TY  - CONF
AU  - Obradović, Maja D.
AU  - Radmilović, Vuk V.
AU  - Radmilović, Velimir R.
AU  - Gojković, Snežana Lj.
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6623
AB  - The necessity of replacement of traditional energy sources with renewable and green alternatives has initiated vast research of direct alcohol fuel cells (DAFC). Ethanol is non-toxic and its crossover through a membrane is lower than methanol due to its larger molecule size. However, the splitting of C–C bond in ethanol is energetically difficult and much effort in electrocatalysts’ improvement is still needed to take the advantage of the high mass energy density of ethanol [1,2]. Electrochemical oxidation of alcohols in requires a noble metal, Pt or Pd, to adsorb the molecule, but also some other oxophilic metal to facilitate further reaction of the adsorbed intermediates Their promoted oxidative desorption can be achieved by introducing oxygen-containing species at the surface, which may also modify the electronic structure of the noble metal centers and thus weaken the strong adsorbate–noble metal bond. Copper is inactive for alcohol oxidation but its addition to palladium enhances the ethanol oxidation reaction (EOR) rate [3,4]. Various forms of Pd-Cu electrocatalysts exhibited improved mass activity for the EOR and oxygen reduction reaction (ORR), but the effect of Cu addition on the specific activity is not so clear. Therefore, in the present work, specific activity for EOR and ORR of synthesized Pd-Cu nanoparticles [5] supported on high area carbon was examined. As reference catalysts, synthesized Pd/C and commercial Pt/C were used.
For the electrochemical characterization the nanocatalysts were applied on a glassy carbon (GC) substrate in the form of a thin–film. Pd/C and Pt/C were characterized by cyclic voltammetry, Cuupd, and COads stripping in an acid and an alkaline solution. Electrochemically active surface area (ECSA) of the Pd-Cu nanocatalyst was calculated from the charge of desorption of CO in the alkaline solution. Cyclic voltammetry showed that in the presence of Cu atoms on the Pd surface, the onsets of CO desorption were negatively shifted. This indicates that Cu atoms provide oxygen-containing species at adjacent Pd sites at a lower potential than that achieved on pure metals. Nanocatalyst’s activity for EOR was investigated under potentiodynamic and potentiostatic conditions. Adding of Cu to Pd enhances the intrinsic activity of Pd for the EOR, with the greatest effect achieved for one Cu atom to 2-4 Pd atoms. Bimetallic catalysts surpassed Pd/C by mass activity, as well. The activity of Pt/C for EOR was higher compared with Pd-based catalysts, both as specific and mass activity, but with a significant decline over 30 min potentiostatic stability test. Therefore, the bifunctional and electronic effect contributed to the good performance of the nanoalloy for EOR. For ORR, Pd-Cu/C showed a negative half-wave potential shift compared to Pd/C and Pt/C of 11 and 30 mV, respectively. However, it was found that the specific ORR activities of Pd-Cu/C and Pd/C are the same at low current densities, i.e. up to a potential of 0.90 V, but higher than the specific activity of Pt/C by a factor of 5.
PB  - Lausanne, Switzerland : International Society of Electrochemistry
C3  - 74th Annual Meeting of the International Society of Electrochemistry, "Bridging Scientific Disciplines to Address the World’s Challenges," Program, 3 - 8 September 2023 Lyon, France
T1  - Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media
SP  - S06-P-079
UR  - https://hdl.handle.net/21.15107/rcub_cer_6623
ER  - 

@conference{
author = "Obradović, Maja D. and Radmilović, Vuk V. and Radmilović, Velimir R. and Gojković, Snežana Lj.",
year = "2023",
abstract = "The necessity of replacement of traditional energy sources with renewable and green alternatives has initiated vast research of direct alcohol fuel cells (DAFC). Ethanol is non-toxic and its crossover through a membrane is lower than methanol due to its larger molecule size. However, the splitting of C–C bond in ethanol is energetically difficult and much effort in electrocatalysts’ improvement is still needed to take the advantage of the high mass energy density of ethanol [1,2]. Electrochemical oxidation of alcohols in requires a noble metal, Pt or Pd, to adsorb the molecule, but also some other oxophilic metal to facilitate further reaction of the adsorbed intermediates Their promoted oxidative desorption can be achieved by introducing oxygen-containing species at the surface, which may also modify the electronic structure of the noble metal centers and thus weaken the strong adsorbate–noble metal bond. Copper is inactive for alcohol oxidation but its addition to palladium enhances the ethanol oxidation reaction (EOR) rate [3,4]. Various forms of Pd-Cu electrocatalysts exhibited improved mass activity for the EOR and oxygen reduction reaction (ORR), but the effect of Cu addition on the specific activity is not so clear. Therefore, in the present work, specific activity for EOR and ORR of synthesized Pd-Cu nanoparticles [5] supported on high area carbon was examined. As reference catalysts, synthesized Pd/C and commercial Pt/C were used.
For the electrochemical characterization the nanocatalysts were applied on a glassy carbon (GC) substrate in the form of a thin–film. Pd/C and Pt/C were characterized by cyclic voltammetry, Cuupd, and COads stripping in an acid and an alkaline solution. Electrochemically active surface area (ECSA) of the Pd-Cu nanocatalyst was calculated from the charge of desorption of CO in the alkaline solution. Cyclic voltammetry showed that in the presence of Cu atoms on the Pd surface, the onsets of CO desorption were negatively shifted. This indicates that Cu atoms provide oxygen-containing species at adjacent Pd sites at a lower potential than that achieved on pure metals. Nanocatalyst’s activity for EOR was investigated under potentiodynamic and potentiostatic conditions. Adding of Cu to Pd enhances the intrinsic activity of Pd for the EOR, with the greatest effect achieved for one Cu atom to 2-4 Pd atoms. Bimetallic catalysts surpassed Pd/C by mass activity, as well. The activity of Pt/C for EOR was higher compared with Pd-based catalysts, both as specific and mass activity, but with a significant decline over 30 min potentiostatic stability test. Therefore, the bifunctional and electronic effect contributed to the good performance of the nanoalloy for EOR. For ORR, Pd-Cu/C showed a negative half-wave potential shift compared to Pd/C and Pt/C of 11 and 30 mV, respectively. However, it was found that the specific ORR activities of Pd-Cu/C and Pd/C are the same at low current densities, i.e. up to a potential of 0.90 V, but higher than the specific activity of Pt/C by a factor of 5.",
publisher = "Lausanne, Switzerland : International Society of Electrochemistry",
journal = "74th Annual Meeting of the International Society of Electrochemistry, "Bridging Scientific Disciplines to Address the World’s Challenges," Program, 3 - 8 September 2023 Lyon, France",
title = "Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media",
pages = "S06-P-079",
url = "https://hdl.handle.net/21.15107/rcub_cer_6623"
}

Obradović, M. D., Radmilović, V. V., Radmilović, V. R.,& Gojković, S. Lj.. (2023). Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media. in 74th Annual Meeting of the International Society of Electrochemistry, "Bridging Scientific Disciplines to Address the World’s Challenges," Program, 3 - 8 September 2023 Lyon, France
Lausanne, Switzerland : International Society of Electrochemistry., S06-P-079.
https://hdl.handle.net/21.15107/rcub_cer_6623

Obradović MD, Radmilović VV, Radmilović VR, Gojković SL. Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media. in 74th Annual Meeting of the International Society of Electrochemistry, "Bridging Scientific Disciplines to Address the World’s Challenges," Program, 3 - 8 September 2023 Lyon, France. 2023;:S06-P-079.
https://hdl.handle.net/21.15107/rcub_cer_6623 .

Obradović, Maja D., Radmilović, Vuk V., Radmilović, Velimir R., Gojković, Snežana Lj., "Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media" in 74th Annual Meeting of the International Society of Electrochemistry, "Bridging Scientific Disciplines to Address the World’s Challenges," Program, 3 - 8 September 2023 Lyon, France (2023):S06-P-079,
https://hdl.handle.net/21.15107/rcub_cer_6623 .

TY  - JOUR
AU  - Obradović, Maja
AU  - Lačnjevac, Uroš
AU  - Radmilović, Vuk
AU  - Gavrilović-Wohlmuther, Aleksandra
AU  - Kovač, Janez
AU  - Rogan, Jelena
AU  - Radmilović, Velimir
AU  - Gojković, Snežana
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/7178
AB  - Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticles modified with a sub-monolayer of underpotentially deposited Cu (Cu@Pd/C) and Pd-Cu alloy nanoparticles (Pd-Cu/C), and examined for the ethanol oxidation reaction (EOR) in alkaline solution. The catalysts were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, as well as cyclic voltammetry. As reference catalysts, Pd/C and Pt/C were used. The electrochemically active surface area of all samples was determined from COads and Cuupd desorption and Pd oxide reduction, and used to assess their intrinsic activity for EOR. Intimate contact of Pd with Cu atoms enhanced its activity, regardless of the type of bimetal catalyst. The atomic Pd:Cu ratio between 2:1 and 4:1 appears to be optimal for high activity. The most active catalyst under the potentiodynamic conditions was Cu@Pd/C with θ(Cu) = 0.21,although Pd-Cu/C was superior during the potentiostatic test. All bimetallic catalysts surpassed Pd/C in mass activity. The EOR activity of Pt/C was higher compared to Pd-based catalysts at low potentials, both in terms of specific and mass activity, but with a significant decline over a 30-min potentiostatic stability test.
PB  - Elsevier
T2  - Journal of Electroanalytical Chemistry
T1  - Palladium-copper bimetallic surfaces as electrocatalysts for the ethanol oxidation in an alkaline medium
VL  - 944
SP  - 117673
DO  - 10.1016/j.jelechem.2023.117673
ER  - 

@article{
author = "Obradović, Maja and Lačnjevac, Uroš and Radmilović, Vuk and Gavrilović-Wohlmuther, Aleksandra and Kovač, Janez and Rogan, Jelena and Radmilović, Velimir and Gojković, Snežana",
year = "2023",
abstract = "Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticles modified with a sub-monolayer of underpotentially deposited Cu (Cu@Pd/C) and Pd-Cu alloy nanoparticles (Pd-Cu/C), and examined for the ethanol oxidation reaction (EOR) in alkaline solution. The catalysts were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, as well as cyclic voltammetry. As reference catalysts, Pd/C and Pt/C were used. The electrochemically active surface area of all samples was determined from COads and Cuupd desorption and Pd oxide reduction, and used to assess their intrinsic activity for EOR. Intimate contact of Pd with Cu atoms enhanced its activity, regardless of the type of bimetal catalyst. The atomic Pd:Cu ratio between 2:1 and 4:1 appears to be optimal for high activity. The most active catalyst under the potentiodynamic conditions was Cu@Pd/C with θ(Cu) = 0.21,although Pd-Cu/C was superior during the potentiostatic test. All bimetallic catalysts surpassed Pd/C in mass activity. The EOR activity of Pt/C was higher compared to Pd-based catalysts at low potentials, both in terms of specific and mass activity, but with a significant decline over a 30-min potentiostatic stability test.",
publisher = "Elsevier",
journal = "Journal of Electroanalytical Chemistry",
title = "Palladium-copper bimetallic surfaces as electrocatalysts for the ethanol oxidation in an alkaline medium",
volume = "944",
pages = "117673",
doi = "10.1016/j.jelechem.2023.117673"
}

Obradović, M., Lačnjevac, U., Radmilović, V., Gavrilović-Wohlmuther, A., Kovač, J., Rogan, J., Radmilović, V.,& Gojković, S.. (2023). Palladium-copper bimetallic surfaces as electrocatalysts for the ethanol oxidation in an alkaline medium. in Journal of Electroanalytical Chemistry
Elsevier., 944, 117673.
https://doi.org/10.1016/j.jelechem.2023.117673

Obradović M, Lačnjevac U, Radmilović V, Gavrilović-Wohlmuther A, Kovač J, Rogan J, Radmilović V, Gojković S. Palladium-copper bimetallic surfaces as electrocatalysts for the ethanol oxidation in an alkaline medium. in Journal of Electroanalytical Chemistry. 2023;944:117673.
doi:10.1016/j.jelechem.2023.117673 .

Obradović, Maja, Lačnjevac, Uroš, Radmilović, Vuk, Gavrilović-Wohlmuther, Aleksandra, Kovač, Janez, Rogan, Jelena, Radmilović, Velimir, Gojković, Snežana, "Palladium-copper bimetallic surfaces as electrocatalysts for the ethanol oxidation in an alkaline medium" in Journal of Electroanalytical Chemistry, 944 (2023):117673,
https://doi.org/10.1016/j.jelechem.2023.117673 . .

TY  - CONF
AU  - Obradović, Maja D.
AU  - Radmilović, Vuk V.
AU  - Radmilović, Velimir R.
AU  - Gojković, Snežana Lj.
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6624
AB  - The necessity of replacement of traditional energy sources with renewable and green alternatives has initiated vast research of direct alcohol fuel cells (DAFC). Ethanol is non-toxic and its crossover through a membrane is lower than methanol due to its larger molecule size. However, the splitting of C–C bond in ethanol is energetically difficult and much effort in electrocatalysts’ improvement is still needed to take the advantage of the high mass energy density of ethanol [1,2]. Electrochemical oxidation of alcohols in requires a noble metal, Pt or Pd, to adsorb the molecule, but also some other oxophilic metal to facilitate further reaction of the adsorbed intermediates Their promoted oxidative desorption can be achieved by introducing oxygen-containing species at the surface, which may also modify the electronic structure of the noble metal centers and thus weaken the strong adsorbate–noble metal bond. Copper is inactive for alcohol oxidation but its addition to palladium enhances the ethanol oxidation reaction (EOR) rate [3,4]. Various forms of Pd-Cu electrocatalysts exhibited improved mass activity for the EOR and oxygen reduction reaction (ORR), but the effect of Cu addition on the specific activity is not so clear. Therefore, in the present work, specific activity for EOR and ORR of synthesized Pd-Cu nanoparticles [5] supported on high area carbon was examined. As reference catalysts, synthesized Pd/C and commercial Pt/C were used.For the electrochemical characterization the nanocatalysts were applied on a glassy carbon (GC) substrate in the form of a thin–film. Pd/C and Pt/C were characterized by cyclic voltammetry, Cuupd, and COads stripping in an acid and an alkaline solution. Electrochemically active surface area (ECSA) of the Pd-Cu nanocatalyst was calculated from the charge of desorption of CO in the alkaline solution. Cyclic voltammetry showed that in the presence of Cu atoms on the Pd surface, the onsets of CO desorption were negatively shifted. This indicates that Cu atoms provide oxygen-containing species at adjacent Pd sites at a lower potential than that achieved on pure metals. Nanocatalyst’s activity for EOR was investigated under potentiodynamic and potentiostatic conditions. Adding of Cu to Pd enhances the intrinsic activity of Pd for the EOR, with the greatest effect achieved for one Cu atom to 2-4 Pd atoms. Bimetallic catalysts surpassed Pd/C by mass activity, as well. The activity of Pt/C for EOR was higher compared with Pd-based catalysts, both as specific and mass activity, but with a significant decline over 30 min potentiostatic stability test. Therefore, the bifunctional and electronic effect contributed to the good performance of the nanoalloy for EOR. For ORR, Pd-Cu/C showed a negative half-wave potential shift compared to Pd/C and Pt/C of 11 and 30 mV, respectively. However, it was found that the specific ORR activities of Pd-Cu/C and Pd/C are the same at low current densities, i.e. up to a potential of 0.90 V, but higher than the specific activity of Pt/C by a factor of 5.
T1  - Poster presentation: "Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media"
UR  - https://hdl.handle.net/21.15107/rcub_cer_6624
ER  - 

