TY  - JOUR
AU  - Vidoeski, Bojan
AU  - Jovanović, Svetlana P.
AU  - Holclajtner-Antunović, Ivanka D.
AU  - Bajuk-Bogdanović, Danica V.
AU  - Budimir, Milica
AU  - Marković, Zoran M.
AU  - Todorović-Marković, Biljana
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1219
AB  - Heteropoly acids (HPAs) have found wide applications, such as in catalysis, energy conversion and storage, analytical chemistry, clinical medicine, materials science and others, but their use is limited due to their low surface area and high solubility in water. One of the possible ways to overcome these obstacles is to use height specific surface area supports for HPAs, such as carbon nanomaterials. Raman spectroscopy was applied for a studying the interaction between HPAs and highly ordered pyrolytic graphite (HOPG) as a model of a support. HOPG was exposed to two different HPAs: 12-tungsto-phosphoric acid and 12-molybodphosphoric acid, at different concentrations. It was noticed that 12-molybodphosphoric acid had stronger effects on the HOPG structure causing a weak doping and an increase of structural disorder. It was supposed that HOPG interacts with especially external oxygen atoms of 12-molybodphosphoric acid. Atomic force microscopy showed that the surface roughness of HOPG treated with 12-molybodphosphoric acid increases with increasing acid concentration, while in the case of HOPG exposed to 12-tungsto-phosphoric acid, the surface roughness concentration independent. The growth trend in the measured surface roughness (RMS) was in the agreement with the changes in the intensity ratio I-D/I-G obtained from the Raman spectra of the HOPG samples treated with 12-molybdophosphoric acid.
T2  - Journal of the Serbian Chemical Society
T1  - Raman study of the interactions between highly ordered pyrolytic graphite (HOPG) and polyoxometalates: The effects of acid concentration
VL  - 81
IS  - 7
SP  - 777
EP  - 787
DO  - 10.2298/JSC160301055V
ER  - 

@article{
author = "Vidoeski, Bojan and Jovanović, Svetlana P. and Holclajtner-Antunović, Ivanka D. and Bajuk-Bogdanović, Danica V. and Budimir, Milica and Marković, Zoran M. and Todorović-Marković, Biljana",
year = "2016",
abstract = "Heteropoly acids (HPAs) have found wide applications, such as in catalysis, energy conversion and storage, analytical chemistry, clinical medicine, materials science and others, but their use is limited due to their low surface area and high solubility in water. One of the possible ways to overcome these obstacles is to use height specific surface area supports for HPAs, such as carbon nanomaterials. Raman spectroscopy was applied for a studying the interaction between HPAs and highly ordered pyrolytic graphite (HOPG) as a model of a support. HOPG was exposed to two different HPAs: 12-tungsto-phosphoric acid and 12-molybodphosphoric acid, at different concentrations. It was noticed that 12-molybodphosphoric acid had stronger effects on the HOPG structure causing a weak doping and an increase of structural disorder. It was supposed that HOPG interacts with especially external oxygen atoms of 12-molybodphosphoric acid. Atomic force microscopy showed that the surface roughness of HOPG treated with 12-molybodphosphoric acid increases with increasing acid concentration, while in the case of HOPG exposed to 12-tungsto-phosphoric acid, the surface roughness concentration independent. The growth trend in the measured surface roughness (RMS) was in the agreement with the changes in the intensity ratio I-D/I-G obtained from the Raman spectra of the HOPG samples treated with 12-molybdophosphoric acid.",
journal = "Journal of the Serbian Chemical Society",
title = "Raman study of the interactions between highly ordered pyrolytic graphite (HOPG) and polyoxometalates: The effects of acid concentration",
volume = "81",
number = "7",
pages = "777-787",
doi = "10.2298/JSC160301055V"
}

Vidoeski, B., Jovanović, S. P., Holclajtner-Antunović, I. D., Bajuk-Bogdanović, D. V., Budimir, M., Marković, Z. M.,& Todorović-Marković, B.. (2016). Raman study of the interactions between highly ordered pyrolytic graphite (HOPG) and polyoxometalates: The effects of acid concentration. in Journal of the Serbian Chemical Society, 81(7), 777-787.
https://doi.org/10.2298/JSC160301055V

Vidoeski B, Jovanović SP, Holclajtner-Antunović ID, Bajuk-Bogdanović DV, Budimir M, Marković ZM, Todorović-Marković B. Raman study of the interactions between highly ordered pyrolytic graphite (HOPG) and polyoxometalates: The effects of acid concentration. in Journal of the Serbian Chemical Society. 2016;81(7):777-787.
doi:10.2298/JSC160301055V .

Vidoeski, Bojan, Jovanović, Svetlana P., Holclajtner-Antunović, Ivanka D., Bajuk-Bogdanović, Danica V., Budimir, Milica, Marković, Zoran M., Todorović-Marković, Biljana, "Raman study of the interactions between highly ordered pyrolytic graphite (HOPG) and polyoxometalates: The effects of acid concentration" in Journal of the Serbian Chemical Society, 81, no. 7 (2016):777-787,
https://doi.org/10.2298/JSC160301055V . .

