Mravik, Željko

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  • Mravik, Željko (7)

Author's Bibliography

Structural and electrochemical properties of carbon ion beam irradiated 12-tungstophosphoric acid

Mravik, Željko; Bajuk-Bogdanović, Danica V.; Mraković, Ana Đ.; Vukosavljević, Ljubiša; Trajić, Ivan; Kovač, Janez; Peruško, Davor; Gavrilov, Nemanja; Jovanović, Zoran M.

(2021)

TY  - JOUR
AU  - Mravik, Željko
AU  - Bajuk-Bogdanović, Danica V.
AU  - Mraković, Ana Đ.
AU  - Vukosavljević, Ljubiša
AU  - Trajić, Ivan
AU  - Kovač, Janez
AU  - Peruško, Davor
AU  - Gavrilov, Nemanja
AU  - Jovanović, Zoran M.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9150
AB  - In recent years polyoxometalates (POMs) have attracted significant research interest due to versatile properties. These properties are determined by the size, structure and elemental composition of POMs and hence play an important role in their application. In the present study, the ion beam irradiation (10 keV C+ ions, 5 × 1014–2.5 × 1015 ions/cm2) has been utilized for modification of physicochemical properties of 120 nm-thick layer of 12-tungstophosphoric acid (WPA). Scanning electron microscopy analysis of irradiated films showed change of morphology i.e. an increase of WPA grain size with irradiation and coalescence of grains at the highest fluence. This was accompanied by structural changes. Attenuated total reflectance Fourier transform infrared analysis revealed that vibration bands of Keggin anion became less pronounced as fluence increased, while Raman spectra appeared as strongly modified. The effect of irradiation with 1.25 × 1015 ions/cm2 on the structure of WPA was similar to the effect of thermal treatment at 600 °C. Irradiation of WPA led to decrease of the band gap (from 4.07 to 3.92 eV), which was correlated to transformation Keggin anions into a network of WO6 octahedra and PO4 tetrahedra. This is in line with increased number of W=Od bonds observed by UV–Visible diffuse reflectance spectroscopy. Beside transformation to bronzes a reduction of WPA was observed by X-ray Photoelectron Spectroscopy (shift to lower binding energy) and Raman methods, whereas the Raman spectra of irradiated samples were similar to heteropoly blue. The electrochemical properties of irradiated WPA were also assessed. Cyclic voltammetry measurements showed that at up to 1.25 × 1015 ions/cm2 lithiation capacity of WPA increases and activity for hydrogen evolution reaction (HER) improves. The highest fluence caused interconnection of WO6 octahedra, closing of lithiation pathways and decrease in the number of active sites for HER. Our results provide a novel insight into the effects of ion beam irradiation on WPA and demonstrate high potential for tuning of physicochemical properties of POMs that are relevant in wide range of applications. © 2021 Elsevier Ltd
T2  - Radiation Physics and Chemistry
T1  - Structural and electrochemical properties of carbon ion beam irradiated 12-tungstophosphoric acid
VL  - 183
SP  - 109422
DO  - 10.1016/j.radphyschem.2021.109422
ER  - 
@article{
author = "Mravik, Željko and Bajuk-Bogdanović, Danica V. and Mraković, Ana Đ. and Vukosavljević, Ljubiša and Trajić, Ivan and Kovač, Janez and Peruško, Davor and Gavrilov, Nemanja and Jovanović, Zoran M.",
year = "2021",
url = "https://vinar.vin.bg.ac.rs/handle/123456789/9150",
