TY  - JOUR
AU  - Stamenković, V
AU  - Grgur, Branimir
AU  - Ross, PN
AU  - Marković, NM
PY  - 2005
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/827
AB  - The oxygen reduction reaction (ORR) has been studied on CO-covered Pt(111), Pt(110), Pt-poly, Pt-Ru, Pt3Sn(111), and Pt3Sn( 110) electrodes in 0.5 M H2SO4 solution at temperatures varying between 298 and 333 K using the rotating ring-disk electrode (RRDE) method. The RRDE measurements showed that even during O-2 reduction a substantial amount (approximate to40% of saturation) of CO still remains on all surfaces. Only a very small fraction of consumed 02 is used for CO oxidation, while the major fraction reacts via the competing ORR, producing H2O2. The H2O2 yield is strongly dependent on the fractional coverage by adsorbed CO, the surface structure, and the composition of the electrode. While at Theta(CO)  gt  0.5 monolayer (ML) the H2O2 yield is very high (depending on the structure/nature of the electrode ca. 60-100%), when Theta(CO) falls to its steady-state value of approximate to0.4 ML, the H2O2 yield is almost the same as on the respective CO-free surfaces. Although the production of peroxide on some electrodes is rather low at 333 K (e.g., 5% on PtRu and 10% on Pt-poly), the practical consequences of the H2O2 production can be significant; e.g., H2O2 may cause an enhanced long-term degradation of the membrane.
PB  - Electrochemical Soc Inc, Pennington
T2  - Journal of the Electrochemical Society
T1  - Oxygen reduction reaction on Pt and Pt-bimetallic electrodes covered by CO - Mechanism of the air bleed effect with reformate
EP  - A282
IS  - 2
SP  - A277
VL  - 152
DO  - 10.1149/1.1845321
ER  - 

@article{
author = "Stamenković, V and Grgur, Branimir and Ross, PN and Marković, NM",
year = "2005",
abstract = "The oxygen reduction reaction (ORR) has been studied on CO-covered Pt(111), Pt(110), Pt-poly, Pt-Ru, Pt3Sn(111), and Pt3Sn( 110) electrodes in 0.5 M H2SO4 solution at temperatures varying between 298 and 333 K using the rotating ring-disk electrode (RRDE) method. The RRDE measurements showed that even during O-2 reduction a substantial amount (approximate to40% of saturation) of CO still remains on all surfaces. Only a very small fraction of consumed 02 is used for CO oxidation, while the major fraction reacts via the competing ORR, producing H2O2. The H2O2 yield is strongly dependent on the fractional coverage by adsorbed CO, the surface structure, and the composition of the electrode. While at Theta(CO)  gt  0.5 monolayer (ML) the H2O2 yield is very high (depending on the structure/nature of the electrode ca. 60-100%), when Theta(CO) falls to its steady-state value of approximate to0.4 ML, the H2O2 yield is almost the same as on the respective CO-free surfaces. Although the production of peroxide on some electrodes is rather low at 333 K (e.g., 5% on PtRu and 10% on Pt-poly), the practical consequences of the H2O2 production can be significant; e.g., H2O2 may cause an enhanced long-term degradation of the membrane.",
publisher = "Electrochemical Soc Inc, Pennington",
journal = "Journal of the Electrochemical Society",
title = "Oxygen reduction reaction on Pt and Pt-bimetallic electrodes covered by CO - Mechanism of the air bleed effect with reformate",
pages = "A282-A277",
number = "2",
volume = "152",
doi = "10.1149/1.1845321"
}

Stamenković, V., Grgur, B., Ross, P.,& Marković, N.. (2005). Oxygen reduction reaction on Pt and Pt-bimetallic electrodes covered by CO - Mechanism of the air bleed effect with reformate. in Journal of the Electrochemical Society
Electrochemical Soc Inc, Pennington., 152(2), A277-A282.
https://doi.org/10.1149/1.1845321

Stamenković V, Grgur B, Ross P, Marković N. Oxygen reduction reaction on Pt and Pt-bimetallic electrodes covered by CO - Mechanism of the air bleed effect with reformate. in Journal of the Electrochemical Society. 2005;152(2):A277-A282.
doi:10.1149/1.1845321 .

Stamenković, V, Grgur, Branimir, Ross, PN, Marković, NM, "Oxygen reduction reaction on Pt and Pt-bimetallic electrodes covered by CO - Mechanism of the air bleed effect with reformate" in Journal of the Electrochemical Society, 152, no. 2 (2005):A277-A282,
https://doi.org/10.1149/1.1845321 . .

TY  - JOUR
AU  - Marković, NM
AU  - Grgur, Branimir
AU  - Lucas, CA
AU  - Ross, PN
PY  - 2000
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/280
AB  - The surface chemistry of coadsorbed CO and metal adatoms on the Pt(100) surface in acid electrolyte has been studied by means of rotating ring disk electrode (RRDE) measurements. These results showed that Cu and Pb adatoms are readily displaced from the Pt(100) surface by CO. The consequence of the observed displacement phenomenon is that the kinetics of the electrooxidation of CO on Pt(100) surfaces in Cu2+- (Pb2+-) containing solution is the same as in Cu2+- (Pb2+-) free solution.
PB  - Amer Chemical Soc, Washington
T2  - Langmuir
T1  - Surface chemistry of CO on Pt(100)-bimetallic surfaces: Displacement effects
EP  - 2005
IS  - 4
SP  - 1998
VL  - 16
DO  - 10.1021/la990255u
ER  - 

@article{
author = "Marković, NM and Grgur, Branimir and Lucas, CA and Ross, PN",
year = "2000",
abstract = "The surface chemistry of coadsorbed CO and metal adatoms on the Pt(100) surface in acid electrolyte has been studied by means of rotating ring disk electrode (RRDE) measurements. These results showed that Cu and Pb adatoms are readily displaced from the Pt(100) surface by CO. The consequence of the observed displacement phenomenon is that the kinetics of the electrooxidation of CO on Pt(100) surfaces in Cu2+- (Pb2+-) containing solution is the same as in Cu2+- (Pb2+-) free solution.",
publisher = "Amer Chemical Soc, Washington",
journal = "Langmuir",
title = "Surface chemistry of CO on Pt(100)-bimetallic surfaces: Displacement effects",
pages = "2005-1998",
number = "4",
volume = "16",
doi = "10.1021/la990255u"
}

Marković, N., Grgur, B., Lucas, C.,& Ross, P.. (2000). Surface chemistry of CO on Pt(100)-bimetallic surfaces: Displacement effects. in Langmuir
Amer Chemical Soc, Washington., 16(4), 1998-2005.
https://doi.org/10.1021/la990255u

Marković N, Grgur B, Lucas C, Ross P. Surface chemistry of CO on Pt(100)-bimetallic surfaces: Displacement effects. in Langmuir. 2000;16(4):1998-2005.
doi:10.1021/la990255u .

Marković, NM, Grgur, Branimir, Lucas, CA, Ross, PN, "Surface chemistry of CO on Pt(100)-bimetallic surfaces: Displacement effects" in Langmuir, 16, no. 4 (2000):1998-2005,
https://doi.org/10.1021/la990255u . .

TY  - JOUR
AU  - Schmidt, TJ
AU  - Behm, RJ
AU  - Grgur, Branimir
AU  - Marković, NM
AU  - Ross, PN
PY  - 2000
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/304
AB  - Temperature effects on the kinetics of formic acid electrooxidation are studied on Pt(111) and on Pt(111) modified by irreversibly adsorbed Bi under both potentiodynamic and potentiostatic conditions. We propose two modes of action of irreversibly adsorbed Pi on the kinetics of HCOOH oxidation: (i) the inhibiting effect due to a blocking of active Pt sites and (ii) the catalytic effect due to the enhanced adsorption of OHad on the Pt sites adjacent to Bi. This counteracting behavior led to the fact that under steady-state conditions no difference in the overall activity was observed between Pt(111) and Pt(111)/Bi. Therefore, Pt(111)/Bi does not represent a catalytically active system of technological relevance.
PB  - Amer Chemical Soc, Washington
T2  - Langmuir
T1  - Formic acid oxidation on pure and Bi-modified Pt(111): Temperature effects
EP  - 8166
IS  - 21
SP  - 8159
VL  - 16
DO  - 10.1021/la000339z
ER  - 

@article{
author = "Schmidt, TJ and Behm, RJ and Grgur, Branimir and Marković, NM and Ross, PN",
year = "2000",
abstract = "Temperature effects on the kinetics of formic acid electrooxidation are studied on Pt(111) and on Pt(111) modified by irreversibly adsorbed Bi under both potentiodynamic and potentiostatic conditions. We propose two modes of action of irreversibly adsorbed Pi on the kinetics of HCOOH oxidation: (i) the inhibiting effect due to a blocking of active Pt sites and (ii) the catalytic effect due to the enhanced adsorption of OHad on the Pt sites adjacent to Bi. This counteracting behavior led to the fact that under steady-state conditions no difference in the overall activity was observed between Pt(111) and Pt(111)/Bi. Therefore, Pt(111)/Bi does not represent a catalytically active system of technological relevance.",
publisher = "Amer Chemical Soc, Washington",
journal = "Langmuir",
title = "Formic acid oxidation on pure and Bi-modified Pt(111): Temperature effects",
pages = "8166-8159",
number = "21",
volume = "16",
doi = "10.1021/la000339z"
}

Schmidt, T., Behm, R., Grgur, B., Marković, N.,& Ross, P.. (2000). Formic acid oxidation on pure and Bi-modified Pt(111): Temperature effects. in Langmuir
Amer Chemical Soc, Washington., 16(21), 8159-8166.
https://doi.org/10.1021/la000339z

Schmidt T, Behm R, Grgur B, Marković N, Ross P. Formic acid oxidation on pure and Bi-modified Pt(111): Temperature effects. in Langmuir. 2000;16(21):8159-8166.
doi:10.1021/la000339z .

Schmidt, TJ, Behm, RJ, Grgur, Branimir, Marković, NM, Ross, PN, "Formic acid oxidation on pure and Bi-modified Pt(111): Temperature effects" in Langmuir, 16, no. 21 (2000):8159-8166,
https://doi.org/10.1021/la000339z . .

