TY  - JOUR
AU  - Brkovic, Danijela V
AU  - Avramov Ivić, Milka
AU  - Rakić, Vesna M.
AU  - Valentini, Luca
AU  - Uskoković, Petar S.
AU  - Marinković, Aleksandar D.
PY  - 2015
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1663
AB  - Covalent sidewall functionalization of multiwalled carbon nanotubes (MWCNTs) has been performed using two approaches, direct and indirect cycloaddition through diethyl malonate, based on the Bingel reaction. The results revealed that functionalized MWCNTs demonstrated enhanced electrical properties and significantly lower sheet resistance, especially after electric field thermal assisted annealing at 80 degrees C was performed. The presence of 1,3-dicarbonyl compounds caused the surface of MWCNTs to be more hydrophilic, approachable for the electrolyte and improved the capacitance performance of Au/MWCNTs electrodes. The modified MWCNTs have been incorporated into nanocomposites by using solution mixing method with polyaniline and drop-casting resulting mixture on the paper substrate. The reduction in the sheet resistance with increasing the content of MWCNTs in the prepared nanocomposite films has been achieved.
PB  - Oxford : Pergamon-Elsevier Science Ltd
T2  - Journal of Physics and Chemistry of Solids
T1  - Electrical and morphological characterization of multiwalled carbon nanotubes functionalized via the Bingel reaction
VL  - 83
SP  - 121
EP  - 134
DO  - 10.1016/j.jpcs.2015.04.004
ER  - 

@article{
author = "Brkovic, Danijela V and Avramov Ivić, Milka and Rakić, Vesna M. and Valentini, Luca and Uskoković, Petar S. and Marinković, Aleksandar D.",
year = "2015",
abstract = "Covalent sidewall functionalization of multiwalled carbon nanotubes (MWCNTs) has been performed using two approaches, direct and indirect cycloaddition through diethyl malonate, based on the Bingel reaction. The results revealed that functionalized MWCNTs demonstrated enhanced electrical properties and significantly lower sheet resistance, especially after electric field thermal assisted annealing at 80 degrees C was performed. The presence of 1,3-dicarbonyl compounds caused the surface of MWCNTs to be more hydrophilic, approachable for the electrolyte and improved the capacitance performance of Au/MWCNTs electrodes. The modified MWCNTs have been incorporated into nanocomposites by using solution mixing method with polyaniline and drop-casting resulting mixture on the paper substrate. The reduction in the sheet resistance with increasing the content of MWCNTs in the prepared nanocomposite films has been achieved.",
publisher = "Oxford : Pergamon-Elsevier Science Ltd",
journal = "Journal of Physics and Chemistry of Solids",
title = "Electrical and morphological characterization of multiwalled carbon nanotubes functionalized via the Bingel reaction",
volume = "83",
pages = "121-134",
doi = "10.1016/j.jpcs.2015.04.004"
}

Brkovic, D. V., Avramov Ivić, M., Rakić, V. M., Valentini, L., Uskoković, P. S.,& Marinković, A. D.. (2015). Electrical and morphological characterization of multiwalled carbon nanotubes functionalized via the Bingel reaction. in Journal of Physics and Chemistry of Solids
Oxford : Pergamon-Elsevier Science Ltd., 83, 121-134.
https://doi.org/10.1016/j.jpcs.2015.04.004

Brkovic DV, Avramov Ivić M, Rakić VM, Valentini L, Uskoković PS, Marinković AD. Electrical and morphological characterization of multiwalled carbon nanotubes functionalized via the Bingel reaction. in Journal of Physics and Chemistry of Solids. 2015;83:121-134.
doi:10.1016/j.jpcs.2015.04.004 .