@conference{
author = "Obradović, Maja D. and Radmilović, Vuk V. and Radmilović, Velimir R. and Gojković, Snežana Lj.",
year = "2023",
abstract = "The necessity of replacement of traditional energy sources with renewable and green alternatives has initiated vast research of direct alcohol fuel cells (DAFC). Ethanol is non-toxic and its crossover through a membrane is lower than methanol due to its larger molecule size. However, the splitting of C–C bond in ethanol is energetically difficult and much effort in electrocatalysts’ improvement is still needed to take the advantage of the high mass energy density of ethanol [1,2]. Electrochemical oxidation of alcohols in requires a noble metal, Pt or Pd, to adsorb the molecule, but also some other oxophilic metal to facilitate further reaction of the adsorbed intermediates Their promoted oxidative desorption can be achieved by introducing oxygen-containing species at the surface, which may also modify the electronic structure of the noble metal centers and thus weaken the strong adsorbate–noble metal bond. Copper is inactive for alcohol oxidation but its addition to palladium enhances the ethanol oxidation reaction (EOR) rate [3,4]. Various forms of Pd-Cu electrocatalysts exhibited improved mass activity for the EOR and oxygen reduction reaction (ORR), but the effect of Cu addition on the specific activity is not so clear. Therefore, in the present work, specific activity for EOR and ORR of synthesized Pd-Cu nanoparticles [5] supported on high area carbon was examined. As reference catalysts, synthesized Pd/C and commercial Pt/C were used.For the electrochemical characterization the nanocatalysts were applied on a glassy carbon (GC) substrate in the form of a thin–film. Pd/C and Pt/C were characterized by cyclic voltammetry, Cuupd, and COads stripping in an acid and an alkaline solution. Electrochemically active surface area (ECSA) of the Pd-Cu nanocatalyst was calculated from the charge of desorption of CO in the alkaline solution. Cyclic voltammetry showed that in the presence of Cu atoms on the Pd surface, the onsets of CO desorption were negatively shifted. This indicates that Cu atoms provide oxygen-containing species at adjacent Pd sites at a lower potential than that achieved on pure metals. Nanocatalyst’s activity for EOR was investigated under potentiodynamic and potentiostatic conditions. Adding of Cu to Pd enhances the intrinsic activity of Pd for the EOR, with the greatest effect achieved for one Cu atom to 2-4 Pd atoms. Bimetallic catalysts surpassed Pd/C by mass activity, as well. The activity of Pt/C for EOR was higher compared with Pd-based catalysts, both as specific and mass activity, but with a significant decline over 30 min potentiostatic stability test. Therefore, the bifunctional and electronic effect contributed to the good performance of the nanoalloy for EOR. For ORR, Pd-Cu/C showed a negative half-wave potential shift compared to Pd/C and Pt/C of 11 and 30 mV, respectively. However, it was found that the specific ORR activities of Pd-Cu/C and Pd/C are the same at low current densities, i.e. up to a potential of 0.90 V, but higher than the specific activity of Pt/C by a factor of 5.",
title = "Poster presentation: "Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media"",
url = "https://hdl.handle.net/21.15107/rcub_cer_6624"
}

Obradović, M. D., Radmilović, V. V., Radmilović, V. R.,& Gojković, S. Lj.. (2023). Poster presentation: "Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media". .
https://hdl.handle.net/21.15107/rcub_cer_6624

Obradović MD, Radmilović VV, Radmilović VR, Gojković SL. Poster presentation: "Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media". 2023;.
https://hdl.handle.net/21.15107/rcub_cer_6624 .

Obradović, Maja D., Radmilović, Vuk V., Radmilović, Velimir R., Gojković, Snežana Lj., "Poster presentation: "Palladium-copper bimetallic nanocatalyst for electrochemical ethanol oxidation and oxygen reduction in alkaline media"" (2023),
https://hdl.handle.net/21.15107/rcub_cer_6624 .

TY  - JOUR
AU  - Obradović, Maja
AU  - Gojković, Snežana Lj.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5242
AB  - Thin films of Ni-oxy-hydroxides of different composition and thickness were electrochemically grown on Ni foil electrode: hydrated α-phase, anhydrous β-phase, and two mixed α- and β-phase electrodeposited by potential cycling. The characterization of bare Ni and the deposited films by cycling voltammetry (CV) and electrochemical impedance spectroscopy (EIS) provided data of the initial electrochemically active surface area (ECSA), an amount of Ni-active oxide species, double-layer capacitance, ionic adsorption capacitance and the adsorption pseudocapacitance in the oxygen evolution reaction (OER) potential range. Ni-oxy-hydroxide films were deposited with loading up to 18 monolayers or 25 nmol cm−2. The specific pseudocapacitance was calculated from a linear correlation of the capacitance and the film thickness. Steady-state polarization curves of OER were presented as specific activity obtained by normalization of the currents by ECSA derived from the maximum adsorption pseudocapacitance. Also, polarization curves were given as turnover frequency calculated from the amount of Ni-active oxide species derived from CV. Both method of evaluation of intrinsic activity of Ni-oxy-hydroxide films towards OER gave consistent results and can be used to compare the activity of similar Ni-oxide catalysts.
PB  - Elsevier
T2  - Journal of Electroanalytical Chemistry
T1  - Challenges in determining the electrochemically active surface area of Ni-oxides in the oxygen evolution reaction
VL  - 918
SP  - 116479
DO  - 10.1016/j.jelechem.2022.116479
ER  - 

@article{
author = "Obradović, Maja and Gojković, Snežana Lj.",
year = "2022",
abstract = "Thin films of Ni-oxy-hydroxides of different composition and thickness were electrochemically grown on Ni foil electrode: hydrated α-phase, anhydrous β-phase, and two mixed α- and β-phase electrodeposited by potential cycling. The characterization of bare Ni and the deposited films by cycling voltammetry (CV) and electrochemical impedance spectroscopy (EIS) provided data of the initial electrochemically active surface area (ECSA), an amount of Ni-active oxide species, double-layer capacitance, ionic adsorption capacitance and the adsorption pseudocapacitance in the oxygen evolution reaction (OER) potential range. Ni-oxy-hydroxide films were deposited with loading up to 18 monolayers or 25 nmol cm−2. The specific pseudocapacitance was calculated from a linear correlation of the capacitance and the film thickness. Steady-state polarization curves of OER were presented as specific activity obtained by normalization of the currents by ECSA derived from the maximum adsorption pseudocapacitance. Also, polarization curves were given as turnover frequency calculated from the amount of Ni-active oxide species derived from CV. Both method of evaluation of intrinsic activity of Ni-oxy-hydroxide films towards OER gave consistent results and can be used to compare the activity of similar Ni-oxide catalysts.",
publisher = "Elsevier",
journal = "Journal of Electroanalytical Chemistry",
title = "Challenges in determining the electrochemically active surface area of Ni-oxides in the oxygen evolution reaction",
volume = "918",
pages = "116479",
doi = "10.1016/j.jelechem.2022.116479"
}

Obradović, M.,& Gojković, S. Lj.. (2022). Challenges in determining the electrochemically active surface area of Ni-oxides in the oxygen evolution reaction. in Journal of Electroanalytical Chemistry
Elsevier., 918, 116479.
https://doi.org/10.1016/j.jelechem.2022.116479

Obradović M, Gojković SL. Challenges in determining the electrochemically active surface area of Ni-oxides in the oxygen evolution reaction. in Journal of Electroanalytical Chemistry. 2022;918:116479.
doi:10.1016/j.jelechem.2022.116479 .

Obradović, Maja, Gojković, Snežana Lj., "Challenges in determining the electrochemically active surface area of Ni-oxides in the oxygen evolution reaction" in Journal of Electroanalytical Chemistry, 918 (2022):116479,
https://doi.org/10.1016/j.jelechem.2022.116479 . .

TY  - CONF
AU  - Obradović, Maja
AU  - Gojković, Snežana
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5941
AB  - Easy storage and handling, high energy density, wide availability, and low toxicity are features that make ethanol attractive fuel cell liquid combustibles and the most promising among alternative power sources [1,2]. Unfortunately, the slow and incomplete ethanol oxidation reaction (EOR) occurs at the anode even on the best available catalysts known to date. Pure Pt and Pd are not capable of catalyzing the oxidation of ethanol through the total oxidation pathway [2]. However, Pt and Pd are necessary catalyst constituents to provide efficient adsorption of ethanol, which is the first reaction step in ethanol oxidation. The activity of Pd and Pt for alcohol oxidation can be enhanced by adding a co-catalytic element, mainly oxophilic metal (either d- or p-metals), or compounds such as oxides [3]. Therefore, in the present work, the influence of Cu sub-monolayers decoration of carbon-supported Pd and Pt nanoparticles was investigated for ethanol oxidation reaction (EOR) in the alkaline solution.
Commercial Pt/C (E-TEK) and Pd/C catalyst synthesized by borohydride reduction method [4] were electrochemically characterized by cyclic voltammetry and COads stripping in acid and alkaline solutions. The onset potential and the peak potential of COads oxidation on Pd/C were more positive than those for Pt/C in both solutions, indicating lower oxophilicity and/or stronger bonding with COads in the case of Pd than Pt. Catalysts were decorated by underpotential deposition of Cu atoms (Cuupd) in acid solution with various surface coverages (up to 0.5). Electrochemically active surface area (ECSA) of undecorated catalysts was calculated from the charge of desorption of CO and Cuupd in acid solution, while ECSA of Cuupd decorated catalyst was calculated from the charge of CO desorption in alkaline solution. Cyclic voltammetry showed that on the Cuupd decorated surfaces the onset of CO desorption was negatively shifted. This indicates that Cuupd atoms provide oxygen-containing species at adjacent Pt or Pd sites at a lower potential than that achieved on pure metals.
The influence of Cuupd decoration of the Pt/C and Pd/C catalysts on activity for EOR in 0.1 M KOH was investi¬gated under potentiodynamic conditions. Although the onset potential was the same, Pd/C was more active for EOR than Pt/C with the 1.5-fold enhancement of maximum current. Pd/C with Cuupd coverage of 0.30 exhibited lower onset potential and up to 2.5-fold increase in EOR activity with respect to Pd/C (calculated per Pd ECSA). However, with further increase in coverage the positive effect of Cuupd disappeared and activity even decreased. In the case of Pt/C the promotion effect of Cuupd was negligible, because only the catalyst with coverage of 0.11 showed lower onset potential and slightly higher current at low potentials. The higher EOR activity of Pd/C compared to Pt/C can be attributed to the optimum oxo¬philicity of Pd which provides ample space for adsorption of ethanol and still provides oxygen containing species for its oxidation. Decoration of Pd/C by 0.3 monolayer of Cuupd increases the amount of oxygen containing species that intensify ethanol oxidation rate on Pd.
PB  - Association of South-East European Electrochemists (ASEEE)
C3  - Abstractbook - The 8th Regional Symposium on Electrochemistry of South-East Europe, 11-15 July 2022, Graz, Austria
T1  - Cu sub-monolayer decorated Pd/C and Pt/C as electrocatalyst for ethanol oxidation in alkaline solution
SP  - 183
DO  - 10.3217/978-3-85125-907-0
ER  - 

@conference{
author = "Obradović, Maja and Gojković, Snežana",
year = "2022",
abstract = "Easy storage and handling, high energy density, wide availability, and low toxicity are features that make ethanol attractive fuel cell liquid combustibles and the most promising among alternative power sources [1,2]. Unfortunately, the slow and incomplete ethanol oxidation reaction (EOR) occurs at the anode even on the best available catalysts known to date. Pure Pt and Pd are not capable of catalyzing the oxidation of ethanol through the total oxidation pathway [2]. However, Pt and Pd are necessary catalyst constituents to provide efficient adsorption of ethanol, which is the first reaction step in ethanol oxidation. The activity of Pd and Pt for alcohol oxidation can be enhanced by adding a co-catalytic element, mainly oxophilic metal (either d- or p-metals), or compounds such as oxides [3]. Therefore, in the present work, the influence of Cu sub-monolayers decoration of carbon-supported Pd and Pt nanoparticles was investigated for ethanol oxidation reaction (EOR) in the alkaline solution.
Commercial Pt/C (E-TEK) and Pd/C catalyst synthesized by borohydride reduction method [4] were electrochemically characterized by cyclic voltammetry and COads stripping in acid and alkaline solutions. The onset potential and the peak potential of COads oxidation on Pd/C were more positive than those for Pt/C in both solutions, indicating lower oxophilicity and/or stronger bonding with COads in the case of Pd than Pt. Catalysts were decorated by underpotential deposition of Cu atoms (Cuupd) in acid solution with various surface coverages (up to 0.5). Electrochemically active surface area (ECSA) of undecorated catalysts was calculated from the charge of desorption of CO and Cuupd in acid solution, while ECSA of Cuupd decorated catalyst was calculated from the charge of CO desorption in alkaline solution. Cyclic voltammetry showed that on the Cuupd decorated surfaces the onset of CO desorption was negatively shifted. This indicates that Cuupd atoms provide oxygen-containing species at adjacent Pt or Pd sites at a lower potential than that achieved on pure metals.
The influence of Cuupd decoration of the Pt/C and Pd/C catalysts on activity for EOR in 0.1 M KOH was investi¬gated under potentiodynamic conditions. Although the onset potential was the same, Pd/C was more active for EOR than Pt/C with the 1.5-fold enhancement of maximum current. Pd/C with Cuupd coverage of 0.30 exhibited lower onset potential and up to 2.5-fold increase in EOR activity with respect to Pd/C (calculated per Pd ECSA). However, with further increase in coverage the positive effect of Cuupd disappeared and activity even decreased. In the case of Pt/C the promotion effect of Cuupd was negligible, because only the catalyst with coverage of 0.11 showed lower onset potential and slightly higher current at low potentials. The higher EOR activity of Pd/C compared to Pt/C can be attributed to the optimum oxo¬philicity of Pd which provides ample space for adsorption of ethanol and still provides oxygen containing species for its oxidation. Decoration of Pd/C by 0.3 monolayer of Cuupd increases the amount of oxygen containing species that intensify ethanol oxidation rate on Pd.",
publisher = "Association of South-East European Electrochemists (ASEEE)",
journal = "Abstractbook - The 8th Regional Symposium on Electrochemistry of South-East Europe, 11-15 July 2022, Graz, Austria",
title = "Cu sub-monolayer decorated Pd/C and Pt/C as electrocatalyst for ethanol oxidation in alkaline solution",
pages = "183",
doi = "10.3217/978-3-85125-907-0"
}

Obradović, M.,& Gojković, S.. (2022). Cu sub-monolayer decorated Pd/C and Pt/C as electrocatalyst for ethanol oxidation in alkaline solution. in Abstractbook - The 8th Regional Symposium on Electrochemistry of South-East Europe, 11-15 July 2022, Graz, Austria
Association of South-East European Electrochemists (ASEEE)., 183.
https://doi.org/10.3217/978-3-85125-907-0

Obradović M, Gojković S. Cu sub-monolayer decorated Pd/C and Pt/C as electrocatalyst for ethanol oxidation in alkaline solution. in Abstractbook - The 8th Regional Symposium on Electrochemistry of South-East Europe, 11-15 July 2022, Graz, Austria. 2022;:183.
doi:10.3217/978-3-85125-907-0 .

