TY  - CONF
AU  - Vasiljević, Zorka Ž.
AU  - Dojčinović, Milena P.
AU  - Vujančević, Jelena
AU  - Spreitzer, Matjaž
AU  - Kovač, Janez
AU  - Janković-Čaštvan, Ivona
AU  - Bartolić, Dragana
AU  - Marković, Smilja
AU  - Tadić, Nenad
AU  - Nikolić, Maria Vesna
PY  - 2021
UR  - https://dais.sanu.ac.rs/123456789/15358
AB  - Novel crystalline iron-titanate fibers were synthesized for the first time to the best of our knowledge, through a simple, low cost electrospinning method followed by calcination treatment at different temperatures (500–750 °C for 3 h and at 500 °C for 6 h and at 550 °C for 4 h). The fibers were prepared from a precursor solution containing polyvinylpyrrolidone (PVP), iron(III) nonahydrate, titanium isopropoxide, N,N-Dimethylformamide and ethanol. As spun fibers were smooth, straight, beadless and uniform forming a nonwoven fibrous mat, with an average diameter of ca. 205 nm. Upon calcination in air the PVP matrice was removed and XRD and FTIR analysis showed that the duration of the calcination process, besides the temperature, had a direct influence on phase formation. Pure phase of pseudobrookite was obtained at 600 °C, 500 °C for 6 h and at 550 °C for 4 h. In addition, the morphology of obtained nanofibers was directly affected by the calcination temperature. The surface of fibers obtained after calcination was no longer smooth and the fiber diameter decreased due to complete degradation of PVP. At 700 oC and 750 °C, fibers were thicker which can be attributed to growth of Fe2TiO5 nanoparticles and simultaneous coalescence of small particles. All samples exhibited a type IV nitrogen adsorption isotherm with a type- H3 indicating slit-shaped mesoporous structure. The BET surface areas of 500 °C for 6 h, 550 °C for 4 h and 600 °C for 3 h were estimated to be 62, 38.7 and 33.2 m2/g, respectively.
PB  - Novi Sad : Faculty of Technology
C3  - Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad, 2021
T1  - Influence of calcination temperature on the structure, morphology and optical properties of electrospun pseudobrookite nanofibers
SP  - 124
EP  - 124
UR  - https://hdl.handle.net/21.15107/rcub_dais_15358
ER  - 

@conference{
author = "Vasiljević, Zorka Ž. and Dojčinović, Milena P. and Vujančević, Jelena and Spreitzer, Matjaž and Kovač, Janez and Janković-Čaštvan, Ivona and Bartolić, Dragana and Marković, Smilja and Tadić, Nenad and Nikolić, Maria Vesna",
year = "2021",
abstract = "Novel crystalline iron-titanate fibers were synthesized for the first time to the best of our knowledge, through a simple, low cost electrospinning method followed by calcination treatment at different temperatures (500–750 °C for 3 h and at 500 °C for 6 h and at 550 °C for 4 h). The fibers were prepared from a precursor solution containing polyvinylpyrrolidone (PVP), iron(III) nonahydrate, titanium isopropoxide, N,N-Dimethylformamide and ethanol. As spun fibers were smooth, straight, beadless and uniform forming a nonwoven fibrous mat, with an average diameter of ca. 205 nm. Upon calcination in air the PVP matrice was removed and XRD and FTIR analysis showed that the duration of the calcination process, besides the temperature, had a direct influence on phase formation. Pure phase of pseudobrookite was obtained at 600 °C, 500 °C for 6 h and at 550 °C for 4 h. In addition, the morphology of obtained nanofibers was directly affected by the calcination temperature. The surface of fibers obtained after calcination was no longer smooth and the fiber diameter decreased due to complete degradation of PVP. At 700 oC and 750 °C, fibers were thicker which can be attributed to growth of Fe2TiO5 nanoparticles and simultaneous coalescence of small particles. All samples exhibited a type IV nitrogen adsorption isotherm with a type- H3 indicating slit-shaped mesoporous structure. The BET surface areas of 500 °C for 6 h, 550 °C for 4 h and 600 °C for 3 h were estimated to be 62, 38.7 and 33.2 m2/g, respectively.",
publisher = "Novi Sad : Faculty of Technology",
journal = "Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad, 2021",
title = "Influence of calcination temperature on the structure, morphology and optical properties of electrospun pseudobrookite nanofibers",
pages = "124-124",
url = "https://hdl.handle.net/21.15107/rcub_dais_15358"
}

Vasiljević, Z. Ž., Dojčinović, M. P., Vujančević, J., Spreitzer, M., Kovač, J., Janković-Čaštvan, I., Bartolić, D., Marković, S., Tadić, N.,& Nikolić, M. V.. (2021). Influence of calcination temperature on the structure, morphology and optical properties of electrospun pseudobrookite nanofibers. in Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad, 2021
Novi Sad : Faculty of Technology., 124-124.
https://hdl.handle.net/21.15107/rcub_dais_15358

Vasiljević ZŽ, Dojčinović MP, Vujančević J, Spreitzer M, Kovač J, Janković-Čaštvan I, Bartolić D, Marković S, Tadić N, Nikolić MV. Influence of calcination temperature on the structure, morphology and optical properties of electrospun pseudobrookite nanofibers. in Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad, 2021. 2021;:124-124.
https://hdl.handle.net/21.15107/rcub_dais_15358 .

Vasiljević, Zorka Ž., Dojčinović, Milena P., Vujančević, Jelena, Spreitzer, Matjaž, Kovač, Janez, Janković-Čaštvan, Ivona, Bartolić, Dragana, Marković, Smilja, Tadić, Nenad, Nikolić, Maria Vesna, "Influence of calcination temperature on the structure, morphology and optical properties of electrospun pseudobrookite nanofibers" in Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad, 2021 (2021):124-124,
https://hdl.handle.net/21.15107/rcub_dais_15358 .