TY  - JOUR
AU  - Lucas, CA
AU  - Marković, NM
AU  - Grgur, Branimir
AU  - Ross, PN
PY  - 2000
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/283
AB  - Synchrotron surface X-ray scattering (SXS) and rotating ring disk electrode (RRDE) measurements have been performed during the coadsorption of metal adatoms and carbon monoxide on the Pt(100) surface in an electrochemical environment. Whereas RRDE experiments give a macroscopic view of the coadsorption process, via the adsorption isotherms of deposited metal adatoms, the SXS measurements give insight into the structural changes that occur on the atomic level. The results show that both underpotentially deposited (UPD) Cu and Pb are displaced by CO from the Pt(100) surface, the driving force being the resulting negative shift in the surface free energy. When bromide is present in a c(2 x 2) structure on top of the Cu monolayer there is an activation barrier to the displacement effect. Coadsorption of CO then enhances the c(2 x 2) structure by displacing disordered Cu or Br that is present on the surface. Cycling the electrode potential, during which the Cu monolayer is desorbed, leads to complete blocking of the UPD process by CO. In contrast to these results, the reversible formation of a Bi c(2 x 2) UPD adlayer is unaffected by the presence of solution CO.
PB  - Elsevier, Amsterdam
T2  - Surface Science
T1  - Structural effects during CO adsorption on Pt-bimetallic surfaces I. The Pt(100) electrode
EP  - 76
IS  - 2-3
SP  - 65
VL  - 448
DO  - 10.1016/S0039-6028(99)01127-9
ER  - 

@article{
author = "Lucas, CA and Marković, NM and Grgur, Branimir and Ross, PN",
year = "2000",
abstract = "Synchrotron surface X-ray scattering (SXS) and rotating ring disk electrode (RRDE) measurements have been performed during the coadsorption of metal adatoms and carbon monoxide on the Pt(100) surface in an electrochemical environment. Whereas RRDE experiments give a macroscopic view of the coadsorption process, via the adsorption isotherms of deposited metal adatoms, the SXS measurements give insight into the structural changes that occur on the atomic level. The results show that both underpotentially deposited (UPD) Cu and Pb are displaced by CO from the Pt(100) surface, the driving force being the resulting negative shift in the surface free energy. When bromide is present in a c(2 x 2) structure on top of the Cu monolayer there is an activation barrier to the displacement effect. Coadsorption of CO then enhances the c(2 x 2) structure by displacing disordered Cu or Br that is present on the surface. Cycling the electrode potential, during which the Cu monolayer is desorbed, leads to complete blocking of the UPD process by CO. In contrast to these results, the reversible formation of a Bi c(2 x 2) UPD adlayer is unaffected by the presence of solution CO.",
publisher = "Elsevier, Amsterdam",
journal = "Surface Science",
title = "Structural effects during CO adsorption on Pt-bimetallic surfaces I. The Pt(100) electrode",
pages = "76-65",
number = "2-3",
volume = "448",
doi = "10.1016/S0039-6028(99)01127-9"
}

Lucas, C., Marković, N., Grgur, B.,& Ross, P.. (2000). Structural effects during CO adsorption on Pt-bimetallic surfaces I. The Pt(100) electrode. in Surface Science
Elsevier, Amsterdam., 448(2-3), 65-76.
https://doi.org/10.1016/S0039-6028(99)01127-9

Lucas C, Marković N, Grgur B, Ross P. Structural effects during CO adsorption on Pt-bimetallic surfaces I. The Pt(100) electrode. in Surface Science. 2000;448(2-3):65-76.
doi:10.1016/S0039-6028(99)01127-9 .

Lucas, CA, Marković, NM, Grgur, Branimir, Ross, PN, "Structural effects during CO adsorption on Pt-bimetallic surfaces I. The Pt(100) electrode" in Surface Science, 448, no. 2-3 (2000):65-76,
https://doi.org/10.1016/S0039-6028(99)01127-9 . .

TY  - JOUR
AU  - Schmidt, TJ
AU  - Grgur, Branimir
AU  - Behm, RJ
AU  - Marković, NM
AU  - Ross, PN
PY  - 2000
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/303
AB  - The surface electrochemistry of reversibly and irreversibly adsorbed bismuth (Bi-ad) was studied on Pt(111) electrodes in 0.1 M HClO4. The valence state of irreversibly adsorbed Bi (Bi-ir) was determined by ex situ X-ray photoelectron spectroscopy (XPS). It was shown that Bi-ir does not change its valence state during potential cycling and is adsorbed in its metallic (i.e., zero-valent) state. Underpotential deposition (UPD) of Bi (Bi-upd) onto Pt(111) was studied using the rotating ring-disk electrode (RRDE) technique for measurements of the Bi3+ ion specific flux. The total amount of Bi deposited at underpotential (Theta(Bi,upd)) was determined by integration of the ion specific flux, and found to be approximate to 0.16 ML (1 ML=1 Bi/1 Pt). The UPD Bi is assumed to deposit at bare Pt sites not occupied by the irreversibly adsorbed Bi. The difference between Theta(Bi,upd) and the maximum coverage of a close-packed monolayer of fully discharged Bi adatoms (Theta(Biad)=0.56 ML) is taken to equal the coverage by Bi-ir, or approximate to 1/3 ML. The charge under the reversible peak in the Pt(111)/Bi-ir voltammetry (Q=160 mu C cm(-2)) for Theta(Bi,ir)similar to 1/3 ML is ascribed to enhanced adsorption of OH on Pt sites adjacent to Bi due to a change of the local potential of zero charge (p.z.c.) induced by Bi. Contrasting kinetic effects of Bi-ir were observed on the hydrogen and carbon monoxide oxidation reactions. These effects are discussed in terms of the known role of OHad in these reactions on the Pt(111) surface.
PB  - Royal Soc Chemistry, Cambridge
T2  - Physical Chemistry Chemical Physics
T1  - Bi adsorption on Pt(111) in perchloric acid solution: A rotating ring-disk electrode and XPS study
EP  - 4386
IS  - 19
SP  - 4379
VL  - 2
DO  - 10.1039/b003767m
ER  - 

@article{
author = "Schmidt, TJ and Grgur, Branimir and Behm, RJ and Marković, NM and Ross, PN",
year = "2000",
abstract = "The surface electrochemistry of reversibly and irreversibly adsorbed bismuth (Bi-ad) was studied on Pt(111) electrodes in 0.1 M HClO4. The valence state of irreversibly adsorbed Bi (Bi-ir) was determined by ex situ X-ray photoelectron spectroscopy (XPS). It was shown that Bi-ir does not change its valence state during potential cycling and is adsorbed in its metallic (i.e., zero-valent) state. Underpotential deposition (UPD) of Bi (Bi-upd) onto Pt(111) was studied using the rotating ring-disk electrode (RRDE) technique for measurements of the Bi3+ ion specific flux. The total amount of Bi deposited at underpotential (Theta(Bi,upd)) was determined by integration of the ion specific flux, and found to be approximate to 0.16 ML (1 ML=1 Bi/1 Pt). The UPD Bi is assumed to deposit at bare Pt sites not occupied by the irreversibly adsorbed Bi. The difference between Theta(Bi,upd) and the maximum coverage of a close-packed monolayer of fully discharged Bi adatoms (Theta(Biad)=0.56 ML) is taken to equal the coverage by Bi-ir, or approximate to 1/3 ML. The charge under the reversible peak in the Pt(111)/Bi-ir voltammetry (Q=160 mu C cm(-2)) for Theta(Bi,ir)similar to 1/3 ML is ascribed to enhanced adsorption of OH on Pt sites adjacent to Bi due to a change of the local potential of zero charge (p.z.c.) induced by Bi. Contrasting kinetic effects of Bi-ir were observed on the hydrogen and carbon monoxide oxidation reactions. These effects are discussed in terms of the known role of OHad in these reactions on the Pt(111) surface.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Physical Chemistry Chemical Physics",
title = "Bi adsorption on Pt(111) in perchloric acid solution: A rotating ring-disk electrode and XPS study",
pages = "4386-4379",
number = "19",
volume = "2",
doi = "10.1039/b003767m"
}

Schmidt, T., Grgur, B., Behm, R., Marković, N.,& Ross, P.. (2000). Bi adsorption on Pt(111) in perchloric acid solution: A rotating ring-disk electrode and XPS study. in Physical Chemistry Chemical Physics
Royal Soc Chemistry, Cambridge., 2(19), 4379-4386.
https://doi.org/10.1039/b003767m

Schmidt T, Grgur B, Behm R, Marković N, Ross P. Bi adsorption on Pt(111) in perchloric acid solution: A rotating ring-disk electrode and XPS study. in Physical Chemistry Chemical Physics. 2000;2(19):4379-4386.
doi:10.1039/b003767m .

Schmidt, TJ, Grgur, Branimir, Behm, RJ, Marković, NM, Ross, PN, "Bi adsorption on Pt(111) in perchloric acid solution: A rotating ring-disk electrode and XPS study" in Physical Chemistry Chemical Physics, 2, no. 19 (2000):4379-4386,
https://doi.org/10.1039/b003767m . .