abstract = "In recent years polyoxometalates (POMs) have attracted significant research interest due to versatile properties. These properties are determined by the size, structure and elemental composition of POMs and hence play an important role in their application. In the present study, the ion beam irradiation (10 keV C+ ions, 5 × 1014–2.5 × 1015 ions/cm2) has been utilized for modification of physicochemical properties of 120 nm-thick layer of 12-tungstophosphoric acid (WPA). Scanning electron microscopy analysis of irradiated films showed change of morphology i.e. an increase of WPA grain size with irradiation and coalescence of grains at the highest fluence. This was accompanied by structural changes. Attenuated total reflectance Fourier transform infrared analysis revealed that vibration bands of Keggin anion became less pronounced as fluence increased, while Raman spectra appeared as strongly modified. The effect of irradiation with 1.25 × 1015 ions/cm2 on the structure of WPA was similar to the effect of thermal treatment at 600 °C. Irradiation of WPA led to decrease of the band gap (from 4.07 to 3.92 eV), which was correlated to transformation Keggin anions into a network of WO6 octahedra and PO4 tetrahedra. This is in line with increased number of W=Od bonds observed by UV–Visible diffuse reflectance spectroscopy. Beside transformation to bronzes a reduction of WPA was observed by X-ray Photoelectron Spectroscopy (shift to lower binding energy) and Raman methods, whereas the Raman spectra of irradiated samples were similar to heteropoly blue. The electrochemical properties of irradiated WPA were also assessed. Cyclic voltammetry measurements showed that at up to 1.25 × 1015 ions/cm2 lithiation capacity of WPA increases and activity for hydrogen evolution reaction (HER) improves. The highest fluence caused interconnection of WO6 octahedra, closing of lithiation pathways and decrease in the number of active sites for HER. Our results provide a novel insight into the effects of ion beam irradiation on WPA and demonstrate high potential for tuning of physicochemical properties of POMs that are relevant in wide range of applications. © 2021 Elsevier Ltd",
journal = "Radiation Physics and Chemistry",
title = "Structural and electrochemical properties of carbon ion beam irradiated 12-tungstophosphoric acid",
volume = "183",
pages = "109422",
doi = "10.1016/j.radphyschem.2021.109422"
}
Mravik, Ž., Bajuk-Bogdanović, D. V., Mraković, A. Đ., Vukosavljević, L., Trajić, I., Kovač, J., Peruško, D., Gavrilov, N.,& Jovanović, Z. M. (2021). Structural and electrochemical properties of carbon ion beam irradiated 12-tungstophosphoric acid.
Radiation Physics and Chemistry, 183, 109422.
https://doi.org/10.1016/j.radphyschem.2021.109422
Mravik Ž, Bajuk-Bogdanović DV, Mraković AĐ, Vukosavljević L, Trajić I, Kovač J, Peruško D, Gavrilov N, Jovanović ZM. Structural and electrochemical properties of carbon ion beam irradiated 12-tungstophosphoric acid. Radiation Physics and Chemistry. 2021;183:109422
Mravik Željko, Bajuk-Bogdanović Danica V., Mraković Ana Đ., Vukosavljević Ljubiša, Trajić Ivan, Kovač Janez, Peruško Davor, Gavrilov Nemanja, Jovanović Zoran M., "Structural and electrochemical properties of carbon ion beam irradiated 12-tungstophosphoric acid" Radiation Physics and Chemistry, 183 (2021):109422,
https://doi.org/10.1016/j.radphyschem.2021.109422 .

