TY  - JOUR
AU  - Stevanović, Sanja
AU  - Tripković, Dušan
AU  - Tripković, Vladimir
AU  - Minić, Dragica M.
AU  - Gavrilović, Aleksandra
AU  - Tripković, Amalija
AU  - Jovanović, Vladislava M.
PY  - 2014
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1526
AB  - The role of Sn on the catalytic activity for CO and formic acid oxidation is studied by comparing the activities of differently treated PtSn/C and Pt/C catalysts. The catalysts are prepared by a microwave-assisted polyol synthesis method. As revealed by scanning tunneling and transmission electron microscopic (STM and TEM) characterization, the outcomes of the synthesis procedure for both Pt and PtSn are small particles, similar to 1.5 nm in diameter. Upon deposition on the carbon support, the particle size increases to similar to 2.5 nm due to sintering. X-ray diffraction (XRD) analysis shows that PtSn/C has a low alloying degree and is mainly composed of Pt and Pt3Sn phases. The remaining Sn is present in the form of very small tin oxide particles. Different surfaces are obtained by double-layer, oxide, and CO annealing of the Pt/C and PtSn/C catalysts and by modifying the CO-annealed surfaces with irreversibly adsorbed tin, Sn-irr. The presence of Sn in any form (oxide, alloyed, or Sn-irr) on the surface shifts the onset potential for the CO oxidation negatively by more than 0.4 V in comparison to equivalently treated Pt/C catalysts. For the CO-annealed PtSn/C catalyst, a so-called skeleton structure, Sn is present only in the subsurface layers. The subsurface Sn has a mild effect on the CO activity, and hence the onset potential is only marginally shifted to cathodic potentials by similar to 50 mV compared to that on Pt/C. The formic acid oxidation is enhanced at any of the PtSn/C surfaces with Sn in the surface layer. The activity enhancement is explained by a reduced CO poisoning of the surface Pt sites. As a consequence, the current is not entering plateau as on the Pt/C catalysts. Furthermore, the skeleton PtSn/C similar to 2 is times more active than similarly treated Pt/C. The results have been substantiated and explained by comprehensive density functional theory (DFT) simulations. The DFT results indicate that the increased oxidation rates are not only due to surface Sn but also due to a weakened CO binding in the vicinity of the surface SnOHx moieties and SnO2 particles.
PB  - American Chemical Society (ACS)
T2  - Journal of Physical Chemistry C
T1  - Insight into the Effect of Sn on CO and Formic Acid Oxidation at PtSn Catalysts
VL  - 118
IS  - 1
SP  - 278
EP  - 289
DO  - 10.1021/jp408207u
ER  - 