TY  - JOUR
AU  - Marković, NM
AU  - Lucas, CA
AU  - Grgur, Branimir
AU  - Ross, PN
PY  - 1999
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/253
AB  - The Pt(100)-CO interaction in aqueous electrolytes was examined by using rotating disk methods in combination with in-situ surface X-ray scattering (SXS) measurements. The analysis of the SXS results indicates that the topmost platinum atoms expand away from the second layer by ca. 4% when H-upd was completely displaced from Pt(100) by CO to form a saturated layer of CO. Assuming that gas-phase heats of adsorption for CO apply as well to the liquid-solid interface, we estimate that the Gibbs energy change for the displacement of Hupd by CO On Pt(100) is close to -90 kJ/mol. A Pt(100)-CO surface normal interlayer spacing of 1.4 +/- 0.4 Angstrom was extracted from SXS measurements, suggesting that CO is adsorbed primarily at the 2-fold bridge-bonded sites, or possibly a mixture of bridge and atop sites. In contrast to the Pt(111)-CO system, no structures of COad with long-range order were formed on Pt(100). Two different forms of COad are formed at the Pt(100)-electrolyte interface: the weakly adsorbed state which is oxidized in the pre-ignition potential region, and the strongly adsorbed state which is oxidized in the ignition potential region. Although the nature of COad is different before and after the ignition potential, we proposed that the mechanism for CO oxidation on Pt(100) is the same in both the pre-ignition and ignition potential regions, e.g., adsorbed CO reacts with hydroxyl species (OHad) through a Langmuir-Hinshelwood type reaction. The kinetics of CO oxidation on Pt(hkl) surfaces is found to vary with crystal face. The difference in activity is attributed to the structure-sensitive adsorption of CO, OHad, and anions from the supporting electrolytes.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Physical Chemistry B
T1  - Surface electrochemistry of CO and H-2/CO mixtures at Pt(100) interface: Electrode kinetics and interfacial structures
EP  - 9623
IS  - 44
SP  - 9616
VL  - 103
DO  - 10.1021/jp991566g
ER  - 

@article{
author = "Marković, NM and Lucas, CA and Grgur, Branimir and Ross, PN",
year = "1999",
abstract = "The Pt(100)-CO interaction in aqueous electrolytes was examined by using rotating disk methods in combination with in-situ surface X-ray scattering (SXS) measurements. The analysis of the SXS results indicates that the topmost platinum atoms expand away from the second layer by ca. 4% when H-upd was completely displaced from Pt(100) by CO to form a saturated layer of CO. Assuming that gas-phase heats of adsorption for CO apply as well to the liquid-solid interface, we estimate that the Gibbs energy change for the displacement of Hupd by CO On Pt(100) is close to -90 kJ/mol. A Pt(100)-CO surface normal interlayer spacing of 1.4 +/- 0.4 Angstrom was extracted from SXS measurements, suggesting that CO is adsorbed primarily at the 2-fold bridge-bonded sites, or possibly a mixture of bridge and atop sites. In contrast to the Pt(111)-CO system, no structures of COad with long-range order were formed on Pt(100). Two different forms of COad are formed at the Pt(100)-electrolyte interface: the weakly adsorbed state which is oxidized in the pre-ignition potential region, and the strongly adsorbed state which is oxidized in the ignition potential region. Although the nature of COad is different before and after the ignition potential, we proposed that the mechanism for CO oxidation on Pt(100) is the same in both the pre-ignition and ignition potential regions, e.g., adsorbed CO reacts with hydroxyl species (OHad) through a Langmuir-Hinshelwood type reaction. The kinetics of CO oxidation on Pt(hkl) surfaces is found to vary with crystal face. The difference in activity is attributed to the structure-sensitive adsorption of CO, OHad, and anions from the supporting electrolytes.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Physical Chemistry B",
title = "Surface electrochemistry of CO and H-2/CO mixtures at Pt(100) interface: Electrode kinetics and interfacial structures",
pages = "9623-9616",
number = "44",
volume = "103",
doi = "10.1021/jp991566g"
}

Marković, N., Lucas, C., Grgur, B.,& Ross, P.. (1999). Surface electrochemistry of CO and H-2/CO mixtures at Pt(100) interface: Electrode kinetics and interfacial structures. in Journal of Physical Chemistry B
Amer Chemical Soc, Washington., 103(44), 9616-9623.
https://doi.org/10.1021/jp991566g

Marković N, Lucas C, Grgur B, Ross P. Surface electrochemistry of CO and H-2/CO mixtures at Pt(100) interface: Electrode kinetics and interfacial structures. in Journal of Physical Chemistry B. 1999;103(44):9616-9623.
doi:10.1021/jp991566g .

Marković, NM, Lucas, CA, Grgur, Branimir, Ross, PN, "Surface electrochemistry of CO and H-2/CO mixtures at Pt(100) interface: Electrode kinetics and interfacial structures" in Journal of Physical Chemistry B, 103, no. 44 (1999):9616-9623,
https://doi.org/10.1021/jp991566g . .

TY  - JOUR
AU  - Mukerjee, S
AU  - Lee, SJ
AU  - Ticianelli, EA
AU  - McBreen, J
AU  - Grgur, Branimir
AU  - Marković, NM
AU  - Ross, PN
AU  - Giallombardo, JR
AU  - De Castro, ES
PY  - 1999
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/250
AB  - We report a two- to threefold enhancement of CO tolerance in a proton exchange membrane (PEM) fuel cell, exhibited by carbon supported nanocrystalline PtMo/C as compared to the current state of the art PtRu/C electrocatalysts. The bulk of these nanocrystals were comprised of Pt alloyed with Mo in the ratio 8.7: 1.3 as shown by both X-ray diffraction and in situ extended X-ray absorption fine structure measurements. Rotating disk electrode measurements and cyclic voltammetry in a PEM fuel cell indicate the onset of CO oxidation at potentials as low as 0.1 V. Further, the oxidation of CO exhibits two distinct peaks, indicating redox behavior involving oxyhydroxides of Mo. This is supported by in situ X-ray absorption near edge structure measurements at the Mo K edge.
PB  - Electrochemical Soc Inc, Pennington
T2  - Electrochemical and Solid State Letters
T1  - Investigation of enhanced CO tolerance in proton exchange membrane fuel cells by carbon supported PtMo alloy catalyst
EP  - 15
IS  - 1
SP  - 12
VL  - 2
DO  - 10.1149/1.1390718
ER  - 

@article{
author = "Mukerjee, S and Lee, SJ and Ticianelli, EA and McBreen, J and Grgur, Branimir and Marković, NM and Ross, PN and Giallombardo, JR and De Castro, ES",
year = "1999",
abstract = "We report a two- to threefold enhancement of CO tolerance in a proton exchange membrane (PEM) fuel cell, exhibited by carbon supported nanocrystalline PtMo/C as compared to the current state of the art PtRu/C electrocatalysts. The bulk of these nanocrystals were comprised of Pt alloyed with Mo in the ratio 8.7: 1.3 as shown by both X-ray diffraction and in situ extended X-ray absorption fine structure measurements. Rotating disk electrode measurements and cyclic voltammetry in a PEM fuel cell indicate the onset of CO oxidation at potentials as low as 0.1 V. Further, the oxidation of CO exhibits two distinct peaks, indicating redox behavior involving oxyhydroxides of Mo. This is supported by in situ X-ray absorption near edge structure measurements at the Mo K edge.",
publisher = "Electrochemical Soc Inc, Pennington",
journal = "Electrochemical and Solid State Letters",
title = "Investigation of enhanced CO tolerance in proton exchange membrane fuel cells by carbon supported PtMo alloy catalyst",
pages = "15-12",
number = "1",
volume = "2",
doi = "10.1149/1.1390718"
}

Mukerjee, S., Lee, S., Ticianelli, E., McBreen, J., Grgur, B., Marković, N., Ross, P., Giallombardo, J.,& De Castro, E.. (1999). Investigation of enhanced CO tolerance in proton exchange membrane fuel cells by carbon supported PtMo alloy catalyst. in Electrochemical and Solid State Letters
Electrochemical Soc Inc, Pennington., 2(1), 12-15.
https://doi.org/10.1149/1.1390718

Mukerjee S, Lee S, Ticianelli E, McBreen J, Grgur B, Marković N, Ross P, Giallombardo J, De Castro E. Investigation of enhanced CO tolerance in proton exchange membrane fuel cells by carbon supported PtMo alloy catalyst. in Electrochemical and Solid State Letters. 1999;2(1):12-15.
doi:10.1149/1.1390718 .

Mukerjee, S, Lee, SJ, Ticianelli, EA, McBreen, J, Grgur, Branimir, Marković, NM, Ross, PN, Giallombardo, JR, De Castro, ES, "Investigation of enhanced CO tolerance in proton exchange membrane fuel cells by carbon supported PtMo alloy catalyst" in Electrochemical and Solid State Letters, 2, no. 1 (1999):12-15,
https://doi.org/10.1149/1.1390718 . .

TY  - JOUR
AU  - Marković, NM
AU  - Grgur, Branimir
AU  - Lucas, CA
AU  - Ross, PN
PY  - 1999
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/247
AB  - Electrocatalysis of CO oxidation and the interfacial structure of the CO adlayer (COad) on the Pt(111) surface in 0.5 M H2SO4 were examined by using the rotating disk electrode method in combination with in situ surface X-ray diffraction measurements. The results presented here elucidate the roles played by two different forms of COad: one which is oxidized at lower overpotentials, in the so-called preoxidation region, we characterize as a weakly adsorbed state (COad.w), and a strongly adsorbed state (COad,s) which is oxidized at higher overpotentials. The COad,w state forms at saturation coverage by adsorption at E  lt  0.15 V and assumes a compressed p(2 x 2) structure containing 3 CO molecules in the unit cell (0.75 CO/Pt). We propose that oxidative removal of COad,w is accompanied by simultaneous relaxation of the CO adlayer, and that the remaining COad (approximate to 0.6 CO/Pt) assumes a new bonding state which we identify as COad,s. The COad,s state is present in a structure lacking long-range order. Despite the reduced coverage by COad, H-2 electrooxidation is still completely poisoned at potentials below 0.6 V. The electrooxidation of CO in solution is proposed to occur via the COad,w state at 0.6-0.8 V, and via the COad,s at higher potentials.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Physical Chemistry B
T1  - Electrooxidation of CO and H-2/CO mixtures on Pt(111) in acid solutions
EP  - 495
IS  - 3
SP  - 487
VL  - 103
DO  - 10.1021/jp983177c
ER  - 