Brkovic, Danijela V, Avramov Ivić, Milka, Rakić, Vesna M., Valentini, Luca, Uskoković, Petar S., Marinković, Aleksandar D., "Electrical and morphological characterization of multiwalled carbon nanotubes functionalized via the Bingel reaction" in Journal of Physics and Chemistry of Solids, 83 (2015):121-134,
https://doi.org/10.1016/j.jpcs.2015.04.004 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Babić, Biljana M.
AU  - Radmilović, Velimir R.
AU  - Krstajić, Nedeljko V.
AU  - Gojković, Snežana Lj.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/977
AB  - Tungsten carbide was synthesized by calcination of carbon cryogel containing tungsten in a form of metatungstate. Characterization by X-ray diffraction and transmission electron microscopy indicated core-shell structure of the particles with tungsten core and tungsten carbide shell, attached to graphitized carbon. Pt nanoparticles were deposited on this material and most of them were nucleated on tungsten carbide. Cyclic voltammetry of W-C support and Pt/W-C catalyst indicated hydrogen intercalation in surface hydrous tungsten oxide. Oxidation of COads on Pt/W-C commences earlier than on Pt/C for about 100 mV. The onset potentials of MOR on Pt/W-C and Pt/C are the same, but at more positive potentials Pt/W-C catalyst is more active. It was proposed that promotion of MOR is based on bifunctional mechanism that facilitates COads removal. Stability test was performed by potential cycling of Pt/W-C and Pt/C in the supporting electrolyte and in the presence of methanol. Pt surface area loss observed in the supporting electrolyte of both catalysts after 250 cycles was about 20%. Decrease in the activity for methanol oxidation was 30% for Pt/W-C, but even 48% for Pt/C. The difference was explained by the presence of hydrous tungsten oxide on Pt in Pt/W-C catalyst, which reduces accumulation of poisoning COads. Copyright
PB  - Oxford : Pergamon-Elsevier Science Ltd
T2  - International Journal of Hydrogen Energy
T1  - Core-shell structured tungsten-tungsten carbide as a Pt catalyst support and its activity for methanol electrooxidation
VL  - 37
IS  - 14
SP  - 10671
EP  - 10679
DO  - 10.1016/j.ijhydene.2012.04.114
ER  - 

@article{
author = "Obradović, Maja and Babić, Biljana M. and Radmilović, Velimir R. and Krstajić, Nedeljko V. and Gojković, Snežana Lj.",
year = "2012",
abstract = "Tungsten carbide was synthesized by calcination of carbon cryogel containing tungsten in a form of metatungstate. Characterization by X-ray diffraction and transmission electron microscopy indicated core-shell structure of the particles with tungsten core and tungsten carbide shell, attached to graphitized carbon. Pt nanoparticles were deposited on this material and most of them were nucleated on tungsten carbide. Cyclic voltammetry of W-C support and Pt/W-C catalyst indicated hydrogen intercalation in surface hydrous tungsten oxide. Oxidation of COads on Pt/W-C commences earlier than on Pt/C for about 100 mV. The onset potentials of MOR on Pt/W-C and Pt/C are the same, but at more positive potentials Pt/W-C catalyst is more active. It was proposed that promotion of MOR is based on bifunctional mechanism that facilitates COads removal. Stability test was performed by potential cycling of Pt/W-C and Pt/C in the supporting electrolyte and in the presence of methanol. Pt surface area loss observed in the supporting electrolyte of both catalysts after 250 cycles was about 20%. Decrease in the activity for methanol oxidation was 30% for Pt/W-C, but even 48% for Pt/C. The difference was explained by the presence of hydrous tungsten oxide on Pt in Pt/W-C catalyst, which reduces accumulation of poisoning COads. Copyright",
publisher = "Oxford : Pergamon-Elsevier Science Ltd",
journal = "International Journal of Hydrogen Energy",
title = "Core-shell structured tungsten-tungsten carbide as a Pt catalyst support and its activity for methanol electrooxidation",
volume = "37",
number = "14",
pages = "10671-10679",
doi = "10.1016/j.ijhydene.2012.04.114"
}

