TY  - JOUR
AU  - Obradovic, Maja D.
AU  - Balanč, Bojana
AU  - Lačnjevac, Uroš C.
AU  - Gojković, Snežana Lj.
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4928
AB  - Hydrated iridiumoxyhydroxide (IrOx) films were electrochemically deposited from an alkaline oxalic solution at constant anodic potentials and by applying a potential cycling protocol, in both cases with variation of the electrodeposition time. FromUV-vis spetroscopy of the solution for the deposition and their characterization it was concluded that a mixture of Ir(III)/Ir(IV) monomers participates in the deposition of IrOx film. X-ray photoelectron spectroscopy (XPS) of IrOx films indicated that both types of films contained hydrated Ir(IV) hydroxide as the dominant species, but in the film deposited by potential cycling the presence of the additional Ir(III) species was evident. The scanning electon microscopy (SEM) analysis of the surface morphology revealed that films deposited by potential cycling were more uniform than the films deposited at a constant potential. The amount of electrochemically active Ir-species on the surface of deposited IrOx films was estimated from the voltammetric charge of the Ir(III)/Ir(IV) transition. Depending on the film electrodeposition parameters, the values between 15 and 1080 nmol cm-2 were obtained. The electrochemically active surface area (ECSA) of IrOx films was calculated from cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements and ranged from 3 to 131 cm(2) per 1 cm(2) of geometric surface area for various films. The activity and stability of IrOx films toward oxygen evolution reaction (OER) was investigated in 0.5 M H2SO4 solution under potentiostatic conditions. The intrinsic activity, stated as turnover frequency and specific current density normalized per ECSA, showed that the OER activity of IrOx films deposited by potential cycling are up to two and a half times higher than the activity of films deposited at a constant anodic potential. Potentiostatic stability test showed a decrease in OER current over time for both type of the films. Determination of ECSA, the amount of electroactive Ir species, XPS spectrum and SEM imaging after the test indicated that the decrease in OER activity was caused by partial dissolution and delamination of the film as well as by oxidation of highly active hydroxide Ir(III) species.
T2  - Journal of Electroanalytical Chemistry
T1  - Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution
VL  - 881
DO  - 10.1016/j.jelechem.2020.114944
ER  - 

@article{
author = "Obradovic, Maja D. and Balanč, Bojana and Lačnjevac, Uroš C. and Gojković, Snežana Lj.",
year = "2021",
abstract = "Hydrated iridiumoxyhydroxide (IrOx) films were electrochemically deposited from an alkaline oxalic solution at constant anodic potentials and by applying a potential cycling protocol, in both cases with variation of the electrodeposition time. FromUV-vis spetroscopy of the solution for the deposition and their characterization it was concluded that a mixture of Ir(III)/Ir(IV) monomers participates in the deposition of IrOx film. X-ray photoelectron spectroscopy (XPS) of IrOx films indicated that both types of films contained hydrated Ir(IV) hydroxide as the dominant species, but in the film deposited by potential cycling the presence of the additional Ir(III) species was evident. The scanning electon microscopy (SEM) analysis of the surface morphology revealed that films deposited by potential cycling were more uniform than the films deposited at a constant potential. The amount of electrochemically active Ir-species on the surface of deposited IrOx films was estimated from the voltammetric charge of the Ir(III)/Ir(IV) transition. Depending on the film electrodeposition parameters, the values between 15 and 1080 nmol cm-2 were obtained. The electrochemically active surface area (ECSA) of IrOx films was calculated from cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements and ranged from 3 to 131 cm(2) per 1 cm(2) of geometric surface area for various films. The activity and stability of IrOx films toward oxygen evolution reaction (OER) was investigated in 0.5 M H2SO4 solution under potentiostatic conditions. The intrinsic activity, stated as turnover frequency and specific current density normalized per ECSA, showed that the OER activity of IrOx films deposited by potential cycling are up to two and a half times higher than the activity of films deposited at a constant anodic potential. Potentiostatic stability test showed a decrease in OER current over time for both type of the films. Determination of ECSA, the amount of electroactive Ir species, XPS spectrum and SEM imaging after the test indicated that the decrease in OER activity was caused by partial dissolution and delamination of the film as well as by oxidation of highly active hydroxide Ir(III) species.",
journal = "Journal of Electroanalytical Chemistry",
title = "Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution",
volume = "881",
doi = "10.1016/j.jelechem.2020.114944"
}

Obradovic, M. D., Balanč, B., Lačnjevac, U. C.,& Gojković, S. Lj.. (2021). Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution. in Journal of Electroanalytical Chemistry, 881.
https://doi.org/10.1016/j.jelechem.2020.114944

Obradovic MD, Balanč B, Lačnjevac UC, Gojković SL. Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution. in Journal of Electroanalytical Chemistry. 2021;881.
doi:10.1016/j.jelechem.2020.114944 .