@article{
author = "Marković, NM and Grgur, Branimir and Lucas, CA and Ross, PN",
year = "1999",
abstract = "Electrocatalysis of CO oxidation and the interfacial structure of the CO adlayer (COad) on the Pt(111) surface in 0.5 M H2SO4 were examined by using the rotating disk electrode method in combination with in situ surface X-ray diffraction measurements. The results presented here elucidate the roles played by two different forms of COad: one which is oxidized at lower overpotentials, in the so-called preoxidation region, we characterize as a weakly adsorbed state (COad.w), and a strongly adsorbed state (COad,s) which is oxidized at higher overpotentials. The COad,w state forms at saturation coverage by adsorption at E  lt  0.15 V and assumes a compressed p(2 x 2) structure containing 3 CO molecules in the unit cell (0.75 CO/Pt). We propose that oxidative removal of COad,w is accompanied by simultaneous relaxation of the CO adlayer, and that the remaining COad (approximate to 0.6 CO/Pt) assumes a new bonding state which we identify as COad,s. The COad,s state is present in a structure lacking long-range order. Despite the reduced coverage by COad, H-2 electrooxidation is still completely poisoned at potentials below 0.6 V. The electrooxidation of CO in solution is proposed to occur via the COad,w state at 0.6-0.8 V, and via the COad,s at higher potentials.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Physical Chemistry B",
title = "Electrooxidation of CO and H-2/CO mixtures on Pt(111) in acid solutions",
pages = "495-487",
number = "3",
volume = "103",
doi = "10.1021/jp983177c"
}

Marković, N., Grgur, B., Lucas, C.,& Ross, P.. (1999). Electrooxidation of CO and H-2/CO mixtures on Pt(111) in acid solutions. in Journal of Physical Chemistry B
Amer Chemical Soc, Washington., 103(3), 487-495.
https://doi.org/10.1021/jp983177c

Marković N, Grgur B, Lucas C, Ross P. Electrooxidation of CO and H-2/CO mixtures on Pt(111) in acid solutions. in Journal of Physical Chemistry B. 1999;103(3):487-495.
doi:10.1021/jp983177c .

Marković, NM, Grgur, Branimir, Lucas, CA, Ross, PN, "Electrooxidation of CO and H-2/CO mixtures on Pt(111) in acid solutions" in Journal of Physical Chemistry B, 103, no. 3 (1999):487-495,
https://doi.org/10.1021/jp983177c . .

TY  - JOUR
AU  - Marković, NM
AU  - Gasteiger, HA
AU  - Grgur, Branimir
AU  - Ross, PN
PY  - 1999
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/251
AB  - Using the rotating ring-disk technique (RRDE) the oxygen reduction reaction (orr) was studied on the Pt(111) surface in the presence of Br- anions. We found that the orr at the Pt(111) \ Br-ad interface is always accompanied quantitatively by H2O2 oxidation currents on the ring electrode, implying that in the presence of Br- anions the orr does not proceed entirely through the 4e(-) reduction pathway, as in the Br--free solution. We propose that strongly adsorbed Br- can simultaneously suppress both the adsorption of the O-2 molecule and the formation of pairs of platinum sites needed for the breaking of the O-O bond. Besides elucidating the effects of Br-ad, these studies also shed some light on the role of OHad on the kinetics of the orr on the Pt(111) surface in solution free of Br anions. We have developed a theoretical model and from simulations of I-E curves we propose two modes of action of the OHad state on the kinetics of the orr on the Pt(111) surface: (i) OHad can block the adsorption of O-2 on active platinum sites, i.e. they compete for the same sites, and (ii) OHad can alter the adsorption energy of intermediates which are formed during the orr on the bare Pt sites adjacent to the OHad.
PB  - Elsevier Science Sa, Lausanne
T2  - Journal of Electroanalytical Chemistry
T1  - Oxygen reduction reaction on Pt(111): effects of bromide
EP  - 163
IS  - 1-2
SP  - 157
VL  - 467
DO  - 10.1016/S0022-0728(99)00020-0
ER  - 

@article{
author = "Marković, NM and Gasteiger, HA and Grgur, Branimir and Ross, PN",
year = "1999",
abstract = "Using the rotating ring-disk technique (RRDE) the oxygen reduction reaction (orr) was studied on the Pt(111) surface in the presence of Br- anions. We found that the orr at the Pt(111) \ Br-ad interface is always accompanied quantitatively by H2O2 oxidation currents on the ring electrode, implying that in the presence of Br- anions the orr does not proceed entirely through the 4e(-) reduction pathway, as in the Br--free solution. We propose that strongly adsorbed Br- can simultaneously suppress both the adsorption of the O-2 molecule and the formation of pairs of platinum sites needed for the breaking of the O-O bond. Besides elucidating the effects of Br-ad, these studies also shed some light on the role of OHad on the kinetics of the orr on the Pt(111) surface in solution free of Br anions. We have developed a theoretical model and from simulations of I-E curves we propose two modes of action of the OHad state on the kinetics of the orr on the Pt(111) surface: (i) OHad can block the adsorption of O-2 on active platinum sites, i.e. they compete for the same sites, and (ii) OHad can alter the adsorption energy of intermediates which are formed during the orr on the bare Pt sites adjacent to the OHad.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Journal of Electroanalytical Chemistry",
title = "Oxygen reduction reaction on Pt(111): effects of bromide",
pages = "163-157",
number = "1-2",
volume = "467",
doi = "10.1016/S0022-0728(99)00020-0"
}

Marković, N., Gasteiger, H., Grgur, B.,& Ross, P.. (1999). Oxygen reduction reaction on Pt(111): effects of bromide. in Journal of Electroanalytical Chemistry
Elsevier Science Sa, Lausanne., 467(1-2), 157-163.
https://doi.org/10.1016/S0022-0728(99)00020-0

Marković N, Gasteiger H, Grgur B, Ross P. Oxygen reduction reaction on Pt(111): effects of bromide. in Journal of Electroanalytical Chemistry. 1999;467(1-2):157-163.
doi:10.1016/S0022-0728(99)00020-0 .

Marković, NM, Gasteiger, HA, Grgur, Branimir, Ross, PN, "Oxygen reduction reaction on Pt(111): effects of bromide" in Journal of Electroanalytical Chemistry, 467, no. 1-2 (1999):157-163,
https://doi.org/10.1016/S0022-0728(99)00020-0 . .

TY  - JOUR
AU  - Marković, NM
AU  - Schmidt, TJ
AU  - Grgur, Branimir
AU  - Gasteiger, HA
AU  - Behm, RJ
AU  - Ross, PN
PY  - 1999
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/266
AB  - The variation of the adsorption pseudocapacitance with temperature is used to obtain the enthalpy, entropy, and free energies of adsorption of H-upd and OHad on Pt(lll) as a function of pH and nature of the anion of the supporting electrolyte. It is shown that the heat (enthalpy) of adsorption of hydrogen on Pt(lll) at the electrochemical interface is essentially independent of either the pH of the electrolyte or the nature of the supporting anion. The heat of adsorption has a linear decrease with Theta(Hupd,) from similar to 42 kJ/mol at Theta(Hupd) = 0 ML to similar to 24 kJ/mol at Theta(Hupd) = 0.66 ML. The heat of adsorption of OHad is more sensitive to the nature of the anion in the supporting electrolyte. This is presumably due to coadsorption of the anion and OHad in electrolytes other than the simple alkali bases. From the isosteric heat of adsorption of OHad in alkaline solution (ca. similar to 200 kJ/mol) and the enthalpy of formation of OH. we estimated the Pt(111)-OHad bond energy of 136 kJ/mol. This value is much. smaller than the Pt-O-ad bond energy at a gas-solid interface (similar to 350 kJ/mol). In basic solution the electrooxidation of CO proceeds at low overpotentials ( lt 0.2 V) between the adsorbed states of COad and OHad, the latter forming at low overpotentials selectively at defect sites. In acid solution, however; these sites are not active because they are blocked by specific adsorption of anions of the supporting electrolyte.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Physical Chemistry B
T1  - Effect of temperature on surface processes at the Pt(111)-liquid interface: Hydrogen adsorption, oxide formation, and CO oxidation
EP  - 8577
IS  - 40
SP  - 8568
VL  - 103
DO  - 10.1021/jp991826u
ER  - 

@article{
author = "Marković, NM and Schmidt, TJ and Grgur, Branimir and Gasteiger, HA and Behm, RJ and Ross, PN",
year = "1999",
abstract = "The variation of the adsorption pseudocapacitance with temperature is used to obtain the enthalpy, entropy, and free energies of adsorption of H-upd and OHad on Pt(lll) as a function of pH and nature of the anion of the supporting electrolyte. It is shown that the heat (enthalpy) of adsorption of hydrogen on Pt(lll) at the electrochemical interface is essentially independent of either the pH of the electrolyte or the nature of the supporting anion. The heat of adsorption has a linear decrease with Theta(Hupd,) from similar to 42 kJ/mol at Theta(Hupd) = 0 ML to similar to 24 kJ/mol at Theta(Hupd) = 0.66 ML. The heat of adsorption of OHad is more sensitive to the nature of the anion in the supporting electrolyte. This is presumably due to coadsorption of the anion and OHad in electrolytes other than the simple alkali bases. From the isosteric heat of adsorption of OHad in alkaline solution (ca. similar to 200 kJ/mol) and the enthalpy of formation of OH. we estimated the Pt(111)-OHad bond energy of 136 kJ/mol. This value is much. smaller than the Pt-O-ad bond energy at a gas-solid interface (similar to 350 kJ/mol). In basic solution the electrooxidation of CO proceeds at low overpotentials ( lt 0.2 V) between the adsorbed states of COad and OHad, the latter forming at low overpotentials selectively at defect sites. In acid solution, however; these sites are not active because they are blocked by specific adsorption of anions of the supporting electrolyte.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Physical Chemistry B",
title = "Effect of temperature on surface processes at the Pt(111)-liquid interface: Hydrogen adsorption, oxide formation, and CO oxidation",
pages = "8577-8568",
number = "40",
volume = "103",
doi = "10.1021/jp991826u"
}

Marković, N., Schmidt, T., Grgur, B., Gasteiger, H., Behm, R.,& Ross, P.. (1999). Effect of temperature on surface processes at the Pt(111)-liquid interface: Hydrogen adsorption, oxide formation, and CO oxidation. in Journal of Physical Chemistry B
Amer Chemical Soc, Washington., 103(40), 8568-8577.
https://doi.org/10.1021/jp991826u

Marković N, Schmidt T, Grgur B, Gasteiger H, Behm R, Ross P. Effect of temperature on surface processes at the Pt(111)-liquid interface: Hydrogen adsorption, oxide formation, and CO oxidation. in Journal of Physical Chemistry B. 1999;103(40):8568-8577.
doi:10.1021/jp991826u .