Obradović, M., Babić, B. M., Radmilović, V. R., Krstajić, N. V.,& Gojković, S. Lj.. (2012). Core-shell structured tungsten-tungsten carbide as a Pt catalyst support and its activity for methanol electrooxidation. in International Journal of Hydrogen Energy
Oxford : Pergamon-Elsevier Science Ltd., 37(14), 10671-10679.
https://doi.org/10.1016/j.ijhydene.2012.04.114

Obradović M, Babić BM, Radmilović VR, Krstajić NV, Gojković SL. Core-shell structured tungsten-tungsten carbide as a Pt catalyst support and its activity for methanol electrooxidation. in International Journal of Hydrogen Energy. 2012;37(14):10671-10679.
doi:10.1016/j.ijhydene.2012.04.114 .

Obradović, Maja, Babić, Biljana M., Radmilović, Velimir R., Krstajić, Nedeljko V., Gojković, Snežana Lj., "Core-shell structured tungsten-tungsten carbide as a Pt catalyst support and its activity for methanol electrooxidation" in International Journal of Hydrogen Energy, 37, no. 14 (2012):10671-10679,
https://doi.org/10.1016/j.ijhydene.2012.04.114 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Rogan, Jelena R.
AU  - Babić, Biljana M.
AU  - Tripković, Amalija
AU  - Gautam, A. R. S.
AU  - Radmilović, Velimir R.
AU  - Gojković, Snežana Lj.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1086
AB  - Pt-Au nanoparticles supported on high area carbon were prepared by simultaneous reduction of Au and Pt precursors and by reduction of Pt precursor on already prepared Au nanoparticles. The first method produced a solid solution of Pt in Au containing similar to 5% Pt with the remaining Pt on the nanoparticles' surface. For the Pt:Au precursor ratio of 1:4 and 1:9, the surface ratio was found to be 0.70:0.30 and 0.55:0.45, respectively. By the second method with the Pt:Au precursors ratio of 1:12, the surface ratio was 0.30:0.70. The voltammetric peaks of Pt-oxide reduction and CO(ads) oxidation demonstrated electronic modification of Pt by Au in all catalysts. With decreasing Pt:Au surface ratio the activity for HCOOH oxidation increases and surface coverage by CO(ads) decreases. The highest activity under potentiodynamic and quasi steady-state conditions without poisoning by CO(ads) was observed for the catalyst with the lowest Pt:Au surface ratio. Chronoamperometic test showed that its high catalytic activity is associated with a high deactivation rate. It was postulated that too strong adsorption of a reactive or non-reactive intermediate caused by electron modification of Pt by underlying Au, is responsible for the deactivation. This result stresses that high Pt dispersion, necessary for promotion of the dehydrogenation path in HCOOH oxidation, can produce too strong adsorption of intermediates causing deactivation of the catalyst.
PB  - Elsevier
T2  - Journal of Power Sources
T1  - Formic acid oxidation on Pt-Au nanoparticles: Relation between the catalyst activity and the poisoning rate
VL  - 197
SP  - 72
EP  - 79
DO  - 10.1016/j.jpowsour.2011.09.043
ER  - 

