate ions as oxidizing agents. After the exothermic reaction, amorphous powders were calcined at 700 °C followed by characterization with XRD, FTIR, XPS, EDS and Raman spectroscopy and FESEM microscopy. Synthesized powders were tested as humidity- and temperature-sensing materials in the form of thick films on interdigitated electrodes on alumina substrate in a climatic chamber. The physicochemical investigation of synthesized materials revealed a cubic spinel Fd3m phase, nanosized but agglomerated particles with a partially to completely inverse spinel structure with increasing Ni content. Ni0.1Mg0.9Fe2O4 showed the highest material constant (B30,90) value of 3747 K and temperature sensitivity (α) of −4.08%/K compared to pure magnesium ferrite (B30,90 value of 3426 K and α of −3.73%/K) and the highest average sensitivity towards humidity of 922 kΩ/%RH in the relative humidity (RH) range of 40–90% at the working temperature of 25 °C.
PB  - MDPI (Basel, Switzerland)
T2  - Chemosensors
T1  - Humidity and Temperature Sensing of Mixed Nickel–Magnesium Spinel Ferrites
IS  - 1
SP  - 34
VL  - 11
DO  - https://doi.org/10.3390/chemosensors11010034
ER  - 

@article{
author = "Dojčinović, Milena  and Vasiljević, Zorka Ž. and Rakočević, Lazar and Pavlović, Vera P. and Ammar-Merah, Souad and Vujančević, Jelena  and Nikolić, Maria Vesna",
year = "2023",
abstract = "Temperature- and humidity-sensing properties were evaluated of NixMg1-x spinel ferrites (0 ≤ x ≤ 1) synthesized by a sol-gel combustion method using citric acid as fuel and nitrate ions as oxidizing agents. After the exothermic reaction, amorphous powders were calcined at 700 °C followed by characterization with XRD, FTIR, XPS, EDS and Raman spectroscopy and FESEM microscopy. Synthesized powders were tested as humidity- and temperature-sensing materials in the form of thick films on interdigitated electrodes on alumina substrate in a climatic chamber. The physicochemical investigation of synthesized materials revealed a cubic spinel Fd3m phase, nanosized but agglomerated particles with a partially to completely inverse spinel structure with increasing Ni content. Ni0.1Mg0.9Fe2O4 showed the highest material constant (B30,90) value of 3747 K and temperature sensitivity (α) of −4.08%/K compared to pure magnesium ferrite (B30,90 value of 3426 K and α of −3.73%/K) and the highest average sensitivity towards humidity of 922 kΩ/%RH in the relative humidity (RH) range of 40–90% at the working temperature of 25 °C.",
publisher = "MDPI (Basel, Switzerland)",
journal = "Chemosensors",
title = "Humidity and Temperature Sensing of Mixed Nickel–Magnesium Spinel Ferrites",
number = "1",
pages = "34",
volume = "11",
doi = "https://doi.org/10.3390/chemosensors11010034"
}

Dojčinović, M., Vasiljević, Z. Ž., Rakočević, L., Pavlović, V. P., Ammar-Merah, S., Vujančević, J.,& Nikolić, M. V.. (2023). Humidity and Temperature Sensing of Mixed Nickel–Magnesium Spinel Ferrites. in Chemosensors
MDPI (Basel, Switzerland)., 11(1), 34.
https://doi.org/https://doi.org/10.3390/chemosensors11010034

Dojčinović M, Vasiljević ZŽ, Rakočević L, Pavlović VP, Ammar-Merah S, Vujančević J, Nikolić MV. Humidity and Temperature Sensing of Mixed Nickel–Magnesium Spinel Ferrites. in Chemosensors. 2023;11(1):34.
doi:https://doi.org/10.3390/chemosensors11010034 .