Obradovic, Maja D., Balanč, Bojana, Lačnjevac, Uroš C., Gojković, Snežana Lj., "Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution" in Journal of Electroanalytical Chemistry, 881 (2021),
https://doi.org/10.1016/j.jelechem.2020.114944 . .

TY  - JOUR
AU  - Mijailović, Daniel
AU  - Radmilović, Vuk
AU  - Lačnjevac, Uroš C.
AU  - Stojanović, Dušica
AU  - Bustillo, Karen C.
AU  - Jović, Vladimir D.
AU  - Radmilović, Velimir R.
AU  - Uskoković, Petar
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4768
AB  - We herein report a simple two-step procedure for fabricating tetragonal CoMn2O4 spinel nanocrystals on carbon fibers. The battery-type behavior of these composite fibers arises from the redox activity of CoMn2O4 in an alkaline aqueous solution, which, in combination with the carbon fibers, endows good electrochemical performance and long-term stability. The C"CoMn2O4 electrode exhibited high specific capacity, up to 62 mA h g(-1) at 1 A g(-1) with a capacity retention of around 90% after 4000 cycles. A symmetrical coin-cell device assembled with the composite electrodes delivered a high energy density of 7.3 W h kg(-1) at a power density of 0.1 kW kg(-1), which is around 13 times higher than that of bare carbon electrodes. The coin cell was cycled for 5000 cycles with 96.3% capacitance retention, at a voltage of up to 0.8 V, demonstrating excellent cycling stability.
PB  - Royal Society of Chemistry
T2  - Dalton Transactions
T1  - Tetragonal CoMn2O4 nanocrystals on electrospun carbon fibers as high-performance battery-type supercapacitor electrode materials
EP  - 15678
IS  - 43
SP  - 15669
VL  - 50
DO  - 10.1039/d1dt02829d
ER  - 

@article{
author = "Mijailović, Daniel and Radmilović, Vuk and Lačnjevac, Uroš C. and Stojanović, Dušica and Bustillo, Karen C. and Jović, Vladimir D. and Radmilović, Velimir R. and Uskoković, Petar",
year = "2021",
abstract = "We herein report a simple two-step procedure for fabricating tetragonal CoMn2O4 spinel nanocrystals on carbon fibers. The battery-type behavior of these composite fibers arises from the redox activity of CoMn2O4 in an alkaline aqueous solution, which, in combination with the carbon fibers, endows good electrochemical performance and long-term stability. The C"CoMn2O4 electrode exhibited high specific capacity, up to 62 mA h g(-1) at 1 A g(-1) with a capacity retention of around 90% after 4000 cycles. A symmetrical coin-cell device assembled with the composite electrodes delivered a high energy density of 7.3 W h kg(-1) at a power density of 0.1 kW kg(-1), which is around 13 times higher than that of bare carbon electrodes. The coin cell was cycled for 5000 cycles with 96.3% capacitance retention, at a voltage of up to 0.8 V, demonstrating excellent cycling stability.",
publisher = "Royal Society of Chemistry",
journal = "Dalton Transactions",
title = "Tetragonal CoMn2O4 nanocrystals on electrospun carbon fibers as high-performance battery-type supercapacitor electrode materials",
pages = "15678-15669",
number = "43",
volume = "50",
doi = "10.1039/d1dt02829d"
}

Mijailović, D., Radmilović, V., Lačnjevac, U. C., Stojanović, D., Bustillo, K. C., Jović, V. D., Radmilović, V. R.,& Uskoković, P.. (2021). Tetragonal CoMn2O4 nanocrystals on electrospun carbon fibers as high-performance battery-type supercapacitor electrode materials. in Dalton Transactions
Royal Society of Chemistry., 50(43), 15669-15678.
https://doi.org/10.1039/d1dt02829d

Mijailović D, Radmilović V, Lačnjevac UC, Stojanović D, Bustillo KC, Jović VD, Radmilović VR, Uskoković P. Tetragonal CoMn2O4 nanocrystals on electrospun carbon fibers as high-performance battery-type supercapacitor electrode materials. in Dalton Transactions. 2021;50(43):15669-15678.
doi:10.1039/d1dt02829d .