@article{
author = "Obradović, Maja and Rogan, Jelena R. and Babić, Biljana M. and Tripković, Amalija and Gautam, A. R. S. and Radmilović, Velimir R. and Gojković, Snežana Lj.",
year = "2012",
abstract = "Pt-Au nanoparticles supported on high area carbon were prepared by simultaneous reduction of Au and Pt precursors and by reduction of Pt precursor on already prepared Au nanoparticles. The first method produced a solid solution of Pt in Au containing similar to 5% Pt with the remaining Pt on the nanoparticles' surface. For the Pt:Au precursor ratio of 1:4 and 1:9, the surface ratio was found to be 0.70:0.30 and 0.55:0.45, respectively. By the second method with the Pt:Au precursors ratio of 1:12, the surface ratio was 0.30:0.70. The voltammetric peaks of Pt-oxide reduction and CO(ads) oxidation demonstrated electronic modification of Pt by Au in all catalysts. With decreasing Pt:Au surface ratio the activity for HCOOH oxidation increases and surface coverage by CO(ads) decreases. The highest activity under potentiodynamic and quasi steady-state conditions without poisoning by CO(ads) was observed for the catalyst with the lowest Pt:Au surface ratio. Chronoamperometic test showed that its high catalytic activity is associated with a high deactivation rate. It was postulated that too strong adsorption of a reactive or non-reactive intermediate caused by electron modification of Pt by underlying Au, is responsible for the deactivation. This result stresses that high Pt dispersion, necessary for promotion of the dehydrogenation path in HCOOH oxidation, can produce too strong adsorption of intermediates causing deactivation of the catalyst.",
publisher = "Elsevier",
journal = "Journal of Power Sources",
title = "Formic acid oxidation on Pt-Au nanoparticles: Relation between the catalyst activity and the poisoning rate",
volume = "197",
pages = "72-79",
doi = "10.1016/j.jpowsour.2011.09.043"
}

Obradović, M., Rogan, J. R., Babić, B. M., Tripković, A., Gautam, A. R. S., Radmilović, V. R.,& Gojković, S. Lj.. (2012). Formic acid oxidation on Pt-Au nanoparticles: Relation between the catalyst activity and the poisoning rate. in Journal of Power Sources
Elsevier., 197, 72-79.
https://doi.org/10.1016/j.jpowsour.2011.09.043

Obradović M, Rogan JR, Babić BM, Tripković A, Gautam ARS, Radmilović VR, Gojković SL. Formic acid oxidation on Pt-Au nanoparticles: Relation between the catalyst activity and the poisoning rate. in Journal of Power Sources. 2012;197:72-79.
doi:10.1016/j.jpowsour.2011.09.043 .

Obradović, Maja, Rogan, Jelena R., Babić, Biljana M., Tripković, Amalija, Gautam, A. R. S., Radmilović, Velimir R., Gojković, Snežana Lj., "Formic acid oxidation on Pt-Au nanoparticles: Relation between the catalyst activity and the poisoning rate" in Journal of Power Sources, 197 (2012):72-79,
https://doi.org/10.1016/j.jpowsour.2011.09.043 . .

TY  - JOUR
AU  - Vukovic, Goran D.
AU  - Obradović, Maja
AU  - Marinković, Aleksandar D.
AU  - Rogan, Jelena R.
AU  - Uskoković, Petar S.
AU  - Radmilović, Velimir R.
AU  - Gojković, Snežana Lj.
PY  - 2011
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/801
AB  - Multi-walled carbon nanotubes (MWCNTs) were used as a support for Pt nanoparticles prepared by the microwave-assisted polyol method. The MWCNTs were pretreated by chemical oxidation (o-MWCNTs) followed by modification by ethylenediamine (eda-MWCNTs). Characterization of both oxidized and eda-modified materials by UV-spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy revealed that the modification by eda leads to (i) agglomeration of the MWCNTs, (ii) a decrease in the capacitance of the material and (iii) reduced rate of electron transfer between the MWCNTs and solution species. However, the Pt loading of Pt/o-MWCNTs was only 2 mass% while the loading of Pt/eda-MWCNTs was 20 mass%. Much higher efficiency of Pt deposition on eda-MWCNTs than on o-MWCNTs was ascribed to the shift in pH(pzc) value of the MWCNT surface from 2.43 to 5.91 upon modification by eda. Transmission electron microscopy revealed that the mean diameter of the Pt particles in Pt/eda-MWCNTs is 2.5 +/- 0.5 nm and that their distribution on the support is homogenous with no evidence of pronounced particle agglomeration. Cyclic voltammetry of a Pt/eda-MWCNT thin film indicated a clean Pt surface with well-resolved peaks characteristic of polycrystalline Pt. Its electrocatalytic activity for oxygen reduction was examined and the results corresponded to the commercial Pt nanocatalyst. This study shows that modification of o-MWCNTs by eda helps to achieve homogenous distribution of small Pt nanoparticles and does not impede its electrocatalytic activity.
PB  - Elsevier Science Sa, Lausanne
T2  - Materials Chemistry and Physics
T1  - Ethylenediamine-modified multiwall carbon nanotubes as a Pt catalyst support
VL  - 130
IS  - 1-2
SP  - 657
EP  - 664
DO  - 10.1016/j.matchemphys.2011.07.046
ER  - 

