TY  - JOUR
AU  - Popov, Nina
AU  - Bošković, Marko
AU  - Perović, Marija M.
AU  - Németh, Zoltán
AU  - Wang, Junhu
AU  - Kuang, Zhichong
AU  - Reissner, Michael
AU  - Kuzmann, Ernő
AU  - Homonnay, Zoltán
AU  - Kubuki, Shiro
AU  - Marciuš, Marijan
AU  - Ristić, Mira
AU  - Musić, Svetozar
AU  - Stanković, Dalibor M.
AU  - Krehula, Stjepko
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9516
AB  - Pure hematite nanorods and very long and thin cobalt-doped hematite nanorods (nanoneedles) were prepared by a combined precipitation and annealing method. The influence of the level of cobalt doping on different properties of hematite nanorods was investigated. Incorporation of cobalt in the form of low-spin Co3+ ions into the structure of hematite by substitution for high-spin Fe3+ ions was proved by determination of a significant unit cell contraction by powder X-ray diffraction (PXRD) and characteristic positions of the absorption edge in X-ray absorption near edge structure (XANES) spectra and peaks in X-ray emission (XES) spectra. Cobalt doping caused a gradual elongation and thinning of hematite nanorods – very long and thin 1D nanoparticles (nanoneedles) were formed in the presence of 10 and 12 mol% Co. Magnetic measurements showed a strong increase in low-temperature remanent magnetization and coercivity upon cobalt doping, as well as a disappearance of the Morin transition, which was also confirmed by Mössbauer spectroscopy. Cobalt doping significantly affected optical properties of hematite nanorods – absorption in the visible and NIR ranges increased, which was accompanied by narrowing of the optical band gap. Compared with pure hematite nanorods cobalt-doped hematite nanoneedles showed a significantly better electrocatalytic activity for the oxygen evolution reaction (OER). © 2020 Elsevier Ltd
T2  - Journal of Physics and Chemistry of Solids
T1  - Influence of low-spin Co3+ for high-spin Fe3+ substitution on the structural, magnetic, optical and catalytic properties of hematite (α-Fe2O3) nanorods
VL  - 152
SP  - 109929
DO  - 10.1016/j.jpcs.2020.109929
ER  - 

@article{
author = "Popov, Nina and Bošković, Marko and Perović, Marija M. and Németh, Zoltán and Wang, Junhu and Kuang, Zhichong and Reissner, Michael and Kuzmann, Ernő and Homonnay, Zoltán and Kubuki, Shiro and Marciuš, Marijan and Ristić, Mira and Musić, Svetozar and Stanković, Dalibor M. and Krehula, Stjepko",
year = "2021",
abstract = "Pure hematite nanorods and very long and thin cobalt-doped hematite nanorods (nanoneedles) were prepared by a combined precipitation and annealing method. The influence of the level of cobalt doping on different properties of hematite nanorods was investigated. Incorporation of cobalt in the form of low-spin Co3+ ions into the structure of hematite by substitution for high-spin Fe3+ ions was proved by determination of a significant unit cell contraction by powder X-ray diffraction (PXRD) and characteristic positions of the absorption edge in X-ray absorption near edge structure (XANES) spectra and peaks in X-ray emission (XES) spectra. Cobalt doping caused a gradual elongation and thinning of hematite nanorods – very long and thin 1D nanoparticles (nanoneedles) were formed in the presence of 10 and 12 mol% Co. Magnetic measurements showed a strong increase in low-temperature remanent magnetization and coercivity upon cobalt doping, as well as a disappearance of the Morin transition, which was also confirmed by Mössbauer spectroscopy. Cobalt doping significantly affected optical properties of hematite nanorods – absorption in the visible and NIR ranges increased, which was accompanied by narrowing of the optical band gap. Compared with pure hematite nanorods cobalt-doped hematite nanoneedles showed a significantly better electrocatalytic activity for the oxygen evolution reaction (OER). © 2020 Elsevier Ltd",
journal = "Journal of Physics and Chemistry of Solids",
title = "Influence of low-spin Co3+ for high-spin Fe3+ substitution on the structural, magnetic, optical and catalytic properties of hematite (α-Fe2O3) nanorods",
volume = "152",
pages = "109929",
doi = "10.1016/j.jpcs.2020.109929"
}