Self-limiting interactions in 2D–0D systems: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite

Jovanović, Zoran M.; Mravik, Željko; Bajuk-Bogdanović, Danica V.; Jovanović, Sonja; Marković, Smilja; Vujković, Milica; Kovač, Janez; Vengust, Damjan; Uskoković-Marković, Snežana; Holclajtner-Antunović, Ivanka D.

(2020)

TY  - JOUR
AU  - Jovanović, Zoran M.
AU  - Mravik, Željko
AU  - Bajuk-Bogdanović, Danica V.
AU  - Jovanović, Sonja
AU  - Marković, Smilja
AU  - Vujković, Milica
AU  - Kovač, Janez
AU  - Vengust, Damjan
AU  - Uskoković-Marković, Snežana
AU  - Holclajtner-Antunović, Ivanka D.
PY  - 2020
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/8520
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. © 2019 Elsevier Ltd
T2  - Carbon
T1  - Self-limiting interactions in 2D–0D systems: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite
VL  - 156
SP  - 166
EP  - 178
DO  - 10.1016/j.carbon.2019.09.072
ER  - 
@article{
author = "Jovanović, Zoran M. and Mravik, Željko and Bajuk-Bogdanović, Danica V. and Jovanović, Sonja and Marković, Smilja and Vujković, Milica and Kovač, Janez and Vengust, Damjan and Uskoković-Marković, Snežana and Holclajtner-Antunović, Ivanka D.",
year = "2020",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/8520",
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. © 2019 Elsevier Ltd",
journal = "Carbon",
title = "Self-limiting interactions in 2D–0D systems: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite",
volume = "156",
pages = "166-178",
doi = "10.1016/j.carbon.2019.09.072"
}
Jovanović, Z. M., Mravik, Ž., Bajuk-Bogdanović, D. V., Jovanović, S., Marković, S., Vujković, M., Kovač, J., Vengust, D., Uskoković-Marković, S.,& Holclajtner-Antunović, I. D. (2020). Self-limiting interactions in 2D–0D systems: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite.
Carbon, 156, 166-178.
https://doi.org/10.1016/j.carbon.2019.09.072
Jovanović ZM, Mravik Ž, Bajuk-Bogdanović DV, Jovanović S, Marković S, Vujković M, Kovač J, Vengust D, Uskoković-Marković S, Holclajtner-Antunović ID. Self-limiting interactions in 2D–0D systems: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite. Carbon. 2020;156:166-178
Jovanović Zoran M., Mravik Željko, Bajuk-Bogdanović Danica V., Jovanović Sonja, Marković Smilja, Vujković Milica, Kovač Janez, Vengust Damjan, Uskoković-Marković Snežana, Holclajtner-Antunović Ivanka D., "Self-limiting interactions in 2D–0D systems: A case study of graphene oxide and 12-tungstophosphoric acid nanocomposite" Carbon, 156 (2020):166-178,
https://doi.org/10.1016/j.carbon.2019.09.072 .
3
3