Marković, NM, Schmidt, TJ, Grgur, Branimir, Gasteiger, HA, Behm, RJ, Ross, PN, "Effect of temperature on surface processes at the Pt(111)-liquid interface: Hydrogen adsorption, oxide formation, and CO oxidation" in Journal of Physical Chemistry B, 103, no. 40 (1999):8568-8577,
https://doi.org/10.1021/jp991826u . .

TY  - JOUR
AU  - Grgur, Branimir
AU  - Marković, NM
AU  - Ross, PN
PY  - 1999
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/242
AB  - Electro-oxidation kinetics of H-2 and H-2/CO mixture were studied on bimetallic Pt-Mo catalysts supported on a high-surface-area carbon black. The Pt:Mo atomic ratios in the catalysts were 3:1 and 4:1. Characterization of these catalysts by X-ray diffraction indicated the existence of a face-centered cubic metallic phase with an average particle size of ca. 4 nm. Because the lattice constants for the Pt-Mo solid solutions are so close to those of pure Pt, the composition of the nanocrystalline phase, could not be determined. The kinetic results with the supported catalysts were compared quantitatively with results from bulk alloy electrodes having well-characterized surface compositions varying from 15 to 33 atom % Mo. The kinetic properties of the supported catalysts were comparable to those of bulk alloys having somewhat higher Mo concentrations than the atomic ratios in the catalysts. This suggests that either the surface segregation phenomena in the alloy nanocrystals are different from those in the bulk or that the alloying by Pt is incomplete, and the alloy nanocrystals are rich in Mo relative to the atomic ratios in the catalysts. We prefer the latter interpretation. These Pt-Mo alloy catalysts are predicted to have significantly better "CO tolerance" in polymer electrolyte membrane fuel cells than Pt-Ru alloy catalyts, consistent with previous predictions based on studies of bulk alloy electrodes.
PB  - Electrochemical Soc Inc, Pennington
T2  - Journal of the Electrochemical Society
T1  - The electro-oxidation of H-2 and H-2/CO mixtures on carbon-supported PtxMoy alloy catalysts
EP  - 1619
IS  - 5
SP  - 1613
VL  - 146
DO  - 10.1149/1.1391815
ER  - 

@article{
author = "Grgur, Branimir and Marković, NM and Ross, PN",
year = "1999",
abstract = "Electro-oxidation kinetics of H-2 and H-2/CO mixture were studied on bimetallic Pt-Mo catalysts supported on a high-surface-area carbon black. The Pt:Mo atomic ratios in the catalysts were 3:1 and 4:1. Characterization of these catalysts by X-ray diffraction indicated the existence of a face-centered cubic metallic phase with an average particle size of ca. 4 nm. Because the lattice constants for the Pt-Mo solid solutions are so close to those of pure Pt, the composition of the nanocrystalline phase, could not be determined. The kinetic results with the supported catalysts were compared quantitatively with results from bulk alloy electrodes having well-characterized surface compositions varying from 15 to 33 atom % Mo. The kinetic properties of the supported catalysts were comparable to those of bulk alloys having somewhat higher Mo concentrations than the atomic ratios in the catalysts. This suggests that either the surface segregation phenomena in the alloy nanocrystals are different from those in the bulk or that the alloying by Pt is incomplete, and the alloy nanocrystals are rich in Mo relative to the atomic ratios in the catalysts. We prefer the latter interpretation. These Pt-Mo alloy catalysts are predicted to have significantly better "CO tolerance" in polymer electrolyte membrane fuel cells than Pt-Ru alloy catalyts, consistent with previous predictions based on studies of bulk alloy electrodes.",
publisher = "Electrochemical Soc Inc, Pennington",
journal = "Journal of the Electrochemical Society",
title = "The electro-oxidation of H-2 and H-2/CO mixtures on carbon-supported PtxMoy alloy catalysts",
pages = "1619-1613",
number = "5",
volume = "146",
doi = "10.1149/1.1391815"
}

Grgur, B., Marković, N.,& Ross, P.. (1999). The electro-oxidation of H-2 and H-2/CO mixtures on carbon-supported PtxMoy alloy catalysts. in Journal of the Electrochemical Society
Electrochemical Soc Inc, Pennington., 146(5), 1613-1619.
https://doi.org/10.1149/1.1391815

Grgur B, Marković N, Ross P. The electro-oxidation of H-2 and H-2/CO mixtures on carbon-supported PtxMoy alloy catalysts. in Journal of the Electrochemical Society. 1999;146(5):1613-1619.
doi:10.1149/1.1391815 .

Grgur, Branimir, Marković, NM, Ross, PN, "The electro-oxidation of H-2 and H-2/CO mixtures on carbon-supported PtxMoy alloy catalysts" in Journal of the Electrochemical Society, 146, no. 5 (1999):1613-1619,
https://doi.org/10.1149/1.1391815 . .

TY  - JOUR
AU  - Marković, NM
AU  - Grgur, Branimir
AU  - Lucas, CA
AU  - Ross, PN
PY  - 1998
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/194
AB  - The underpotential deposition (UPD) of Pb onto Pt(100) in pure perchloric acid and in solution containing Br- was examined by classical rotating ring disk electrode (RRDPt(100)E) electrochemical methods in combination with in-situ surface X-ray scattering measurements. The total amount of Pb deposited underpotentially in 0.1 M HClO4 is approximate to 0.62 +/- 5% ML (1 ML equals 1 Pb atom per Pt surface atom), nearly equivalent to a close-packed monolayer of fully discharged Pb adatoms, e.g. 0.63 ML. In pure perchloric acid, deposition of Pb adatoms is accompanied by complete displacement of OHad from the Pt(100) surface, and in the potential range 0.15 V  lt  E  lt  0.35 V we found an ordered surface structure with a c(2 x 2) unit cell. In perchloric acid containing bromide, the maximum Pb-upd surface coverage is approximate to 0.5 ML; the deposition of 0.5 ML of Pb adatoms is accompanied by desorption of about 0.22 ML of the Br-ad adsorbed on the Pt surface at 0.6 V (ca. 0.42 ML). Thus, Pb UPD on Pt(100) from solution containing Br- is a competitive process, with the total amount of Pb deposited at underpotential being less than the amount needed to form a close-packed monolayer. As a consequence, the formation of an ordered c(2 x 2) structure is observed only at E  lt  0.15 V.
PB  - Royal Soc Chemistry, Cambridge
T2  - Journal of the Chemical Society-Faraday Transactions
T1  - Underpotential deposition of lead onto Pt(100) in acid solutions: Adsorption isotherms and interface structures
EP  - 3379
IS  - 22
SP  - 3373
VL  - 94
DO  - 10.1039/a804620d
ER  - 

@article{
author = "Marković, NM and Grgur, Branimir and Lucas, CA and Ross, PN",
year = "1998",
abstract = "The underpotential deposition (UPD) of Pb onto Pt(100) in pure perchloric acid and in solution containing Br- was examined by classical rotating ring disk electrode (RRDPt(100)E) electrochemical methods in combination with in-situ surface X-ray scattering measurements. The total amount of Pb deposited underpotentially in 0.1 M HClO4 is approximate to 0.62 +/- 5% ML (1 ML equals 1 Pb atom per Pt surface atom), nearly equivalent to a close-packed monolayer of fully discharged Pb adatoms, e.g. 0.63 ML. In pure perchloric acid, deposition of Pb adatoms is accompanied by complete displacement of OHad from the Pt(100) surface, and in the potential range 0.15 V  lt  E  lt  0.35 V we found an ordered surface structure with a c(2 x 2) unit cell. In perchloric acid containing bromide, the maximum Pb-upd surface coverage is approximate to 0.5 ML; the deposition of 0.5 ML of Pb adatoms is accompanied by desorption of about 0.22 ML of the Br-ad adsorbed on the Pt surface at 0.6 V (ca. 0.42 ML). Thus, Pb UPD on Pt(100) from solution containing Br- is a competitive process, with the total amount of Pb deposited at underpotential being less than the amount needed to form a close-packed monolayer. As a consequence, the formation of an ordered c(2 x 2) structure is observed only at E  lt  0.15 V.",
publisher = "Royal Soc Chemistry, Cambridge",
journal = "Journal of the Chemical Society-Faraday Transactions",
title = "Underpotential deposition of lead onto Pt(100) in acid solutions: Adsorption isotherms and interface structures",
pages = "3379-3373",
number = "22",
volume = "94",
doi = "10.1039/a804620d"
}

Marković, N., Grgur, B., Lucas, C.,& Ross, P.. (1998). Underpotential deposition of lead onto Pt(100) in acid solutions: Adsorption isotherms and interface structures. in Journal of the Chemical Society-Faraday Transactions
Royal Soc Chemistry, Cambridge., 94(22), 3373-3379.
https://doi.org/10.1039/a804620d

Marković N, Grgur B, Lucas C, Ross P. Underpotential deposition of lead onto Pt(100) in acid solutions: Adsorption isotherms and interface structures. in Journal of the Chemical Society-Faraday Transactions. 1998;94(22):3373-3379.
doi:10.1039/a804620d .

Marković, NM, Grgur, Branimir, Lucas, CA, Ross, PN, "Underpotential deposition of lead onto Pt(100) in acid solutions: Adsorption isotherms and interface structures" in Journal of the Chemical Society-Faraday Transactions, 94, no. 22 (1998):3373-3379,
https://doi.org/10.1039/a804620d . .