Dojčinović, Milena , Vasiljević, Zorka Ž., Rakočević, Lazar, Pavlović, Vera P., Ammar-Merah, Souad, Vujančević, Jelena , Nikolić, Maria Vesna, "Humidity and Temperature Sensing of Mixed Nickel–Magnesium Spinel Ferrites" in Chemosensors, 11, no. 1 (2023):34,
https://doi.org/https://doi.org/10.3390/chemosensors11010034 . .

TY  - CONF
AU  - Dojčinović, Milena 
AU  - Vasiljević, Zorka Ž.
AU  - Pavlović, Vera P.
AU  - Vujančević, Jelena
AU  - Tadić, Nenad
AU  - Nikolić, Maria Vesna
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4225
AB  - Problems that countries all over the world have in common are dependence of economy and energy production on fossil fuels. There is a growing need for energy production and storage routes that are safe for the environment, renewable, efficient and cheap. One of the directions in which science is moving forward is discovering materials suitable for use in batteries and supercapacitors to improve their operating potential, electrical capacity or biocompatibility. The objective is also to synthesize materials for batteries or supercapacitors that are cheap, consist of earth abundant elements and have high electrochemical activity.In this work, mixed nickel-magnesium ferrites NixMg1−xFe2O4, with x being 0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1, were synthesized via sol-gel combustion synthesis with citric acid used as fuel and nitrate ions used as oxidizing agents. Combusted powders were calcined at 700 °C. The structure and morphology of the powders were characterized with X-ray diffraction method (XRD), field emission scanning electron microscopy (FESEM), Raman and FTIR spectroscopy. The band gap was calculated by using UV/Vis diffuse reflectance spectroscopy (DRS). Samples were cast on nickel foam and tested as energy storage materials in a three-electrode setup in 3 M KOH aqueous solution as electrolyte. The methods used were cyclic voltammetry (CV) and constant current chronopotentiometry to obtain galvanostatic charge-discharge (GCD) curves. Results show that all of the synthesized materials show battery-type charge storage in alkaline electrolyte due to the formation of metal cation oxyhydroxides. With increasing nickel content, electrochemical activity drops. The highest value of capacity, 34.3 mA h g-1 at the current density of 500 mA g-1 is ascribed to magnesium ferrite, MgFe2O4.
PB  - University of Belgrade, Faculty of Physical Chemistry, Belgrade, Serbia
C3  - COIN2022 - Contemporary Batteries and Supercapacitors - International Symposium Belgrade 2022 - Program and Book of Abstracts, June 1-2, 2022
T1  - Mixed Ni-Mg Spinel Ferrites Used as Materials for Charge Storage Electrodes
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4225
ER  - 

@conference{
author = "Dojčinović, Milena  and Vasiljević, Zorka Ž. and Pavlović, Vera P. and Vujančević, Jelena and Tadić, Nenad and Nikolić, Maria Vesna",
year = "2022",
abstract = "Problems that countries all over the world have in common are dependence of economy and energy production on fossil fuels. There is a growing need for energy production and storage routes that are safe for the environment, renewable, efficient and cheap. One of the directions in which science is moving forward is discovering materials suitable for use in batteries and supercapacitors to improve their operating potential, electrical capacity or biocompatibility. The objective is also to synthesize materials for batteries or supercapacitors that are cheap, consist of earth abundant elements and have high electrochemical activity.In this work, mixed nickel-magnesium ferrites NixMg1−xFe2O4, with x being 0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1, were synthesized via sol-gel combustion synthesis with citric acid used as fuel and nitrate ions used as oxidizing agents. Combusted powders were calcined at 700 °C. The structure and morphology of the powders were characterized with X-ray diffraction method (XRD), field emission scanning electron microscopy (FESEM), Raman and FTIR spectroscopy. The band gap was calculated by using UV/Vis diffuse reflectance spectroscopy (DRS). Samples were cast on nickel foam and tested as energy storage materials in a three-electrode setup in 3 M KOH aqueous solution as electrolyte. The methods used were cyclic voltammetry (CV) and constant current chronopotentiometry to obtain galvanostatic charge-discharge (GCD) curves. Results show that all of the synthesized materials show battery-type charge storage in alkaline electrolyte due to the formation of metal cation oxyhydroxides. With increasing nickel content, electrochemical activity drops. The highest value of capacity, 34.3 mA h g-1 at the current density of 500 mA g-1 is ascribed to magnesium ferrite, MgFe2O4.",
publisher = "University of Belgrade, Faculty of Physical Chemistry, Belgrade, Serbia",
journal = "COIN2022 - Contemporary Batteries and Supercapacitors - International Symposium Belgrade 2022 - Program and Book of Abstracts, June 1-2, 2022",
title = "Mixed Ni-Mg Spinel Ferrites Used as Materials for Charge Storage Electrodes",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4225"
}