Tailoring the electrochemical charge storage properties of carbonaceous support by redox properties of heteropoly acids: where does the synergy come from?

Bajuk-Bogdanović, Danica V.; Holclajtner-Antunović, Ivanka D.; Jovanović, Zoran M.; Mravik, Željko; Krstić, Jugoslav B.; Uskoković-Marković, Snežana; Vujković, Milica

(2019)

TY  - JOUR
AU  - Bajuk-Bogdanović, Danica V.
AU  - Holclajtner-Antunović, Ivanka D.
AU  - Jovanović, Zoran M.
AU  - Mravik, Željko
AU  - Krstić, Jugoslav B.
AU  - Uskoković-Marković, Snežana
AU  - Vujković, Milica
PY  - 2019
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/8500
AB  - The synergistic effects between two Keggin-type heteropoly acids (HPAs) and carbon surface were examined and elucidated. An improved high rate capability (and potential high capacitor electrode for supercapacitors) of the hybrid materials, obtained by anchoring of α-dodecamolybdophosphoric (MoPA), α-dodecatungstophosphoric (WPA), and their mixture to activated carbon (AC), was achieved through the different mechanism of interaction. In order to elaborate this, a detailed analysis of AC-HPA composites has been performed by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, temperature-programmed desorption (TPD), Fourier-transform infrared spectroscopy (FTIR), micro Raman spectroscopy, and zeta potential measurements. The zeta potential measurements revealed positive charge of carbon surface thus indicating attractive interactions with negatively charged Keggin anion. The surface analysis has shown that WPA spontaneously reduces the carbon surface, while interaction with MoPA leads to its oxidation. As the consequence of the tailoring of the functional groups at carbon surface through HPAs’ action, the distortion of cyclic voltammograms (CVs) decreased in the following order: AC-MoPA, AC-MoPA-WPA, and AC-WPA. A prominent rectangular shape of AC-WPA, even at an extremely high scan rate of 400 mVs−1, was measured, which is rarely demonstrated for carbon-based composites. By applying the theory of electrode potentials, the HPA-AC synergistic effect was explained and discussed in terms of charge storage improvement of HPA-modified carbon. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
T2  - Journal of Solid State Electrochemistry
T1  - Tailoring the electrochemical charge storage properties of carbonaceous support by redox properties of heteropoly acids: where does the synergy come from?
VL  - 23
IS  - 9
SP  - 2747
EP  - 2758
DO  - 10.1007/s10008-019-04369-4
ER  - 
@article{
author = "Bajuk-Bogdanović, Danica V. and Holclajtner-Antunović, Ivanka D. and Jovanović, Zoran M. and Mravik, Željko and Krstić, Jugoslav B. and Uskoković-Marković, Snežana and Vujković, Milica",
year = "2019",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/8500",
abstract = "The synergistic effects between two Keggin-type heteropoly acids (HPAs) and carbon surface were examined and elucidated. An improved high rate capability (and potential high capacitor electrode for supercapacitors) of the hybrid materials, obtained by anchoring of α-dodecamolybdophosphoric (MoPA), α-dodecatungstophosphoric (WPA), and their mixture to activated carbon (AC), was achieved through the different mechanism of interaction. In order to elaborate this, a detailed analysis of AC-HPA composites has been performed by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, temperature-programmed desorption (TPD), Fourier-transform infrared spectroscopy (FTIR), micro Raman spectroscopy, and zeta potential measurements. The zeta potential measurements revealed positive charge of carbon surface thus indicating attractive interactions with negatively charged Keggin anion. The surface analysis has shown that WPA spontaneously reduces the carbon surface, while interaction with MoPA leads to its oxidation. As the consequence of the tailoring of the functional groups at carbon surface through HPAs’ action, the distortion of cyclic voltammograms (CVs) decreased in the following order: AC-MoPA, AC-MoPA-WPA, and AC-WPA. A prominent rectangular shape of AC-WPA, even at an extremely high scan rate of 400 mVs−1, was measured, which is rarely demonstrated for carbon-based composites. By applying the theory of electrode potentials, the HPA-AC synergistic effect was explained and discussed in terms of charge storage improvement of HPA-modified carbon. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.",
journal = "Journal of Solid State Electrochemistry",
title = "Tailoring the electrochemical charge storage properties of carbonaceous support by redox properties of heteropoly acids: where does the synergy come from?",
volume = "23",
number = "9",
pages = "2747-2758",
doi = "10.1007/s10008-019-04369-4"
}
Bajuk-Bogdanović, D. V., Holclajtner-Antunović, I. D., Jovanović, Z. M., Mravik, Ž., Krstić, J. B., Uskoković-Marković, S.,& Vujković, M. (2019). Tailoring the electrochemical charge storage properties of carbonaceous support by redox properties of heteropoly acids: where does the synergy come from?.
Journal of Solid State Electrochemistry, 23(9), 2747-2758.
https://doi.org/10.1007/s10008-019-04369-4
Bajuk-Bogdanović DV, Holclajtner-Antunović ID, Jovanović ZM, Mravik Ž, Krstić JB, Uskoković-Marković S, Vujković M. Tailoring the electrochemical charge storage properties of carbonaceous support by redox properties of heteropoly acids: where does the synergy come from?. Journal of Solid State Electrochemistry. 2019;23(9):2747-2758
Bajuk-Bogdanović Danica V., Holclajtner-Antunović Ivanka D., Jovanović Zoran M., Mravik Željko, Krstić Jugoslav B., Uskoković-Marković Snežana, Vujković Milica, "Tailoring the electrochemical charge storage properties of carbonaceous support by redox properties of heteropoly acids: where does the synergy come from?" Journal of Solid State Electrochemistry, 23, no. 9 (2019):2747-2758,
https://doi.org/10.1007/s10008-019-04369-4 .
1
1
1