Obradović, Maja, Gojković, Snežana, "Cu sub-monolayer decorated Pd/C and Pt/C as electrocatalyst for ethanol oxidation in alkaline solution" in Abstractbook - The 8th Regional Symposium on Electrochemistry of South-East Europe, 11-15 July 2022, Graz, Austria (2022):183,
https://doi.org/10.3217/978-3-85125-907-0 . .

TY  - CONF
AU  - Obradović, Maja
AU  - Rogan, Jelena
AU  - Lačnjevac, Uroš
AU  - Gavrilović-Wohlmuther, Aleksandra
AU  - Radmilović, Vuk V.
AU  - Radmilović, Velimir R.
AU  - Gojković, Snežana
PY  - 2022
UR  - http://elmina.tmf.bg.ac.rs
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5942
AB  - Nanocatalysts Pd/C and Pd-Cu/C were synthesized by a borohydride reduction method and 
characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and transmission 
electron microscopy (TEM). In addition, the Pd/C catalyst was decorated by Cuupd in an acid solution with various surface coverages (up to 0.5). The catalysts were electrochemically characterized by cyclic voltammetry (CV) and COads stripping in acid and alkaline solutions.  The electrochemically active surface area (ECSA) was estimated from the charge under the CO desorption peak in the alkaline solution and used for determining specific and mass activity for the EOR.
PB  - Belgrade : Serbian Academy of Sciences and Arts
PB  - Belgrade : Faculty of Technology and Metallurgy, University of Belgrade
C3  - Program and Book of Abstracts - Second International Conference on Electron Microscopy of Nanostructures, ELMINA 2022, August 22nd-26th, 2022, Belgrade, Serbia
T1  - Cuupd@Pd/C and Pd-Cu/C Nanocatalysts for Electrochemical Ethanol Oxidation in Alkaline Solution
SP  - 182
EP  - 183
UR  - https://hdl.handle.net/21.15107/rcub_cer_5942
ER  - 

@conference{
author = "Obradović, Maja and Rogan, Jelena and Lačnjevac, Uroš and Gavrilović-Wohlmuther, Aleksandra and Radmilović, Vuk V. and Radmilović, Velimir R. and Gojković, Snežana",
year = "2022",
abstract = "Nanocatalysts Pd/C and Pd-Cu/C were synthesized by a borohydride reduction method and 
characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD) and transmission 
electron microscopy (TEM). In addition, the Pd/C catalyst was decorated by Cuupd in an acid solution with various surface coverages (up to 0.5). The catalysts were electrochemically characterized by cyclic voltammetry (CV) and COads stripping in acid and alkaline solutions.  The electrochemically active surface area (ECSA) was estimated from the charge under the CO desorption peak in the alkaline solution and used for determining specific and mass activity for the EOR.",
publisher = "Belgrade : Serbian Academy of Sciences and Arts, Belgrade : Faculty of Technology and Metallurgy, University of Belgrade",
journal = "Program and Book of Abstracts - Second International Conference on Electron Microscopy of Nanostructures, ELMINA 2022, August 22nd-26th, 2022, Belgrade, Serbia",
title = "Cuupd@Pd/C and Pd-Cu/C Nanocatalysts for Electrochemical Ethanol Oxidation in Alkaline Solution",
pages = "182-183",
url = "https://hdl.handle.net/21.15107/rcub_cer_5942"
}

Obradović, M., Rogan, J., Lačnjevac, U., Gavrilović-Wohlmuther, A., Radmilović, V. V., Radmilović, V. R.,& Gojković, S.. (2022). Cuupd@Pd/C and Pd-Cu/C Nanocatalysts for Electrochemical Ethanol Oxidation in Alkaline Solution. in Program and Book of Abstracts - Second International Conference on Electron Microscopy of Nanostructures, ELMINA 2022, August 22nd-26th, 2022, Belgrade, Serbia
Belgrade : Serbian Academy of Sciences and Arts., 182-183.
https://hdl.handle.net/21.15107/rcub_cer_5942

Obradović M, Rogan J, Lačnjevac U, Gavrilović-Wohlmuther A, Radmilović VV, Radmilović VR, Gojković S. Cuupd@Pd/C and Pd-Cu/C Nanocatalysts for Electrochemical Ethanol Oxidation in Alkaline Solution. in Program and Book of Abstracts - Second International Conference on Electron Microscopy of Nanostructures, ELMINA 2022, August 22nd-26th, 2022, Belgrade, Serbia. 2022;:182-183.
https://hdl.handle.net/21.15107/rcub_cer_5942 .

Obradović, Maja, Rogan, Jelena, Lačnjevac, Uroš, Gavrilović-Wohlmuther, Aleksandra, Radmilović, Vuk V., Radmilović, Velimir R., Gojković, Snežana, "Cuupd@Pd/C and Pd-Cu/C Nanocatalysts for Electrochemical Ethanol Oxidation in Alkaline Solution" in Program and Book of Abstracts - Second International Conference on Electron Microscopy of Nanostructures, ELMINA 2022, August 22nd-26th, 2022, Belgrade, Serbia (2022):182-183,
https://hdl.handle.net/21.15107/rcub_cer_5942 .

TY  - JOUR
AU  - Obradović, Maja
AU  - Balanč, Bojana
AU  - Lačnjevac, Uroš
AU  - Gojković, Snežana Lj.
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4234
AB  - Hydrated iridium oxyhydroxide (IrOx) films were electrochemically deposited from an alkaline oxalic solution at constant anodic potentials and by applying a potential cycling protocol, in both cases with variation of the electrodeposition time. From UV–vis spetroscopy of the solution for the deposition and their characterization it was concluded that a mixture of Ir(III)/Ir(IV) monomers participates in the deposition of IrOx film. X-ray photoelectron spectroscopy (XPS) of IrOx films indicated that both types of films contained hydrated Ir(IV) hydroxide as the dominant species, but in the film deposited by potential cycling the presence of the additional Ir(III) species was evident. The scanning electon microscopy (SEM) analysis of the surface morphology revealed that films deposited by potential cycling were more uniform than the films deposited at a constant potential. The amount of electrochemically active Ir-species on the surface of deposited IrOx films was estimated from the voltammetric charge of the Ir(III)/Ir(IV) transition. Depending on the film electrodeposition parameters, the values between 15 and 1080 nmol cm−2 were obtained. The electrochemically active surface area (ECSA) of IrOx films was calculated from cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements and ranged from 3 to 131 cm2 per 1 cm2 of geometric surface area for various films. The activity and stability of IrOx films toward oxygen evolution reaction (OER) was investigated in 0.5 M H2SO4 solution under potentiostatic conditions. The intrinsic activity, stated as turnover frequency and specific current density normalized per ECSA, showed that the OER activity of IrOx films deposited by potential cycling are up to two and a half times higher than the activity of films deposited at a constant anodic potential. Potentiostatic stability test showed a decrease in OER current over time for both type of the films. Determination of ECSA, the amount of electroactive Ir species, XPS spectrum and SEM imaging after the test indicated that the decrease in OER activity was caused by partial dissolution and delamination of the film as well as by oxidation of highly active hydroxide Ir(III) species.
PB  - Elsevier
T2  - Journal of Electroanalytical Chemistry
T1  - Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution
VL  - 881
SP  - 114944
DO  - 10.1016/j.jelechem.2020.114944
ER  - 

@article{
author = "Obradović, Maja and Balanč, Bojana and Lačnjevac, Uroš and Gojković, Snežana Lj.",
year = "2021",
abstract = "Hydrated iridium oxyhydroxide (IrOx) films were electrochemically deposited from an alkaline oxalic solution at constant anodic potentials and by applying a potential cycling protocol, in both cases with variation of the electrodeposition time. From UV–vis spetroscopy of the solution for the deposition and their characterization it was concluded that a mixture of Ir(III)/Ir(IV) monomers participates in the deposition of IrOx film. X-ray photoelectron spectroscopy (XPS) of IrOx films indicated that both types of films contained hydrated Ir(IV) hydroxide as the dominant species, but in the film deposited by potential cycling the presence of the additional Ir(III) species was evident. The scanning electon microscopy (SEM) analysis of the surface morphology revealed that films deposited by potential cycling were more uniform than the films deposited at a constant potential. The amount of electrochemically active Ir-species on the surface of deposited IrOx films was estimated from the voltammetric charge of the Ir(III)/Ir(IV) transition. Depending on the film electrodeposition parameters, the values between 15 and 1080 nmol cm−2 were obtained. The electrochemically active surface area (ECSA) of IrOx films was calculated from cyclic voltammetry and electrochemical impedance spectroscopy (EIS) measurements and ranged from 3 to 131 cm2 per 1 cm2 of geometric surface area for various films. The activity and stability of IrOx films toward oxygen evolution reaction (OER) was investigated in 0.5 M H2SO4 solution under potentiostatic conditions. The intrinsic activity, stated as turnover frequency and specific current density normalized per ECSA, showed that the OER activity of IrOx films deposited by potential cycling are up to two and a half times higher than the activity of films deposited at a constant anodic potential. Potentiostatic stability test showed a decrease in OER current over time for both type of the films. Determination of ECSA, the amount of electroactive Ir species, XPS spectrum and SEM imaging after the test indicated that the decrease in OER activity was caused by partial dissolution and delamination of the film as well as by oxidation of highly active hydroxide Ir(III) species.",
publisher = "Elsevier",
journal = "Journal of Electroanalytical Chemistry",
title = "Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution",
volume = "881",
pages = "114944",
doi = "10.1016/j.jelechem.2020.114944"
}

Obradović, M., Balanč, B., Lačnjevac, U.,& Gojković, S. Lj.. (2021). Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution. in Journal of Electroanalytical Chemistry
Elsevier., 881, 114944.
https://doi.org/10.1016/j.jelechem.2020.114944

Obradović M, Balanč B, Lačnjevac U, Gojković SL. Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution. in Journal of Electroanalytical Chemistry. 2021;881:114944.
doi:10.1016/j.jelechem.2020.114944 .

Obradović, Maja, Balanč, Bojana, Lačnjevac, Uroš, Gojković, Snežana Lj., "Electrochemically deposited iridium-oxide: Estimation of intrinsic activity and stability in oxygen evolution in acid solution" in Journal of Electroanalytical Chemistry, 881 (2021):114944,
https://doi.org/10.1016/j.jelechem.2020.114944 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Gojković, Snežana Lj.
PY  - 2018
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2273
AB  - The oxidation of pure H2 and H2/CO mixture (100 ppm CO) was investigated on Pt nanocatalyst supported on Ru0.7Ti0.3O2 (Pt /Ru0.7Ti0.3O2) by linear sweep voltammetry at a rotating disc electrode in 0.1 M HClO4. The results were compared with those on the commercial Pt/C catalyst. It was demonstrated that Pt/Ru0.7Ti0.3O2 electrode possesses good conductivity and stability of the supports in the electrochemical experiments. The onset potential of COads oxidation on Pt/Ru0.7Ti0.3O2 is lower than Pt/C indicating that the Pt nanoparticles are in close contact with Ru atoms from support, which enable bifunctional mechanism and electronic effects to be operable. The influence of the poisoning of Pt/Ru0.7Ti0.3O2 and Pt/C catalyst by COads on the HOR was examined at several surface coverages ranging from 0 to 0.6. The decrease in HOR current on COads poisoned surface in low over-potential region of 0.05-0.50 V is less pronounced on Pt/Ru0.7Ti0.3O2 than on Pt/C. This is ascribed to a weakening of the Pt-CO interaction and consequently higher mobility of COads on Pt particles contacting Ru from the Ru0.7Ti0.3O2 support.
AB  - Oksidacija čistog H2 i smeše H2/CO (100 ppm CO) je ispitivana na nanokatalizatoru koji se sastojao od čestica Pt na nosaču Ru0,7Ti0,3O2 (Pt/Ru0,7Ti0,3O2). Korišćene su metoda linearne voltametrije u rastvoru 0,1 M HClO4 i rotirajuća disk elektroda. Rezultati su upoređeni sa komercijalnim katalizatorom Pt/C. Za katalizator Pt/Ru0,7Ti0,3O2 je utvrđena dobra provodnost i stabilnost nosača u elektrohemijskim eksperimentima. Pokazano je da oksidacija adorbovanog CO na Pt/Ru0,7Ti0,3O2 počinje na negativnijim potencijalima nego na Pt/C. To ukazuje da su nanočestice Pt u bliskom kontaktu sa atomima Ru iz nosača, što omogućuje odigravanje bifunkcionalnog mehanizma i ispoljavanje elektronskog efekta. Uticaj trovanja katalizatora Pt/Ru0,7Ti0,3O2 i Pt/C adsorbovanim CO na oksidaciju H2 je ispitivan na nekoliko stepena pokrivenosti u opsegu od 0 do 0,6. Smanjenje struje oksidacije vodonika na površini delimično pokrivenoj adsorbovanim CO u oblasti malih prenapetosti 0,05-0,50 V je manje izraženo na Pt/Ru0,7Ti0,3O2 u odnosu na Pt/C. Ovo se pripisuje slabljenju interakcija Pt-CO što dovodi do povećane pokretljivosti CO na česticama Pt koje su u kontaktu sa Ru iz nosača Ru0,7Ti0,3O2.
PB  - Belgrade, Serbia : Engineering Society for Corrosion
T2  - Zaštita materijala
T1  - CO tolerant Pt/Ru0.7Ti0.3O2 nanocatalyst for hydrogen oxidation reaction
T1  - Pt/Ru0,7Ti0,3O2 kao nanokatalizator za oksidaciju vodonika i njegova tolerancija na CO
VL  - 59
IS  - 2
SP  - 265
EP  - 272
DO  - 10.5937/ZasMat1802265O
ER  - 

