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
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  - Stevanović, Jasmina
AU  - Gojković, Snežana
AU  - Despić, A.R.
AU  - Obradović, Maja D.
AU  - Nakić, Vjekoslav M.
PY  - 1998
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6344
AB  - Zn-Ni alloys were electrodeposited from a berate-citrate and TEPA bath in potentiostatic and galvanostatic regimes. Potential of electrodeposition or current density were varied and chemical composition and phase structure were determined. It was found that both chemical composition and phase structure of alloys electrodeposited at the same potential or current density but in the two electrolytes were different. Differences were found even when one and the same chemical composition was achieved. Hydrogen evolution kinetics at the Zn-Ni alloys deposited from the two baths was investigated in alkaline solution (1 M NaOH). Substantial differences in the reaction rates at the alloys with the same chemical but different phase composition were found.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Electrochimica Acta
T1  - Hydrogen evolution at Zn-Ni alloys
VL  - 43
IS  - 7
SP  - 705
EP  - 711
DO  - 10.1016/S0013-4686(97)00142-4
ER  - 

@article{
author = "Stevanović, Jasmina and Gojković, Snežana and Despić, A.R. and Obradović, Maja D. and Nakić, Vjekoslav M.",
year = "1998",
abstract = "Zn-Ni alloys were electrodeposited from a berate-citrate and TEPA bath in potentiostatic and galvanostatic regimes. Potential of electrodeposition or current density were varied and chemical composition and phase structure were determined. It was found that both chemical composition and phase structure of alloys electrodeposited at the same potential or current density but in the two electrolytes were different. Differences were found even when one and the same chemical composition was achieved. Hydrogen evolution kinetics at the Zn-Ni alloys deposited from the two baths was investigated in alkaline solution (1 M NaOH). Substantial differences in the reaction rates at the alloys with the same chemical but different phase composition were found.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Electrochimica Acta",
title = "Hydrogen evolution at Zn-Ni alloys",
volume = "43",
number = "7",
pages = "705-711",
doi = "10.1016/S0013-4686(97)00142-4"
}

Stevanović, J., Gojković, S., Despić, A.R., Obradović, M. D.,& Nakić, V. M.. (1998). Hydrogen evolution at Zn-Ni alloys. in Electrochimica Acta
Pergamon-Elsevier Science Ltd, Oxford., 43(7), 705-711.
https://doi.org/10.1016/S0013-4686(97)00142-4

Stevanović J, Gojković S, Despić A, Obradović MD, Nakić VM. Hydrogen evolution at Zn-Ni alloys. in Electrochimica Acta. 1998;43(7):705-711.
doi:10.1016/S0013-4686(97)00142-4 .

Stevanović, Jasmina, Gojković, Snežana, Despić, A.R., Obradović, Maja D., Nakić, Vjekoslav M., "Hydrogen evolution at Zn-Ni alloys" in Electrochimica Acta, 43, no. 7 (1998):705-711,
https://doi.org/10.1016/S0013-4686(97)00142-4 . .