TY  - JOUR
AU  - Vasiljević, Zorka Ž.
AU  - Dojčinović, Milena P.
AU  - Vujančević, Jelena D.
AU  - Spreitzer, Matjaž
AU  - Kovač, Janez
AU  - Bartolić, Dragana
AU  - Marković, Smilja
AU  - Janković-Čaštvan, Ivona
AU  - Tadić, Nenad B.
AU  - Nikolić, Maria Vesna
PY  - 2021
UR  - https://dais.sanu.ac.rs/123456789/12338
AB  - Nanostructured Fe2TiO5 (pseudobrookite), a mixed metal oxide material holds significant promise for utilization in energy and environmental applications. However, its full application is still hindered due to the difficulty to synthesize monophasic Fe2TiO5 with high crystallinity and a large specific surface area. Herein, Fe2TiO5 nanofibers were synthesized via a versatile and low-cost electrospinning method, followed by a calcination process at different temperatures. We found a significant effect of the calcination process and its duration on the crystalline phase in the form of either pseudobrookite or pseudobrookite–hematite–rutile and the morphology of calcined nanofibers. The crystallite size increased whereas the specific surface area decreased with an increase in calcination temperature. At higher temperatures, the growth of Fe2TiO5 nanoparticles and simultaneous coalescence of small particles was noted. The highest specific surface area was obtained for the sample calcined at 500 °C for 6 h (SBET = 64.4 m2 g−1). This work opens new opportunities in the synthesis of Fe2TiO5 nanostructures using the electrospinning method and a subsequent optimized calcination process for energy-related applications.
PB  - Royal Society of Chemistry (RSC)
T2  - RSC Advances
T1  - Exploring the impact of calcination parameters on the crystal structure, morphology, and optical properties of electrospun Fe                    2                    TiO                    5                    nanofibers
SP  - 32358
EP  - 32368
VL  - 11
IS  - 51
DO  - 10.1039/D1RA05748K
UR  - https://hdl.handle.net/21.15107/rcub_dais_12338
ER  - 

@article{
author = "Vasiljević, Zorka Ž. and Dojčinović, Milena P. and Vujančević, Jelena D. and Spreitzer, Matjaž and Kovač, Janez and Bartolić, Dragana and Marković, Smilja and Janković-Čaštvan, Ivona and Tadić, Nenad B. and Nikolić, Maria Vesna",
year = "2021",
abstract = "Nanostructured Fe2TiO5 (pseudobrookite), a mixed metal oxide material holds significant promise for utilization in energy and environmental applications. However, its full application is still hindered due to the difficulty to synthesize monophasic Fe2TiO5 with high crystallinity and a large specific surface area. Herein, Fe2TiO5 nanofibers were synthesized via a versatile and low-cost electrospinning method, followed by a calcination process at different temperatures. We found a significant effect of the calcination process and its duration on the crystalline phase in the form of either pseudobrookite or pseudobrookite–hematite–rutile and the morphology of calcined nanofibers. The crystallite size increased whereas the specific surface area decreased with an increase in calcination temperature. At higher temperatures, the growth of Fe2TiO5 nanoparticles and simultaneous coalescence of small particles was noted. The highest specific surface area was obtained for the sample calcined at 500 °C for 6 h (SBET = 64.4 m2 g−1). This work opens new opportunities in the synthesis of Fe2TiO5 nanostructures using the electrospinning method and a subsequent optimized calcination process for energy-related applications.",
publisher = "Royal Society of Chemistry (RSC)",
journal = "RSC Advances",
title = "Exploring the impact of calcination parameters on the crystal structure, morphology, and optical properties of electrospun Fe                    2                    TiO                    5                    nanofibers",
pages = "32358-32368",
volume = "11",
number = "51",
doi = "10.1039/D1RA05748K",
url = "https://hdl.handle.net/21.15107/rcub_dais_12338"
}

Vasiljević, Z. Ž., Dojčinović, M. P., Vujančević, J. D., Spreitzer, M., Kovač, J., Bartolić, D., Marković, S., Janković-Čaštvan, I., Tadić, N. B.,& Nikolić, M. V.. (2021). Exploring the impact of calcination parameters on the crystal structure, morphology, and optical properties of electrospun Fe                    2                    TiO                    5                    nanofibers. in RSC Advances
Royal Society of Chemistry (RSC)., 11(51), 32358-32368.
https://doi.org/10.1039/D1RA05748K
https://hdl.handle.net/21.15107/rcub_dais_12338

Vasiljević ZŽ, Dojčinović MP, Vujančević JD, Spreitzer M, Kovač J, Bartolić D, Marković S, Janković-Čaštvan I, Tadić NB, Nikolić MV. Exploring the impact of calcination parameters on the crystal structure, morphology, and optical properties of electrospun Fe                    2                    TiO                    5                    nanofibers. in RSC Advances. 2021;11(51):32358-32368.
doi:10.1039/D1RA05748K
https://hdl.handle.net/21.15107/rcub_dais_12338 .

Vasiljević, Zorka Ž., Dojčinović, Milena P., Vujančević, Jelena D., Spreitzer, Matjaž, Kovač, Janez, Bartolić, Dragana, Marković, Smilja, Janković-Čaštvan, Ivona, Tadić, Nenad B., Nikolić, Maria Vesna, "Exploring the impact of calcination parameters on the crystal structure, morphology, and optical properties of electrospun Fe                    2                    TiO                    5                    nanofibers" in RSC Advances, 11, no. 51 (2021):32358-32368,
https://doi.org/10.1039/D1RA05748K .,
https://hdl.handle.net/21.15107/rcub_dais_12338 .

TY  - CONF
AU  - Dojčinović, Milena
AU  - Vasiljević, Zorka Ž.
AU  - Tadić, Nenad B.
AU  - Krstić, Jugoslav B.
AU  - Marković, Smilja
AU  - Spreitzer, Matjaž
AU  - Kovač, Janez
AU  - Nikolić, Maria Vesna
PY  - 2021
UR  - https://dais.sanu.ac.rs/123456789/12397
AB  - NiMn2O4, with a cubic spinel structure and numerous and various applications in modern technology, were synthesized with two synthetic routes: sol-gel combustion method with glycine as fuel and electrospinning method with polyvinylpyrrolidone (PVP). Both amorphous powders from sol-gel synthesis and as-spun fibers from electrospinning synthesis were calcined, electrospun fibers at 400 °C and the sol-gel synthesized powders at 800 °C. Electrospun fibers were previously characterized with DTA-TGA to investigate the influence of thermal process on a polymer fiber.
The obtained powders were characterized accordingly. Structural analysis was done via X-ray diffraction (XRD) and results show spinel structure with no impurity. The texture and morphology was investigated via N2 physisorption and transmission electron microscopy (TEM), respectively. Chemical states of elements were investigated by X-ray photoelectron spectroscopy (XPS). The electrochemical performance of the synthesized materials as supercapacitors was tested via cyclic voltammetry (CV), electric impedance spectroscopy (EIS), and chronopotentiometry (CP) to aquire galvanostatic charge-discharge (GCD) curves. Experiments were done in 6 M KOH solution with nickel foam as a working electrode. The results show good electrochemical capacity circa 200 F/g, with the potential for further structural improvement of the materials.
PB  - Novi Sad : Faculty of Technology
C3  - Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad
T1  - Synthesis, structure and electrochemical performance of NiMn2O4
SP  - 81
EP  - 81
UR  - https://hdl.handle.net/21.15107/rcub_dais_12397
ER  - 