Popov, N., Bošković, M., Perović, M. M., Németh, Z., Wang, J., Kuang, Z., Reissner, M., Kuzmann, E., Homonnay, Z., Kubuki, S., Marciuš, M., Ristić, M., Musić, S., Stanković, D. M.,& Krehula, S.. (2021). Influence of low-spin Co3+ for high-spin Fe3+ substitution on the structural, magnetic, optical and catalytic properties of hematite (α-Fe2O3) nanorods. in Journal of Physics and Chemistry of Solids, 152, 109929.
https://doi.org/10.1016/j.jpcs.2020.109929

Popov N, Bošković M, Perović MM, Németh Z, Wang J, Kuang Z, Reissner M, Kuzmann E, Homonnay Z, Kubuki S, Marciuš M, Ristić M, Musić S, Stanković DM, Krehula S. Influence of low-spin Co3+ for high-spin Fe3+ substitution on the structural, magnetic, optical and catalytic properties of hematite (α-Fe2O3) nanorods. in Journal of Physics and Chemistry of Solids. 2021;152:109929.
doi:10.1016/j.jpcs.2020.109929 .

Popov, Nina, Bošković, Marko, Perović, Marija M., Németh, Zoltán, Wang, Junhu, Kuang, Zhichong, Reissner, Michael, Kuzmann, Ernő, Homonnay, Zoltán, Kubuki, Shiro, Marciuš, Marijan, Ristić, Mira, Musić, Svetozar, Stanković, Dalibor M., Krehula, Stjepko, "Influence of low-spin Co3+ for high-spin Fe3+ substitution on the structural, magnetic, optical and catalytic properties of hematite (α-Fe2O3) nanorods" in Journal of Physics and Chemistry of Solids, 152 (2021):109929,
https://doi.org/10.1016/j.jpcs.2020.109929 . .

TY  - JOUR
AU  - Krehula, Stjepko
AU  - Ristić, Mira
AU  - Wu, Chuchu
AU  - Li, Xuning
AU  - Jiang, Luhua
AU  - Wang, Junhu H.
AU  - Sun, Gongquan
AU  - Zhang, Tao
AU  - Perović, Marija M.
AU  - Bošković, Marko
AU  - Antić, Bratislav
AU  - Kratofil Krehula, Ljerka
AU  - Kobzi, Balazs
AU  - Kubuki, Shiro
AU  - Musić, Svetozar
PY  - 2018
UR  - http://linkinghub.elsevier.com/retrieve/pii/S0925838818313197
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7744
AB  - This paper systematically examines the influence of the level of Fe(III) doping on the crystal structure and other properties of Ni(OH)(2). Reference beta-Ni(OH)(2) and Fe-doped Ni(OH)(2) samples were synthesized by hydrothermal precipitation of mixed Ni(II) and Fe(III) nitrate aqueous solutions in a highly alkaline medium. The samples were investigated using X-ray powder diffraction (XRPD), scanning and transmission electron microscopy (FE-SEM and TEM), energy dispersive X-ray spectroscopy (EDS), Mossbauer spectroscopy, magnetic measurements, Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy, thermogravimetric analysis (TGA) and electrochemical measurements. Incorporation of Fe in beta-Ni(OH)(2) by cation substitution was confirmed from the shifts in position of XRPD lines due to the difference in the ionic radius of Fe3+ and Ni-2. The Fe-3-for-Ni2+ substitution in beta-Ni(OH)(2) caused formation of an interstratifled structure with beta-Ni(OH)(2) and alpha-Ni(OH)(2) structural units interconnected within the same structural layers and crystallites. Mossbauer spectra revealed the presence of Fe3+ ions in highly distorted octahedral sites, presumably at the boundary between the alpha-Ni(OH)(2) and beta-Ni(OH)(2) structural units within the same structural layer. Electrochemical measurements showed significant increase in oxygen evolution reaction (OER) catalytic activity of Fe-doped Ni(OH)(2) compared to pure phase. (C) 2018 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Influence of Fe(III) doping on the crystal structure and properties of hydrothermally prepared β-Ni(OH) 2 nanostructures
VL  - 750
SP  - 687
EP  - 695
DO  - 10.1016/j.jallcom.2018.04.032
ER  - 