Dojčinović, M., Vasiljević, Z. Ž., Pavlović, V. P., Vujančević, J., Tadić, N.,& Nikolić, M. V.. (2022). Mixed Ni-Mg Spinel Ferrites Used as Materials for Charge Storage Electrodes. in COIN2022 - Contemporary Batteries and Supercapacitors - International Symposium Belgrade 2022 - Program and Book of Abstracts, June 1-2, 2022
University of Belgrade, Faculty of Physical Chemistry, Belgrade, Serbia..
https://hdl.handle.net/21.15107/rcub_machinery_4225

Dojčinović M, Vasiljević ZŽ, Pavlović VP, Vujančević J, Tadić N, Nikolić MV. Mixed Ni-Mg Spinel Ferrites Used as Materials for Charge Storage Electrodes. in COIN2022 - Contemporary Batteries and Supercapacitors - International Symposium Belgrade 2022 - Program and Book of Abstracts, June 1-2, 2022. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_4225 .

Dojčinović, Milena , Vasiljević, Zorka Ž., Pavlović, Vera P., Vujančević, Jelena, Tadić, Nenad, Nikolić, Maria Vesna, "Mixed Ni-Mg Spinel Ferrites Used as Materials for Charge Storage Electrodes" in COIN2022 - Contemporary Batteries and Supercapacitors - International Symposium Belgrade 2022 - Program and Book of Abstracts, June 1-2, 2022 (2022),
https://hdl.handle.net/21.15107/rcub_machinery_4225 .

TY  - JOUR
AU  - Jovanović, Jelena
AU  - Ćirković, Jovana
AU  - Radojković, Aleksandar
AU  - Mutavdzić, Dragosav
AU  - Tanasijević, Gordana
AU  - Joksimović, Kristina
AU  - Bakić, Gordana
AU  - Branković, Goran
AU  - Branković, Zorica
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3527
AB  - This investigation was aimed to develop films and coatings based on natural biopolymers and active components, with physicochemical and functional properties for application in antimicrobial packaging. Biopolymer films were obtained from emulsions and dispersions by casting method. Coatings were formed by the application of emulsions on existing packaging. Synthesis of emulsions and dispersions were performed by combining biopolymers (chitosan-gelatin, pectin-gelatin) with lemongrass essential oil (LEO), Zn(CH3COO)2.2H2O, or ZnO, as active components. Fourier transform infrared (FTIR) spectra of the films showed that the addition of glycerol contributed to the forming of strong hydrogen bonds between glycerol and chitosan-gelatin or pectin-gelatin composites, facilitating the process of polymer branching, which is substantial for encapsulation. Thermal analyses revealed two characteristic processes occurring at 110 degrees C (water evaporation) and within 215-235 degrees C (degradation of polysaccharide and glycerol). Major weight losses were observed at 290 degrees C (chitosan-gelatin films) and 215 degrees C (pectin-gelatin films). The chitosan-gelatin films exhibited a lower degree of solubility (31-21%), and better mechanical properties comparing with the pectin-gelatin films. The chitosan-gelatin emulsions and dispersions exhibited a higher antibacterial effect in vitro against E. coli, B. subtilis, and S. aureus. In the case of the pectin-gelatin emulsions, the impact of LEO on the antibacterial activity was evident. The effects of biopolymer coatings on the development of microorganisms on fresh raspberries (Rubus idaeus L.) were performed in vivo during eight days of raspberry storage at refrigerator temperature. The tested coatings extended the shelf life of stored raspberries from four to eight days. The synergistic effect between LEO and ZnO or Zn-Ac was observed both in vivo and in vitro.
PB  - Elsevier Science Sa, Lausanne
T2  - Progress in Organic Coatings
T1  - Chitosan and pectin-based films and coatings with active components for application in antimicrobial food packaging
VL  - 158
DO  - 10.1016/j.porgcoat.2021.106349
ER  - 