Analiza površinskih funkcionalnih grupa termički redukovanog grafen oksida metodom temperaturski programirane desorpcije

Mravik, Željko; Jovanović, Zoran M.

(2018)

TY  - JOUR
AU  - Mravik, Željko
AU  - Jovanović, Zoran M.
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9134
AB  - U ovom radu ispitan je uticaj termičke redukcije na karakteristike grafen oksida sintetisanog modifikovanim Hamerovim postupkom, sa posebnim osvrtom na promene njegovih površinskih funkcionalnih grupa. Početni grafen oksid karakterisan je metodama rentgeno-strukturne analize, spektrofotometrije vidljivog i ultraljubičastog zračenja, skenirajuće i transmisione elektronske mikrosko-pije. Mikroskopija atomskih sila upotrebljena je za merenje debljine slojeva grafen oksida pre i posle termičke redukcije. Promene površinskih funkcionalnih grupa termički redukovanog grafen oksida praćene su metodom temperaturski programirane desorpcije (TPD) pri čemu je analiza uzoraka pokazala desorpciju površinskih funkcionalnih grupa čiji se opseg stabilnosti nalazi ispod temperature tretmana. Termičkom redukcijom na 300°C dolazi do dekompozicije epoksi, alkoksi i karboksilnih grupa kao i karbonilnih grupa sklonih ka transformaciji do α-supstituisanih aldehida i ketona. Takođe, termičkom redukcijom na 600 °C sa površine se desorbuju i karboksilni anhidridi. TPD krive uzoraka snimanih nakon određenog vremenskog perioda po redukciji, pokazale su delimično vraćanje površinskih funkcionalnih grupa sa vremenom.
T2  - Tehnika
T1  - Analiza površinskih funkcionalnih grupa termički redukovanog grafen oksida metodom temperaturski programirane desorpcije
VL  - 73
IS  - 2
SP  - 186
EP  - 191
DO  - 10.5937/tehnika1802186M
ER  - 
@article{
author = "Mravik, Željko and Jovanović, Zoran M.",
year = "2018",
url = "https://vinar.vin.bg.ac.rs/handle/123456789/9134",
abstract = "U ovom radu ispitan je uticaj termičke redukcije na karakteristike grafen oksida sintetisanog modifikovanim Hamerovim postupkom, sa posebnim osvrtom na promene njegovih površinskih funkcionalnih grupa. Početni grafen oksid karakterisan je metodama rentgeno-strukturne analize, spektrofotometrije vidljivog i ultraljubičastog zračenja, skenirajuće i transmisione elektronske mikrosko-pije. Mikroskopija atomskih sila upotrebljena je za merenje debljine slojeva grafen oksida pre i posle termičke redukcije. Promene površinskih funkcionalnih grupa termički redukovanog grafen oksida praćene su metodom temperaturski programirane desorpcije (TPD) pri čemu je analiza uzoraka pokazala desorpciju površinskih funkcionalnih grupa čiji se opseg stabilnosti nalazi ispod temperature tretmana. Termičkom redukcijom na 300°C dolazi do dekompozicije epoksi, alkoksi i karboksilnih grupa kao i karbonilnih grupa sklonih ka transformaciji do α-supstituisanih aldehida i ketona. Takođe, termičkom redukcijom na 600 °C sa površine se desorbuju i karboksilni anhidridi. TPD krive uzoraka snimanih nakon određenog vremenskog perioda po redukciji, pokazale su delimično vraćanje površinskih funkcionalnih grupa sa vremenom.",
journal = "Tehnika",
title = "Analiza površinskih funkcionalnih grupa termički redukovanog grafen oksida metodom temperaturski programirane desorpcije",
volume = "73",
number = "2",
pages = "186-191",
doi = "10.5937/tehnika1802186M"
}
Mravik, Ž.,& Jovanović, Z. M. (2018). Analiza površinskih funkcionalnih grupa termički redukovanog grafen oksida metodom temperaturski programirane desorpcije.
Tehnika, 73(2), 186-191.
https://doi.org/10.5937/tehnika1802186M
Mravik Ž, Jovanović ZM. Analiza površinskih funkcionalnih grupa termički redukovanog grafen oksida metodom temperaturski programirane desorpcije. Tehnika. 2018;73(2):186-191
Mravik Željko, Jovanović Zoran M., "Analiza površinskih funkcionalnih grupa termički redukovanog grafen oksida metodom temperaturski programirane desorpcije" Tehnika, 73, no. 2 (2018):186-191,
https://doi.org/10.5937/tehnika1802186M .

Effect of thermal treatment on the charge storage properties of graphene oxide/12-tungstophosphoric acid nanocomposite

Jovanović, Zoran M.; Holclajtner-Antunović, Ivanka D.; Bajuk-Bogdanović, Danica V.; Jovanović, Sonja; Mravik, Željko; Vujković, Milica

(2017)