@article{
author = "Obradović, Maja and Gojković, Snežana Lj.",
year = "2018",
abstract = "The oxidation of pure H2 and H2/CO mixture (100 ppm CO) was investigated on Pt nanocatalyst supported on Ru0.7Ti0.3O2 (Pt /Ru0.7Ti0.3O2) by linear sweep voltammetry at a rotating disc electrode in 0.1 M HClO4. The results were compared with those on the commercial Pt/C catalyst. It was demonstrated that Pt/Ru0.7Ti0.3O2 electrode possesses good conductivity and stability of the supports in the electrochemical experiments. The onset potential of COads oxidation on Pt/Ru0.7Ti0.3O2 is lower than Pt/C indicating that the Pt nanoparticles are in close contact with Ru atoms from support, which enable bifunctional mechanism and electronic effects to be operable. The influence of the poisoning of Pt/Ru0.7Ti0.3O2 and Pt/C catalyst by COads on the HOR was examined at several surface coverages ranging from 0 to 0.6. The decrease in HOR current on COads poisoned surface in low over-potential region of 0.05-0.50 V is less pronounced on Pt/Ru0.7Ti0.3O2 than on Pt/C. This is ascribed to a weakening of the Pt-CO interaction and consequently higher mobility of COads on Pt particles contacting Ru from the Ru0.7Ti0.3O2 support., Oksidacija čistog H2 i smeše H2/CO (100 ppm CO) je ispitivana na nanokatalizatoru koji se sastojao od čestica Pt na nosaču Ru0,7Ti0,3O2 (Pt/Ru0,7Ti0,3O2). Korišćene su metoda linearne voltametrije u rastvoru 0,1 M HClO4 i rotirajuća disk elektroda. Rezultati su upoređeni sa komercijalnim katalizatorom Pt/C. Za katalizator Pt/Ru0,7Ti0,3O2 je utvrđena dobra provodnost i stabilnost nosača u elektrohemijskim eksperimentima. Pokazano je da oksidacija adorbovanog CO na Pt/Ru0,7Ti0,3O2 počinje na negativnijim potencijalima nego na Pt/C. To ukazuje da su nanočestice Pt u bliskom kontaktu sa atomima Ru iz nosača, što omogućuje odigravanje bifunkcionalnog mehanizma i ispoljavanje elektronskog efekta. Uticaj trovanja katalizatora Pt/Ru0,7Ti0,3O2 i Pt/C adsorbovanim CO na oksidaciju H2 je ispitivan na nekoliko stepena pokrivenosti u opsegu od 0 do 0,6. Smanjenje struje oksidacije vodonika na površini delimično pokrivenoj adsorbovanim CO u oblasti malih prenapetosti 0,05-0,50 V je manje izraženo na Pt/Ru0,7Ti0,3O2 u odnosu na Pt/C. Ovo se pripisuje slabljenju interakcija Pt-CO što dovodi do povećane pokretljivosti CO na česticama Pt koje su u kontaktu sa Ru iz nosača Ru0,7Ti0,3O2.",
publisher = "Belgrade, Serbia : Engineering Society for Corrosion",
journal = "Zaštita materijala",
title = "CO tolerant Pt/Ru0.7Ti0.3O2 nanocatalyst for hydrogen oxidation reaction, Pt/Ru0,7Ti0,3O2 kao nanokatalizator za oksidaciju vodonika i njegova tolerancija na CO",
volume = "59",
number = "2",
pages = "265-272",
doi = "10.5937/ZasMat1802265O"
}

Obradović, M.,& Gojković, S. Lj.. (2018). CO tolerant Pt/Ru0.7Ti0.3O2 nanocatalyst for hydrogen oxidation reaction. in Zaštita materijala
Belgrade, Serbia : Engineering Society for Corrosion., 59(2), 265-272.
https://doi.org/10.5937/ZasMat1802265O

Obradović M, Gojković SL. CO tolerant Pt/Ru0.7Ti0.3O2 nanocatalyst for hydrogen oxidation reaction. in Zaštita materijala. 2018;59(2):265-272.
doi:10.5937/ZasMat1802265O .

Obradović, Maja, Gojković, Snežana Lj., "CO tolerant Pt/Ru0.7Ti0.3O2 nanocatalyst for hydrogen oxidation reaction" in Zaštita materijala, 59, no. 2 (2018):265-272,
https://doi.org/10.5937/ZasMat1802265O . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Stancic, Z M
AU  - Lačnjevac, Uroš
AU  - Radmilović, Vuk V.
AU  - Gavrilović-Wohlmuther, Aleksandra
AU  - Radmilović, Velimir R.
AU  - Gojković, Snežana Lj.
PY  - 2016
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/2001
AB  - Pd-Ni/C catalyst was synthesized employing a borohydride reduction method. The high area Ni was first dispersed on the carbon support and then modified by Pd nanoparticles. Transmission electron microscopy confirmed relatively even distribution of Ni across the carbon support with discrete palladium particles of about 3.3 nm mean diameter on it. Cyclic voltammetry confirmed the presence of Ni on the catalyst surface. The activity of the Pd-Ni/C catalysts for ethanol oxidation reaction (EOR) in alkaline solution was tested under the potentiodynamic and potentiostatic conditions and the results were compared to those obtained on the Pd/C catalyst. It was found that Pd-Ni/C is more active for the EOR compared to Pd/C by a factor up to 3, depending on the type of experiments and whether specific activity or mass activity are considered. During the potentiodynamic stability test an interesting phenomenon of activation of Pd-Ni/C catalyst was observed. It was found that maximum activity is attained after fifty cycles with the positive potential limit of 1.2 V, regardless of whether they were performed in the electrolyte with or without ethanol. It was postulated that potential cycling of the Pd-Ni surface causes reorganization of the catalyst surface bringing Pd and Ni sites to a more suitable arrangement for the efficient ethanol oxidation.
PB  - Elsevier
T2  - Applied Catalysis B-Environmental
T1  - Electrochemical oxidation of ethanol on palladium-nickel nanocatalyst in alkaline media
VL  - 189
SP  - 110
EP  - 118
DO  - 10.1016/j.apcatb.2016.02.039
ER  - 

@article{
author = "Obradović, Maja and Stancic, Z M and Lačnjevac, Uroš and Radmilović, Vuk V. and Gavrilović-Wohlmuther, Aleksandra and Radmilović, Velimir R. and Gojković, Snežana Lj.",
year = "2016",
abstract = "Pd-Ni/C catalyst was synthesized employing a borohydride reduction method. The high area Ni was first dispersed on the carbon support and then modified by Pd nanoparticles. Transmission electron microscopy confirmed relatively even distribution of Ni across the carbon support with discrete palladium particles of about 3.3 nm mean diameter on it. Cyclic voltammetry confirmed the presence of Ni on the catalyst surface. The activity of the Pd-Ni/C catalysts for ethanol oxidation reaction (EOR) in alkaline solution was tested under the potentiodynamic and potentiostatic conditions and the results were compared to those obtained on the Pd/C catalyst. It was found that Pd-Ni/C is more active for the EOR compared to Pd/C by a factor up to 3, depending on the type of experiments and whether specific activity or mass activity are considered. During the potentiodynamic stability test an interesting phenomenon of activation of Pd-Ni/C catalyst was observed. It was found that maximum activity is attained after fifty cycles with the positive potential limit of 1.2 V, regardless of whether they were performed in the electrolyte with or without ethanol. It was postulated that potential cycling of the Pd-Ni surface causes reorganization of the catalyst surface bringing Pd and Ni sites to a more suitable arrangement for the efficient ethanol oxidation.",
publisher = "Elsevier",
journal = "Applied Catalysis B-Environmental",
title = "Electrochemical oxidation of ethanol on palladium-nickel nanocatalyst in alkaline media",
volume = "189",
pages = "110-118",
doi = "10.1016/j.apcatb.2016.02.039"
}

Obradović, M., Stancic, Z. M., Lačnjevac, U., Radmilović, V. V., Gavrilović-Wohlmuther, A., Radmilović, V. R.,& Gojković, S. Lj.. (2016). Electrochemical oxidation of ethanol on palladium-nickel nanocatalyst in alkaline media. in Applied Catalysis B-Environmental
Elsevier., 189, 110-118.
https://doi.org/10.1016/j.apcatb.2016.02.039

Obradović M, Stancic ZM, Lačnjevac U, Radmilović VV, Gavrilović-Wohlmuther A, Radmilović VR, Gojković SL. Electrochemical oxidation of ethanol on palladium-nickel nanocatalyst in alkaline media. in Applied Catalysis B-Environmental. 2016;189:110-118.
doi:10.1016/j.apcatb.2016.02.039 .

Obradović, Maja, Stancic, Z M, Lačnjevac, Uroš, Radmilović, Vuk V., Gavrilović-Wohlmuther, Aleksandra, Radmilović, Velimir R., Gojković, Snežana Lj., "Electrochemical oxidation of ethanol on palladium-nickel nanocatalyst in alkaline media" in Applied Catalysis B-Environmental, 189 (2016):110-118,
https://doi.org/10.1016/j.apcatb.2016.02.039 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Lačnjevac, Uroš
AU  - Babic, B M
AU  - Ercius, P
AU  - Radmilović, Velimir R.
AU  - Krstajić, Nedeljko V.
AU  - Gojković, Snežana Lj.
PY  - 2015
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1763
AB  - Two binary Ru-Ti oxides, Rum Ti0.9O2 and Ru0.7Ti0.3O2, were synthesized by the sol-gel method and used as an electrocatalyst support. The system was characterized by XRD, EDS, TEM and cyclic voltammetry. The Rum Ti0.9O2 and Ru0.7Ti0.3O2 consist of two phases of anatase and rutile structure. An average size of the Pt nanoparticles supported on them is similar to 3.5 nm and they are deposited on both Ru and Ti-rich domains. The supports exhibited good conductivity and electrochemical stability. The onset potentials of COads oxidation on the synthesized catalysts and on commercial PtRu/C are similar to each other and lower than that on Pt/C. This suggests that in Pt/Rum Ti0.9O2 and Pt/Ru0(.7)Ti(0.3)O(2) the Pt nanoparticles are in close contact with Ru atoms from the support, which enables the bifunctional mechanism. The activity and stability of the catalysts for methanol oxidation were examined under potentiodynamic and potentiostatic conditions. While the activity of Pt/Rum Ti0.9O2 is unsatisfactory, the performance of Pt/Ru0.7Ti0.3O2 is comparable to PtRu/C. For example, in the potentiostatic test at 0.5 V the activities after 25 min are 0.035 mA cm(-2) and 0.022 mA cm(-2) for Pt/Ru0.7Ti0.3O2 and PtRu/C, respectively. In potentiodynamic test the activities at 0.5V after 250 cycles are around 0.02 mA cm(-2) for both catalysts.
PB  - Elsevier
T2  - Applied Catalysis B-Environmental
T1  - RuxTi1-xO2 as the support for Pt nanoparticles: Electrocatalysis of methanol oxidation
VL  - 170
SP  - 144
EP  - 152
DO  - 10.1016/j.apcatb.2015.01.038
ER  - 

@article{
author = "Obradović, Maja and Lačnjevac, Uroš and Babic, B M and Ercius, P and Radmilović, Velimir R. and Krstajić, Nedeljko V. and Gojković, Snežana Lj.",
year = "2015",
abstract = "Two binary Ru-Ti oxides, Rum Ti0.9O2 and Ru0.7Ti0.3O2, were synthesized by the sol-gel method and used as an electrocatalyst support. The system was characterized by XRD, EDS, TEM and cyclic voltammetry. The Rum Ti0.9O2 and Ru0.7Ti0.3O2 consist of two phases of anatase and rutile structure. An average size of the Pt nanoparticles supported on them is similar to 3.5 nm and they are deposited on both Ru and Ti-rich domains. The supports exhibited good conductivity and electrochemical stability. The onset potentials of COads oxidation on the synthesized catalysts and on commercial PtRu/C are similar to each other and lower than that on Pt/C. This suggests that in Pt/Rum Ti0.9O2 and Pt/Ru0(.7)Ti(0.3)O(2) the Pt nanoparticles are in close contact with Ru atoms from the support, which enables the bifunctional mechanism. The activity and stability of the catalysts for methanol oxidation were examined under potentiodynamic and potentiostatic conditions. While the activity of Pt/Rum Ti0.9O2 is unsatisfactory, the performance of Pt/Ru0.7Ti0.3O2 is comparable to PtRu/C. For example, in the potentiostatic test at 0.5 V the activities after 25 min are 0.035 mA cm(-2) and 0.022 mA cm(-2) for Pt/Ru0.7Ti0.3O2 and PtRu/C, respectively. In potentiodynamic test the activities at 0.5V after 250 cycles are around 0.02 mA cm(-2) for both catalysts.",
publisher = "Elsevier",
journal = "Applied Catalysis B-Environmental",
title = "RuxTi1-xO2 as the support for Pt nanoparticles: Electrocatalysis of methanol oxidation",
volume = "170",
pages = "144-152",
doi = "10.1016/j.apcatb.2015.01.038"
}

Obradović, M., Lačnjevac, U., Babic, B. M., Ercius, P., Radmilović, V. R., Krstajić, N. V.,& Gojković, S. Lj.. (2015). RuxTi1-xO2 as the support for Pt nanoparticles: Electrocatalysis of methanol oxidation. in Applied Catalysis B-Environmental
Elsevier., 170, 144-152.
https://doi.org/10.1016/j.apcatb.2015.01.038

Obradović M, Lačnjevac U, Babic BM, Ercius P, Radmilović VR, Krstajić NV, Gojković SL. RuxTi1-xO2 as the support for Pt nanoparticles: Electrocatalysis of methanol oxidation. in Applied Catalysis B-Environmental. 2015;170:144-152.
doi:10.1016/j.apcatb.2015.01.038 .

Obradović, Maja, Lačnjevac, Uroš, Babic, B M, Ercius, P, Radmilović, Velimir R., Krstajić, Nedeljko V., Gojković, Snežana Lj., "RuxTi1-xO2 as the support for Pt nanoparticles: Electrocatalysis of methanol oxidation" in Applied Catalysis B-Environmental, 170 (2015):144-152,
https://doi.org/10.1016/j.apcatb.2015.01.038 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Gojković, Snežana Lj.
PY  - 2014
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1420
AB  - Pd black was modified by a very low amount of Pt corresponding to a sub-monolayer (ML). Spontaneous displacement method was employed. The catalysts with 0.02-0.12 ML were characterized by cyclic voltammetry and COads stripping and were tested for HCOOH oxidation under the potentiodynamic and potentiostatic conditions. All the Pt"Pd catalysts were more active for HCOOH oxidation than Pd black. The Pt"Pd with 0.08 ML of Pt exhibited the highest activity with the maximum current density under the potentiodynamic conditions of 8 mA cm(-2) (vs. 2.7 mA cm(-2) on Pd black). Contrasting HCOOH oxidation kinetics on Pt"Pd and Pt"Au catalysts revealed that the current densities are higher, and the poisoning rate is lower on Pt"Pd catalyst. This was ascribed to an optimal strength of the Pt-adsorbate bond when Pt is supported on Pd and to a possible influence of the Pt atoms on the Pd substrate.
PB  - Springer, New York
T2  - Journal of Solid State Electrochemistry
T1  - Pd black decorated by Pt sub-monolayers as an electrocatalyst for the HCOOH oxidation
VL  - 18
IS  - 9
SP  - 2599
EP  - 2607
DO  - 10.1007/s10008-014-2509-9
ER  - 

@article{
author = "Obradović, Maja and Gojković, Snežana Lj.",
year = "2014",
abstract = "Pd black was modified by a very low amount of Pt corresponding to a sub-monolayer (ML). Spontaneous displacement method was employed. The catalysts with 0.02-0.12 ML were characterized by cyclic voltammetry and COads stripping and were tested for HCOOH oxidation under the potentiodynamic and potentiostatic conditions. All the Pt"Pd catalysts were more active for HCOOH oxidation than Pd black. The Pt"Pd with 0.08 ML of Pt exhibited the highest activity with the maximum current density under the potentiodynamic conditions of 8 mA cm(-2) (vs. 2.7 mA cm(-2) on Pd black). Contrasting HCOOH oxidation kinetics on Pt"Pd and Pt"Au catalysts revealed that the current densities are higher, and the poisoning rate is lower on Pt"Pd catalyst. This was ascribed to an optimal strength of the Pt-adsorbate bond when Pt is supported on Pd and to a possible influence of the Pt atoms on the Pd substrate.",
publisher = "Springer, New York",
journal = "Journal of Solid State Electrochemistry",
title = "Pd black decorated by Pt sub-monolayers as an electrocatalyst for the HCOOH oxidation",
volume = "18",
number = "9",
pages = "2599-2607",
doi = "10.1007/s10008-014-2509-9"
}

Obradović, M.,& Gojković, S. Lj.. (2014). Pd black decorated by Pt sub-monolayers as an electrocatalyst for the HCOOH oxidation. in Journal of Solid State Electrochemistry
Springer, New York., 18(9), 2599-2607.
https://doi.org/10.1007/s10008-014-2509-9

Obradović M, Gojković SL. Pd black decorated by Pt sub-monolayers as an electrocatalyst for the HCOOH oxidation. in Journal of Solid State Electrochemistry. 2014;18(9):2599-2607.
doi:10.1007/s10008-014-2509-9 .