@conference{
author = "Dojčinović, Milena and Vasiljević, Zorka Ž. and Tadić, Nenad B. and Krstić, Jugoslav B. and Marković, Smilja and Spreitzer, Matjaž and Kovač, Janez and Nikolić, Maria Vesna",
year = "2021",
abstract = "NiMn2O4, with a cubic spinel structure and numerous and various applications in modern technology, were synthesized with two synthetic routes: sol-gel combustion method with glycine as fuel and electrospinning method with polyvinylpyrrolidone (PVP). Both amorphous powders from sol-gel synthesis and as-spun fibers from electrospinning synthesis were calcined, electrospun fibers at 400 °C and the sol-gel synthesized powders at 800 °C. Electrospun fibers were previously characterized with DTA-TGA to investigate the influence of thermal process on a polymer fiber.
The obtained powders were characterized accordingly. Structural analysis was done via X-ray diffraction (XRD) and results show spinel structure with no impurity. The texture and morphology was investigated via N2 physisorption and transmission electron microscopy (TEM), respectively. Chemical states of elements were investigated by X-ray photoelectron spectroscopy (XPS). The electrochemical performance of the synthesized materials as supercapacitors was tested via cyclic voltammetry (CV), electric impedance spectroscopy (EIS), and chronopotentiometry (CP) to aquire galvanostatic charge-discharge (GCD) curves. Experiments were done in 6 M KOH solution with nickel foam as a working electrode. The results show good electrochemical capacity circa 200 F/g, with the potential for further structural improvement of the materials.",
publisher = "Novi Sad : Faculty of Technology",
journal = "Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad",
title = "Synthesis, structure and electrochemical performance of NiMn2O4",
pages = "81-81",
url = "https://hdl.handle.net/21.15107/rcub_dais_12397"
}

Dojčinović, M., Vasiljević, Z. Ž., Tadić, N. B., Krstić, J. B., Marković, S., Spreitzer, M., Kovač, J.,& Nikolić, M. V.. (2021). Synthesis, structure and electrochemical performance of NiMn2O4. in Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad
Novi Sad : Faculty of Technology., 81-81.
https://hdl.handle.net/21.15107/rcub_dais_12397

Dojčinović M, Vasiljević ZŽ, Tadić NB, Krstić JB, Marković S, Spreitzer M, Kovač J, Nikolić MV. Synthesis, structure and electrochemical performance of NiMn2O4. in Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad. 2021;:81-81.
https://hdl.handle.net/21.15107/rcub_dais_12397 .

Dojčinović, Milena, Vasiljević, Zorka Ž., Tadić, Nenad B., Krstić, Jugoslav B., Marković, Smilja, Spreitzer, Matjaž, Kovač, Janez, Nikolić, Maria Vesna, "Synthesis, structure and electrochemical performance of NiMn2O4" in Programme and book of abstracts / 14th ECerS Conference for Young Scientists in Ceramics (CYSC-2021), October 20-23, 2021, Novi Sad (2021):81-81,
https://hdl.handle.net/21.15107/rcub_dais_12397 .

TY  - JOUR
AU  - Jovanović, Zoran
AU  - Mravik, Željko
AU  - Bajuk Bogdanović, Danica
AU  - Jovanović, Sonja
AU  - Marković, Smilja
AU  - Vujković, Milica
AU  - Kovač, Janez
AU  - Vengust, Damjan
AU  - Uskoković-Marković, Snežana
AU  - Holclajtner Antunović, Ivanka
PY  - 2020
UR  - https://dais.sanu.ac.rs/123456789/6882
AB  - In the present study we investigated the interaction between 12-tungstophosphoric acid (WPA) and graphene oxide (GO) in their nanocomposite by utilizing the loading of WPA as an intrinsic parameter for interaction tuning. The Fourier-transform infrared spectroscopy, temperature-programmed desorption, X-ray photoelectron spectroscopy, zeta-potential measurements, thermogravimetric analysis, X-ray diffraction, Raman spectroscopy and transmission electron microscopy methods revealed that ∼5–13 wt% of WPA represents critical loading that separates two distinct contributions to GO-WPA interaction. This was explained by the self-limiting nature of GO-WPA interaction, initially controlled by high dispersion of WPA on GO (up to 13 wt%), that is eventually overpowered by WPA-WPA interaction as loading increases. As a result, the WPA agglomerates are being formed because of which the hybrid character of the nanocomposite diminishes, i.e., the properties of independent components start to be manifested to greater extent. The obtained results provide an important framework for considering possible outcomes in other 2D-0D systems, whose interaction is relevant both from fundamental and applicative point of view. Thus, the GO/WPA nanocomposite illustrates how the interactions between the components can be used for tuning the properties of nanocomposite as a whole.
T2  - Carbon
T1  - Self-limiting interactions in 2D–0D system: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite
SP  - 166
EP  - 178
VL  - 156
DO  - 10.1016/j.carbon.2019.09.072
UR  - https://hdl.handle.net/21.15107/rcub_dais_6882
ER  - 

@article{
author = "Jovanović, Zoran and Mravik, Željko and Bajuk Bogdanović, Danica and Jovanović, Sonja and Marković, Smilja and Vujković, Milica and Kovač, Janez and Vengust, Damjan and Uskoković-Marković, Snežana and Holclajtner Antunović, Ivanka",
year = "2020",
abstract = "In the present study we investigated the interaction between 12-tungstophosphoric acid (WPA) and graphene oxide (GO) in their nanocomposite by utilizing the loading of WPA as an intrinsic parameter for interaction tuning. The Fourier-transform infrared spectroscopy, temperature-programmed desorption, X-ray photoelectron spectroscopy, zeta-potential measurements, thermogravimetric analysis, X-ray diffraction, Raman spectroscopy and transmission electron microscopy methods revealed that ∼5–13 wt% of WPA represents critical loading that separates two distinct contributions to GO-WPA interaction. This was explained by the self-limiting nature of GO-WPA interaction, initially controlled by high dispersion of WPA on GO (up to 13 wt%), that is eventually overpowered by WPA-WPA interaction as loading increases. As a result, the WPA agglomerates are being formed because of which the hybrid character of the nanocomposite diminishes, i.e., the properties of independent components start to be manifested to greater extent. The obtained results provide an important framework for considering possible outcomes in other 2D-0D systems, whose interaction is relevant both from fundamental and applicative point of view. Thus, the GO/WPA nanocomposite illustrates how the interactions between the components can be used for tuning the properties of nanocomposite as a whole.",
journal = "Carbon",
title = "Self-limiting interactions in 2D–0D system: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite",
pages = "166-178",
volume = "156",
doi = "10.1016/j.carbon.2019.09.072",
url = "https://hdl.handle.net/21.15107/rcub_dais_6882"
}