@article{
author = "Jovanović, Jelena and Ćirković, Jovana and Radojković, Aleksandar and Mutavdzić, Dragosav and Tanasijević, Gordana and Joksimović, Kristina and Bakić, Gordana and Branković, Goran and Branković, Zorica",
year = "2021",
abstract = "This investigation was aimed to develop films and coatings based on natural biopolymers and active components, with physicochemical and functional properties for application in antimicrobial packaging. Biopolymer films were obtained from emulsions and dispersions by casting method. Coatings were formed by the application of emulsions on existing packaging. Synthesis of emulsions and dispersions were performed by combining biopolymers (chitosan-gelatin, pectin-gelatin) with lemongrass essential oil (LEO), Zn(CH3COO)2.2H2O, or ZnO, as active components. Fourier transform infrared (FTIR) spectra of the films showed that the addition of glycerol contributed to the forming of strong hydrogen bonds between glycerol and chitosan-gelatin or pectin-gelatin composites, facilitating the process of polymer branching, which is substantial for encapsulation. Thermal analyses revealed two characteristic processes occurring at 110 degrees C (water evaporation) and within 215-235 degrees C (degradation of polysaccharide and glycerol). Major weight losses were observed at 290 degrees C (chitosan-gelatin films) and 215 degrees C (pectin-gelatin films). The chitosan-gelatin films exhibited a lower degree of solubility (31-21%), and better mechanical properties comparing with the pectin-gelatin films. The chitosan-gelatin emulsions and dispersions exhibited a higher antibacterial effect in vitro against E. coli, B. subtilis, and S. aureus. In the case of the pectin-gelatin emulsions, the impact of LEO on the antibacterial activity was evident. The effects of biopolymer coatings on the development of microorganisms on fresh raspberries (Rubus idaeus L.) were performed in vivo during eight days of raspberry storage at refrigerator temperature. The tested coatings extended the shelf life of stored raspberries from four to eight days. The synergistic effect between LEO and ZnO or Zn-Ac was observed both in vivo and in vitro.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Progress in Organic Coatings",
title = "Chitosan and pectin-based films and coatings with active components for application in antimicrobial food packaging",
volume = "158",
doi = "10.1016/j.porgcoat.2021.106349"
}

Jovanović, J., Ćirković, J., Radojković, A., Mutavdzić, D., Tanasijević, G., Joksimović, K., Bakić, G., Branković, G.,& Branković, Z.. (2021). Chitosan and pectin-based films and coatings with active components for application in antimicrobial food packaging. in Progress in Organic Coatings
Elsevier Science Sa, Lausanne., 158.
https://doi.org/10.1016/j.porgcoat.2021.106349

Jovanović J, Ćirković J, Radojković A, Mutavdzić D, Tanasijević G, Joksimović K, Bakić G, Branković G, Branković Z. Chitosan and pectin-based films and coatings with active components for application in antimicrobial food packaging. in Progress in Organic Coatings. 2021;158.
doi:10.1016/j.porgcoat.2021.106349 .