Obradović, Maja, Gojković, Snežana Lj., "Pd black decorated by Pt sub-monolayers as an electrocatalyst for the HCOOH oxidation" in Journal of Solid State Electrochemistry, 18, no. 9 (2014):2599-2607,
https://doi.org/10.1007/s10008-014-2509-9 . .

TY  - CONF
AU  - Obradović, Maja D.
AU  - Gojković, Snežana Lj.
PY  - 2014
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6362
AB  - Electrochemical oxidation of HCOOH was studied on single metal Pt, Pt/C and Pd black catalysts, on bimetallic surfaces of Pt-Au and Pd-Au bulk electrodes as well as on Pt-Co/C, Pt-Au/C and Pt-Pd nanocatalysts. The electrocatalysts were characterized by cyclic voltammetry and COads stripping, while the HCOOH oxidation was examined under the potentiodynamic and potentiostatic conditions. The results indicate that the ensemble effect is crucial for high selectivity of Pt-based surfaces toward dehydrogenation path. The enhancement of HCOOH oxidation rate on Pd-based surfa-ces was reached through electronic modification exhibited by the second metal. Our results also point out that the self-poisoning of the electrocatalyst by COads produced by the incomplete CO2 reduction is related to the strength of the Pt- and Pd-adsorbate bond, which has to be considered in designing of an electrocatalyst for HCOOH oxidation.
PB  - Society of Physical Chemists of Serbia
C3  - Proceedings - 12th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Physical Chemistry 2014, Belgrade, September 22-26 2014
T1  - Electrochemical oxidation of formic acid on Pt- and Pd-based bimetallic catalysts
VL  - I
SP  - 375
EP  - 382
UR  - https://hdl.handle.net/21.15107/rcub_cer_6362
ER  - 

@conference{
author = "Obradović, Maja D. and Gojković, Snežana Lj.",
year = "2014",
abstract = "Electrochemical oxidation of HCOOH was studied on single metal Pt, Pt/C and Pd black catalysts, on bimetallic surfaces of Pt-Au and Pd-Au bulk electrodes as well as on Pt-Co/C, Pt-Au/C and Pt-Pd nanocatalysts. The electrocatalysts were characterized by cyclic voltammetry and COads stripping, while the HCOOH oxidation was examined under the potentiodynamic and potentiostatic conditions. The results indicate that the ensemble effect is crucial for high selectivity of Pt-based surfaces toward dehydrogenation path. The enhancement of HCOOH oxidation rate on Pd-based surfa-ces was reached through electronic modification exhibited by the second metal. Our results also point out that the self-poisoning of the electrocatalyst by COads produced by the incomplete CO2 reduction is related to the strength of the Pt- and Pd-adsorbate bond, which has to be considered in designing of an electrocatalyst for HCOOH oxidation.",
publisher = "Society of Physical Chemists of Serbia",
journal = "Proceedings - 12th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Physical Chemistry 2014, Belgrade, September 22-26 2014",
title = "Electrochemical oxidation of formic acid on Pt- and Pd-based bimetallic catalysts",
volume = "I",
pages = "375-382",
url = "https://hdl.handle.net/21.15107/rcub_cer_6362"
}

Obradović, M. D.,& Gojković, S. Lj.. (2014). Electrochemical oxidation of formic acid on Pt- and Pd-based bimetallic catalysts. in Proceedings - 12th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Physical Chemistry 2014, Belgrade, September 22-26 2014
Society of Physical Chemists of Serbia., I, 375-382.
https://hdl.handle.net/21.15107/rcub_cer_6362

Obradović MD, Gojković SL. Electrochemical oxidation of formic acid on Pt- and Pd-based bimetallic catalysts. in Proceedings - 12th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Physical Chemistry 2014, Belgrade, September 22-26 2014. 2014;I:375-382.
https://hdl.handle.net/21.15107/rcub_cer_6362 .

Obradović, Maja D., Gojković, Snežana Lj., "Electrochemical oxidation of formic acid on Pt- and Pd-based bimetallic catalysts" in Proceedings - 12th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Physical Chemistry 2014, Belgrade, September 22-26 2014, I (2014):375-382,
https://hdl.handle.net/21.15107/rcub_cer_6362 .

TY  - JOUR
AU  - Obradović, Maja
AU  - Babić, Biljana M.
AU  - Krstajić, Nedeljko V.
AU  - Gojković, Snežana Lj.
PY  - 2013
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1166
AB  - Tungsten carbide was synthesized by calcination of carbon cryogel with embedded tungsten in a form of metatungstate. This material was used as a support for Pt nanoparticles. XRD pattern of W-C support indicated the presence of WC, W2C, and unreacted W, as well as graphitized carbon. According to previous TEM analysis of W-C support, it contains particles with core-shell structure, where the W particle was covered with the shell of a mixture of WC and W2C. The average Pt grain size calculated from XRD pattern was about 6 nm. A cyclic voltammogram of W-C support was recorded within the potential range relevant for its application as a catalyst support in fuel cells. The pair of anodic/cathodic peaks close to the negative potential limit could be ascribed to the intercalation of hydrogen within hydrous tungsten oxide, which is always present on the surface of WC in aqueous solutions. The cyclic voltammogram of Pt/W-C indicated that tungsten oxide species are present on tungsten carbide shell as well as on the surface of Pt nanoparticles. The Pt surface is only partially covered by hydrous tungsten oxide. Hydrogen intercalation in hydrous tungsten oxide is enhanced in the presence of Pt nanoparticles. Also, the presence of hydrated tungsten oxide leads to the decrease of OH chemisorbed on Pt surface. Stripping of underpotentially deposited copper was used for the assessment of Pt surface area and the specific surface area of Pt was estimated to be 41 m2 g-1. The electrochemical oxygen reduction reaction was examined on the synthesized Pt/W-C catalyst and compared with the results on the commercial Pt/C catalyst. It was found that the current densities at Pt/W-C were almost twice as high as those on Pt/C. The Tafel plots for both catalysts are characterized with two Tafel slopes: -0.060 V dec-1 at low current densities, and -0.120 V dec-1 at high current densities. From the rotational dependence of the reaction rate, it was found that oxygen reduction on both Pt/W-C and Pt/C follows the first order kinetics with respect to O2 and that four electrons are transferred per O2 molecule. The results show that the presence of tungsten carbide in support material, i.e. hydrous tungsten oxide on Pt surface, leads to promotion of oxygen reduction on the Pt/W-C catalyst. It was assumed that oxophilic hydrated tungsten oxide hinders OH adsorption on Pt surface, thus increasing Pt surface area available for O2 adsorption and its electrochemical reduction.
AB  - Sintetizovan je nosač katalizatora u kojem se na ugljeničnoj osnovi nalaze nanočestice metalnog volframa obavijene volfram-karbidom i na njega su nanete nanočestice Pt. Karakterizacija sintetizovanog uzorka cikličnom voltametrijom u kiseloj sredini ukazala je na oksidaciju volframovih vrsta iz nosača i formiranje hidratisanih oksidnih vrsta volframa na površini Pt. Elektrohemijska redukcija O2 u kiseloj sredini je ispitivana na sintetizovanom uzorku i rezultati su upoređeni sa komercijalnim katalizatorom u kojem su nanočestice Pt na nosaču od ugljenika razvijene površine. Pokazano je da redukcija O2, bez obzira na nosač katalizatora, sledi kinetiku prvog reda po O2 uz razmenu četiri elektrona, ali da su gustine struje veće u slučaju nosača sa volfram-karbidom. Povećana aktivnost sintetizovanog katalizatora je posledica prisustva oksofiličnih hidratisanih oksida volframa koji sprečavaju adsorpciju hidratisanog oksida na površini Pt i tako povećavaju površinu Pt dostupnu za adsorpciju i redukciju molekula kiseonika.
PB  - Association of Chemical Engineers of Serbia
T2  - Hemijska industrija
T1  - Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution
T1  - Uticaj prisustva volfram-karbida u ugljeničnom nosaču Pt nanočestica na elektrohemijsku redukciju kiseonika u kiselom rastvoru
VL  - 67
IS  - 2
SP  - 303
EP  - 311
DO  - 10.2298/HEMIND120307063O
ER  - 

@article{
author = "Obradović, Maja and Babić, Biljana M. and Krstajić, Nedeljko V. and Gojković, Snežana Lj.",
year = "2013",
abstract = "Tungsten carbide was synthesized by calcination of carbon cryogel with embedded tungsten in a form of metatungstate. This material was used as a support for Pt nanoparticles. XRD pattern of W-C support indicated the presence of WC, W2C, and unreacted W, as well as graphitized carbon. According to previous TEM analysis of W-C support, it contains particles with core-shell structure, where the W particle was covered with the shell of a mixture of WC and W2C. The average Pt grain size calculated from XRD pattern was about 6 nm. A cyclic voltammogram of W-C support was recorded within the potential range relevant for its application as a catalyst support in fuel cells. The pair of anodic/cathodic peaks close to the negative potential limit could be ascribed to the intercalation of hydrogen within hydrous tungsten oxide, which is always present on the surface of WC in aqueous solutions. The cyclic voltammogram of Pt/W-C indicated that tungsten oxide species are present on tungsten carbide shell as well as on the surface of Pt nanoparticles. The Pt surface is only partially covered by hydrous tungsten oxide. Hydrogen intercalation in hydrous tungsten oxide is enhanced in the presence of Pt nanoparticles. Also, the presence of hydrated tungsten oxide leads to the decrease of OH chemisorbed on Pt surface. Stripping of underpotentially deposited copper was used for the assessment of Pt surface area and the specific surface area of Pt was estimated to be 41 m2 g-1. The electrochemical oxygen reduction reaction was examined on the synthesized Pt/W-C catalyst and compared with the results on the commercial Pt/C catalyst. It was found that the current densities at Pt/W-C were almost twice as high as those on Pt/C. The Tafel plots for both catalysts are characterized with two Tafel slopes: -0.060 V dec-1 at low current densities, and -0.120 V dec-1 at high current densities. From the rotational dependence of the reaction rate, it was found that oxygen reduction on both Pt/W-C and Pt/C follows the first order kinetics with respect to O2 and that four electrons are transferred per O2 molecule. The results show that the presence of tungsten carbide in support material, i.e. hydrous tungsten oxide on Pt surface, leads to promotion of oxygen reduction on the Pt/W-C catalyst. It was assumed that oxophilic hydrated tungsten oxide hinders OH adsorption on Pt surface, thus increasing Pt surface area available for O2 adsorption and its electrochemical reduction., Sintetizovan je nosač katalizatora u kojem se na ugljeničnoj osnovi nalaze nanočestice metalnog volframa obavijene volfram-karbidom i na njega su nanete nanočestice Pt. Karakterizacija sintetizovanog uzorka cikličnom voltametrijom u kiseloj sredini ukazala je na oksidaciju volframovih vrsta iz nosača i formiranje hidratisanih oksidnih vrsta volframa na površini Pt. Elektrohemijska redukcija O2 u kiseloj sredini je ispitivana na sintetizovanom uzorku i rezultati su upoređeni sa komercijalnim katalizatorom u kojem su nanočestice Pt na nosaču od ugljenika razvijene površine. Pokazano je da redukcija O2, bez obzira na nosač katalizatora, sledi kinetiku prvog reda po O2 uz razmenu četiri elektrona, ali da su gustine struje veće u slučaju nosača sa volfram-karbidom. Povećana aktivnost sintetizovanog katalizatora je posledica prisustva oksofiličnih hidratisanih oksida volframa koji sprečavaju adsorpciju hidratisanog oksida na površini Pt i tako povećavaju površinu Pt dostupnu za adsorpciju i redukciju molekula kiseonika.",
publisher = "Association of Chemical Engineers of Serbia",
journal = "Hemijska industrija",
title = "Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution, Uticaj prisustva volfram-karbida u ugljeničnom nosaču Pt nanočestica na elektrohemijsku redukciju kiseonika u kiselom rastvoru",
volume = "67",
number = "2",
pages = "303-311",
doi = "10.2298/HEMIND120307063O"
}

Obradović, M., Babić, B. M., Krstajić, N. V.,& Gojković, S. Lj.. (2013). Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution. in Hemijska industrija
Association of Chemical Engineers of Serbia., 67(2), 303-311.
https://doi.org/10.2298/HEMIND120307063O

Obradović M, Babić BM, Krstajić NV, Gojković SL. Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution. in Hemijska industrija. 2013;67(2):303-311.
doi:10.2298/HEMIND120307063O .

Obradović, Maja, Babić, Biljana M., Krstajić, Nedeljko V., Gojković, Snežana Lj., "Effect of tungsten carbide in carbon Pt catalyst support on electrochemical oxygen reduction in acid solution" in Hemijska industrija, 67, no. 2 (2013):303-311,
https://doi.org/10.2298/HEMIND120307063O . .

