TY  - JOUR
AU  - Jović, Borka
AU  - Lačnjevac, Uroš
AU  - Jović, Vladimir
AU  - Gajić Krstajić, Ljiljana
AU  - Kovač, Janez
AU  - Poleti, Dejan
AU  - Krstajić, Nedeljko
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5833
AB  - The oxygen evolution reaction (OER) was studied at pure Ni and Ni-(Ebonex/Ir) composite coatings in 1 M NaOH solution at 25 °C. Ni-(Ebonex-supported Ir) coatings were electrodeposited from a nickel Watts bath containing different concentrations of suspended Ebonex/Ir particles (0–2 g dm−3) onto a Ni 40 mesh substrate. The surface morphology of the coatings was examined by scanning electron microscopy (SEM), the surface composition by energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS), whereas the electrochemical properties were studied by electrochemical impedance spectroscopy (EIS), polarization measurements and cyclic voltammetry (CV). It was shown that the roughness factor of Ni-(Ebonex/Ir) composite coatings calculated relative to the surface area of the pure Ni sample increased with the increasing content of Ebonex/Ir particles in the bath to a maximum value of 40.6. All samples displayed a Tafel slope of about 60 mV dec−1 in the potential range corresponding to lower current densities for the OER. The increase of the apparent activity for the OER at Ni-(Ebonex/Ir) coatings compared with the pure Ni coating was attributed only to the increase of the electrochemically active surface area. Although the pure Ni coating initially exhibited higher intrinsic catalytic activity for the OER than the composite coatings, it also showed a drastic loss of activity after subjecting to continuous oxygen evolution at j = 50 mA cm−2 for 24 h (ΔE = 395 mV). At the same time, the OER overpotential at Ni-(Ebonex/Ir) coatings only negligibly increased after the stability test (ΔE = 22 mV). The improved retention of catalytic activity observed with Ni-(Ebonex/Ir) coatings was ascribed to the presence of IrO2, which inhibited the formation of the inactive γ-NiOOH phase.
PB  - Elsevier Ltd.
T2  - International Journal of Hydrogen Energy
T1  - Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part II: Oxygen evolution
EP  - 20514
IS  - 45
SP  - 20502
VL  - 41
DO  - 10.1016/j.ijhydene.2016.08.226
UR  - https://hdl.handle.net/21.15107/rcub_dais_15978
ER  - 

@article{
author = "Jović, Borka and Lačnjevac, Uroš and Jović, Vladimir and Gajić Krstajić, Ljiljana and Kovač, Janez and Poleti, Dejan and Krstajić, Nedeljko",
year = "2016",
abstract = "The oxygen evolution reaction (OER) was studied at pure Ni and Ni-(Ebonex/Ir) composite coatings in 1 M NaOH solution at 25 °C. Ni-(Ebonex-supported Ir) coatings were electrodeposited from a nickel Watts bath containing different concentrations of suspended Ebonex/Ir particles (0–2 g dm−3) onto a Ni 40 mesh substrate. The surface morphology of the coatings was examined by scanning electron microscopy (SEM), the surface composition by energy dispersive X-ray spectroscopy (EDS), X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS), whereas the electrochemical properties were studied by electrochemical impedance spectroscopy (EIS), polarization measurements and cyclic voltammetry (CV). It was shown that the roughness factor of Ni-(Ebonex/Ir) composite coatings calculated relative to the surface area of the pure Ni sample increased with the increasing content of Ebonex/Ir particles in the bath to a maximum value of 40.6. All samples displayed a Tafel slope of about 60 mV dec−1 in the potential range corresponding to lower current densities for the OER. The increase of the apparent activity for the OER at Ni-(Ebonex/Ir) coatings compared with the pure Ni coating was attributed only to the increase of the electrochemically active surface area. Although the pure Ni coating initially exhibited higher intrinsic catalytic activity for the OER than the composite coatings, it also showed a drastic loss of activity after subjecting to continuous oxygen evolution at j = 50 mA cm−2 for 24 h (ΔE = 395 mV). At the same time, the OER overpotential at Ni-(Ebonex/Ir) coatings only negligibly increased after the stability test (ΔE = 22 mV). The improved retention of catalytic activity observed with Ni-(Ebonex/Ir) coatings was ascribed to the presence of IrO2, which inhibited the formation of the inactive γ-NiOOH phase.",
publisher = "Elsevier Ltd.",
journal = "International Journal of Hydrogen Energy",
title = "Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part II: Oxygen evolution",
pages = "20514-20502",
number = "45",
volume = "41",
doi = "10.1016/j.ijhydene.2016.08.226",
url = "https://hdl.handle.net/21.15107/rcub_dais_15978"
}