@article{
author = "Krehula, Stjepko and Ristić, Mira and Wu, Chuchu and Li, Xuning and Jiang, Luhua and Wang, Junhu H. and Sun, Gongquan and Zhang, Tao and Perović, Marija M. and Bošković, Marko and Antić, Bratislav and Kratofil Krehula, Ljerka and Kobzi, Balazs and Kubuki, Shiro and Musić, Svetozar",
year = "2018",
abstract = "This paper systematically examines the influence of the level of Fe(III) doping on the crystal structure and other properties of Ni(OH)(2). Reference beta-Ni(OH)(2) and Fe-doped Ni(OH)(2) samples were synthesized by hydrothermal precipitation of mixed Ni(II) and Fe(III) nitrate aqueous solutions in a highly alkaline medium. The samples were investigated using X-ray powder diffraction (XRPD), scanning and transmission electron microscopy (FE-SEM and TEM), energy dispersive X-ray spectroscopy (EDS), Mossbauer spectroscopy, magnetic measurements, Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible-near infrared (UV-Vis-NIR) spectroscopy, thermogravimetric analysis (TGA) and electrochemical measurements. Incorporation of Fe in beta-Ni(OH)(2) by cation substitution was confirmed from the shifts in position of XRPD lines due to the difference in the ionic radius of Fe3+ and Ni-2. The Fe-3-for-Ni2+ substitution in beta-Ni(OH)(2) caused formation of an interstratifled structure with beta-Ni(OH)(2) and alpha-Ni(OH)(2) structural units interconnected within the same structural layers and crystallites. Mossbauer spectra revealed the presence of Fe3+ ions in highly distorted octahedral sites, presumably at the boundary between the alpha-Ni(OH)(2) and beta-Ni(OH)(2) structural units within the same structural layer. Electrochemical measurements showed significant increase in oxygen evolution reaction (OER) catalytic activity of Fe-doped Ni(OH)(2) compared to pure phase. (C) 2018 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Influence of Fe(III) doping on the crystal structure and properties of hydrothermally prepared β-Ni(OH) 2 nanostructures",
volume = "750",
pages = "687-695",
doi = "10.1016/j.jallcom.2018.04.032"
}

Krehula, S., Ristić, M., Wu, C., Li, X., Jiang, L., Wang, J. H., Sun, G., Zhang, T., Perović, M. M., Bošković, M., Antić, B., Kratofil Krehula, L., Kobzi, B., Kubuki, S.,& Musić, S.. (2018). Influence of Fe(III) doping on the crystal structure and properties of hydrothermally prepared β-Ni(OH) 2 nanostructures. in Journal of Alloys and Compounds, 750, 687-695.
https://doi.org/10.1016/j.jallcom.2018.04.032

Krehula S, Ristić M, Wu C, Li X, Jiang L, Wang JH, Sun G, Zhang T, Perović MM, Bošković M, Antić B, Kratofil Krehula L, Kobzi B, Kubuki S, Musić S. Influence of Fe(III) doping on the crystal structure and properties of hydrothermally prepared β-Ni(OH) 2 nanostructures. in Journal of Alloys and Compounds. 2018;750:687-695.
doi:10.1016/j.jallcom.2018.04.032 .

Krehula, Stjepko, Ristić, Mira, Wu, Chuchu, Li, Xuning, Jiang, Luhua, Wang, Junhu H., Sun, Gongquan, Zhang, Tao, Perović, Marija M., Bošković, Marko, Antić, Bratislav, Kratofil Krehula, Ljerka, Kobzi, Balazs, Kubuki, Shiro, Musić, Svetozar, "Influence of Fe(III) doping on the crystal structure and properties of hydrothermally prepared β-Ni(OH) 2 nanostructures" in Journal of Alloys and Compounds, 750 (2018):687-695,
https://doi.org/10.1016/j.jallcom.2018.04.032 . .