TY  - JOUR
AU  - Krstajić, Mila N.
AU  - Obradović, Maja
AU  - Babić, Biljana M.
AU  - Radmilović, Velimir R.
AU  - Lačnjevac, Uroš
AU  - Krstajić, Nedeljko V.
AU  - Gojković, Snežana Lj.
PY  - 2013
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1232
AB  - Ru-doped SnO2 powder, (RuxSn1-x)O2, with a Sn:Ru atomic ratio of 9:1 was synthesized and used as a support for Pt nanoparticles (30 mass % loading). The (RuxSn1-x)O2 support and the Pt/(RuxSn1-x)O2 catalyst were characterized by X-ray diffraction measurements, energy dispersive X-ray spectroscopy and transmission electron microscopy (TEM). The (RuxSn1-x)O2 was found to be a two-phase material consisting of probably a solid solution of RuO2 in SnO2 and pure RuO2. The average Pt particle size determined by TEM was 5.3 nm. Cyclic voltammetry of Pt/(RuxSn1-x)O2 indicated good conductivity of the support and displayed the usual features of Pt. The results of the electrochemical oxidation of COads and methanol on Pt/(RuxSn1-x)O2 were compared with those on commercial Pt/C and PtRu/C catalysts. Oxidation of COads on Pt/(RuxSn1-x)O2 starts at lower positive potentials than on PtRu/C and Pt/C. Potentiodynamic polarization curves and chronoamperometric curves of methanol oxidation indicated higher initial activity of the Pt/(RuxSn1-x)O2 catalyst compared to PtRu/C, but also a greater loss in current density over time. A potentiodynamic stability test of the catalysts revealed that deactivation of Pt/(RuxSn1-x)O2 and Pt/C was primarily caused by poisoning of the Pt surface by residues of methanol oxidation, which mostly occurred during the first potential cycle. In the case of PtRu/C, the poisoning of the surface was minor and deactivation was caused by surface area loss of the PtRu.
AB  - Sintetizovan je prah SnO2 dopovan rutenijumom, (RuxSn1-x)O2, sa atomskim odnosom Sn:Ru od 9:1, i korišćen kao nosač nanočestica platine. Udeo Pt u dobijenom katalizatoru, Pt/(RuxSn1-x)O2, bio je 30 mas. %. Nosač i katalizator su karakterisani difrakcijom X-zraka, energetski disperzivnom spektroskopijom X-zraka i transmisionom elektronskom mikroskopijom (TEM). Pokazano je da je (RuxSn1-x)O2 dvofazni materijal koji verovatno sadrži čvrst rastvor RuO2 u SnO2 i čist RuO2. Prosečna veličina zrna Pt, određena TEM analizom, iznosi 5,3 nm. Ciklična voltametrija Pt/(RuxSn1-x)O2 ukazala je na dobru provodnost nosača katalizatora i na uobičajene karakteristike Pt. Upoređeni su rezultati elektrohemijske oksidacije COads na Pt/(RuxSn1-x)O2, Pt/C i PtRu/C. Oksidacija COads na Pt/(RuxSn1-x)O2 počinje na negativnijim potencijalima u odnosu na PtRu/C i Pt/C. Potenciodinamičke polarizacione krive i hronoamperometrijske krive za oksidaciju metanola ukazuju na veću početnu aktivnost katalizatora Pt/(RuxSn1-x)O2 u odnosu na PtRu/C, ali i na veće smanjenje gustine struje tokom vremena. Test potenciodinamičke stabilnosti katalizatora je ukazao da je smanjenje aktivnosti Pt/(RuxSn1-x)O2 i Pt/C prvenstveno prouzrokovano trovanjem površine Pt proizvodima nepotpune oksidacije metanola, koje se uglavnom odigrava tokom prvog ciklusa. Kod PtRu/C trovanje površine je minimalno, a smanjenje aktivnosti je prouzrokovano smanjenjem elektrohemijski aktivne površine PtRu.
PB  - Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - Electrochemical oxidation of methanol on Pt/(RuxSn1-x)O2 nanocatalyst
T1  - Elektrohemijska oksidacija metanola na katalizatoru Pt/(RuxSn1-x)O2
VL  - 78
IS  - 11
SP  - 1703
EP  - 1716
DO  - 10.2298/JSC130718091K
ER  - 

@article{
author = "Krstajić, Mila N. and Obradović, Maja and Babić, Biljana M. and Radmilović, Velimir R. and Lačnjevac, Uroš and Krstajić, Nedeljko V. and Gojković, Snežana Lj.",
year = "2013",
abstract = "Ru-doped SnO2 powder, (RuxSn1-x)O2, with a Sn:Ru atomic ratio of 9:1 was synthesized and used as a support for Pt nanoparticles (30 mass % loading). The (RuxSn1-x)O2 support and the Pt/(RuxSn1-x)O2 catalyst were characterized by X-ray diffraction measurements, energy dispersive X-ray spectroscopy and transmission electron microscopy (TEM). The (RuxSn1-x)O2 was found to be a two-phase material consisting of probably a solid solution of RuO2 in SnO2 and pure RuO2. The average Pt particle size determined by TEM was 5.3 nm. Cyclic voltammetry of Pt/(RuxSn1-x)O2 indicated good conductivity of the support and displayed the usual features of Pt. The results of the electrochemical oxidation of COads and methanol on Pt/(RuxSn1-x)O2 were compared with those on commercial Pt/C and PtRu/C catalysts. Oxidation of COads on Pt/(RuxSn1-x)O2 starts at lower positive potentials than on PtRu/C and Pt/C. Potentiodynamic polarization curves and chronoamperometric curves of methanol oxidation indicated higher initial activity of the Pt/(RuxSn1-x)O2 catalyst compared to PtRu/C, but also a greater loss in current density over time. A potentiodynamic stability test of the catalysts revealed that deactivation of Pt/(RuxSn1-x)O2 and Pt/C was primarily caused by poisoning of the Pt surface by residues of methanol oxidation, which mostly occurred during the first potential cycle. In the case of PtRu/C, the poisoning of the surface was minor and deactivation was caused by surface area loss of the PtRu., Sintetizovan je prah SnO2 dopovan rutenijumom, (RuxSn1-x)O2, sa atomskim odnosom Sn:Ru od 9:1, i korišćen kao nosač nanočestica platine. Udeo Pt u dobijenom katalizatoru, Pt/(RuxSn1-x)O2, bio je 30 mas. %. Nosač i katalizator su karakterisani difrakcijom X-zraka, energetski disperzivnom spektroskopijom X-zraka i transmisionom elektronskom mikroskopijom (TEM). Pokazano je da je (RuxSn1-x)O2 dvofazni materijal koji verovatno sadrži čvrst rastvor RuO2 u SnO2 i čist RuO2. Prosečna veličina zrna Pt, određena TEM analizom, iznosi 5,3 nm. Ciklična voltametrija Pt/(RuxSn1-x)O2 ukazala je na dobru provodnost nosača katalizatora i na uobičajene karakteristike Pt. Upoređeni su rezultati elektrohemijske oksidacije COads na Pt/(RuxSn1-x)O2, Pt/C i PtRu/C. Oksidacija COads na Pt/(RuxSn1-x)O2 počinje na negativnijim potencijalima u odnosu na PtRu/C i Pt/C. Potenciodinamičke polarizacione krive i hronoamperometrijske krive za oksidaciju metanola ukazuju na veću početnu aktivnost katalizatora Pt/(RuxSn1-x)O2 u odnosu na PtRu/C, ali i na veće smanjenje gustine struje tokom vremena. Test potenciodinamičke stabilnosti katalizatora je ukazao da je smanjenje aktivnosti Pt/(RuxSn1-x)O2 i Pt/C prvenstveno prouzrokovano trovanjem površine Pt proizvodima nepotpune oksidacije metanola, koje se uglavnom odigrava tokom prvog ciklusa. Kod PtRu/C trovanje površine je minimalno, a smanjenje aktivnosti je prouzrokovano smanjenjem elektrohemijski aktivne površine PtRu.",
publisher = "Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "Electrochemical oxidation of methanol on Pt/(RuxSn1-x)O2 nanocatalyst, Elektrohemijska oksidacija metanola na katalizatoru Pt/(RuxSn1-x)O2",
volume = "78",
number = "11",
pages = "1703-1716",
doi = "10.2298/JSC130718091K"
}

Krstajić, M. N., Obradović, M., Babić, B. M., Radmilović, V. R., Lačnjevac, U., Krstajić, N. V.,& Gojković, S. Lj.. (2013). Electrochemical oxidation of methanol on Pt/(RuxSn1-x)O2 nanocatalyst. in Journal of the Serbian Chemical Society
Serbian Chemical Society., 78(11), 1703-1716.
https://doi.org/10.2298/JSC130718091K

Krstajić MN, Obradović M, Babić BM, Radmilović VR, Lačnjevac U, Krstajić NV, Gojković SL. Electrochemical oxidation of methanol on Pt/(RuxSn1-x)O2 nanocatalyst. in Journal of the Serbian Chemical Society. 2013;78(11):1703-1716.
doi:10.2298/JSC130718091K .

Krstajić, Mila N., Obradović, Maja, Babić, Biljana M., Radmilović, Velimir R., Lačnjevac, Uroš, Krstajić, Nedeljko V., Gojković, Snežana Lj., "Electrochemical oxidation of methanol on Pt/(RuxSn1-x)O2 nanocatalyst" in Journal of the Serbian Chemical Society, 78, no. 11 (2013):1703-1716,
https://doi.org/10.2298/JSC130718091K . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Gojković, Snežana Lj.
PY  - 2013
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1279
AB  - The oxidation of HCOOH has been investigated on thin Pd layers ranging from 1 to 17 ML equivalents electrodeposited on polycrystalline Au substrate (Pd"Au). The results are compared to those on Pd black. Potentiodynamic polarization curves suggest that on both types of catalyst HCOOH oxidizes through dehydrogenation path. The high current densities achieved on 4-17 ML Pd"Au surpass more than three times the activity of Pd black. Chronoamperometric test reveals that the Pd"Au electrodes lose their activity faster than Pd black. In the stripping experiment performed after the chronoamperometry COads is detected on all the surfaces. On the 4 ML Pd"Au, which exhibits the highest deactivation rate, the COads coverage is the largest. After the chronoamperometric test repeated in the CO2 saturated supporting electrolyte, the anodic stripping shows that COads is present on all the electrodes, again with the highest coverage on 4 ML Pd"Au. It is concluded that deactivation of Pd surfaces is caused by the COads formed in the electrochemical reduction of CO2, which is the product of HCOOH oxidation. Electronic modification of Pd by Au substrate causes stronger interactions of Pd with HCOOH and CO, which increases HCOOH oxidation rate, but also accelerates the poisoning by COads.
PB  - Oxford : Pergamon-Elsevier Science Ltd
T2  - Electrochimica Acta
T1  - HCOOH oxidation on thin Pd layers on Au: Self-poisoning by the subsequent reaction of the reaction product
VL  - 88
SP  - 384
EP  - 389
DO  - 10.1016/j.electacta.2012.10.033
ER  - 

@article{
author = "Obradović, Maja and Gojković, Snežana Lj.",
year = "2013",
abstract = "The oxidation of HCOOH has been investigated on thin Pd layers ranging from 1 to 17 ML equivalents electrodeposited on polycrystalline Au substrate (Pd"Au). The results are compared to those on Pd black. Potentiodynamic polarization curves suggest that on both types of catalyst HCOOH oxidizes through dehydrogenation path. The high current densities achieved on 4-17 ML Pd"Au surpass more than three times the activity of Pd black. Chronoamperometric test reveals that the Pd"Au electrodes lose their activity faster than Pd black. In the stripping experiment performed after the chronoamperometry COads is detected on all the surfaces. On the 4 ML Pd"Au, which exhibits the highest deactivation rate, the COads coverage is the largest. After the chronoamperometric test repeated in the CO2 saturated supporting electrolyte, the anodic stripping shows that COads is present on all the electrodes, again with the highest coverage on 4 ML Pd"Au. It is concluded that deactivation of Pd surfaces is caused by the COads formed in the electrochemical reduction of CO2, which is the product of HCOOH oxidation. Electronic modification of Pd by Au substrate causes stronger interactions of Pd with HCOOH and CO, which increases HCOOH oxidation rate, but also accelerates the poisoning by COads.",
publisher = "Oxford : Pergamon-Elsevier Science Ltd",
journal = "Electrochimica Acta",
title = "HCOOH oxidation on thin Pd layers on Au: Self-poisoning by the subsequent reaction of the reaction product",
volume = "88",
pages = "384-389",
doi = "10.1016/j.electacta.2012.10.033"
}

Obradović, M.,& Gojković, S. Lj.. (2013). HCOOH oxidation on thin Pd layers on Au: Self-poisoning by the subsequent reaction of the reaction product. in Electrochimica Acta
Oxford : Pergamon-Elsevier Science Ltd., 88, 384-389.
https://doi.org/10.1016/j.electacta.2012.10.033

Obradović M, Gojković SL. HCOOH oxidation on thin Pd layers on Au: Self-poisoning by the subsequent reaction of the reaction product. in Electrochimica Acta. 2013;88:384-389.
doi:10.1016/j.electacta.2012.10.033 .

Obradović, Maja, Gojković, Snežana Lj., "HCOOH oxidation on thin Pd layers on Au: Self-poisoning by the subsequent reaction of the reaction product" in Electrochimica Acta, 88 (2013):384-389,
https://doi.org/10.1016/j.electacta.2012.10.033 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Gojković, Snežana Lj.
AU  - Elezović, Nevenka R.
AU  - Ercius, P.
AU  - Radmilović, Velimir R.
AU  - Vracar, Lj. D.
AU  - Krstajić, Nedeljko V.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/948
AB  - The catalytic activity of WC/Pt electrocatalysts towards hydrogen oxidation reaction (HOR) in acid solution was studied. Tungsten carbide (WC) prepared by polycondensation of resorcinol and formaldehyde in the presence of ammonium metatungstate salt and CTABr surfactant was used as the support of a Pt electrocatalyst (WC/Pt). The obtained WC/Pt electrodes were characterized by XRD, HRTEM, EDS, EELS and electrochemical measurements. HRTEM analysis showed that the WC particles possess a core-shell structure with a metallic tungsten core and a shell composed of a mixture of tungsten carbides shell (WC and W2C). The WC/Pt catalyst is composed of well-dispersed sub-nanometer Pt clusters which consist of a few to several tens of Pt atoms. EELS measurements indicate that the WC particles function as nucleation sites for Pt nanoparticles. Based on the Tafel-Heyrovsky-Volmer mechanism the corresponding kinetic equations were derived to describe the HOR current-potential behavior over the entire potential region on RDE. The fitting showed that in the lower potential region HOR on Pt proceeds most likely via the Tafel-Volmer (TV) pathway. The kinetic results also showed that the WC/Pt(1%) when compared to the standard C/Pt(1%) electrode led to a remarkable enhancement of the hydrogen oxidation in an acidic medium, which was explained by H-spill-over between platinum and tungsten carbide.
PB  - Elsevier
T2  - Journal of Electroanalytical Chemistry
T1  - The kinetics of the hydrogen oxidation reaction on WC/Pt catalyst with low content of Pt nano-particles
VL  - 671
SP  - 24
EP  - 32
DO  - 10.1016/j.jelechem.2012.01.026
ER  - 

@article{
author = "Obradović, Maja and Gojković, Snežana Lj. and Elezović, Nevenka R. and Ercius, P. and Radmilović, Velimir R. and Vracar, Lj. D. and Krstajić, Nedeljko V.",
year = "2012",
abstract = "The catalytic activity of WC/Pt electrocatalysts towards hydrogen oxidation reaction (HOR) in acid solution was studied. Tungsten carbide (WC) prepared by polycondensation of resorcinol and formaldehyde in the presence of ammonium metatungstate salt and CTABr surfactant was used as the support of a Pt electrocatalyst (WC/Pt). The obtained WC/Pt electrodes were characterized by XRD, HRTEM, EDS, EELS and electrochemical measurements. HRTEM analysis showed that the WC particles possess a core-shell structure with a metallic tungsten core and a shell composed of a mixture of tungsten carbides shell (WC and W2C). The WC/Pt catalyst is composed of well-dispersed sub-nanometer Pt clusters which consist of a few to several tens of Pt atoms. EELS measurements indicate that the WC particles function as nucleation sites for Pt nanoparticles. Based on the Tafel-Heyrovsky-Volmer mechanism the corresponding kinetic equations were derived to describe the HOR current-potential behavior over the entire potential region on RDE. The fitting showed that in the lower potential region HOR on Pt proceeds most likely via the Tafel-Volmer (TV) pathway. The kinetic results also showed that the WC/Pt(1%) when compared to the standard C/Pt(1%) electrode led to a remarkable enhancement of the hydrogen oxidation in an acidic medium, which was explained by H-spill-over between platinum and tungsten carbide.",
publisher = "Elsevier",
journal = "Journal of Electroanalytical Chemistry",
title = "The kinetics of the hydrogen oxidation reaction on WC/Pt catalyst with low content of Pt nano-particles",
volume = "671",
pages = "24-32",
doi = "10.1016/j.jelechem.2012.01.026"
}

Obradović, M., Gojković, S. Lj., Elezović, N. R., Ercius, P., Radmilović, V. R., Vracar, Lj. D.,& Krstajić, N. V.. (2012). The kinetics of the hydrogen oxidation reaction on WC/Pt catalyst with low content of Pt nano-particles. in Journal of Electroanalytical Chemistry
Elsevier., 671, 24-32.
https://doi.org/10.1016/j.jelechem.2012.01.026

Obradović M, Gojković SL, Elezović NR, Ercius P, Radmilović VR, Vracar LD, Krstajić NV. The kinetics of the hydrogen oxidation reaction on WC/Pt catalyst with low content of Pt nano-particles. in Journal of Electroanalytical Chemistry. 2012;671:24-32.
doi:10.1016/j.jelechem.2012.01.026 .