Jović, B., Lačnjevac, U., Jović, V., Gajić Krstajić, L., Kovač, J., Poleti, D.,& Krstajić, N.. (2016). Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part II: Oxygen evolution. in International Journal of Hydrogen Energy
Elsevier Ltd.., 41(45), 20502-20514.
https://doi.org/10.1016/j.ijhydene.2016.08.226
https://hdl.handle.net/21.15107/rcub_dais_15978

Jović B, Lačnjevac U, Jović V, Gajić Krstajić L, Kovač J, Poleti D, Krstajić N. Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part II: Oxygen evolution. in International Journal of Hydrogen Energy. 2016;41(45):20502-20514.
doi:10.1016/j.ijhydene.2016.08.226
https://hdl.handle.net/21.15107/rcub_dais_15978 .

Jović, Borka, Lačnjevac, Uroš, Jović, Vladimir, Gajić Krstajić, Ljiljana, Kovač, Janez, Poleti, Dejan, Krstajić, Nedeljko, "Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part II: Oxygen evolution" in International Journal of Hydrogen Energy, 41, no. 45 (2016):20502-20514,
https://doi.org/10.1016/j.ijhydene.2016.08.226 .,
https://hdl.handle.net/21.15107/rcub_dais_15978 .

TY  - JOUR
AU  - Elezović, Nevenka
AU  - Radmilović, Velimir R.
AU  - Kovač, Janez
AU  - Babić, Biljana M.
AU  - Gajić Krstajić, Ljiljana
AU  - Krstajić, Nedeljko
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5795
AB  - A platinum nanocatalyst on Sb doped tin oxide support (Sb-SnO2) was synthesized and characterized as a catalyst for oxygen reduction reaction in 0.1 mol dm(-3) NaOH solution at 25 degrees C. Sb (5%) doped tin oxide support was synthesized by a modified hydrazine reduction procedure. The platinum nanocatalyst (20% Pt) on Sb-SnO2 support was synthesized by a borohydride reduction method. The synthesized support and catalyst were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) and X-ray diffraction technique (XRD). X-ray photoelectron spectroscopy was applied to characterize the chemical status of elements before and after Pt-treatment. XPS spectra of Sn 3d, Pt 4f, Sb 3d and O 1s revealed that the Pt-deposition on Sb-SnO2 support induced the reduction of the Sn(4+) oxidation state to Sn(2+) and Sn(0) states, while Pt remained in the metallic state and Sb was in the (3+) oxidation state. Homogenous Pt nanoparticle distribution over the support, without pronounced particle agglomeration, was confirmed by HRTEM technique. The average Pt particle size was 2.9 nm. The electrochemically active Pt surface area of the catalyst was determined by the integration of the cyclic voltammetry curve in the potential region of underpotential deposition of hydrogen, after double layer charge correction, taking into account the reference value of 210 mu C cm(-2) for full monolayer coverage. This calculation gave the value of 51 m(2) g(-1). The kinetics of the oxygen reduction reaction with Pt/[Sb-SnO2 catalyst was studied by cyclic voltammetry and linear sweep voltammetry using a rotating gold disc electrode. Two different Tafel slopes were observed: one close to 60 mV dec(-1) in the low current density region, and another at similar to 120 mV dec(-1) in the higher current densities region, as was already referred in previous reports for the oxygen reduction reaction with polycrystalline Pt, as well as with different Pt based nanocatalysts. The specific activities for oxygen reduction, expressed in terms of kinetic current densities per electrochemically Pt active surface area, as well as per mass of Pt loaded, at the constant potential of practical interest (0.85 V and 0.90 V vs. RHE), were compared to a carbon supported (Vulcan XC-72) catalyst. The Pt/[Sb-SnO2 catalyst exhibited similar catalytic activity for oxygen reduction reaction like carbon supported one. The advantages of the carbon free support application in terms of the durability and stability of the catalysts were proved by accelerated stability tests.
PB  - Royal Society of Chemistry
T2  - RSC Advances
T1  - Pt nanoparticles on tin oxide based support as a beneficial catalyst for oxygen reduction in alkaline solutions
EP  - 15929
IS  - 21
SP  - 15923
VL  - 5
DO  - 10.1039/c4ra13391a
UR  - https://hdl.handle.net/21.15107/rcub_dais_3354
ER  - 