Jovanović, Z., Mravik, Ž., Bajuk Bogdanović, D., Jovanović, S., Marković, S., Vujković, M., Kovač, J., Vengust, D., Uskoković-Marković, S.,& Holclajtner Antunović, I.. (2020). Self-limiting interactions in 2D–0D system: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite. in Carbon, 156, 166-178.
https://doi.org/10.1016/j.carbon.2019.09.072
https://hdl.handle.net/21.15107/rcub_dais_6882

Jovanović Z, Mravik Ž, Bajuk Bogdanović D, Jovanović S, Marković S, Vujković M, Kovač J, Vengust D, Uskoković-Marković S, Holclajtner Antunović I. Self-limiting interactions in 2D–0D system: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite. in Carbon. 2020;156:166-178.
doi:10.1016/j.carbon.2019.09.072
https://hdl.handle.net/21.15107/rcub_dais_6882 .

Jovanović, Zoran, Mravik, Željko, Bajuk Bogdanović, Danica, Jovanović, Sonja, Marković, Smilja, Vujković, Milica, Kovač, Janez, Vengust, Damjan, Uskoković-Marković, Snežana, Holclajtner Antunović, Ivanka, "Self-limiting interactions in 2D–0D system: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite" in Carbon, 156 (2020):166-178,
https://doi.org/10.1016/j.carbon.2019.09.072 .,
https://hdl.handle.net/21.15107/rcub_dais_6882 .

TY  - CONF
AU  - Marković, Smilja
AU  - Rajić, Vladimir
AU  - Veselinović, Ljiljana
AU  - Stojković Simatović, Ivana
AU  - Belošević Čavor, Jelena
AU  - Škapin, Srečo Davor
AU  - Kovač, Janez
AU  - Nikolić, Marko G.
AU  - Uskoković, Dragan
PY  - 2019
UR  - https://dais.sanu.ac.rs/123456789/6997
AB  - During the last decade zinc oxide (ZnO) has attracted considerable attention as a promising material for electronic, optoelectronic and spintronic devices. ZnO has a wide bandgap (3.37 eV at room temperature) and relatively large exciton binding energy (60 meV) which enables multifunctional application. Until now ZnO-based materials have been used as UV and blue light emitters, varistors, thermistors, semiconductors, photoanodes, and other. Various approaches have been applied to improve functional properties of zinc oxide, such as: fabrication of ZnO-based heterojunction particles, particles’ surface sensitization, hydrogenation, etc. It has been found that intrinsic defects (vacancies, interstitials and antisites) in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Thus, correlation of the intrinsic defects concentration with optical and electrical properties of ZnO materials is of great importance for their further application in opto-electronic devices. In this study we investigated the influence of intrinsic defects concentration on the optical, electrical and photoelectrocatalytic properties of ZnO materials. To obtain ZnO powder with a high concentration of intrinsic defects microwave processing of precipitate was employed, while for further varying of defects concentration, the powder was thermally treated in three different atmospheres: air, argon and oxygen. The ZnO powder was uniaxially pressed (P = 100 MPa) in cylindrical compacts (R= 6 mm and h approx. 3 mm) which were sintered in different atmospheres by heating rate of 10 °/min up to 1100 °C, and with dwell time of 1 h. To study a crystal structure of ZnO samples XRD and Raman spectroscopy were used, while for microstructural investigation field emission scanning electron micrographs were recorded. Optical properties were studied using UV–Vis diffuse reflectance spectroscopy. To reveal the role of intrinsic defects in ZnO crystal lattice on functional properties, XPS, photoluminescence, electroluminescence and electrochemical impedance spectra were analyzed. A detailed analysis of the experimental results imply that a high concentration of intrinsic defects, in particular oxygen vacancies, is of the greatest importance for tunable light-emitting diode application and significant for the photoanode properties. To support our experimental observation we performed ab initio calculations based on density functional theory (DFT).
PB  - Budapest : [s. n.]
C3  - Abstracts / International Workshop on Woman in Ceramic Science (WoCeram2019), April 7-9, 2019/ Budapest, Hungary, Novotel Danube Budapest
T1  - Tuning the optical, electrical and photoelectrocatalytic properties of Zno materials by varying of intrinsic defects concentration
SP  - 11
EP  - 11
UR  - https://hdl.handle.net/21.15107/rcub_dais_6997
ER  - 

@conference{
author = "Marković, Smilja and Rajić, Vladimir and Veselinović, Ljiljana and Stojković Simatović, Ivana and Belošević Čavor, Jelena and Škapin, Srečo Davor and Kovač, Janez and Nikolić, Marko G. and Uskoković, Dragan",
year = "2019",
abstract = "During the last decade zinc oxide (ZnO) has attracted considerable attention as a promising material for electronic, optoelectronic and spintronic devices. ZnO has a wide bandgap (3.37 eV at room temperature) and relatively large exciton binding energy (60 meV) which enables multifunctional application. Until now ZnO-based materials have been used as UV and blue light emitters, varistors, thermistors, semiconductors, photoanodes, and other. Various approaches have been applied to improve functional properties of zinc oxide, such as: fabrication of ZnO-based heterojunction particles, particles’ surface sensitization, hydrogenation, etc. It has been found that intrinsic defects (vacancies, interstitials and antisites) in the crystal structure of a ZnO strongly influenced its electrical and optical properties. Thus, correlation of the intrinsic defects concentration with optical and electrical properties of ZnO materials is of great importance for their further application in opto-electronic devices. In this study we investigated the influence of intrinsic defects concentration on the optical, electrical and photoelectrocatalytic properties of ZnO materials. To obtain ZnO powder with a high concentration of intrinsic defects microwave processing of precipitate was employed, while for further varying of defects concentration, the powder was thermally treated in three different atmospheres: air, argon and oxygen. The ZnO powder was uniaxially pressed (P = 100 MPa) in cylindrical compacts (R= 6 mm and h approx. 3 mm) which were sintered in different atmospheres by heating rate of 10 °/min up to 1100 °C, and with dwell time of 1 h. To study a crystal structure of ZnO samples XRD and Raman spectroscopy were used, while for microstructural investigation field emission scanning electron micrographs were recorded. Optical properties were studied using UV–Vis diffuse reflectance spectroscopy. To reveal the role of intrinsic defects in ZnO crystal lattice on functional properties, XPS, photoluminescence, electroluminescence and electrochemical impedance spectra were analyzed. A detailed analysis of the experimental results imply that a high concentration of intrinsic defects, in particular oxygen vacancies, is of the greatest importance for tunable light-emitting diode application and significant for the photoanode properties. To support our experimental observation we performed ab initio calculations based on density functional theory (DFT).",
publisher = "Budapest : [s. n.]",
journal = "Abstracts / International Workshop on Woman in Ceramic Science (WoCeram2019), April 7-9, 2019/ Budapest, Hungary, Novotel Danube Budapest",
title = "Tuning the optical, electrical and photoelectrocatalytic properties of Zno materials by varying of intrinsic defects concentration",
pages = "11-11",
url = "https://hdl.handle.net/21.15107/rcub_dais_6997"
}