TY  - JOUR
AU  - Vujković, Milica
AU  - Vidoeski, Bojan
AU  - Jovanović, Svetlana P.
AU  - Bajuk-Bogdanović, Danica V.
AU  - Budimir, Milica
AU  - Marković, Zoran M.
AU  - Pavlović, Vladimir B.
AU  - Todorović-Marković, Biljana
AU  - Holclajtner-Antunović, Ivanka D.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1274
AB  - A novel electrochemically exfoliated graphene-molybdophosphoric acid nanohybride (EG-MoPA) was prepared via a simple method. Both scanning electron (SEM) and atomic force microscopy (AFM) results show that MoPA clusters are attached to the surfaces of graphene sheets. By changing the mass ratio of EG-MoPA, the morphology of nanohybrid itself can be significantly modulated, from mostly flat graphene like structure at low amount of MoPA to very uneven, wavy surfaces when MoPA is present in higher concentration. The Raman and Fourier transform infra red (FTIR) spectra in conjunction with electrochemical results indicate that strong interaction exists between the components of nanohybride based on charge transfer and electrostatic interaction of graphene sheets and MoPA. The electrochemical performances are improved by synergetic effect of reversible redox properties of MoPA and the double layer capacitance of a high-surface area of the obtained nanohybrides. The higher current capability of EG was achieved by anchoring the small MoPA concentration on the graphene support. The strong bonding of EG with the MoPA prevents acid to dissolve in the electrolyte upon cycling, enabling the stable capacitance behaviour of the low-doped EG sample. The capacitance for the EG doped with the high amount of MoPA was found to be much larger than for EG. However, the obtained capacitance decreases at the beginning of cycling due to the dissolution of excessive amount of surface MoPA, weakly bonded to the graphene support. (C) 2016 Elsevier Ltd. All rights reserved.
T2  - Electrochimica Acta
T1  - Synthesis and Characterization of Electrochemically Exfoliated Graphene-Molybdophosphate Hybrid Materials for Charge Storage Devices
VL  - 217
SP  - 34
EP  - 46
DO  - 10.1016/j.electacta.2016.09.067
ER  - 

@article{
author = "Vujković, Milica and Vidoeski, Bojan and Jovanović, Svetlana P. and Bajuk-Bogdanović, Danica V. and Budimir, Milica and Marković, Zoran M. and Pavlović, Vladimir B. and Todorović-Marković, Biljana and Holclajtner-Antunović, Ivanka D.",
year = "2016",
abstract = "A novel electrochemically exfoliated graphene-molybdophosphoric acid nanohybride (EG-MoPA) was prepared via a simple method. Both scanning electron (SEM) and atomic force microscopy (AFM) results show that MoPA clusters are attached to the surfaces of graphene sheets. By changing the mass ratio of EG-MoPA, the morphology of nanohybrid itself can be significantly modulated, from mostly flat graphene like structure at low amount of MoPA to very uneven, wavy surfaces when MoPA is present in higher concentration. The Raman and Fourier transform infra red (FTIR) spectra in conjunction with electrochemical results indicate that strong interaction exists between the components of nanohybride based on charge transfer and electrostatic interaction of graphene sheets and MoPA. The electrochemical performances are improved by synergetic effect of reversible redox properties of MoPA and the double layer capacitance of a high-surface area of the obtained nanohybrides. The higher current capability of EG was achieved by anchoring the small MoPA concentration on the graphene support. The strong bonding of EG with the MoPA prevents acid to dissolve in the electrolyte upon cycling, enabling the stable capacitance behaviour of the low-doped EG sample. The capacitance for the EG doped with the high amount of MoPA was found to be much larger than for EG. However, the obtained capacitance decreases at the beginning of cycling due to the dissolution of excessive amount of surface MoPA, weakly bonded to the graphene support. (C) 2016 Elsevier Ltd. All rights reserved.",
journal = "Electrochimica Acta",
title = "Synthesis and Characterization of Electrochemically Exfoliated Graphene-Molybdophosphate Hybrid Materials for Charge Storage Devices",
volume = "217",
pages = "34-46",
doi = "10.1016/j.electacta.2016.09.067"
}

Vujković, M., Vidoeski, B., Jovanović, S. P., Bajuk-Bogdanović, D. V., Budimir, M., Marković, Z. M., Pavlović, V. B., Todorović-Marković, B.,& Holclajtner-Antunović, I. D.. (2016). Synthesis and Characterization of Electrochemically Exfoliated Graphene-Molybdophosphate Hybrid Materials for Charge Storage Devices. in Electrochimica Acta, 217, 34-46.
https://doi.org/10.1016/j.electacta.2016.09.067

Vujković M, Vidoeski B, Jovanović SP, Bajuk-Bogdanović DV, Budimir M, Marković ZM, Pavlović VB, Todorović-Marković B, Holclajtner-Antunović ID. Synthesis and Characterization of Electrochemically Exfoliated Graphene-Molybdophosphate Hybrid Materials for Charge Storage Devices. in Electrochimica Acta. 2016;217:34-46.
doi:10.1016/j.electacta.2016.09.067 .