TY  - JOUR
AU  - Krehula, Stjepko
AU  - Ristić, Mira
AU  - Kubuki, Shiro
AU  - Iida, Yusuke
AU  - Perović, Marija M.
AU  - Fabian, Martin
AU  - Musić, Svetozar
PY  - 2015
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/265
AB  - Various mixed Fe-Ga oxides were prepared by the calcination of mixed Fe-Ga oxyhydroxide precursors (alpha-Fe1 xGaxOOH solid solutions, 0 LT = x LT = 1) at 500 or 1000 degrees C. Isostructural corundum-type oxides alpha-Fe2O3 and alpha-Ga2O3, as well as their solid solutions alpha-Fe-2 xGaxO3 in the entire concentration range (x = 0, 0.4, 1, 1.6 and 2) were prepared by calcination at 500 degrees C. An increase in the Ga content in alpha-Fe2 xGaxO3 resulted in a reduction of the unit cell size, a weakened hyperfine magnetic field, a disappearance of the Morin transition, an increase of magnetization at low temperatures, a shift in the position of IR bands to higher wavenumbers, and a lower intensity of absorption bands in the UV-Vis-NIR spectra. The calcination of Fe-Ga oxyhydroxides at 1000 degrees C resulted in the formation of a rhombohedral alpha-Fe-2 xGaxO3 phase for x = 0 and 0.4. An orthorhombic GaFeO3 phase with Fe3+ cations located in 3 different octahedral sites was obtained by the calcination at 1000 degrees C of mixed Fe-Ga oxyhydroxide with the Fe:Ga ratio of 1:1. A monoclinic phase b-Fe-2 xGaxO3 (x = 1.6 and 2) was obtained by the calcination at 1000 degrees C of Fe-Ga oxyhydroxides with 80 and 100 mol% Ga. The monoclinic beta-Ga1.6Fe0.4O3 showed two strong luminescence peaks in the blue region of the PL spectrum. (C) 2015 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Synthesis and microstructural properties of mixed iron-gallium oxides
VL  - 634
SP  - 130
EP  - 141
DO  - 10.1016/j.jallcom.2015.02.065
ER  - 

@article{
author = "Krehula, Stjepko and Ristić, Mira and Kubuki, Shiro and Iida, Yusuke and Perović, Marija M. and Fabian, Martin and Musić, Svetozar",
year = "2015",
abstract = "Various mixed Fe-Ga oxides were prepared by the calcination of mixed Fe-Ga oxyhydroxide precursors (alpha-Fe1 xGaxOOH solid solutions, 0 LT = x LT = 1) at 500 or 1000 degrees C. Isostructural corundum-type oxides alpha-Fe2O3 and alpha-Ga2O3, as well as their solid solutions alpha-Fe-2 xGaxO3 in the entire concentration range (x = 0, 0.4, 1, 1.6 and 2) were prepared by calcination at 500 degrees C. An increase in the Ga content in alpha-Fe2 xGaxO3 resulted in a reduction of the unit cell size, a weakened hyperfine magnetic field, a disappearance of the Morin transition, an increase of magnetization at low temperatures, a shift in the position of IR bands to higher wavenumbers, and a lower intensity of absorption bands in the UV-Vis-NIR spectra. The calcination of Fe-Ga oxyhydroxides at 1000 degrees C resulted in the formation of a rhombohedral alpha-Fe-2 xGaxO3 phase for x = 0 and 0.4. An orthorhombic GaFeO3 phase with Fe3+ cations located in 3 different octahedral sites was obtained by the calcination at 1000 degrees C of mixed Fe-Ga oxyhydroxide with the Fe:Ga ratio of 1:1. A monoclinic phase b-Fe-2 xGaxO3 (x = 1.6 and 2) was obtained by the calcination at 1000 degrees C of Fe-Ga oxyhydroxides with 80 and 100 mol% Ga. The monoclinic beta-Ga1.6Fe0.4O3 showed two strong luminescence peaks in the blue region of the PL spectrum. (C) 2015 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Synthesis and microstructural properties of mixed iron-gallium oxides",
volume = "634",
pages = "130-141",
doi = "10.1016/j.jallcom.2015.02.065"
}

Krehula, S., Ristić, M., Kubuki, S., Iida, Y., Perović, M. M., Fabian, M.,& Musić, S.. (2015). Synthesis and microstructural properties of mixed iron-gallium oxides. in Journal of Alloys and Compounds, 634, 130-141.
https://doi.org/10.1016/j.jallcom.2015.02.065

Krehula S, Ristić M, Kubuki S, Iida Y, Perović MM, Fabian M, Musić S. Synthesis and microstructural properties of mixed iron-gallium oxides. in Journal of Alloys and Compounds. 2015;634:130-141.
doi:10.1016/j.jallcom.2015.02.065 .

Krehula, Stjepko, Ristić, Mira, Kubuki, Shiro, Iida, Yusuke, Perović, Marija M., Fabian, Martin, Musić, Svetozar, "Synthesis and microstructural properties of mixed iron-gallium oxides" in Journal of Alloys and Compounds, 634 (2015):130-141,
https://doi.org/10.1016/j.jallcom.2015.02.065 . .