Jovanović, Jelena, Ćirković, Jovana, Radojković, Aleksandar, Mutavdzić, Dragosav, Tanasijević, Gordana, Joksimović, Kristina, Bakić, Gordana, Branković, Goran, Branković, Zorica, "Chitosan and pectin-based films and coatings with active components for application in antimicrobial food packaging" in Progress in Organic Coatings, 158 (2021),
https://doi.org/10.1016/j.porgcoat.2021.106349 . .

TY  - JOUR
AU  - Dojčinović, Milena 
AU  - Vasiljević, Zorka Ž.
AU  - Pavlović, Vera P.
AU  - Barišić, Dario
AU  - Pajić, Damir
AU  - Tadić, Nenad B.
AU  - Nikolić, Maria Vesna
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4068
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
T2  - Journal of Alloys and Compounds
T1  - Mixed Mg-Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties
IS  - 1
SP  - 157429
VL  - 855
DO  - 10.1016/j.jallcom.2020.157429
ER  - 

@article{
author = "Dojčinović, Milena  and Vasiljević, Zorka Ž. and Pavlović, Vera P. and Barišić, 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",
journal = "Journal of Alloys and Compounds",
title = "Mixed Mg-Co spinel ferrites: Structure, morphology, magnetic and photocatalytic properties",
number = "1",
pages = "157429",
volume = "855",
doi = "10.1016/j.jallcom.2020.157429"
}

Dojčinović, M., Vasiljević, Z. Ž., Pavlović, V. P., Barišić, 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., 855(1), 157429.
https://doi.org/10.1016/j.jallcom.2020.157429

Dojčinović M, Vasiljević ZŽ, Pavlović VP, Barišić 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(1):157429.
doi:10.1016/j.jallcom.2020.157429 .

Dojčinović, Milena , Vasiljević, Zorka Ž., Pavlović, Vera P., Barišić, 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, no. 1 (2021):157429,
https://doi.org/10.1016/j.jallcom.2020.157429 . .

TY  - JOUR
AU  - Dojčinović, Milena 
AU  - Vasiljević, Zorka Ž.
AU  - Pavlović, Vera P.
AU  - Barišić, Dario
AU  - Pajić, Damir
AU  - Tadić, Nenad B.
AU  - Nikolić, Maria Vesna
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3604
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 Ž. and Pavlović, Vera P. and Barišić, 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. Ž., Pavlović, V. P., Barišić, 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 ZŽ, Pavlović VP, Barišić 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 Ž., Pavlović, Vera P., Barišić, 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 . .

TY  - JOUR
AU  - Nikolić, Maria Vesna
AU  - Labus, Nebojša J.
AU  - Pavlović, Vera P.
AU  - Marković, Smilja
AU  - Luković, Miloljub D.
AU  - Tadić, Nenad B.
AU  - Vujančević, Jelena
AU  - Vlahović, Branislav
AU  - Pavlović, Vladimir B.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3373
AB  - Nanocrystalline Zn2SnO4/SnO2 powder was obtained by a solid state reaction of ZnO and SnO2 nanopowders mixed in the molar ratio 1:1. The phase composition of the obtained powder was studied by XRD and Raman spectroscopy, morphology and texture were characterized by FESEM, TEM, BET and Hg porosimetry, while XPS and FTIR spectroscopy were used to determine the surface chemistry. The influence of humidity on complex impedance was monitored on bulk samples in the relative humidity (RH) range 30-90% in a climatic chamber in the frequency range 42 Hz- 1 MHz at working temperatures of 25 and 50 degrees C. Change in RH had a significant influence on impedance reduction, especially noticeable in the lower frequency range, indicating potential application of this nanocomposite as a humidity sensing material. Increase in RH led to an increase in AC conductivity that changed with frequency according to the Jonscher power law. The frequency exponent decreased with increase in RH and sample temperature indicating that the correlated hopping barrier model is the dominant conduction mechanism. Complex impedance was analyzed using an equivalent circuit consisting of a parallel resistance and constant phase element, showing the dominant influence of grain boundaries at both working temperatures (25 and 50 degrees C). The resistance decreased, while the capacitance and relaxation frequency increased with increase in RH. At high humidity an added Wartburg element enabled modeling of the charge diffusion process.
PB  - Springer, Dordrecht
T2  - Journal of Electroceramics
T1  - Nanocrystalline Zn2SnO4/SnO2: Crystal structure and humidity influence on complex impedance
EP  - 147
IS  - 4
SP  - 135
VL  - 45
DO  - 10.1007/s10832-021-00232-z
ER  - 