@article{
author = "Stevanović, Sanja and Tripković, Dušan and Tripković, Vladimir and Minić, Dragica M. and Gavrilović, Aleksandra and Tripković, Amalija and Jovanović, Vladislava M.",
year = "2014",
abstract = "The role of Sn on the catalytic activity for CO and formic acid oxidation is studied by comparing the activities of differently treated PtSn/C and Pt/C catalysts. The catalysts are prepared by a microwave-assisted polyol synthesis method. As revealed by scanning tunneling and transmission electron microscopic (STM and TEM) characterization, the outcomes of the synthesis procedure for both Pt and PtSn are small particles, similar to 1.5 nm in diameter. Upon deposition on the carbon support, the particle size increases to similar to 2.5 nm due to sintering. X-ray diffraction (XRD) analysis shows that PtSn/C has a low alloying degree and is mainly composed of Pt and Pt3Sn phases. The remaining Sn is present in the form of very small tin oxide particles. Different surfaces are obtained by double-layer, oxide, and CO annealing of the Pt/C and PtSn/C catalysts and by modifying the CO-annealed surfaces with irreversibly adsorbed tin, Sn-irr. The presence of Sn in any form (oxide, alloyed, or Sn-irr) on the surface shifts the onset potential for the CO oxidation negatively by more than 0.4 V in comparison to equivalently treated Pt/C catalysts. For the CO-annealed PtSn/C catalyst, a so-called skeleton structure, Sn is present only in the subsurface layers. The subsurface Sn has a mild effect on the CO activity, and hence the onset potential is only marginally shifted to cathodic potentials by similar to 50 mV compared to that on Pt/C. The formic acid oxidation is enhanced at any of the PtSn/C surfaces with Sn in the surface layer. The activity enhancement is explained by a reduced CO poisoning of the surface Pt sites. As a consequence, the current is not entering plateau as on the Pt/C catalysts. Furthermore, the skeleton PtSn/C similar to 2 is times more active than similarly treated Pt/C. The results have been substantiated and explained by comprehensive density functional theory (DFT) simulations. The DFT results indicate that the increased oxidation rates are not only due to surface Sn but also due to a weakened CO binding in the vicinity of the surface SnOHx moieties and SnO2 particles.",
publisher = "American Chemical Society (ACS)",
journal = "Journal of Physical Chemistry C",
title = "Insight into the Effect of Sn on CO and Formic Acid Oxidation at PtSn Catalysts",
volume = "118",
number = "1",
pages = "278-289",
doi = "10.1021/jp408207u"
}

Stevanović, S., Tripković, D., Tripković, V., Minić, D. M., Gavrilović, A., Tripković, A.,& Jovanović, V. M.. (2014). Insight into the Effect of Sn on CO and Formic Acid Oxidation at PtSn Catalysts. in Journal of Physical Chemistry C
American Chemical Society (ACS)., 118(1), 278-289.
https://doi.org/10.1021/jp408207u

Stevanović S, Tripković D, Tripković V, Minić DM, Gavrilović A, Tripković A, Jovanović VM. Insight into the Effect of Sn on CO and Formic Acid Oxidation at PtSn Catalysts. in Journal of Physical Chemistry C. 2014;118(1):278-289.
doi:10.1021/jp408207u .

Stevanović, Sanja, Tripković, Dušan, Tripković, Vladimir, Minić, Dragica M., Gavrilović, Aleksandra, Tripković, Amalija, Jovanović, Vladislava M., "Insight into the Effect of Sn on CO and Formic Acid Oxidation at PtSn Catalysts" in Journal of Physical Chemistry C, 118, no. 1 (2014):278-289,
https://doi.org/10.1021/jp408207u . .

TY  - JOUR
AU  - Lović, Jelena
AU  - Stevanović, Sanja
AU  - Tripković, Dušan
AU  - Tripković, Vladimir
AU  - Stevanović, Rade M.
AU  - Popović, Ksenija
AU  - Jovanović, Vladislava M.
PY  - 2014
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1553
AB  - Formic acid oxidation was studied on platinum-bismuth deposits on glassy carbon (GC) substrate. The catalysts of equimolar ratio were prepared by potentiostatic deposition using chronocoulometry. Bimetallic structures obtained by two-step process, comprising deposition of Bi followed by deposition of Pt, were characterized by AFM spectroscopy which indicated that Pt crystallizes preferentially onto previously formed Bi particles. The issue of Bi leaching (dissolution) from PtBi catalysts, and their catalytic effect alongside the HCOOH oxidation is rather unresolved. In order to control Bi dissolution, deposits were subjected to electrochemical oxidation, in the relevant potential range and supporting electrolyte, prior to use as catalysts for HCOOH oxidation. Anodic striping charges indicated that along oxidation procedure most of deposited Bi was oxidized. ICP mass spectroscopy analysis of the electrolyte after this electrochemical treatment revealed that Bi was only partly dissolved indicating the possibility for formation of some Bi oxide species. Moreover, EDX analysis of the as prepared (Pt"Bi/GC) catalysts and those oxidized confirmed appreciably higher content of oxygen in the latter. Catalysts prepared in this way exhibit about 10 times higher activity for formic acid oxidation in comparison to pure Pt, as revealed both by potentiodynamic and quasy-potentiostatic measurements. This high activity is the result of well-balanced ensemble effect induced by Bi-oxide species interrupting Pt domains. Prolonged cycling and chronoamperometry tests disclosed exceptional stability of the catalyst during formic acid oxidation. The activity is compatible with the activity of previously studied Pt2Bi alloy but the stability is significantly better.
PB  - Electrochemical Soc Inc, Pennington
T2  - Journal of the Electrochemical Society
T1  - Formic Acid Oxidation at Platinum-Bismuth Clusters
VL  - 161
IS  - 9
DO  - 10.1149/2.0831409jes
ER  - 