TY  - JOUR
AU  - Grgur, Branimir
AU  - Marković, NM
AU  - Ross, PN
PY  - 1998
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/218
AB  - We report new results for the electrooxidation of Hz, CO and H-2/CO mixtures on a Pt75Re25 bulk alloy using surface preparation in a UHV chamber and characterization by X-ray photoelectron spectroscopy (XPS). Sputter-cleaned but not-annealed surfaces having the bulk composition were used. This alloy surface has unique properties for CO electrooxidation: finite current densities below 0.2 V (rhe), a positive reaction order in CO partial pressure of +0.5, but an unusually high slope in the log i vs E curve, about 220;mV per decade. Anodic stripping of the irreversibly adsorbed CO on this surface also occurs at an unusually low potential, initiating at about 0.15 V, but only about 1/3 of the total amount of CO on the surface is oxidized at 0.15-0.4 V, the remainder being oxidized at 0.6-0.8 V. The polarization curves for the oxidation of H-2/CO mixtures containing 0.1-2% CO are, however, very Pt-like. It appears that the low-potential oxidation of both dissolved CO and adsorbed CO on this surface occurs exclusively at Re sites, so that with the H-2/CO mixture the Pt sites remain fully covered (and thus deactivated) by COads.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Electrochimica Acta
T1  - Electrooxidation of H-2, CO and H-2/CO mixtures on a well-characterized Pt-Re bulk alloy electrode and comparison with other Pt binary alloys
EP  - 3635
IS  - 24
SP  - 3631
VL  - 43
DO  - 10.1016/S0013-4686(98)00120-0
ER  - 

@article{
author = "Grgur, Branimir and Marković, NM and Ross, PN",
year = "1998",
abstract = "We report new results for the electrooxidation of Hz, CO and H-2/CO mixtures on a Pt75Re25 bulk alloy using surface preparation in a UHV chamber and characterization by X-ray photoelectron spectroscopy (XPS). Sputter-cleaned but not-annealed surfaces having the bulk composition were used. This alloy surface has unique properties for CO electrooxidation: finite current densities below 0.2 V (rhe), a positive reaction order in CO partial pressure of +0.5, but an unusually high slope in the log i vs E curve, about 220;mV per decade. Anodic stripping of the irreversibly adsorbed CO on this surface also occurs at an unusually low potential, initiating at about 0.15 V, but only about 1/3 of the total amount of CO on the surface is oxidized at 0.15-0.4 V, the remainder being oxidized at 0.6-0.8 V. The polarization curves for the oxidation of H-2/CO mixtures containing 0.1-2% CO are, however, very Pt-like. It appears that the low-potential oxidation of both dissolved CO and adsorbed CO on this surface occurs exclusively at Re sites, so that with the H-2/CO mixture the Pt sites remain fully covered (and thus deactivated) by COads.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Electrochimica Acta",
title = "Electrooxidation of H-2, CO and H-2/CO mixtures on a well-characterized Pt-Re bulk alloy electrode and comparison with other Pt binary alloys",
pages = "3635-3631",
number = "24",
volume = "43",
doi = "10.1016/S0013-4686(98)00120-0"
}

Grgur, B., Marković, N.,& Ross, P.. (1998). Electrooxidation of H-2, CO and H-2/CO mixtures on a well-characterized Pt-Re bulk alloy electrode and comparison with other Pt binary alloys. in Electrochimica Acta
Pergamon-Elsevier Science Ltd, Oxford., 43(24), 3631-3635.
https://doi.org/10.1016/S0013-4686(98)00120-0

Grgur B, Marković N, Ross P. Electrooxidation of H-2, CO and H-2/CO mixtures on a well-characterized Pt-Re bulk alloy electrode and comparison with other Pt binary alloys. in Electrochimica Acta. 1998;43(24):3631-3635.
doi:10.1016/S0013-4686(98)00120-0 .

Grgur, Branimir, Marković, NM, Ross, PN, "Electrooxidation of H-2, CO and H-2/CO mixtures on a well-characterized Pt-Re bulk alloy electrode and comparison with other Pt binary alloys" in Electrochimica Acta, 43, no. 24 (1998):3631-3635,
https://doi.org/10.1016/S0013-4686(98)00120-0 . .

TY  - JOUR
AU  - Marković, NM
AU  - Grgur, Branimir
AU  - Lucas, CA
AU  - Ross, PN
PY  - 1998
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/210
AB  - The underpotential deposition (upd) of Pb onto Pt(lll) in solution containing Br- was examined by classical RRDP(111)E electrochemical methods in combination with in situ surface X-ray scattering measurements. The results show that Pb upd onto Pt(lll) in the presence of bromide is a competitive process with the total amount of Pb deposited at underpotential being only ca. 0.51 +/- 5% ML, less than the amount needed to form a close-packed monolayer, 0.63 ML (1 ML equals 1 Pb atom per Pt surface atom). Deposition of Pb adatoms is accompanied by desorption of about one-half of the bromide adsorbed on the Pt surface at higher potentials, leaving co-adsorbed bromide both in and on-top-of the adlayer. In the potential region where the ratio of co-adsorbed species is close to one (E approximate to OV) there is the slow formation (over a period of ca. 2h) of an ordered surface alloy, which has a p(2 x 2) unit cell. No other ordered structures of Pb are observed in the underpotential region.
PB  - Elsevier Science Sa, Lausanne
T2  - Journal of Electroanalytical Chemistry
T1  - Underpotential deposition of lead on Pt(111) in the presence of bromide: RRDPt(111)E and X-ray scattering studies
EP  - 188
IS  - 2
SP  - 183
VL  - 448
DO  - 10.1016/S0022-0728(97)00012-0
ER  - 

@article{
author = "Marković, NM and Grgur, Branimir and Lucas, CA and Ross, PN",
year = "1998",
abstract = "The underpotential deposition (upd) of Pb onto Pt(lll) in solution containing Br- was examined by classical RRDP(111)E electrochemical methods in combination with in situ surface X-ray scattering measurements. The results show that Pb upd onto Pt(lll) in the presence of bromide is a competitive process with the total amount of Pb deposited at underpotential being only ca. 0.51 +/- 5% ML, less than the amount needed to form a close-packed monolayer, 0.63 ML (1 ML equals 1 Pb atom per Pt surface atom). Deposition of Pb adatoms is accompanied by desorption of about one-half of the bromide adsorbed on the Pt surface at higher potentials, leaving co-adsorbed bromide both in and on-top-of the adlayer. In the potential region where the ratio of co-adsorbed species is close to one (E approximate to OV) there is the slow formation (over a period of ca. 2h) of an ordered surface alloy, which has a p(2 x 2) unit cell. No other ordered structures of Pb are observed in the underpotential region.",
publisher = "Elsevier Science Sa, Lausanne",
journal = "Journal of Electroanalytical Chemistry",
title = "Underpotential deposition of lead on Pt(111) in the presence of bromide: RRDPt(111)E and X-ray scattering studies",
pages = "188-183",
number = "2",
volume = "448",
doi = "10.1016/S0022-0728(97)00012-0"
}

Marković, N., Grgur, B., Lucas, C.,& Ross, P.. (1998). Underpotential deposition of lead on Pt(111) in the presence of bromide: RRDPt(111)E and X-ray scattering studies. in Journal of Electroanalytical Chemistry
Elsevier Science Sa, Lausanne., 448(2), 183-188.
https://doi.org/10.1016/S0022-0728(97)00012-0

Marković N, Grgur B, Lucas C, Ross P. Underpotential deposition of lead on Pt(111) in the presence of bromide: RRDPt(111)E and X-ray scattering studies. in Journal of Electroanalytical Chemistry. 1998;448(2):183-188.
doi:10.1016/S0022-0728(97)00012-0 .

Marković, NM, Grgur, Branimir, Lucas, CA, Ross, PN, "Underpotential deposition of lead on Pt(111) in the presence of bromide: RRDPt(111)E and X-ray scattering studies" in Journal of Electroanalytical Chemistry, 448, no. 2 (1998):183-188,
https://doi.org/10.1016/S0022-0728(97)00012-0 . .

TY  - JOUR
AU  - Grgur, Branimir
AU  - Marković, NM
AU  - Ross, PN
PY  - 1998
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/188
AB  - The electrochemical oxidation of hydrogen (H-2), carbon monoxide (CO), and their mixtures (500 ppm-2%) on a well-characterized Pt70Mo30 bulk alloy was examined using the rotating disk electrode technique in 0.5 M H2SO4 at 333 K, The electrodes were transferred to and from a UHV chamber, where surface analyses were conducted using a combination of low-energy ion scattering (LEIS), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). The surface composition of this alloy after sputter-etching and annealing in UHV was slightly enriched in Pt to a composition of Pt77Mo23 The kinetics of H-2 oxidation are not measurably affected by the presence of the Mo in the surface. The shapes of the polarization curves for the oxidation of the H-2/CO mixtures are qualitatively similar to those for the Pt50Ru50 alloy examined previously: a high current-potential slope ica. 0.5 V/dec at low overpotential followed by a transition to a highly active state when the current approaches the diffusion-limiting current; the potential where the transition to the active state occurs decreases with decreasing CO concentration and decreases with increasing temperature; the current in the low-overpotential region is roughly inverse half-order in the CO partial pressure. The current densities in the low-overpotential region an comparable to those on Pt50Ru50 alloy and about a factor Or 50 times those on a pure rt surface, while the anodic stripping of irreversibly adsorbed CO is very different from that on the Pt50Ru50 alloy, with most of the COads being oxidized only above 0.6 V (RHE), there is direct evidence for the oxidation of small amounts of COads in the low-overpotential region of 0.05-0.5 V. The mechanism of action of Mo in the Pt surface in enhancing Hr oxidation in the presence of CO thus appears to be very similar to that of Ru: a reduction in the steady-state coverage of COads on the Pt sites by oxidative removal, freeing Pt sites for H-2 oxidation.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Physical Chemistry B
T1  - Electrooxidation of H-2, CO, and H-2/CO mixtures on a well-characterized Pt70Mo30 bulk alloy electrode
EP  - 2501
IS  - 14
SP  - 2494
VL  - 102
DO  - 10.1021/jp972692s
ER  - 