@article{
author = "Nikolić, Maria Vesna and Labus, Nebojša J. and Pavlović, Vera P. and Marković, Smilja and Luković, Miloljub D. and Tadić, Nenad B. and Vujančević, Jelena and Vlahović, Branislav and Pavlović, Vladimir B.",
year = "2020",
abstract = "Nanocrystalline Zn2SnO4/SnO2 powder was obtained by a solid state reaction of ZnO and SnO2 nanopowders mixed in the molar ratio 1:1. The phase composition of the obtained powder was studied by XRD and Raman spectroscopy, morphology and texture were characterized by FESEM, TEM, BET and Hg porosimetry, while XPS and FTIR spectroscopy were used to determine the surface chemistry. The influence of humidity on complex impedance was monitored on bulk samples in the relative humidity (RH) range 30-90% in a climatic chamber in the frequency range 42 Hz- 1 MHz at working temperatures of 25 and 50 degrees C. Change in RH had a significant influence on impedance reduction, especially noticeable in the lower frequency range, indicating potential application of this nanocomposite as a humidity sensing material. Increase in RH led to an increase in AC conductivity that changed with frequency according to the Jonscher power law. The frequency exponent decreased with increase in RH and sample temperature indicating that the correlated hopping barrier model is the dominant conduction mechanism. Complex impedance was analyzed using an equivalent circuit consisting of a parallel resistance and constant phase element, showing the dominant influence of grain boundaries at both working temperatures (25 and 50 degrees C). The resistance decreased, while the capacitance and relaxation frequency increased with increase in RH. At high humidity an added Wartburg element enabled modeling of the charge diffusion process.",
publisher = "Springer, Dordrecht",
journal = "Journal of Electroceramics",
title = "Nanocrystalline Zn2SnO4/SnO2: Crystal structure and humidity influence on complex impedance",
pages = "147-135",
number = "4",
volume = "45",
doi = "10.1007/s10832-021-00232-z"
}

Nikolić, M. V., Labus, N. J., Pavlović, V. P., Marković, S., Luković, M. D., Tadić, N. B., Vujančević, J., Vlahović, B.,& Pavlović, V. B.. (2020). Nanocrystalline Zn2SnO4/SnO2: Crystal structure and humidity influence on complex impedance. in Journal of Electroceramics
Springer, Dordrecht., 45(4), 135-147.
https://doi.org/10.1007/s10832-021-00232-z

Nikolić MV, Labus NJ, Pavlović VP, Marković S, Luković MD, Tadić NB, Vujančević J, Vlahović B, Pavlović VB. Nanocrystalline Zn2SnO4/SnO2: Crystal structure and humidity influence on complex impedance. in Journal of Electroceramics. 2020;45(4):135-147.
doi:10.1007/s10832-021-00232-z .

Nikolić, Maria Vesna, Labus, Nebojša J., Pavlović, Vera P., Marković, Smilja, Luković, Miloljub D., Tadić, Nenad B., Vujančević, Jelena, Vlahović, Branislav, Pavlović, Vladimir B., "Nanocrystalline Zn2SnO4/SnO2: Crystal structure and humidity influence on complex impedance" in Journal of Electroceramics, 45, no. 4 (2020):135-147,
https://doi.org/10.1007/s10832-021-00232-z . .