Marković, S., Rajić, V., Veselinović, L., Stojković Simatović, I., Belošević Čavor, J., Škapin, S. D., Kovač, J., Nikolić, M. G.,& Uskoković, D.. (2019). Tuning the optical, electrical and photoelectrocatalytic properties of Zno materials by varying of intrinsic defects concentration. in Abstracts / International Workshop on Woman in Ceramic Science (WoCeram2019), April 7-9, 2019/ Budapest, Hungary, Novotel Danube Budapest
Budapest : [s. n.]., 11-11.
https://hdl.handle.net/21.15107/rcub_dais_6997

Marković S, Rajić V, Veselinović L, Stojković Simatović I, Belošević Čavor J, Škapin SD, Kovač J, Nikolić MG, Uskoković D. Tuning the optical, electrical and photoelectrocatalytic properties of Zno materials by varying of intrinsic defects concentration. in Abstracts / International Workshop on Woman in Ceramic Science (WoCeram2019), April 7-9, 2019/ Budapest, Hungary, Novotel Danube Budapest. 2019;:11-11.
https://hdl.handle.net/21.15107/rcub_dais_6997 .

Marković, Smilja, Rajić, Vladimir, Veselinović, Ljiljana, Stojković Simatović, Ivana, Belošević Čavor, Jelena, Škapin, Srečo Davor, Kovač, Janez, Nikolić, Marko G., Uskoković, Dragan, "Tuning the optical, electrical and photoelectrocatalytic properties of Zno materials by varying of intrinsic defects concentration" in Abstracts / International Workshop on Woman in Ceramic Science (WoCeram2019), April 7-9, 2019/ Budapest, Hungary, Novotel Danube Budapest (2019):11-11,
https://hdl.handle.net/21.15107/rcub_dais_6997 .

TY  - CONF
AU  - Mravik, Željko
AU  - Bajuk-Bogdanović, Danica
AU  - Vujković, Milica
AU  - Marković, Smilja
AU  - Kovač, Janez
AU  - Jovanović, Sonja
AU  - Holclajtner Antunović, Ivanka
AU  - Jovanović, Zoran
PY  - 2018
UR  - https://dais.sanu.ac.rs/123456789/14865
AB  - Graphene oxide (GO) has shown great potential for applications in charge storage devices. Its two dimensional structure, high specific surface area as well as hydrophilicity and pseudocapacity are making it an exceptional candidate for electrochemical supercapacitors. Recent studies have shown that charge storage properties of GO can be significantly improved in nanocomposites with different inorganic materials. Therefore, in the present work we have combined GO and 12-tungstophosphoric acid (WPA) into a nanocomposite that exerts high synergic activity of the components.
Graphene oxide was synthesized via modified Hummers method and characterized by Temperature programmed desorption method (TPD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometry (XPS) in order to establish its initial surface chemistry, while thermal reduction was used for altering the composition of surface oxygen groups. Cyclic voltammetry (CV) was used to access the contribution of individual surface oxygen groups on the capacitance of graphene oxide. Analysis of initial and thermally reduced GO revealed that desorption of low-temperature groups and their conversion to phenolic and carbonyl groups is the reason for almost doubled capacitance at 500 °C.
Next, we studied the interactions between GO and WPA by altering their mass ratio in the nanocomposite. The FTIR analysis have revealed that WPA interacts with GO via terminal oxygen of a tungstate octahedron. Furthermore, these interactions are the most pronounced at 10-20 wt.% of WPA in the nanocomposite.
PB  - Belgrade : Faculty of physical chemistry
C3  - Book of Abstracts / 3rd International Meeting on materials science for energy related applications, september 25-26, 2018, Belgrade
T1  - Synergic activity of graphene oxide and 12-tungstophosphoric acid in their nanocomposite for supercapacitor applications
SP  - 23
EP  - 23
UR  - https://hdl.handle.net/21.15107/rcub_dais_14865
ER  - 

@conference{
author = "Mravik, Željko and Bajuk-Bogdanović, Danica and Vujković, Milica and Marković, Smilja and Kovač, Janez and Jovanović, Sonja and Holclajtner Antunović, Ivanka and Jovanović, Zoran",
year = "2018",
abstract = "Graphene oxide (GO) has shown great potential for applications in charge storage devices. Its two dimensional structure, high specific surface area as well as hydrophilicity and pseudocapacity are making it an exceptional candidate for electrochemical supercapacitors. Recent studies have shown that charge storage properties of GO can be significantly improved in nanocomposites with different inorganic materials. Therefore, in the present work we have combined GO and 12-tungstophosphoric acid (WPA) into a nanocomposite that exerts high synergic activity of the components.
Graphene oxide was synthesized via modified Hummers method and characterized by Temperature programmed desorption method (TPD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometry (XPS) in order to establish its initial surface chemistry, while thermal reduction was used for altering the composition of surface oxygen groups. Cyclic voltammetry (CV) was used to access the contribution of individual surface oxygen groups on the capacitance of graphene oxide. Analysis of initial and thermally reduced GO revealed that desorption of low-temperature groups and their conversion to phenolic and carbonyl groups is the reason for almost doubled capacitance at 500 °C.
Next, we studied the interactions between GO and WPA by altering their mass ratio in the nanocomposite. The FTIR analysis have revealed that WPA interacts with GO via terminal oxygen of a tungstate octahedron. Furthermore, these interactions are the most pronounced at 10-20 wt.% of WPA in the nanocomposite.",
publisher = "Belgrade : Faculty of physical chemistry",
journal = "Book of Abstracts / 3rd International Meeting on materials science for energy related applications, september 25-26, 2018, Belgrade",
title = "Synergic activity of graphene oxide and 12-tungstophosphoric acid in their nanocomposite for supercapacitor applications",
pages = "23-23",
url = "https://hdl.handle.net/21.15107/rcub_dais_14865"
}

Mravik, Ž., Bajuk-Bogdanović, D., Vujković, M., Marković, S., Kovač, J., Jovanović, S., Holclajtner Antunović, I.,& Jovanović, Z.. (2018). Synergic activity of graphene oxide and 12-tungstophosphoric acid in their nanocomposite for supercapacitor applications. in Book of Abstracts / 3rd International Meeting on materials science for energy related applications, september 25-26, 2018, Belgrade
Belgrade : Faculty of physical chemistry., 23-23.
https://hdl.handle.net/21.15107/rcub_dais_14865

Mravik Ž, Bajuk-Bogdanović D, Vujković M, Marković S, Kovač J, Jovanović S, Holclajtner Antunović I, Jovanović Z. Synergic activity of graphene oxide and 12-tungstophosphoric acid in their nanocomposite for supercapacitor applications. in Book of Abstracts / 3rd International Meeting on materials science for energy related applications, september 25-26, 2018, Belgrade. 2018;:23-23.
https://hdl.handle.net/21.15107/rcub_dais_14865 .