@article{
author = "Lović, Jelena and Stevanović, Sanja and Tripković, Dušan and Tripković, Vladimir and Stevanović, Rade M. and Popović, Ksenija and Jovanović, Vladislava M.",
year = "2014",
abstract = "Formic acid oxidation was studied on platinum-bismuth deposits on glassy carbon (GC) substrate. The catalysts of equimolar ratio were prepared by potentiostatic deposition using chronocoulometry. Bimetallic structures obtained by two-step process, comprising deposition of Bi followed by deposition of Pt, were characterized by AFM spectroscopy which indicated that Pt crystallizes preferentially onto previously formed Bi particles. The issue of Bi leaching (dissolution) from PtBi catalysts, and their catalytic effect alongside the HCOOH oxidation is rather unresolved. In order to control Bi dissolution, deposits were subjected to electrochemical oxidation, in the relevant potential range and supporting electrolyte, prior to use as catalysts for HCOOH oxidation. Anodic striping charges indicated that along oxidation procedure most of deposited Bi was oxidized. ICP mass spectroscopy analysis of the electrolyte after this electrochemical treatment revealed that Bi was only partly dissolved indicating the possibility for formation of some Bi oxide species. Moreover, EDX analysis of the as prepared (Pt"Bi/GC) catalysts and those oxidized confirmed appreciably higher content of oxygen in the latter. Catalysts prepared in this way exhibit about 10 times higher activity for formic acid oxidation in comparison to pure Pt, as revealed both by potentiodynamic and quasy-potentiostatic measurements. This high activity is the result of well-balanced ensemble effect induced by Bi-oxide species interrupting Pt domains. Prolonged cycling and chronoamperometry tests disclosed exceptional stability of the catalyst during formic acid oxidation. The activity is compatible with the activity of previously studied Pt2Bi alloy but the stability is significantly better.",
publisher = "Electrochemical Soc Inc, Pennington",
journal = "Journal of the Electrochemical Society",
title = "Formic Acid Oxidation at Platinum-Bismuth Clusters",
volume = "161",
number = "9",
doi = "10.1149/2.0831409jes"
}

Lović, J., Stevanović, S., Tripković, D., Tripković, V., Stevanović, R. M., Popović, K.,& Jovanović, V. M.. (2014). Formic Acid Oxidation at Platinum-Bismuth Clusters. in Journal of the Electrochemical Society
Electrochemical Soc Inc, Pennington., 161(9).
https://doi.org/10.1149/2.0831409jes

Lović J, Stevanović S, Tripković D, Tripković V, Stevanović RM, Popović K, Jovanović VM. Formic Acid Oxidation at Platinum-Bismuth Clusters. in Journal of the Electrochemical Society. 2014;161(9).
doi:10.1149/2.0831409jes .

Lović, Jelena, Stevanović, Sanja, Tripković, Dušan, Tripković, Vladimir, Stevanović, Rade M., Popović, Ksenija, Jovanović, Vladislava M., "Formic Acid Oxidation at Platinum-Bismuth Clusters" in Journal of the Electrochemical Society, 161, no. 9 (2014),
https://doi.org/10.1149/2.0831409jes . .