@article{
author = "Elezović, Nevenka and Radmilović, Velimir R. and Kovač, Janez and Babić, Biljana M. and Gajić Krstajić, Ljiljana and Krstajić, Nedeljko",
year = "2015",
abstract = "A platinum nanocatalyst on Sb doped tin oxide support (Sb-SnO2) was synthesized and characterized as a catalyst for oxygen reduction reaction in 0.1 mol dm(-3) NaOH solution at 25 degrees C. Sb (5%) doped tin oxide support was synthesized by a modified hydrazine reduction procedure. The platinum nanocatalyst (20% Pt) on Sb-SnO2 support was synthesized by a borohydride reduction method. The synthesized support and catalyst were characterized by high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) and X-ray diffraction technique (XRD). X-ray photoelectron spectroscopy was applied to characterize the chemical status of elements before and after Pt-treatment. XPS spectra of Sn 3d, Pt 4f, Sb 3d and O 1s revealed that the Pt-deposition on Sb-SnO2 support induced the reduction of the Sn(4+) oxidation state to Sn(2+) and Sn(0) states, while Pt remained in the metallic state and Sb was in the (3+) oxidation state. Homogenous Pt nanoparticle distribution over the support, without pronounced particle agglomeration, was confirmed by HRTEM technique. The average Pt particle size was 2.9 nm. The electrochemically active Pt surface area of the catalyst was determined by the integration of the cyclic voltammetry curve in the potential region of underpotential deposition of hydrogen, after double layer charge correction, taking into account the reference value of 210 mu C cm(-2) for full monolayer coverage. This calculation gave the value of 51 m(2) g(-1). The kinetics of the oxygen reduction reaction with Pt/[Sb-SnO2 catalyst was studied by cyclic voltammetry and linear sweep voltammetry using a rotating gold disc electrode. Two different Tafel slopes were observed: one close to 60 mV dec(-1) in the low current density region, and another at similar to 120 mV dec(-1) in the higher current densities region, as was already referred in previous reports for the oxygen reduction reaction with polycrystalline Pt, as well as with different Pt based nanocatalysts. The specific activities for oxygen reduction, expressed in terms of kinetic current densities per electrochemically Pt active surface area, as well as per mass of Pt loaded, at the constant potential of practical interest (0.85 V and 0.90 V vs. RHE), were compared to a carbon supported (Vulcan XC-72) catalyst. The Pt/[Sb-SnO2 catalyst exhibited similar catalytic activity for oxygen reduction reaction like carbon supported one. The advantages of the carbon free support application in terms of the durability and stability of the catalysts were proved by accelerated stability tests.",
publisher = "Royal Society of Chemistry",
journal = "RSC Advances",
title = "Pt nanoparticles on tin oxide based support as a beneficial catalyst for oxygen reduction in alkaline solutions",
pages = "15929-15923",
number = "21",
volume = "5",
doi = "10.1039/c4ra13391a",
url = "https://hdl.handle.net/21.15107/rcub_dais_3354"
}

Elezović, N., Radmilović, V. R., Kovač, J., Babić, B. M., Gajić Krstajić, L.,& Krstajić, N.. (2015). Pt nanoparticles on tin oxide based support as a beneficial catalyst for oxygen reduction in alkaline solutions. in RSC Advances
Royal Society of Chemistry., 5(21), 15923-15929.
https://doi.org/10.1039/c4ra13391a
https://hdl.handle.net/21.15107/rcub_dais_3354

Elezović N, Radmilović VR, Kovač J, Babić BM, Gajić Krstajić L, Krstajić N. Pt nanoparticles on tin oxide based support as a beneficial catalyst for oxygen reduction in alkaline solutions. in RSC Advances. 2015;5(21):15923-15929.
doi:10.1039/c4ra13391a
https://hdl.handle.net/21.15107/rcub_dais_3354 .

Elezović, Nevenka, Radmilović, Velimir R., Kovač, Janez, Babić, Biljana M., Gajić Krstajić, Ljiljana, Krstajić, Nedeljko, "Pt nanoparticles on tin oxide based support as a beneficial catalyst for oxygen reduction in alkaline solutions" in RSC Advances, 5, no. 21 (2015):15923-15929,
https://doi.org/10.1039/c4ra13391a .,
https://hdl.handle.net/21.15107/rcub_dais_3354 .