Mravik, Željko, Bajuk-Bogdanović, Danica, Vujković, Milica, Marković, Smilja, Kovač, Janez, Jovanović, Sonja, Holclajtner Antunović, Ivanka, Jovanović, Zoran, "Synergic activity of graphene oxide and 12-tungstophosphoric acid in their nanocomposite for supercapacitor applications" in Book of Abstracts / 3rd International Meeting on materials science for energy related applications, september 25-26, 2018, Belgrade (2018):23-23,
https://hdl.handle.net/21.15107/rcub_dais_14865 .

TY  - CONF
AU  - Mravik, Željko
AU  - Bajuk Bogdanović, Danica
AU  - Marković, Smilja
AU  - Kovač, Janez
AU  - Holclajtner Antunović, Ivanka
AU  - Jovanović, Zoran
PY  - 2018
UR  - https://dais.sanu.ac.rs/123456789/3666
AB  - The rich surface chemistry and large surface area of graphene oxide (GO) provide a platform for various functional materials that synergistically enhance charge storage properties of the composite. In present work we have investigated interaction between GO and 12- thungstophosphoric acid (WPA) in their nanocomposites as a function of different mass ratio of constituents. For this purpose, the Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS), temperature programmed desorption method (TPD) and thermogravimetric/differential thermal analysis (TGA-DTA) methods were used. FTIR spectra have shown shifts and splitting of characteristic bands of WPA as a result of interactions with GO. Both XPS and TPD methods have shown an initial decrease of the total amount of surface oxygen groups of GO, with a minimum at around 10 wt.% of WPA, above which a restoration of the amount of surface oxygen groups was noticed. TGA-DTA analysis revealed an improved thermal stability of the material up to 25 wt.% of WPA; at higher loading of WPA the thermal properties of nanocomposite became alike to the ones of individual components. The obtained results suggest optimal conditions for preparation of GO-WPA nanocomposites for electrochemical charge storage applications.
PB  - Belgrade : Materials Research Society of Serbia
C3  - Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018
T1  - Study of the interaction between graphene oxide and 12-tungstophosphoric acid in their nanocomposite
SP  - 110
EP  - 110
UR  - https://hdl.handle.net/21.15107/rcub_dais_3666
ER  - 

@conference{
author = "Mravik, Željko and Bajuk Bogdanović, Danica and Marković, Smilja and Kovač, Janez and Holclajtner Antunović, Ivanka and Jovanović, Zoran",
year = "2018",
abstract = "The rich surface chemistry and large surface area of graphene oxide (GO) provide a platform for various functional materials that synergistically enhance charge storage properties of the composite. In present work we have investigated interaction between GO and 12- thungstophosphoric acid (WPA) in their nanocomposites as a function of different mass ratio of constituents. For this purpose, the Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS), temperature programmed desorption method (TPD) and thermogravimetric/differential thermal analysis (TGA-DTA) methods were used. FTIR spectra have shown shifts and splitting of characteristic bands of WPA as a result of interactions with GO. Both XPS and TPD methods have shown an initial decrease of the total amount of surface oxygen groups of GO, with a minimum at around 10 wt.% of WPA, above which a restoration of the amount of surface oxygen groups was noticed. TGA-DTA analysis revealed an improved thermal stability of the material up to 25 wt.% of WPA; at higher loading of WPA the thermal properties of nanocomposite became alike to the ones of individual components. The obtained results suggest optimal conditions for preparation of GO-WPA nanocomposites for electrochemical charge storage applications.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018",
title = "Study of the interaction between graphene oxide and 12-tungstophosphoric acid in their nanocomposite",
pages = "110-110",
url = "https://hdl.handle.net/21.15107/rcub_dais_3666"
}

Mravik, Ž., Bajuk Bogdanović, D., Marković, S., Kovač, J., Holclajtner Antunović, I.,& Jovanović, Z.. (2018). Study of the interaction between graphene oxide and 12-tungstophosphoric acid in their nanocomposite. in Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018
Belgrade : Materials Research Society of Serbia., 110-110.
https://hdl.handle.net/21.15107/rcub_dais_3666

Mravik Ž, Bajuk Bogdanović D, Marković S, Kovač J, Holclajtner Antunović I, Jovanović Z. Study of the interaction between graphene oxide and 12-tungstophosphoric acid in their nanocomposite. in Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018. 2018;:110-110.
https://hdl.handle.net/21.15107/rcub_dais_3666 .

Mravik, Željko, Bajuk Bogdanović, Danica, Marković, Smilja, Kovač, Janez, Holclajtner Antunović, Ivanka, Jovanović, Zoran, "Study of the interaction between graphene oxide and 12-tungstophosphoric acid in their nanocomposite" in Programme and The Book of Abstracts / Twentieth Annual Conference YUCOMAT 2018, Herceg Novi, September 3-7, 2018 (2018):110-110,
https://hdl.handle.net/21.15107/rcub_dais_3666 .