Obradović, Maja, Gojković, Snežana Lj., Elezović, Nevenka R., Ercius, P., Radmilović, Velimir R., Vracar, Lj. D., Krstajić, Nedeljko V., "The kinetics of the hydrogen oxidation reaction on WC/Pt catalyst with low content of Pt nano-particles" in Journal of Electroanalytical Chemistry, 671 (2012):24-32,
https://doi.org/10.1016/j.jelechem.2012.01.026 . .

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  - Gojković, Snežana Lj.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/992
AB  - A detrimental effect of CO on the stability of Pt nanoparticles, which is important for fuel cells technology, is demonstrated by the change in HCOOH kinetics on Pt nanoparticles caused by the presence of CO in the electrolyte. Pt nanoparticles supported on high area carbon (Pt/C) were applied on gold and glassy carbon substrates (Pt/C"Au and Pt/C"GC) and three different kinds of Pt surface were prepared by potential cycling in the various potential limits in N-2 and CO saturated electrolyte: untreated, OH-annealed and CO-annealed. On untreated Pt/C"Au catalyst HCOOH is oxidized predominantly through indirect mechanism, after OH-annealing direct path is slightly accelerated, but on CO-annealed catalyst the direct path in HCOOH oxidation is predominant. Based on the fact that more contiguous Pt sites are necessary for indirect than for direct path, it was concluded that OH- and especially CO-annealing of Pt/C produces small Pt domains. Since the same pretreatment did not show any effect on HCOOH oxidation on Pt/C"GC electrode, it was postulated that Pt nanoparticles dissolve in the presence of CO on the surface and in the electrolyte, and successively deposit on Au substrate. The results points out pronounced instability of Pt nanoparticles in the presence of CO.
PB  - Elsevier
T2  - Journal of Electroanalytical Chemistry
T1  - Electrochemical instability of Pt nanoparticles probed by formic acid oxidation
VL  - 664
SP  - 152
EP  - 155
DO  - 10.1016/j.jelechem.2011.10.016
ER  - 

@article{
author = "Obradović, Maja and Gojković, Snežana Lj.",
year = "2012",
abstract = "A detrimental effect of CO on the stability of Pt nanoparticles, which is important for fuel cells technology, is demonstrated by the change in HCOOH kinetics on Pt nanoparticles caused by the presence of CO in the electrolyte. Pt nanoparticles supported on high area carbon (Pt/C) were applied on gold and glassy carbon substrates (Pt/C"Au and Pt/C"GC) and three different kinds of Pt surface were prepared by potential cycling in the various potential limits in N-2 and CO saturated electrolyte: untreated, OH-annealed and CO-annealed. On untreated Pt/C"Au catalyst HCOOH is oxidized predominantly through indirect mechanism, after OH-annealing direct path is slightly accelerated, but on CO-annealed catalyst the direct path in HCOOH oxidation is predominant. Based on the fact that more contiguous Pt sites are necessary for indirect than for direct path, it was concluded that OH- and especially CO-annealing of Pt/C produces small Pt domains. Since the same pretreatment did not show any effect on HCOOH oxidation on Pt/C"GC electrode, it was postulated that Pt nanoparticles dissolve in the presence of CO on the surface and in the electrolyte, and successively deposit on Au substrate. The results points out pronounced instability of Pt nanoparticles in the presence of CO.",
publisher = "Elsevier",
journal = "Journal of Electroanalytical Chemistry",
title = "Electrochemical instability of Pt nanoparticles probed by formic acid oxidation",
volume = "664",
pages = "152-155",
doi = "10.1016/j.jelechem.2011.10.016"
}

Obradović, M.,& Gojković, S. Lj.. (2012). Electrochemical instability of Pt nanoparticles probed by formic acid oxidation. in Journal of Electroanalytical Chemistry
Elsevier., 664, 152-155.
https://doi.org/10.1016/j.jelechem.2011.10.016

Obradović M, Gojković SL. Electrochemical instability of Pt nanoparticles probed by formic acid oxidation. in Journal of Electroanalytical Chemistry. 2012;664:152-155.
doi:10.1016/j.jelechem.2011.10.016 .

Obradović, Maja, Gojković, Snežana Lj., "Electrochemical instability of Pt nanoparticles probed by formic acid oxidation" in Journal of Electroanalytical Chemistry, 664 (2012):152-155,
https://doi.org/10.1016/j.jelechem.2011.10.016 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Tripković, Amalija
AU  - Gojković, Snežana Lj.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1036
AB  - Bulk Pt3Co and nanosized Pt3Co and PtCo alloys supported on high area carbon were investigated as the electrocatalysts for the COads and HCOOH oxidation. Pt3Co alloy with Co electrochemically leached from the surface (Pt skeleton) was employed to separate electronic from ensemble and bifunctional effects of Co. Cyclic voltammetry in 0.1 M HClO4 showed reduced amount of adsorbed hydrogen on Pt sites on Pt3Co alloy compared to pure Pt. However, no significant difference in hydrogen adsorption/desorption and Pt-oxide reduction features between Pt3Co with Pt skeleton structure and bulk Pt was observed. The oxidation of COads on Pt3Co alloy commenced earlier than on Pt, but this effect on Pt3Co with Pt skeleton structure was minor indicating that bifunctional mechanism is stronger than the electronic modification of Pt by Co. The HCOOH oxidation rate on Pt3Co alloy was about seven times higher than on bulk Pt when the reaction rates were compared at 0.4 V, i.e., in the middle of the potential range for the HCOOH oxidation. Like in the case of COads oxidation, Pt skeleton showed similar activity as bulk Pt indicating that the ensemble effect is responsible for the enhanced activity of Pt3Co alloy toward HCOOH oxidation. The comparison of COads and HCOOH oxidation on Pt3Co/C and PtCo/C with the same reaction on Pt/C were qualitatively the same as on bulk materials.
PB  - Springer, New York
T2  - Journal of Solid State Electrochemistry
T1  - Oxidation of carbon monoxide and formic acid on bulk and nanosized Pt-Co alloys
VL  - 16
IS  - 2
SP  - 587
EP  - 595
DO  - 10.1007/s10008-011-1389-5
ER  - 

@article{
author = "Obradović, Maja and Tripković, Amalija and Gojković, Snežana Lj.",
year = "2012",
abstract = "Bulk Pt3Co and nanosized Pt3Co and PtCo alloys supported on high area carbon were investigated as the electrocatalysts for the COads and HCOOH oxidation. Pt3Co alloy with Co electrochemically leached from the surface (Pt skeleton) was employed to separate electronic from ensemble and bifunctional effects of Co. Cyclic voltammetry in 0.1 M HClO4 showed reduced amount of adsorbed hydrogen on Pt sites on Pt3Co alloy compared to pure Pt. However, no significant difference in hydrogen adsorption/desorption and Pt-oxide reduction features between Pt3Co with Pt skeleton structure and bulk Pt was observed. The oxidation of COads on Pt3Co alloy commenced earlier than on Pt, but this effect on Pt3Co with Pt skeleton structure was minor indicating that bifunctional mechanism is stronger than the electronic modification of Pt by Co. The HCOOH oxidation rate on Pt3Co alloy was about seven times higher than on bulk Pt when the reaction rates were compared at 0.4 V, i.e., in the middle of the potential range for the HCOOH oxidation. Like in the case of COads oxidation, Pt skeleton showed similar activity as bulk Pt indicating that the ensemble effect is responsible for the enhanced activity of Pt3Co alloy toward HCOOH oxidation. The comparison of COads and HCOOH oxidation on Pt3Co/C and PtCo/C with the same reaction on Pt/C were qualitatively the same as on bulk materials.",
publisher = "Springer, New York",
journal = "Journal of Solid State Electrochemistry",
title = "Oxidation of carbon monoxide and formic acid on bulk and nanosized Pt-Co alloys",
volume = "16",
number = "2",
pages = "587-595",
doi = "10.1007/s10008-011-1389-5"
}

Obradović, M., Tripković, A.,& Gojković, S. Lj.. (2012). Oxidation of carbon monoxide and formic acid on bulk and nanosized Pt-Co alloys. in Journal of Solid State Electrochemistry
Springer, New York., 16(2), 587-595.
https://doi.org/10.1007/s10008-011-1389-5

Obradović M, Tripković A, Gojković SL. Oxidation of carbon monoxide and formic acid on bulk and nanosized Pt-Co alloys. in Journal of Solid State Electrochemistry. 2012;16(2):587-595.
doi:10.1007/s10008-011-1389-5 .

Obradović, Maja, Tripković, Amalija, Gojković, Snežana Lj., "Oxidation of carbon monoxide and formic acid on bulk and nanosized Pt-Co alloys" in Journal of Solid State Electrochemistry, 16, no. 2 (2012):587-595,
https://doi.org/10.1007/s10008-011-1389-5 . .

TY  - JOUR
AU  - Lović, Jelena
AU  - Obradović, Maja
AU  - Tripković, Dušan
AU  - Popović, Ksenija
AU  - Jovanović, Vladislava M.
AU  - Gojković, Snežana Lj.
AU  - Tripković, Amalija
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1061
AB  - Formic acid oxidation was studied on a new prepared Pt2Bi characterized by X-ray diffraction spectroscopy (phase composition), scanning tunneling microscopy (STM) (surface morphology), and COads stripping voltammetry (surface composition). Bulk composition of Pt2Bi revealed two phases-55% PtBi alloy and 45% Pt. Estimated contribution of pure Pt on the Pt2Bi surface (43.5%) determined by COads stripping voltammetry corresponds closely to bulk composition. Pt2Bi reveals high activity and stability in formic acid oxidation. High activity originates from the fact that formic acid oxidation proceeds completely through dehydrogenation path based on an ensemble effect. The high stability of Pt2Bi surface is induced by the suppression of Bi leaching as it was evidenced by insignificant changes of surface morphology and surface roughness shown by STM images before and after electrochemical treatment in formic acid containing solution. Pt2Bi is found to be powerful catalyst exhibiting up to two orders of magnitude larger current densities at 0.0 V and onset potential shifted for similar to 0.2 V to more negative value relative to Pt under steady-state condition.
PB  - Springer, New York
T2  - Electrocatalysis
T1  - High Activity and Stability of Pt2Bi Catalyst in Formic Acid Oxidation
VL  - 3
IS  - 3-4
SP  - 346
EP  - 352
DO  - 10.1007/s12678-012-0099-9
ER  - 

@article{
author = "Lović, Jelena and Obradović, Maja and Tripković, Dušan and Popović, Ksenija and Jovanović, Vladislava M. and Gojković, Snežana Lj. and Tripković, Amalija",
year = "2012",
abstract = "Formic acid oxidation was studied on a new prepared Pt2Bi characterized by X-ray diffraction spectroscopy (phase composition), scanning tunneling microscopy (STM) (surface morphology), and COads stripping voltammetry (surface composition). Bulk composition of Pt2Bi revealed two phases-55% PtBi alloy and 45% Pt. Estimated contribution of pure Pt on the Pt2Bi surface (43.5%) determined by COads stripping voltammetry corresponds closely to bulk composition. Pt2Bi reveals high activity and stability in formic acid oxidation. High activity originates from the fact that formic acid oxidation proceeds completely through dehydrogenation path based on an ensemble effect. The high stability of Pt2Bi surface is induced by the suppression of Bi leaching as it was evidenced by insignificant changes of surface morphology and surface roughness shown by STM images before and after electrochemical treatment in formic acid containing solution. Pt2Bi is found to be powerful catalyst exhibiting up to two orders of magnitude larger current densities at 0.0 V and onset potential shifted for similar to 0.2 V to more negative value relative to Pt under steady-state condition.",
publisher = "Springer, New York",
journal = "Electrocatalysis",
title = "High Activity and Stability of Pt2Bi Catalyst in Formic Acid Oxidation",
volume = "3",
number = "3-4",
pages = "346-352",
doi = "10.1007/s12678-012-0099-9"
}

Lović, J., Obradović, M., Tripković, D., Popović, K., Jovanović, V. M., Gojković, S. Lj.,& Tripković, A.. (2012). High Activity and Stability of Pt2Bi Catalyst in Formic Acid Oxidation. in Electrocatalysis
Springer, New York., 3(3-4), 346-352.
https://doi.org/10.1007/s12678-012-0099-9

Lović J, Obradović M, Tripković D, Popović K, Jovanović VM, Gojković SL, Tripković A. High Activity and Stability of Pt2Bi Catalyst in Formic Acid Oxidation. in Electrocatalysis. 2012;3(3-4):346-352.
doi:10.1007/s12678-012-0099-9 .

Lović, Jelena, Obradović, Maja, Tripković, Dušan, Popović, Ksenija, Jovanović, Vladislava M., Gojković, Snežana Lj., Tripković, Amalija, "High Activity and Stability of Pt2Bi Catalyst in Formic Acid Oxidation" in Electrocatalysis, 3, no. 3-4 (2012):346-352,
https://doi.org/10.1007/s12678-012-0099-9 . .

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 . .