@article{
author = "Vukovic, Goran D. and Obradović, Maja and Marinković, Aleksandar D. and Rogan, Jelena R. and Uskoković, Petar S. and Radmilović, Velimir R. and Gojković, Snežana Lj.",
year = "2011",
abstract = "Multi-walled carbon nanotubes (MWCNTs) were used as a support for Pt nanoparticles prepared by the microwave-assisted polyol method. The MWCNTs were pretreated by chemical oxidation (o-MWCNTs) followed by modification by ethylenediamine (eda-MWCNTs). Characterization of both oxidized and eda-modified materials by UV-spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy revealed that the modification by eda leads to (i) agglomeration of the MWCNTs, (ii) a decrease in the capacitance of the material and (iii) reduced rate of electron transfer between the MWCNTs and solution species. However, the Pt loading of Pt/o-MWCNTs was only 2 mass% while the loading of Pt/eda-MWCNTs was 20 mass%. Much higher efficiency of Pt deposition on eda-MWCNTs than on o-MWCNTs was ascribed to the shift in pH(pzc) value of the MWCNT surface from 2.43 to 5.91 upon modification by eda. Transmission electron microscopy revealed that the mean diameter of the Pt particles in Pt/eda-MWCNTs is 2.5 +/- 0.5 nm and that their distribution on the support is homogenous with no evidence of pronounced particle agglomeration. Cyclic voltammetry of a Pt/eda-MWCNT thin film indicated a clean Pt surface with well-resolved peaks characteristic of polycrystalline Pt. Its electrocatalytic activity for oxygen reduction was examined and the results corresponded to the commercial Pt nanocatalyst. This study shows that modification of o-MWCNTs by eda helps to achieve homogenous distribution of small Pt nanoparticles and does not impede its electrocatalytic activity.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Materials Chemistry and Physics",
title = "Ethylenediamine-modified multiwall carbon nanotubes as a Pt catalyst support",
volume = "130",
number = "1-2",
pages = "657-664",
doi = "10.1016/j.matchemphys.2011.07.046"
}

Vukovic, G. D., Obradović, M., Marinković, A. D., Rogan, J. R., Uskoković, P. S., Radmilović, V. R.,& Gojković, S. Lj.. (2011). Ethylenediamine-modified multiwall carbon nanotubes as a Pt catalyst support. in Materials Chemistry and Physics
Elsevier Science Sa, Lausanne., 130(1-2), 657-664.
https://doi.org/10.1016/j.matchemphys.2011.07.046

Vukovic GD, Obradović M, Marinković AD, Rogan JR, Uskoković PS, Radmilović VR, Gojković SL. Ethylenediamine-modified multiwall carbon nanotubes as a Pt catalyst support. in Materials Chemistry and Physics. 2011;130(1-2):657-664.
doi:10.1016/j.matchemphys.2011.07.046 .

Vukovic, Goran D., Obradović, Maja, Marinković, Aleksandar D., Rogan, Jelena R., Uskoković, Petar S., Radmilović, Velimir R., Gojković, Snežana Lj., "Ethylenediamine-modified multiwall carbon nanotubes as a Pt catalyst support" in Materials Chemistry and Physics, 130, no. 1-2 (2011):657-664,
https://doi.org/10.1016/j.matchemphys.2011.07.046 . .