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  - https://dais.sanu.ac.rs/123456789/15978
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.
T2  - International Journal of Hydrogen Energy
T1  - Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part II: Oxygen evolution
SP  - 20502
EP  - 20514
VL  - 41
IS  - 45
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.",
journal = "International Journal of Hydrogen Energy",
title = "Ni-(Ebonex-supported Ir) composite coatings as electrocatalysts for alkaline water electrolysis. Part II: Oxygen evolution",
pages = "20502-20514",
volume = "41",
number = "45",
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, 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  - https://dais.sanu.ac.rs/123456789/3354
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.
T2  - RSC Advances
T1  - Pt nanoparticles on tin oxide based support as a beneficial catalyst for oxygen reduction in alkaline solutions
SP  - 15923
EP  - 15929
VL  - 5
IS  - 21
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.",
journal = "RSC Advances",
title = "Pt nanoparticles on tin oxide based support as a beneficial catalyst for oxygen reduction in alkaline solutions",
pages = "15923-15929",
volume = "5",
number = "21",
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, 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  - CONF
AU  - Gajić Krstajić, Ljiljana
AU  - Elezović, Nevenka
AU  - Babić, Biljana M.
AU  - Kovač, Janez
AU  - Radmilović, Velimir R.
AU  - Krstajić, Nedeljko
PY  - 2014
UR  - https://dais.sanu.ac.rs/123456789/560
AB  - Platinum on Sb doped tin oxide support (Sb/SnO2) was synthesized and characterized as the catalyst for oxygen reduction reaction in 0.1 mol dm-3NaOH solution, at 25oC. Sb (5%) doped tin oxide support was synthesized by sol-gel procedure. Platinum nanocatalyst (20% Pt) on Sb-SnO2 support was synthesized by borohydride reduction method. Synthesized support and catalyst were characterized by BET (Brunauer, Emmett, Teller), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). XRD diffraction spectra of the support contained only SnO2 belonging peaks. X-ray photoelectron spectroscopy was applied to characterize chemical status of elements before and after Pt-treatment. XPS spectra Sn 3d, Pt 4f, Sb 3d and O 1s revealed that the Pt-deposition on Sb+SnO2 support induced reduction of Sn(4+) oxidation state to Sn(2+) and Sn(0) states, while Pt remained in metallic state and Sb was in (3+) oxidation state. Homogenous Pt nanoparticles distribution over the support, without pronounced particle agglomeration was confirmed by HRTEM technique. The average Pt particle size was 2.9 nm. Electrochemically active Pt surface area of the catalyst was determined by 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 μC cm-2 for full monolayer coverage. This calculation gave the value of 51 m2 g-1. Kinetics of the oxygen reduction reaction at Pt/Sb-SnO2 catalyst was studied by cyclic voltammetry and linear sweep voltammetry at rotating gold disc electrode. Two different Tafel slope were observed: one close to 60 mV dec-1 in low current density region, and other ~120 mV dec-1 in higher current densities region, as it was already referred in literature for oxygen reduction reaction at polycrystalline Pt, as well as at 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 carbon supported (Vulcan XC-72) catalyst. Pt/Sb-SnO2 catalyst exhibited similar catalytic activity for oxygen reduction reaction like carbon supported one. The advantages of carbon free support application in terms of durability and stability of the catalysts were discussed.
PB  - Belgrade : Materials Research Society of Serbia
C3  - The Sixteenth Annual Conference YUCOMAT 2014: Programme and the Book of Abstracts
T1  - Electrochemical oxygen reduction at platinum catalyst on tin oxide based support in alkaline solution
SP  - 90
EP  - 90
UR  - https://hdl.handle.net/21.15107/rcub_dais_560
ER  - 

@conference{
author = "Gajić Krstajić, Ljiljana and Elezović, Nevenka and Babić, Biljana M. and Kovač, Janez and Radmilović, Velimir R. and Krstajić, Nedeljko",
year = "2014",
abstract = "Platinum on Sb doped tin oxide support (Sb/SnO2) was synthesized and characterized as the catalyst for oxygen reduction reaction in 0.1 mol dm-3NaOH solution, at 25oC. Sb (5%) doped tin oxide support was synthesized by sol-gel procedure. Platinum nanocatalyst (20% Pt) on Sb-SnO2 support was synthesized by borohydride reduction method. Synthesized support and catalyst were characterized by BET (Brunauer, Emmett, Teller), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). XRD diffraction spectra of the support contained only SnO2 belonging peaks. X-ray photoelectron spectroscopy was applied to characterize chemical status of elements before and after Pt-treatment. XPS spectra Sn 3d, Pt 4f, Sb 3d and O 1s revealed that the Pt-deposition on Sb+SnO2 support induced reduction of Sn(4+) oxidation state to Sn(2+) and Sn(0) states, while Pt remained in metallic state and Sb was in (3+) oxidation state. Homogenous Pt nanoparticles distribution over the support, without pronounced particle agglomeration was confirmed by HRTEM technique. The average Pt particle size was 2.9 nm. Electrochemically active Pt surface area of the catalyst was determined by 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 μC cm-2 for full monolayer coverage. This calculation gave the value of 51 m2 g-1. Kinetics of the oxygen reduction reaction at Pt/Sb-SnO2 catalyst was studied by cyclic voltammetry and linear sweep voltammetry at rotating gold disc electrode. Two different Tafel slope were observed: one close to 60 mV dec-1 in low current density region, and other ~120 mV dec-1 in higher current densities region, as it was already referred in literature for oxygen reduction reaction at polycrystalline Pt, as well as at 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 carbon supported (Vulcan XC-72) catalyst. Pt/Sb-SnO2 catalyst exhibited similar catalytic activity for oxygen reduction reaction like carbon supported one. The advantages of carbon free support application in terms of durability and stability of the catalysts were discussed.",
publisher = "Belgrade : Materials Research Society of Serbia",
journal = "The Sixteenth Annual Conference YUCOMAT 2014: Programme and the Book of Abstracts",
title = "Electrochemical oxygen reduction at platinum catalyst on tin oxide based support in alkaline solution",
pages = "90-90",
url = "https://hdl.handle.net/21.15107/rcub_dais_560"
}

Gajić Krstajić, L., Elezović, N., Babić, B. M., Kovač, J., Radmilović, V. R.,& Krstajić, N.. (2014). Electrochemical oxygen reduction at platinum catalyst on tin oxide based support in alkaline solution. in The Sixteenth Annual Conference YUCOMAT 2014: Programme and the Book of Abstracts
Belgrade : Materials Research Society of Serbia., 90-90.
https://hdl.handle.net/21.15107/rcub_dais_560

Gajić Krstajić L, Elezović N, Babić BM, Kovač J, Radmilović VR, Krstajić N. Electrochemical oxygen reduction at platinum catalyst on tin oxide based support in alkaline solution. in The Sixteenth Annual Conference YUCOMAT 2014: Programme and the Book of Abstracts. 2014;:90-90.
https://hdl.handle.net/21.15107/rcub_dais_560 .

Gajić Krstajić, Ljiljana, Elezović, Nevenka, Babić, Biljana M., Kovač, Janez, Radmilović, Velimir R., Krstajić, Nedeljko, "Electrochemical oxygen reduction at platinum catalyst on tin oxide based support in alkaline solution" in The Sixteenth Annual Conference YUCOMAT 2014: Programme and the Book of Abstracts (2014):90-90,
https://hdl.handle.net/21.15107/rcub_dais_560 .