@article{
author = "Grgur, Branimir and Marković, NM and Ross, PN",
year = "1998",
abstract = "The electrochemical oxidation of hydrogen (H-2), carbon monoxide (CO), and their mixtures (500 ppm-2%) on a well-characterized Pt70Mo30 bulk alloy was examined using the rotating disk electrode technique in 0.5 M H2SO4 at 333 K, The electrodes were transferred to and from a UHV chamber, where surface analyses were conducted using a combination of low-energy ion scattering (LEIS), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). The surface composition of this alloy after sputter-etching and annealing in UHV was slightly enriched in Pt to a composition of Pt77Mo23 The kinetics of H-2 oxidation are not measurably affected by the presence of the Mo in the surface. The shapes of the polarization curves for the oxidation of the H-2/CO mixtures are qualitatively similar to those for the Pt50Ru50 alloy examined previously: a high current-potential slope ica. 0.5 V/dec at low overpotential followed by a transition to a highly active state when the current approaches the diffusion-limiting current; the potential where the transition to the active state occurs decreases with decreasing CO concentration and decreases with increasing temperature; the current in the low-overpotential region is roughly inverse half-order in the CO partial pressure. The current densities in the low-overpotential region an comparable to those on Pt50Ru50 alloy and about a factor Or 50 times those on a pure rt surface, while the anodic stripping of irreversibly adsorbed CO is very different from that on the Pt50Ru50 alloy, with most of the COads being oxidized only above 0.6 V (RHE), there is direct evidence for the oxidation of small amounts of COads in the low-overpotential region of 0.05-0.5 V. The mechanism of action of Mo in the Pt surface in enhancing Hr oxidation in the presence of CO thus appears to be very similar to that of Ru: a reduction in the steady-state coverage of COads on the Pt sites by oxidative removal, freeing Pt sites for H-2 oxidation.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Physical Chemistry B",
title = "Electrooxidation of H-2, CO, and H-2/CO mixtures on a well-characterized Pt70Mo30 bulk alloy electrode",
pages = "2501-2494",
number = "14",
volume = "102",
doi = "10.1021/jp972692s"
}

Grgur, B., Marković, N.,& Ross, P.. (1998). Electrooxidation of H-2, CO, and H-2/CO mixtures on a well-characterized Pt70Mo30 bulk alloy electrode. in Journal of Physical Chemistry B
Amer Chemical Soc, Washington., 102(14), 2494-2501.
https://doi.org/10.1021/jp972692s

Grgur B, Marković N, Ross P. Electrooxidation of H-2, CO, and H-2/CO mixtures on a well-characterized Pt70Mo30 bulk alloy electrode. in Journal of Physical Chemistry B. 1998;102(14):2494-2501.
doi:10.1021/jp972692s .

Grgur, Branimir, Marković, NM, Ross, PN, "Electrooxidation of H-2, CO, and H-2/CO mixtures on a well-characterized Pt70Mo30 bulk alloy electrode" in Journal of Physical Chemistry B, 102, no. 14 (1998):2494-2501,
https://doi.org/10.1021/jp972692s . .

TY  - JOUR
AU  - Grgur, Branimir
AU  - Marković, NM
AU  - Ross, PN
PY  - 1997
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/112
AB  - Underpotential deposition (UPD) of lead (Pb-upd) on Pt(111) in perchloric acid solution was studied using the rotation ring disk, electrode (RRDPt(111)E) method for measurements of the Pb2+ ion-specific flux. The total amount of Pb deposited underpotentially is 0.62 +/- 5% monolayer (1 monolayer = 1 Pb per Pt) equivalent to a close-packed monolayer of fully discharged Pb adatoms. The electrosorption valence, gamma(Pb), of Pb-upd is approximate to gamma(Pb) = 2, implying that two electrons per Pb-upd adatom are exchanged through the interface. In this work we showed that the formation of this close-packed monolayer of Pb-upd occurs through four distinctive voltammetric features: two major sharp peaks at approximate to 0.5 V (vs saturated calomel electrode) and 0.3 V and smaller reversible peaks at 0 V and -0.15 V. We concluded that the adsorption of OHad is shifted negatively by Pb-upd adatoms, with the shift attributed to induced adsorption of OHad onto Pt atoms neighboring the Pb-upd adatoms due to lowering of the local point of zero charge (pcz) by the Pb-upd. Consequently, the pH dependence of the Pb UPD peak at 0.3 V appears entirely through a pH-dependent adsorption of OHad onto the Pt(111) surface modified by Pb-upd adatoms. The pH independence of the peak at 0.5 V is consistent with the Pb2+ ion-flux measurements that the main process associated with this pseudocapacitance is Pb UPD. The smaller peaks observed at lower potentials are probably associated with a final deposition of Pb-upd adatoms along step edges and compacting of adatoms on the (111)-terraces to form an ordered (3 x root 3) close-packed structure.
PB  - Amer Chemical Soc, Washington
T2  - Langmuir
T1  - Underpotential deposition of lead on Pt(111) in perchloric acid solution: RRDPt(111)E measurements
EP  - 6374
IS  - 24
SP  - 6370
VL  - 13
DO  - 10.1021/la970699v
ER  - 

@article{
author = "Grgur, Branimir and Marković, NM and Ross, PN",
year = "1997",
abstract = "Underpotential deposition (UPD) of lead (Pb-upd) on Pt(111) in perchloric acid solution was studied using the rotation ring disk, electrode (RRDPt(111)E) method for measurements of the Pb2+ ion-specific flux. The total amount of Pb deposited underpotentially is 0.62 +/- 5% monolayer (1 monolayer = 1 Pb per Pt) equivalent to a close-packed monolayer of fully discharged Pb adatoms. The electrosorption valence, gamma(Pb), of Pb-upd is approximate to gamma(Pb) = 2, implying that two electrons per Pb-upd adatom are exchanged through the interface. In this work we showed that the formation of this close-packed monolayer of Pb-upd occurs through four distinctive voltammetric features: two major sharp peaks at approximate to 0.5 V (vs saturated calomel electrode) and 0.3 V and smaller reversible peaks at 0 V and -0.15 V. We concluded that the adsorption of OHad is shifted negatively by Pb-upd adatoms, with the shift attributed to induced adsorption of OHad onto Pt atoms neighboring the Pb-upd adatoms due to lowering of the local point of zero charge (pcz) by the Pb-upd. Consequently, the pH dependence of the Pb UPD peak at 0.3 V appears entirely through a pH-dependent adsorption of OHad onto the Pt(111) surface modified by Pb-upd adatoms. The pH independence of the peak at 0.5 V is consistent with the Pb2+ ion-flux measurements that the main process associated with this pseudocapacitance is Pb UPD. The smaller peaks observed at lower potentials are probably associated with a final deposition of Pb-upd adatoms along step edges and compacting of adatoms on the (111)-terraces to form an ordered (3 x root 3) close-packed structure.",
publisher = "Amer Chemical Soc, Washington",
journal = "Langmuir",
title = "Underpotential deposition of lead on Pt(111) in perchloric acid solution: RRDPt(111)E measurements",
pages = "6374-6370",
number = "24",
volume = "13",
doi = "10.1021/la970699v"
}

Grgur, B., Marković, N.,& Ross, P.. (1997). Underpotential deposition of lead on Pt(111) in perchloric acid solution: RRDPt(111)E measurements. in Langmuir
Amer Chemical Soc, Washington., 13(24), 6370-6374.
https://doi.org/10.1021/la970699v

Grgur B, Marković N, Ross P. Underpotential deposition of lead on Pt(111) in perchloric acid solution: RRDPt(111)E measurements. in Langmuir. 1997;13(24):6370-6374.
doi:10.1021/la970699v .

Grgur, Branimir, Marković, NM, Ross, PN, "Underpotential deposition of lead on Pt(111) in perchloric acid solution: RRDPt(111)E measurements" in Langmuir, 13, no. 24 (1997):6370-6374,
https://doi.org/10.1021/la970699v . .

TY  - JOUR
AU  - Grgur, Branimir
AU  - Zhuang, G
AU  - Marković, NM
AU  - Ross, PN
PY  - 1997
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/137
AB  - The electrochemical oxidation of hydrogen in the presence of carbon monoxide (0.05-2%) on a well-characterized Pt75Mo25 alloy surface was examined using the rotating disk electrode technique in 0.5 M H2SO4 at 333 K. The surface composition of this alloy determined by low-energy ion scattering after sputter cleaning and annealing in UHV was essentially the same as the bulk. The shapes of the polarization curves are qualitatively similar to those for the Pt50Ru50 alloy examined previously: a high Tafel-slope (ca. 0.5 V/dec) region at low overpotential followed by a transition to a highly actively state where the current approaches the diffusion-limiting current; the potential where the transition to the active state occurs decreases with decreasing CO concentration, and the current in the low-overpotential region is roughly inverse half-order in the CO partial pressure. The magnitude of the current in the low-overpotential region on the Pt75Mo25 alloy is nearly the same as on the Pt50Ru50 alloy, but the potential for the transition to the active state is about 0.15 V higher. The magnitude of the current at 0.05-0.1 V with H-2 containing 100 ppm CO is sufficiently high that Pt-Mo alloy is of technical interest as an anode catalyst for low-temperature fuel cells fed with a reformed hydrocarbon fuel.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Physical Chemistry B
T1  - Electrooxidation of H-2/CO mixtures on a well-characterized Pt75Mo25 alloy surface
EP  - 3913
IS  - 20
SP  - 3910
VL  - 101
DO  - 10.1021/jp9704168
ER  - 

@article{
author = "Grgur, Branimir and Zhuang, G and Marković, NM and Ross, PN",
year = "1997",
abstract = "The electrochemical oxidation of hydrogen in the presence of carbon monoxide (0.05-2%) on a well-characterized Pt75Mo25 alloy surface was examined using the rotating disk electrode technique in 0.5 M H2SO4 at 333 K. The surface composition of this alloy determined by low-energy ion scattering after sputter cleaning and annealing in UHV was essentially the same as the bulk. The shapes of the polarization curves are qualitatively similar to those for the Pt50Ru50 alloy examined previously: a high Tafel-slope (ca. 0.5 V/dec) region at low overpotential followed by a transition to a highly actively state where the current approaches the diffusion-limiting current; the potential where the transition to the active state occurs decreases with decreasing CO concentration, and the current in the low-overpotential region is roughly inverse half-order in the CO partial pressure. The magnitude of the current in the low-overpotential region on the Pt75Mo25 alloy is nearly the same as on the Pt50Ru50 alloy, but the potential for the transition to the active state is about 0.15 V higher. The magnitude of the current at 0.05-0.1 V with H-2 containing 100 ppm CO is sufficiently high that Pt-Mo alloy is of technical interest as an anode catalyst for low-temperature fuel cells fed with a reformed hydrocarbon fuel.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Physical Chemistry B",
title = "Electrooxidation of H-2/CO mixtures on a well-characterized Pt75Mo25 alloy surface",
pages = "3913-3910",
number = "20",
volume = "101",
doi = "10.1021/jp9704168"
}

Grgur, B., Zhuang, G., Marković, N.,& Ross, P.. (1997). Electrooxidation of H-2/CO mixtures on a well-characterized Pt75Mo25 alloy surface. in Journal of Physical Chemistry B
Amer Chemical Soc, Washington., 101(20), 3910-3913.
https://doi.org/10.1021/jp9704168

Grgur B, Zhuang G, Marković N, Ross P. Electrooxidation of H-2/CO mixtures on a well-characterized Pt75Mo25 alloy surface. in Journal of Physical Chemistry B. 1997;101(20):3910-3913.
doi:10.1021/jp9704168 .

