TY  - JOUR
AU  - Obradović, Maja D.
AU  - Babić, Biljana M.
AU  - Radmilovíć, Velimir R.
AU  - Krstajic, N. V.
AU  - Gojković, Snežana Lj.
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4946
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 (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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 D. and Babić, Biljana M. and Radmilovíć, Velimir R. and Krstajic, N. 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 (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.",
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. D., Babić, B. M., Radmilovíć, V. R., Krstajic, 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, 37(14), 10671-10679.
https://doi.org/10.1016/j.ijhydene.2012.04.114

Obradović MD, Babić BM, Radmilovíć VR, Krstajic 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 D., Babić, Biljana M., Radmilovíć, Velimir R., Krstajic, N. 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 D.
AU  - Rogan, Jelena R.
AU  - Babić, Biljana M.
AU  - Tripkovic, A. V.
AU  - Gautam, A. R. S.
AU  - Radmilovíć, Velimir R.
AU  - Gojković, Snežana Lj.
PY  - 2012
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/4583
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. (C) 2011 Elsevier B.V. All rights reserved.
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 D. and Rogan, Jelena R. and Babić, Biljana M. and Tripkovic, A. V. and Gautam, A. R. S. and Radmilovíć, 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. (C) 2011 Elsevier B.V. All rights reserved.",
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. D., Rogan, J. R., Babić, B. M., Tripkovic, A. V., Gautam, A. R. S., Radmilovíć, 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, 197, 72-79.
https://doi.org/10.1016/j.jpowsour.2011.09.043

Obradović MD, Rogan JR, Babić BM, Tripkovic AV, Gautam ARS, Radmilovíć 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 D., Rogan, Jelena R., Babić, Biljana M., Tripkovic, A. V., Gautam, A. R. S., Radmilovíć, 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 . .