TY  - JOUR
AU  - Jović, Borka
AU  - Jović, Vladimir
AU  - Lačnjevac, Uroš
AU  - Gajić Krstajić, Ljiljana
AU  - Krstajić, Nedeljko
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5793
AB  - The hydrogen evolution reaction (HER) was studied at electrodeposited Ni and Ni-(Ebonex/Ir) composite coatings in 1 mol dm-3 NaOH solution at 25 °C. The Ni-(Ebonex/Ir) coatings were electrodeposited from a nickel Watts type bath containing different amounts of suspended Ebonex/Ir(30 wt.%) powder particles (0-2 g dm-3) onto a Ni 40 mesh substrate. The electrodes were investigated by cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), electrochemical impedance spectroscopy (EIS) and polarization measurements. It was shown that the roughness factor of coatings increased to a maximum value of 27 with increasing the concentration of Ebonex/Ir particles in the deposition bath, while that of a pure Ni coating was found to be 3.2. In the whole potential range of the HER only one Tafel slope of about -120 mV dec-1 was observed at all polarization curves. Considerably improved intrinsic catalytic activity for the HER compared to pure Ni was achieved with the composite coating deposited from the bath with the lowest concentration of Ebonex/Ir particles (0.1 g dm-3). Further enhancement of the apparent catalytic activity for the HER of Ni-(Ebonex/Ir) composite coatings obtained at higher concentrations of suspended Ebonex/Ir particles in the bath was attributed only to the increase of their electrochemically active surface area. © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
PB  - Elsevier
T2  - International Journal of Hydrogen Energy
T1  - Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part I: Hydrogen evolution
EP  - 10490
IS  - 33
SP  - 10480
VL  - 40
DO  - 10.1016/j.ijhydene.2015.06.127
UR  - https://hdl.handle.net/21.15107/rcub_dais_3530
ER  - 

@article{
author = "Jović, Borka and Jović, Vladimir and Lačnjevac, Uroš and Gajić Krstajić, Ljiljana and Krstajić, Nedeljko",
year = "2015",
abstract = "The hydrogen evolution reaction (HER) was studied at electrodeposited Ni and Ni-(Ebonex/Ir) composite coatings in 1 mol dm-3 NaOH solution at 25 °C. The Ni-(Ebonex/Ir) coatings were electrodeposited from a nickel Watts type bath containing different amounts of suspended Ebonex/Ir(30 wt.%) powder particles (0-2 g dm-3) onto a Ni 40 mesh substrate. The electrodes were investigated by cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), electrochemical impedance spectroscopy (EIS) and polarization measurements. It was shown that the roughness factor of coatings increased to a maximum value of 27 with increasing the concentration of Ebonex/Ir particles in the deposition bath, while that of a pure Ni coating was found to be 3.2. In the whole potential range of the HER only one Tafel slope of about -120 mV dec-1 was observed at all polarization curves. Considerably improved intrinsic catalytic activity for the HER compared to pure Ni was achieved with the composite coating deposited from the bath with the lowest concentration of Ebonex/Ir particles (0.1 g dm-3). Further enhancement of the apparent catalytic activity for the HER of Ni-(Ebonex/Ir) composite coatings obtained at higher concentrations of suspended Ebonex/Ir particles in the bath was attributed only to the increase of their electrochemically active surface area. © 2015 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.",
publisher = "Elsevier",
journal = "International Journal of Hydrogen Energy",
title = "Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part I: Hydrogen evolution",
pages = "10490-10480",
number = "33",
volume = "40",
doi = "10.1016/j.ijhydene.2015.06.127",
url = "https://hdl.handle.net/21.15107/rcub_dais_3530"
}

Jović, B., Jović, V., Lačnjevac, U., Gajić Krstajić, L.,& Krstajić, N.. (2015). Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part I: Hydrogen evolution. in International Journal of Hydrogen Energy
Elsevier., 40(33), 10480-10490.
https://doi.org/10.1016/j.ijhydene.2015.06.127
https://hdl.handle.net/21.15107/rcub_dais_3530

Jović B, Jović V, Lačnjevac U, Gajić Krstajić L, Krstajić N. Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part I: Hydrogen evolution. in International Journal of Hydrogen Energy. 2015;40(33):10480-10490.
doi:10.1016/j.ijhydene.2015.06.127
https://hdl.handle.net/21.15107/rcub_dais_3530 .

Jović, Borka, Jović, Vladimir, Lačnjevac, Uroš, Gajić Krstajić, Ljiljana, Krstajić, Nedeljko, "Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part I: Hydrogen evolution" in International Journal of Hydrogen Energy, 40, no. 33 (2015):10480-10490,
https://doi.org/10.1016/j.ijhydene.2015.06.127 .,
https://hdl.handle.net/21.15107/rcub_dais_3530 .