TY  - JOUR
AU  - Obradović, Maja
AU  - Lessard, Jean
AU  - Jerkiewicz, Gregory
PY  - 2010
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/668
AB  - Pt(1 1 1) is modified with an overlayer of C6H6 ads by immersion in 005 or 050 M HClO4 + 1 mM C6H6 and cycling in the 0 05-0 80 V vs RHE potential range The influence of the C6H6 concentration (1-20 mM) scan rate (10-100 mV s(-1)) and temperature (278-318 K) on cyclic-voltammetry (CV) features of Pt(1 1 1) and C6H6 surface excess are examined The surface excess of C6H6 Gamma(C6H6) is evaluated through its oxidative desorption The amount of adsorbed C6H6 corresponds to a sub-monolayer with C6H6 molecules being parallel to the Pt(1 1 1) surface As the amount of dissolved C6H6 increases the surface excess of C6H6 increases to ca 2 monolayers indicating that the C6H6 ads molecules adopt a tilted orientation on Pt(1 1 1) Increase of the scan rate from 10 to 100 mV s(-1) does not result in any shift of the anodic peak but induces a shift of the cathodic peak towards lower potentials An increase of temperature from 278 to 318 K shifts both cathodic and anodic peaks towards higher potentials while at the same time reducing the peak current density However it does not modify the peaks charge density or the C6H6 surface excess The cathodic and anodic CV peaks obtained in 005 or 0 50 M HClO4 + 1 mM C6H6 are assigned to H-UPD adsorption and desorption Repetitive cycling of C6H6-modified Pt(1 1 1) in 005 or 050 M HClO4 (free of C6H6) regenerates the CV profile characteristic of a well ordered Pt(1 1 1) electrode thus indicating that C6H6 adsorption and desorption does not disorder Pt(1 1 1)
PB  - Elsevier
T2  - Journal of Electroanalytical Chemistry
T1  - Cyclic-voltammetry behavior of Pt(1 1 1) in aqueous HClO4+C6H6 Influence of C6H6 concentration, scan rate and temperature
VL  - 649
IS  - 1-2
SP  - 248
EP  - 256
DO  - 10.1016/j.jelechem.2010.04.022
ER  - 

@article{
author = "Obradović, Maja and Lessard, Jean and Jerkiewicz, Gregory",
year = "2010",
abstract = "Pt(1 1 1) is modified with an overlayer of C6H6 ads by immersion in 005 or 050 M HClO4 + 1 mM C6H6 and cycling in the 0 05-0 80 V vs RHE potential range The influence of the C6H6 concentration (1-20 mM) scan rate (10-100 mV s(-1)) and temperature (278-318 K) on cyclic-voltammetry (CV) features of Pt(1 1 1) and C6H6 surface excess are examined The surface excess of C6H6 Gamma(C6H6) is evaluated through its oxidative desorption The amount of adsorbed C6H6 corresponds to a sub-monolayer with C6H6 molecules being parallel to the Pt(1 1 1) surface As the amount of dissolved C6H6 increases the surface excess of C6H6 increases to ca 2 monolayers indicating that the C6H6 ads molecules adopt a tilted orientation on Pt(1 1 1) Increase of the scan rate from 10 to 100 mV s(-1) does not result in any shift of the anodic peak but induces a shift of the cathodic peak towards lower potentials An increase of temperature from 278 to 318 K shifts both cathodic and anodic peaks towards higher potentials while at the same time reducing the peak current density However it does not modify the peaks charge density or the C6H6 surface excess The cathodic and anodic CV peaks obtained in 005 or 0 50 M HClO4 + 1 mM C6H6 are assigned to H-UPD adsorption and desorption Repetitive cycling of C6H6-modified Pt(1 1 1) in 005 or 050 M HClO4 (free of C6H6) regenerates the CV profile characteristic of a well ordered Pt(1 1 1) electrode thus indicating that C6H6 adsorption and desorption does not disorder Pt(1 1 1)",
publisher = "Elsevier",
journal = "Journal of Electroanalytical Chemistry",
title = "Cyclic-voltammetry behavior of Pt(1 1 1) in aqueous HClO4+C6H6 Influence of C6H6 concentration, scan rate and temperature",
volume = "649",
number = "1-2",
pages = "248-256",
doi = "10.1016/j.jelechem.2010.04.022"
}

Obradović, M., Lessard, J.,& Jerkiewicz, G.. (2010). Cyclic-voltammetry behavior of Pt(1 1 1) in aqueous HClO4+C6H6 Influence of C6H6 concentration, scan rate and temperature. in Journal of Electroanalytical Chemistry
Elsevier., 649(1-2), 248-256.
https://doi.org/10.1016/j.jelechem.2010.04.022

Obradović M, Lessard J, Jerkiewicz G. Cyclic-voltammetry behavior of Pt(1 1 1) in aqueous HClO4+C6H6 Influence of C6H6 concentration, scan rate and temperature. in Journal of Electroanalytical Chemistry. 2010;649(1-2):248-256.
doi:10.1016/j.jelechem.2010.04.022 .

Obradović, Maja, Lessard, Jean, Jerkiewicz, Gregory, "Cyclic-voltammetry behavior of Pt(1 1 1) in aqueous HClO4+C6H6 Influence of C6H6 concentration, scan rate and temperature" in Journal of Electroanalytical Chemistry, 649, no. 1-2 (2010):248-256,
https://doi.org/10.1016/j.jelechem.2010.04.022 . .

TY  - JOUR
AU  - Obradović, Maja
PY  - 2010
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/677
AB  - The results of an investigation of two samples of commercial multi-walled carbon nanotubes and a sample of carbon black, in the raw and activated state, were presented in the lecture. The activation of the carbon materials led to the formation of an abundance of oxygen-containing functional groups on the surface, an increased electrochemically active surface area, an enhanced charge storage ability and a promotion of the electron-transfer kinetics. It was presented that the morphology of the carbon nanotubes is important for the electrochemical properties, because nanotubes with a higher proportion of edge and defect sites showed faster electron transfer and pseudocapacitive redox kinetics. Modification of oxidized nanotubes by ethylenediamine and wrapping by poly(diallyldimethylammonium chloride) led to a decrease in the electrochemically active surface area and to reduced electrontransfer kinetics. Pt nanoparticles prepared by the microwave-assisted polyol method were deposited at the investigated carbon materials. A much higher efficiency of Pt deposition was observed on the modified CNTs than on the activated CNTs. The activity of the synthesized catalyst toward electrochemical oxygen reduction was almost the same as the activity of the commercial Pt/XC-72 catalyst.
AB  - U okviru predavanja su prikazani rezultati ispitivanja dve vrste komercijalnih višeslojnih ugljeničnih nanocevi i uzorka ugljeničnog praha razvijene površine pre i nakon aktivacije hemijskom oksidacijom. Oksidacija uzoraka dovodi do izraženog formiranja kiseoničnih grupa na površini ugljeničnih materijala, povećanja elektrohemijski aktivne površine kao i do ubrzanja prenosa naelektrisanja. Pokazano je da morfologija ugljeničnih nanocevi ima značajan uticaj na njihove elektrohemijske karakteristike. Uzorak sa većim udelom ivica i defekata pokazao je bržu kinetiku prenosa naelektrisanja i veću pseudokapacitivnost. Modifikovanje oksidovanih nanocevi etilendiaminom i polimerom poli(dialildimetilamonijum-hloridom) dovodi do smanjenja aktivne površine i do sporijeg prenosa naelektrisanja. Nanočestice platine, sintetisane u rastvoru etilenglikola u mikrotalasnoj pećnici, nanete su na ispitivane ugljenične materijale. Količina nanete Pt je mnogo veća na modifikovanim nego na oksidovanim nanocevima. Aktivnost sintetisanih uzoraka za elektrohemijsku redukciju kiseonika je upoređena sa aktivnošću komercijalnog katalizatora Pt/XC-72 za istu reakciju i pokazalo se da su njihove specifične aktivnosti približno jednake.
PB  - Serbian Chemical Society
T2  - Journal of the Serbian Chemical Society
T1  - The electrochemical properties of carbon nanotubes and carbon XC-72R and their application as Pt supports
T1  - Elektrohemijske karakteristike ugljeničnih nanocevi i ugljenika XC-72R i njihova primena u sintezi Pt katalizatora
VL  - 75
IS  - 10
SP  - 1435
EP  - 1439
DO  - 10.2298/JSC100520081O
ER  - 

@article{
author = "Obradović, Maja",
year = "2010",
abstract = "The results of an investigation of two samples of commercial multi-walled carbon nanotubes and a sample of carbon black, in the raw and activated state, were presented in the lecture. The activation of the carbon materials led to the formation of an abundance of oxygen-containing functional groups on the surface, an increased electrochemically active surface area, an enhanced charge storage ability and a promotion of the electron-transfer kinetics. It was presented that the morphology of the carbon nanotubes is important for the electrochemical properties, because nanotubes with a higher proportion of edge and defect sites showed faster electron transfer and pseudocapacitive redox kinetics. Modification of oxidized nanotubes by ethylenediamine and wrapping by poly(diallyldimethylammonium chloride) led to a decrease in the electrochemically active surface area and to reduced electrontransfer kinetics. Pt nanoparticles prepared by the microwave-assisted polyol method were deposited at the investigated carbon materials. A much higher efficiency of Pt deposition was observed on the modified CNTs than on the activated CNTs. The activity of the synthesized catalyst toward electrochemical oxygen reduction was almost the same as the activity of the commercial Pt/XC-72 catalyst., U okviru predavanja su prikazani rezultati ispitivanja dve vrste komercijalnih višeslojnih ugljeničnih nanocevi i uzorka ugljeničnog praha razvijene površine pre i nakon aktivacije hemijskom oksidacijom. Oksidacija uzoraka dovodi do izraženog formiranja kiseoničnih grupa na površini ugljeničnih materijala, povećanja elektrohemijski aktivne površine kao i do ubrzanja prenosa naelektrisanja. Pokazano je da morfologija ugljeničnih nanocevi ima značajan uticaj na njihove elektrohemijske karakteristike. Uzorak sa većim udelom ivica i defekata pokazao je bržu kinetiku prenosa naelektrisanja i veću pseudokapacitivnost. Modifikovanje oksidovanih nanocevi etilendiaminom i polimerom poli(dialildimetilamonijum-hloridom) dovodi do smanjenja aktivne površine i do sporijeg prenosa naelektrisanja. Nanočestice platine, sintetisane u rastvoru etilenglikola u mikrotalasnoj pećnici, nanete su na ispitivane ugljenične materijale. Količina nanete Pt je mnogo veća na modifikovanim nego na oksidovanim nanocevima. Aktivnost sintetisanih uzoraka za elektrohemijsku redukciju kiseonika je upoređena sa aktivnošću komercijalnog katalizatora Pt/XC-72 za istu reakciju i pokazalo se da su njihove specifične aktivnosti približno jednake.",
publisher = "Serbian Chemical Society",
journal = "Journal of the Serbian Chemical Society",
title = "The electrochemical properties of carbon nanotubes and carbon XC-72R and their application as Pt supports, Elektrohemijske karakteristike ugljeničnih nanocevi i ugljenika XC-72R i njihova primena u sintezi Pt katalizatora",
volume = "75",
number = "10",
pages = "1435-1439",
doi = "10.2298/JSC100520081O"
}

Obradović, M.. (2010). The electrochemical properties of carbon nanotubes and carbon XC-72R and their application as Pt supports. in Journal of the Serbian Chemical Society
Serbian Chemical Society., 75(10), 1435-1439.
https://doi.org/10.2298/JSC100520081O

Obradović M. The electrochemical properties of carbon nanotubes and carbon XC-72R and their application as Pt supports. in Journal of the Serbian Chemical Society. 2010;75(10):1435-1439.
doi:10.2298/JSC100520081O .

Obradović, Maja, "The electrochemical properties of carbon nanotubes and carbon XC-72R and their application as Pt supports" in Journal of the Serbian Chemical Society, 75, no. 10 (2010):1435-1439,
https://doi.org/10.2298/JSC100520081O . .

TY  - CONF
AU  - Obradović, Maja
AU  - Tripković, Amalija
AU  - Gojković, Snežana Lj.
PY  - 2010
UR  - http://www.aseee.eu/index.php/rsesee2-home
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3536
AB  - Bulk Pt3Co and nanosized Pt3Co and PtCo alloys supported on XC-72 high area carbon were investigated as the electrocatalysts for the oxidation of formic acid. Cyclic voltammetry in 0.1 M HClO4 and stripping voltammetry of COads in the same electrolyte show a small difference in the potentials of Pt-oxide formation and reduction and COads oxidation. Based on these results, we concluded that electronic modification of Pt by Co atoms, which was theoretically predicted and experimentally proved on solid/gas interface, is exhibited in the electrochemical environment. Promotion of HCOOH oxidation rate on bimetallic Pt-Co surfaces with respect to pure Pt was found to be up to factor of eight in the case of PtCo/XC-72 catalyst. This moderate increase of the reaction rate is ascribed mostly to the ensemble effect, because partial leaching of Co increased Pt:Co ratio at the bimetallic surfaces, diminishing the efficiency of the ensemble effect.
PB  - Serbian Chemical Society, Belgrade
C3  - Second Regional Symposium on Electrochemistry South-East Europe, RSE-SEE, Program and Book of Abstracts
T1  - Oxidation of formic acid on bulk and nanosized Pt-Co alloys
SP  - 57
EP  - 57
UR  - https://hdl.handle.net/21.15107/rcub_cer_3536
ER  - 

@conference{
author = "Obradović, Maja and Tripković, Amalija and Gojković, Snežana Lj.",
year = "2010",
abstract = "Bulk Pt3Co and nanosized Pt3Co and PtCo alloys supported on XC-72 high area carbon were investigated as the electrocatalysts for the oxidation of formic acid. Cyclic voltammetry in 0.1 M HClO4 and stripping voltammetry of COads in the same electrolyte show a small difference in the potentials of Pt-oxide formation and reduction and COads oxidation. Based on these results, we concluded that electronic modification of Pt by Co atoms, which was theoretically predicted and experimentally proved on solid/gas interface, is exhibited in the electrochemical environment. Promotion of HCOOH oxidation rate on bimetallic Pt-Co surfaces with respect to pure Pt was found to be up to factor of eight in the case of PtCo/XC-72 catalyst. This moderate increase of the reaction rate is ascribed mostly to the ensemble effect, because partial leaching of Co increased Pt:Co ratio at the bimetallic surfaces, diminishing the efficiency of the ensemble effect.",
publisher = "Serbian Chemical Society, Belgrade",
journal = "Second Regional Symposium on Electrochemistry South-East Europe, RSE-SEE, Program and Book of Abstracts",
title = "Oxidation of formic acid on bulk and nanosized Pt-Co alloys",
pages = "57-57",
url = "https://hdl.handle.net/21.15107/rcub_cer_3536"
}

Obradović, M., Tripković, A.,& Gojković, S. Lj.. (2010). Oxidation of formic acid on bulk and nanosized Pt-Co alloys. in Second Regional Symposium on Electrochemistry South-East Europe, RSE-SEE, Program and Book of Abstracts
Serbian Chemical Society, Belgrade., 57-57.
https://hdl.handle.net/21.15107/rcub_cer_3536

Obradović M, Tripković A, Gojković SL. Oxidation of formic acid on bulk and nanosized Pt-Co alloys. in Second Regional Symposium on Electrochemistry South-East Europe, RSE-SEE, Program and Book of Abstracts. 2010;:57-57.
https://hdl.handle.net/21.15107/rcub_cer_3536 .

Obradović, Maja, Tripković, Amalija, Gojković, Snežana Lj., "Oxidation of formic acid on bulk and nanosized Pt-Co alloys" in Second Regional Symposium on Electrochemistry South-East Europe, RSE-SEE, Program and Book of Abstracts (2010):57-57,
https://hdl.handle.net/21.15107/rcub_cer_3536 .