TY  - JOUR
AU  - Lačnjevac, Uroš
AU  - Jović, Borka
AU  - Gajić Krstajić, Ljiljana
AU  - Kovač, Janez
AU  - Jović, Vladimir
AU  - Krstajić, Nedeljko
PY  - 2013
UR  - https://dais.sanu.ac.rs/123456789/358
AB  - The aim of this work was to investigate the possibility of preparation of the composite Cr–MoO2 coatings onto steel and titanium substrates as cathode materials with high selective properties which imply the suppression of hypochlorite reduction as a side reaction during hypochlorite commercial production. The electrodes were prepared by simultaneous deposition of chromium and suspended MoO2 particles on titanium substrate from acid chromium (VI) bath. The current efficiency for electrodeposition of the composite coatings did not vary significantly with the concentration of suspended MoO2 particles. The content of molybdenum in the deposits was relatively low (0.2–1.5 at.%) and increased with increasing the concentration of suspended MoO2 particles in the bath, in the range from 0 to 10 g dm−3. With further increase in the concentration of MoO2, the content of molybdenum in the coating varied insignificantly.

X-ray photoelectron spectroscopy-XPS and EDS analysis were applied to analyze elemental composition and chemical bonding of elements on the surface and in the sub-surface region of obtained coatings. When the concentration of MoO2 particles in the bath was raised above 5 g dm−3, the appearance of the coating changed from the typical pure chromium deposit to needle-like deposit with the appearance of black inclusions on the surface. XPS analysis and corresponding Cr 2p spectra showed the presence of chromium oxide, probably Cr2O3 with Cr(3+) valence state on the surface and in the sub-surface region of Cr–MoO2 coatings.

Investigation of the current efficiency for the hydrogen evolution reaction (HER) on Cr–MoO2 cathodes showed that it increased with the increase of the content of MoO2 particles in the coating, exceeding the value of 97% in the solution with the hypochlorite concentration of 0.21 mol dm−3. Under the same conditions, the current efficiency for the HER on Ti and Ti/Cr cathodes is very low (≈20%), and corresponding polarization curves confirmed the fact that the side reaction of hypochlorite reduction takes place in the diffusion-controlled regime on these electrodes. The high selectivity of Cr–MoO2 coating is probably caused by the presence of chromium oxide (hydroxide) formed at the surface of the coating during co-deposition of Cr and MoO2 particles, which prevents hypochlorite reduction on the cathode during the HER.
PB  - Elsevier
T2  - Electrochimica Acta
T1  - Ti substrate coated with composite Cr–MoO2 coatings as highly selective cathode materials in hypochlorite production
SP  - 34
EP  - 42
VL  - 96
IS  - 30
DO  - 10.1016/j.electacta.2013.02.086
UR  - https://hdl.handle.net/21.15107/rcub_dais_358
ER  - 

@article{
author = "Lačnjevac, Uroš and Jović, Borka and Gajić Krstajić, Ljiljana and Kovač, Janez and Jović, Vladimir and Krstajić, Nedeljko",
year = "2013",
abstract = "The aim of this work was to investigate the possibility of preparation of the composite Cr–MoO2 coatings onto steel and titanium substrates as cathode materials with high selective properties which imply the suppression of hypochlorite reduction as a side reaction during hypochlorite commercial production. The electrodes were prepared by simultaneous deposition of chromium and suspended MoO2 particles on titanium substrate from acid chromium (VI) bath. The current efficiency for electrodeposition of the composite coatings did not vary significantly with the concentration of suspended MoO2 particles. The content of molybdenum in the deposits was relatively low (0.2–1.5 at.%) and increased with increasing the concentration of suspended MoO2 particles in the bath, in the range from 0 to 10 g dm−3. With further increase in the concentration of MoO2, the content of molybdenum in the coating varied insignificantly.

X-ray photoelectron spectroscopy-XPS and EDS analysis were applied to analyze elemental composition and chemical bonding of elements on the surface and in the sub-surface region of obtained coatings. When the concentration of MoO2 particles in the bath was raised above 5 g dm−3, the appearance of the coating changed from the typical pure chromium deposit to needle-like deposit with the appearance of black inclusions on the surface. XPS analysis and corresponding Cr 2p spectra showed the presence of chromium oxide, probably Cr2O3 with Cr(3+) valence state on the surface and in the sub-surface region of Cr–MoO2 coatings.

Investigation of the current efficiency for the hydrogen evolution reaction (HER) on Cr–MoO2 cathodes showed that it increased with the increase of the content of MoO2 particles in the coating, exceeding the value of 97% in the solution with the hypochlorite concentration of 0.21 mol dm−3. Under the same conditions, the current efficiency for the HER on Ti and Ti/Cr cathodes is very low (≈20%), and corresponding polarization curves confirmed the fact that the side reaction of hypochlorite reduction takes place in the diffusion-controlled regime on these electrodes. The high selectivity of Cr–MoO2 coating is probably caused by the presence of chromium oxide (hydroxide) formed at the surface of the coating during co-deposition of Cr and MoO2 particles, which prevents hypochlorite reduction on the cathode during the HER.",
publisher = "Elsevier",
journal = "Electrochimica Acta",
title = "Ti substrate coated with composite Cr–MoO2 coatings as highly selective cathode materials in hypochlorite production",
pages = "34-42",
volume = "96",
number = "30",
doi = "10.1016/j.electacta.2013.02.086",
url = "https://hdl.handle.net/21.15107/rcub_dais_358"
}

Lačnjevac, U., Jović, B., Gajić Krstajić, L., Kovač, J., Jović, V.,& Krstajić, N.. (2013). Ti substrate coated with composite Cr–MoO2 coatings as highly selective cathode materials in hypochlorite production. in Electrochimica Acta
Elsevier., 96(30), 34-42.
https://doi.org/10.1016/j.electacta.2013.02.086
https://hdl.handle.net/21.15107/rcub_dais_358

Lačnjevac U, Jović B, Gajić Krstajić L, Kovač J, Jović V, Krstajić N. Ti substrate coated with composite Cr–MoO2 coatings as highly selective cathode materials in hypochlorite production. in Electrochimica Acta. 2013;96(30):34-42.
doi:10.1016/j.electacta.2013.02.086
https://hdl.handle.net/21.15107/rcub_dais_358 .

Lačnjevac, Uroš, Jović, Borka, Gajić Krstajić, Ljiljana, Kovač, Janez, Jović, Vladimir, Krstajić, Nedeljko, "Ti substrate coated with composite Cr–MoO2 coatings as highly selective cathode materials in hypochlorite production" in Electrochimica Acta, 96, no. 30 (2013):34-42,
https://doi.org/10.1016/j.electacta.2013.02.086 .,
https://hdl.handle.net/21.15107/rcub_dais_358 .