TY  - JOUR
AU  - Jovanović, Zoran M.
AU  - Holclajtner-Antunović, Ivanka D.
AU  - Bajuk-Bogdanović, Danica V.
AU  - Jovanović, Sonja
AU  - Mravik, Željko
AU  - Vujković, Milica
PY  - 2017
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/1737
AB  - The influence of thermal treatment in an inert atmosphere on the charge storage properties of graphene oxide (GO)/12-tungstophosphoric acid (WPA) nanocomposite was examined. The transmission electron microscopy analysis revealed high dispersion of WPA on GO matrix, while the surface analysis showed thermal activation of structural changes of WPA and desorption of oxygen functional groups from GO and GO/WPA nanocomposite. Initial GO/WPA nanocomposite had approximately two times higher capacitance compared to initial GO. The thermal treatment of initial GO and GO/WPA to 500 degrees C induced twofold increase of capacitance of GO and 40% increase of GO/WPA, accompanied with significant increase of operating voltage compared to GO (for 300 mV). Above 500 degrees C, a decrease of capacitance of both GO and GO/WPA was observed. The results suggest that understanding of structural changes of components and their interaction is crucial for improvement of electrochemical properties of considered composite.
T2  - Electrochemistry Communications
T1  - Effect of thermal treatment on the charge storage properties of graphene oxide/12-tungstophosphoric acid nanocomposite
VL  - 83
SP  - 36
EP  - 40
DO  - 10.1016/j.elecom.2017.08.017
ER  - 
@article{
author = "Jovanović, Zoran M. and Holclajtner-Antunović, Ivanka D. and Bajuk-Bogdanović, Danica V. and Jovanović, Sonja and Mravik, Željko and Vujković, Milica",
year = "2017",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/1737",
abstract = "The influence of thermal treatment in an inert atmosphere on the charge storage properties of graphene oxide (GO)/12-tungstophosphoric acid (WPA) nanocomposite was examined. The transmission electron microscopy analysis revealed high dispersion of WPA on GO matrix, while the surface analysis showed thermal activation of structural changes of WPA and desorption of oxygen functional groups from GO and GO/WPA nanocomposite. Initial GO/WPA nanocomposite had approximately two times higher capacitance compared to initial GO. The thermal treatment of initial GO and GO/WPA to 500 degrees C induced twofold increase of capacitance of GO and 40% increase of GO/WPA, accompanied with significant increase of operating voltage compared to GO (for 300 mV). Above 500 degrees C, a decrease of capacitance of both GO and GO/WPA was observed. The results suggest that understanding of structural changes of components and their interaction is crucial for improvement of electrochemical properties of considered composite.",
journal = "Electrochemistry Communications",
title = "Effect of thermal treatment on the charge storage properties of graphene oxide/12-tungstophosphoric acid nanocomposite",
volume = "83",
pages = "36-40",
doi = "10.1016/j.elecom.2017.08.017"
}
Jovanović, Z. M., Holclajtner-Antunović, I. D., Bajuk-Bogdanović, D. V., Jovanović, S., Mravik, Ž.,& Vujković, M. (2017). Effect of thermal treatment on the charge storage properties of graphene oxide/12-tungstophosphoric acid nanocomposite.
Electrochemistry Communications, 83, 36-40.
https://doi.org/10.1016/j.elecom.2017.08.017
Jovanović ZM, Holclajtner-Antunović ID, Bajuk-Bogdanović DV, Jovanović S, Mravik Ž, Vujković M. Effect of thermal treatment on the charge storage properties of graphene oxide/12-tungstophosphoric acid nanocomposite. Electrochemistry Communications. 2017;83:36-40
Jovanović Zoran M., Holclajtner-Antunović Ivanka D., Bajuk-Bogdanović Danica V., Jovanović Sonja, Mravik Željko, Vujković Milica, "Effect of thermal treatment on the charge storage properties of graphene oxide/12-tungstophosphoric acid nanocomposite" Electrochemistry Communications, 83 (2017):36-40,
https://doi.org/10.1016/j.elecom.2017.08.017 .
9
8
8

The role of surface chemistry in the charge storage properties of graphene oxide

Jovanović, Zoran M.; Bajuk-Bogdanović, Danica V.; Jovanović, Sonja; Mravik, Željko; Kovač, Janez; Holclajtner-Antunović, Ivanka D.; Vujković, Milica

(2017)