Mijailović, Daniel, Radmilović, Vuk, Lačnjevac, Uroš C., Stojanović, Dušica, Bustillo, Karen C., Jović, Vladimir D., Radmilović, Velimir R., Uskoković, Petar, "Tetragonal CoMn2O4 nanocrystals on electrospun carbon fibers as high-performance battery-type supercapacitor electrode materials" in Dalton Transactions, 50, no. 43 (2021):15669-15678,
https://doi.org/10.1039/d1dt02829d . .

TY  - JOUR
AU  - Stevanovic, Sanja
AU  - Tripkovic, Dusan
AU  - Gavrilovic-Wohlmuther, Aleksandra
AU  - Rogan, Jelena
AU  - Lačnjevac, Uroš C.
AU  - Jovanovic, Vladislava
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4897
AB  - Pt, PtSn and PtSnO2 catalysts supported on high surface area carbon synthesized by microwave assisted polyol procedure were tested for methanol oxidation. Based on TGA, EDX and XRD analysis, PtSn/C is composed of Pt and Pt3Sn phase while the rest of Sn is present in a form of very small tin oxide particles. This paper focuses on structure-activity relationships for CO tolerance and methanol oxidation reactions after addition of Sn to Pt catalysts. Alloying of Sn with Pt improves the rate of CO oxidation despite the fact that the pure Sn does not react with CO and therefore activity for methanol oxidation increases similar to 2 times in comparison to Pt/C catalyst. PtSn/C catalyst shows small advantage in comparison with PtSnO2/C catalyst due to the alloyed Sn and its electronic effect. Long term stability tests also confirmed that PtSn/C catalyst is somewhat better in comparison to PtSnO2/C.
T2  - International Journal of Electrochemical Science
T1  - Carbon Supported PtSn versus PtSnO2 Catalysts in Methanol Oxidation
IS  - 2
VL  - 16
DO  - 10.20964/2021.02.55
ER  - 

@article{
author = "Stevanovic, Sanja and Tripkovic, Dusan and Gavrilovic-Wohlmuther, Aleksandra and Rogan, Jelena and Lačnjevac, Uroš C. and Jovanovic, Vladislava",
year = "2021",
abstract = "Pt, PtSn and PtSnO2 catalysts supported on high surface area carbon synthesized by microwave assisted polyol procedure were tested for methanol oxidation. Based on TGA, EDX and XRD analysis, PtSn/C is composed of Pt and Pt3Sn phase while the rest of Sn is present in a form of very small tin oxide particles. This paper focuses on structure-activity relationships for CO tolerance and methanol oxidation reactions after addition of Sn to Pt catalysts. Alloying of Sn with Pt improves the rate of CO oxidation despite the fact that the pure Sn does not react with CO and therefore activity for methanol oxidation increases similar to 2 times in comparison to Pt/C catalyst. PtSn/C catalyst shows small advantage in comparison with PtSnO2/C catalyst due to the alloyed Sn and its electronic effect. Long term stability tests also confirmed that PtSn/C catalyst is somewhat better in comparison to PtSnO2/C.",
journal = "International Journal of Electrochemical Science",
title = "Carbon Supported PtSn versus PtSnO2 Catalysts in Methanol Oxidation",
number = "2",
volume = "16",
doi = "10.20964/2021.02.55"
}

Stevanovic, S., Tripkovic, D., Gavrilovic-Wohlmuther, A., Rogan, J., Lačnjevac, U. C.,& Jovanovic, V.. (2021). Carbon Supported PtSn versus PtSnO2 Catalysts in Methanol Oxidation. in International Journal of Electrochemical Science, 16(2).
https://doi.org/10.20964/2021.02.55

Stevanovic S, Tripkovic D, Gavrilovic-Wohlmuther A, Rogan J, Lačnjevac UC, Jovanovic V. Carbon Supported PtSn versus PtSnO2 Catalysts in Methanol Oxidation. in International Journal of Electrochemical Science. 2021;16(2).
doi:10.20964/2021.02.55 .

Stevanovic, Sanja, Tripkovic, Dusan, Gavrilovic-Wohlmuther, Aleksandra, Rogan, Jelena, Lačnjevac, Uroš C., Jovanovic, Vladislava, "Carbon Supported PtSn versus PtSnO2 Catalysts in Methanol Oxidation" in International Journal of Electrochemical Science, 16, no. 2 (2021),
https://doi.org/10.20964/2021.02.55 . .