Vujković, Milica, Vidoeski, Bojan, Jovanović, Svetlana P., Bajuk-Bogdanović, Danica V., Budimir, Milica, Marković, Zoran M., Pavlović, Vladimir B., Todorović-Marković, Biljana, Holclajtner-Antunović, Ivanka D., "Synthesis and Characterization of Electrochemically Exfoliated Graphene-Molybdophosphate Hybrid Materials for Charge Storage Devices" in Electrochimica Acta, 217 (2016):34-46,
https://doi.org/10.1016/j.electacta.2016.09.067 . .

TY  - JOUR
AU  - Jovanović, Svetlana P.
AU  - Marković, Zoran M.
AU  - Budimir, Milica
AU  - Špitalsky, Zdenko
AU  - Vidoeski, Bojan
AU  - Todorović-Marković, Biljana
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1018
AB  - We prepared graphene quantum dots (GQDs) using electrochemical approach. The luminescent properties of GQDs at various excitation wavelengths are examined. In order to study the possibility to improve these properties, we applied a low dose of gamma irradiation (15 kGy) on GQDs dissolved in two media: water and 4 % isopropyl alcohol solution. Upon gamma irradiation of water, various free radical species are formed and they usually cause oxidation. In the presence of isopropyl alcohol in water, during irradiation, oxygen contained radicals are quenched and only hydrogen radicals can survive and reduce the material exposed to irradiation. Morphology of GQDs is examined by atomic force and transmission electron microscopy. After gamma irradiation the increase of photoluminescence was noticed for both GQD samples. A higher intensity of photoluminescence is detected for GQDs irradiated in 4 % isopropyl alcohol solution. This result shows that further increase of gamma irradiation dose has a great potential for improvement of luminescence properties of GQDs.
PB  - Springer
T2  - Optical and Quantum Electronics
T1  - Effects of low gamma irradiation dose on the photoluminescence properties of graphene quantum dots
VL  - 48
IS  - 4
DO  - 10.1007/s11082-016-0516-z
ER  - 

@article{
author = "Jovanović, Svetlana P. and Marković, Zoran M. and Budimir, Milica and Špitalsky, Zdenko and Vidoeski, Bojan and Todorović-Marković, Biljana",
year = "2016",
abstract = "We prepared graphene quantum dots (GQDs) using electrochemical approach. The luminescent properties of GQDs at various excitation wavelengths are examined. In order to study the possibility to improve these properties, we applied a low dose of gamma irradiation (15 kGy) on GQDs dissolved in two media: water and 4 % isopropyl alcohol solution. Upon gamma irradiation of water, various free radical species are formed and they usually cause oxidation. In the presence of isopropyl alcohol in water, during irradiation, oxygen contained radicals are quenched and only hydrogen radicals can survive and reduce the material exposed to irradiation. Morphology of GQDs is examined by atomic force and transmission electron microscopy. After gamma irradiation the increase of photoluminescence was noticed for both GQD samples. A higher intensity of photoluminescence is detected for GQDs irradiated in 4 % isopropyl alcohol solution. This result shows that further increase of gamma irradiation dose has a great potential for improvement of luminescence properties of GQDs.",
publisher = "Springer",
journal = "Optical and Quantum Electronics",
title = "Effects of low gamma irradiation dose on the photoluminescence properties of graphene quantum dots",
volume = "48",
number = "4",
doi = "10.1007/s11082-016-0516-z"
}

Jovanović, S. P., Marković, Z. M., Budimir, M., Špitalsky, Z., Vidoeski, B.,& Todorović-Marković, B.. (2016). Effects of low gamma irradiation dose on the photoluminescence properties of graphene quantum dots. in Optical and Quantum Electronics
Springer., 48(4).
https://doi.org/10.1007/s11082-016-0516-z

Jovanović SP, Marković ZM, Budimir M, Špitalsky Z, Vidoeski B, Todorović-Marković B. Effects of low gamma irradiation dose on the photoluminescence properties of graphene quantum dots. in Optical and Quantum Electronics. 2016;48(4).
doi:10.1007/s11082-016-0516-z .

Jovanović, Svetlana P., Marković, Zoran M., Budimir, Milica, Špitalsky, Zdenko, Vidoeski, Bojan, Todorović-Marković, Biljana, "Effects of low gamma irradiation dose on the photoluminescence properties of graphene quantum dots" in Optical and Quantum Electronics, 48, no. 4 (2016),
https://doi.org/10.1007/s11082-016-0516-z . .