TY  - JOUR
AU  - Jovanović, Zoran M.
AU  - Bajuk-Bogdanović, Danica V.
AU  - Jovanović, Sonja
AU  - Mravik, Željko
AU  - Kovač, Janez
AU  - Holclajtner-Antunović, Ivanka D.
AU  - Vujković, Milica
PY  - 2017
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/1879
AB  - In the present study we have evaluated the contribution of particular oxygen functional groups in the charge storage properties of graphene oxide (GO). This was achieved by a gradual thermal reduction of GO in an inert atmosphere (up to 800 degrees C) and thorough examination of functional groups which remained after each de-functionalization step. After identification of functional groups, the character of additional cyclovoltammetric peak, less pronounced than the main redox quinone/hydroquinone pair, and overall charge storage properties of GO were discussed from the perspective of different thermal stability of its surface groups. The results indicated three-stage deoxidation process of GO, each comprising of specific surface chemistry, structural changes and electrochemical behavior. The low capacitance, similar to 50 F g(-1), at T LT = 300 degrees C was attributed to the presence of epoxy and carboxyl groups. The highest capacitance (120-130 F g(-1)) was observed in the case of GO reduced at 400 and 500 degrees C, which we attributed to positive effects of phenol and carbonyl/quinone groups, while at high temperatures (T GT = 600 degrees C, similar to 30 F g(-1)) the extensive desorption of functional groups and structural changes were emphasized as the main reasons for additional decrease of capacitance. Our results highlight the cases where the duality of interpretation of surface functional groups is likely to happen and indicate that not all functional groups play a positive role in charge storage behavior of graphene oxide. (C) 2017 Elsevier Ltd. All rights reserved.
T2  - Electrochimica Acta
T1  - The role of surface chemistry in the charge storage properties of graphene oxide
VL  - 258
SP  - 1228
EP  - 1243
DO  - 10.1016/j.electacta.2017.11.178
ER  - 
@article{
author = "Jovanović, Zoran M. and Bajuk-Bogdanović, Danica V. and Jovanović, Sonja and Mravik, Željko and Kovač, Janez and Holclajtner-Antunović, Ivanka D. and Vujković, Milica",
year = "2017",
url = "http://vinar.vin.bg.ac.rs/handle/123456789/1879",
abstract = "In the present study we have evaluated the contribution of particular oxygen functional groups in the charge storage properties of graphene oxide (GO). This was achieved by a gradual thermal reduction of GO in an inert atmosphere (up to 800 degrees C) and thorough examination of functional groups which remained after each de-functionalization step. After identification of functional groups, the character of additional cyclovoltammetric peak, less pronounced than the main redox quinone/hydroquinone pair, and overall charge storage properties of GO were discussed from the perspective of different thermal stability of its surface groups. The results indicated three-stage deoxidation process of GO, each comprising of specific surface chemistry, structural changes and electrochemical behavior. The low capacitance, similar to 50 F g(-1), at T LT = 300 degrees C was attributed to the presence of epoxy and carboxyl groups. The highest capacitance (120-130 F g(-1)) was observed in the case of GO reduced at 400 and 500 degrees C, which we attributed to positive effects of phenol and carbonyl/quinone groups, while at high temperatures (T GT = 600 degrees C, similar to 30 F g(-1)) the extensive desorption of functional groups and structural changes were emphasized as the main reasons for additional decrease of capacitance. Our results highlight the cases where the duality of interpretation of surface functional groups is likely to happen and indicate that not all functional groups play a positive role in charge storage behavior of graphene oxide. (C) 2017 Elsevier Ltd. All rights reserved.",
journal = "Electrochimica Acta",
title = "The role of surface chemistry in the charge storage properties of graphene oxide",
volume = "258",
pages = "1228-1243",
doi = "10.1016/j.electacta.2017.11.178"
}
Jovanović, Z. M., Bajuk-Bogdanović, D. V., Jovanović, S., Mravik, Ž., Kovač, J., Holclajtner-Antunović, I. D.,& Vujković, M. (2017). The role of surface chemistry in the charge storage properties of graphene oxide.
Electrochimica Acta, 258, 1228-1243.
https://doi.org/10.1016/j.electacta.2017.11.178
Jovanović ZM, Bajuk-Bogdanović DV, Jovanović S, Mravik Ž, Kovač J, Holclajtner-Antunović ID, Vujković M. The role of surface chemistry in the charge storage properties of graphene oxide. Electrochimica Acta. 2017;258:1228-1243
Jovanović Zoran M., Bajuk-Bogdanović Danica V., Jovanović Sonja, Mravik Željko, Kovač Janez, Holclajtner-Antunović Ivanka D., Vujković Milica, "The role of surface chemistry in the charge storage properties of graphene oxide" Electrochimica Acta, 258 (2017):1228-1243,
https://doi.org/10.1016/j.electacta.2017.11.178 .
16
15
17

Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite

Marković, Smilja; Mravik, Željko; Bajuk-Bogdanović, Danica V.; Marković, Smilja; Holclajtner-Antunović, Ivanka D.; Jovanović, Zoran M.

(Belgrade : Institute of Technical Sciences of SASA, 2017)

TY  - CONF
AU  - Mravik, Željko
AU  - Bajuk-Bogdanović, Danica V.
AU  - Marković, Smilja
AU  - Holclajtner-Antunović, Ivanka D.
AU  - Jovanović, Zoran M.
PY  - 2017
UR  - http://itn.sanu.ac.rs/opus4/frontdoor/index/index/docId/1219
UR  - http://itn.sanu.ac.rs/opus4/files/1219/Mravik_16YRC2017.pdf
UR  - http://dais.sanu.ac.rs/123456789/15450
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/7556
AB  - In recent years the nanocomposites of graphene oxide (GO) and different inorganic and organic compounds have shown great potential for charge storage applications. In present work we have investigated the influence of 12-tungstophosphoric acid (WPA) on surface chemistry of graphene oxide and thermal stability of nanocomposite. For this purpose nanocomposites with different mass ratios of GO and WPA were prepared. The thermal stability of nanocomposites was investigated by thermogravimetric and differential thermal analysis (TGA-DTA) while changes in surface chemistry of GO and structural properties of WPA were investigated by Fourier transform infrared spectroscopy (FTIR) and temperature programmed desorption (TPD) method. The TGA-DTA measurements of composites have shown that the major mass loss, due to carbon combustion, is shifted to higher temperatures (~500 °C vs. 380 °C of pure GO). Furthermore, when the amount of WPA is higher than 25 mass percent the nanocomposites start to act like individual components, which was also confirmed by FTIR analysis. The amount of surface oxygen groups, monitored by both TPD and FTIR methods, showed ˝V˝ shaped dependence from the quantity of WPA with minimum at about 12 mass percent of WPA. At the same time, the FTIR spectra revealed the structural changes of WPA, displayed as shifting and splitting of characteristic bands of Keggin anion structure.
PB  - Belgrade : Institute of Technical Sciences of SASA
C3  - Program and the Book of Abstracts / Sixteenth Young Researchers' Conference Materials Sciences and Engineering, December 6-8, 2017, Belgrade, Serbia
T1  - Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite
SP  - 48
EP  - 48
ER  - 
@conference{
editor = "Marković, Smilja",
author = "Mravik, Željko and Bajuk-Bogdanović, Danica V. and Marković, Smilja and Holclajtner-Antunović, Ivanka D. and Jovanović, Zoran M.",
year = "2017",
url = "http://itn.sanu.ac.rs/opus4/frontdoor/index/index/docId/1219, http://itn.sanu.ac.rs/opus4/files/1219/Mravik_16YRC2017.pdf, http://dais.sanu.ac.rs/123456789/15450, http://vinar.vin.bg.ac.rs/handle/123456789/7556",
abstract = "In recent years the nanocomposites of graphene oxide (GO) and different inorganic and organic compounds have shown great potential for charge storage applications. In present work we have investigated the influence of 12-tungstophosphoric acid (WPA) on surface chemistry of graphene oxide and thermal stability of nanocomposite. For this purpose nanocomposites with different mass ratios of GO and WPA were prepared. The thermal stability of nanocomposites was investigated by thermogravimetric and differential thermal analysis (TGA-DTA) while changes in surface chemistry of GO and structural properties of WPA were investigated by Fourier transform infrared spectroscopy (FTIR) and temperature programmed desorption (TPD) method. The TGA-DTA measurements of composites have shown that the major mass loss, due to carbon combustion, is shifted to higher temperatures (~500 °C vs. 380 °C of pure GO). Furthermore, when the amount of WPA is higher than 25 mass percent the nanocomposites start to act like individual components, which was also confirmed by FTIR analysis. The amount of surface oxygen groups, monitored by both TPD and FTIR methods, showed ˝V˝ shaped dependence from the quantity of WPA with minimum at about 12 mass percent of WPA. At the same time, the FTIR spectra revealed the structural changes of WPA, displayed as shifting and splitting of characteristic bands of Keggin anion structure.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "Program and the Book of Abstracts / Sixteenth Young Researchers' Conference Materials Sciences and Engineering, December 6-8, 2017, Belgrade, Serbia",
title = "Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite",
pages = "48-48"
}
Marković, S., Mravik, Ž., Bajuk-Bogdanović, D. V., Marković, S., Holclajtner-Antunović, I. D.,& Jovanović, Z. M. (2017). Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite.
Program and the Book of Abstracts / Sixteenth Young Researchers' Conference Materials Sciences and Engineering, December 6-8, 2017, Belgrade, Serbia
Belgrade : Institute of Technical Sciences of SASA., 48-48.
Marković S, Mravik Ž, Bajuk-Bogdanović DV, Marković S, Holclajtner-Antunović ID, Jovanović ZM. Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite. Program and the Book of Abstracts / Sixteenth Young Researchers' Conference Materials Sciences and Engineering, December 6-8, 2017, Belgrade, Serbia. 2017;:48-48
Marković Smilja, Mravik Željko, Bajuk-Bogdanović Danica V., Marković Smilja, Holclajtner-Antunović Ivanka D., Jovanović Zoran M., "Surface chemistry, thermal stability and structural properties of graphene oxide/12-tungstophosphoric acid nanocomposite" Program and the Book of Abstracts / Sixteenth Young Researchers' Conference Materials Sciences and Engineering, December 6-8, 2017, Belgrade, Serbia (2017):48-48