Grgur, Branimir, Zhuang, G, Marković, NM, Ross, PN, "Electrooxidation of H-2/CO mixtures on a well-characterized Pt75Mo25 alloy surface" in Journal of Physical Chemistry B, 101, no. 20 (1997):3910-3913,
https://doi.org/10.1021/jp9704168 . .

TY  - JOUR
AU  - Grgur, Branimir
AU  - Marković, NM
AU  - Ross, PN
PY  - 1997
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/148
AB  - Using the rotating ring-disk technique (RRDPt(hkl)E), the oxygen-reduction reaction (ORR) was studied in sulfuric acid solution over the temperature range 298-333 K. At the same temperature, the exchange current density increased in the order, i(111)(0) lt i(100)(0) lt i(110)(0) which gives the order of absolute kinetic activities of Pt(hkl) in 0.05 mol/L H2SO4:Pt(111) lt Pt(100) lt Pt(110). We found that at high current densities every crystal face has an ideally temperature-dependent Tafel slope, i.e., -2 x 2.3(RT/F). The activation energy for the ORR is independent of the surface geometry, Delta H-hkl(#) = 42 kJ/mol. The insensitivity of the activation energy to surface structure implies that the reaction pathway for the ORR is the same on all three single-crystal faces. A "series" pathway for the ORR was proposed, with the first electron transfer being the rate-determining step. The structure sensitivity in the kinetics of the ORR on Pt(hkl) is attributed to the structure-sensitive adsorption of bisulfate and hydroxyl anions and a simple site-blocking effect of these adsorbed anions on the rate of the ORR.
PB  - Natl Research Council Canada, Ottawa
T2  - Canadian Journal of Chemistry-Revue Canadienne De Chimie
T1  - Temperature dependent oxygen electrochemistry on platinum low index single crystal surfaces in acid solutions
EP  - 1471
IS  - 11
SP  - 1465
VL  - 75
DO  - 10.1139/v97-176
ER  - 

@article{
author = "Grgur, Branimir and Marković, NM and Ross, PN",
year = "1997",
abstract = "Using the rotating ring-disk technique (RRDPt(hkl)E), the oxygen-reduction reaction (ORR) was studied in sulfuric acid solution over the temperature range 298-333 K. At the same temperature, the exchange current density increased in the order, i(111)(0) lt i(100)(0) lt i(110)(0) which gives the order of absolute kinetic activities of Pt(hkl) in 0.05 mol/L H2SO4:Pt(111) lt Pt(100) lt Pt(110). We found that at high current densities every crystal face has an ideally temperature-dependent Tafel slope, i.e., -2 x 2.3(RT/F). The activation energy for the ORR is independent of the surface geometry, Delta H-hkl(#) = 42 kJ/mol. The insensitivity of the activation energy to surface structure implies that the reaction pathway for the ORR is the same on all three single-crystal faces. A "series" pathway for the ORR was proposed, with the first electron transfer being the rate-determining step. The structure sensitivity in the kinetics of the ORR on Pt(hkl) is attributed to the structure-sensitive adsorption of bisulfate and hydroxyl anions and a simple site-blocking effect of these adsorbed anions on the rate of the ORR.",
publisher = "Natl Research Council Canada, Ottawa",
journal = "Canadian Journal of Chemistry-Revue Canadienne De Chimie",
title = "Temperature dependent oxygen electrochemistry on platinum low index single crystal surfaces in acid solutions",
pages = "1471-1465",
number = "11",
volume = "75",
doi = "10.1139/v97-176"
}

Grgur, B., Marković, N.,& Ross, P.. (1997). Temperature dependent oxygen electrochemistry on platinum low index single crystal surfaces in acid solutions. in Canadian Journal of Chemistry-Revue Canadienne De Chimie
Natl Research Council Canada, Ottawa., 75(11), 1465-1471.
https://doi.org/10.1139/v97-176

Grgur B, Marković N, Ross P. Temperature dependent oxygen electrochemistry on platinum low index single crystal surfaces in acid solutions. in Canadian Journal of Chemistry-Revue Canadienne De Chimie. 1997;75(11):1465-1471.
doi:10.1139/v97-176 .

Grgur, Branimir, Marković, NM, Ross, PN, "Temperature dependent oxygen electrochemistry on platinum low index single crystal surfaces in acid solutions" in Canadian Journal of Chemistry-Revue Canadienne De Chimie, 75, no. 11 (1997):1465-1471,
https://doi.org/10.1139/v97-176 . .

TY  - JOUR
AU  - Marković, NM
AU  - Grgur, Branimir
AU  - Ross, PN
PY  - 1997
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/145
AB  - The hydrogen evolution (HER) and the hydrogen oxidation reaction (HOR) were studied on platinum single crystals in a sulfuric acid solution over the temperature range 274-333 K. We found, for the first rime, that at a fixed temperature (274 K) the exchange current densities (i(o)) increase in the order (111) much less than (100)  lt  (110), with the i(o) on the (110) surface being 3 times that on the (111) surface. We also found that each crystal face has an unique, temperature-dependent Tafel slope for the HOR, and that the activation energies for the HER and the HOR decrease in the sequence Delta H-111(#)  gt  Delta H-100(#)  gt  Delta H-110(#), the same sequence as the order these differences in activation energy with crystal face are attributed to structure-sensitive heats of adsorption of the active intermediate, H-ad, whose physical state is unclear. We analyzed the kinetic data with a model for the coupling of this unknown state, Had, with the well-known adsorbed state of hydrogen, H-upd, whose adsorption energy is strongly structure-sensitive. We concluded that on Pt(110), the reaction follows the Tafel-Volmer mechanism with the Tafel (recombination) step rate determining. On Pt(100), the reaction follows the Heyrovsky-Volmer sequence, with the Heyrovsky (ion-atom) reaction step being the rate-determining step. The reaction mechanism on Pt(111) could not, however, be resolved by analyzing the kinetic parameters. The relatively low activity and high activation energy for the (111) surface is attributed to strong repulsive interaction between H-ad adatoms on this surface.
PB  - Amer Chemical Soc, Washington
T2  - Journal of Physical Chemistry B
T1  - Temperature-dependent hydrogen electrochemistry on platinum low-index single-crystal surfaces in acid solutions
EP  - 5413
IS  - 27
SP  - 5405
VL  - 101
DO  - 10.1021/jp970930d
ER  - 

@article{
author = "Marković, NM and Grgur, Branimir and Ross, PN",
year = "1997",
abstract = "The hydrogen evolution (HER) and the hydrogen oxidation reaction (HOR) were studied on platinum single crystals in a sulfuric acid solution over the temperature range 274-333 K. We found, for the first rime, that at a fixed temperature (274 K) the exchange current densities (i(o)) increase in the order (111) much less than (100)  lt  (110), with the i(o) on the (110) surface being 3 times that on the (111) surface. We also found that each crystal face has an unique, temperature-dependent Tafel slope for the HOR, and that the activation energies for the HER and the HOR decrease in the sequence Delta H-111(#)  gt  Delta H-100(#)  gt  Delta H-110(#), the same sequence as the order these differences in activation energy with crystal face are attributed to structure-sensitive heats of adsorption of the active intermediate, H-ad, whose physical state is unclear. We analyzed the kinetic data with a model for the coupling of this unknown state, Had, with the well-known adsorbed state of hydrogen, H-upd, whose adsorption energy is strongly structure-sensitive. We concluded that on Pt(110), the reaction follows the Tafel-Volmer mechanism with the Tafel (recombination) step rate determining. On Pt(100), the reaction follows the Heyrovsky-Volmer sequence, with the Heyrovsky (ion-atom) reaction step being the rate-determining step. The reaction mechanism on Pt(111) could not, however, be resolved by analyzing the kinetic parameters. The relatively low activity and high activation energy for the (111) surface is attributed to strong repulsive interaction between H-ad adatoms on this surface.",
publisher = "Amer Chemical Soc, Washington",
journal = "Journal of Physical Chemistry B",
title = "Temperature-dependent hydrogen electrochemistry on platinum low-index single-crystal surfaces in acid solutions",
pages = "5413-5405",
number = "27",
volume = "101",
doi = "10.1021/jp970930d"
}

Marković, N., Grgur, B.,& Ross, P.. (1997). Temperature-dependent hydrogen electrochemistry on platinum low-index single-crystal surfaces in acid solutions. in Journal of Physical Chemistry B
Amer Chemical Soc, Washington., 101(27), 5405-5413.
https://doi.org/10.1021/jp970930d

Marković N, Grgur B, Ross P. Temperature-dependent hydrogen electrochemistry on platinum low-index single-crystal surfaces in acid solutions. in Journal of Physical Chemistry B. 1997;101(27):5405-5413.
doi:10.1021/jp970930d .

Marković, NM, Grgur, Branimir, Ross, PN, "Temperature-dependent hydrogen electrochemistry on platinum low-index single-crystal surfaces in acid solutions" in Journal of Physical Chemistry B, 101, no. 27 (1997):5405-5413,
https://doi.org/10.1021/jp970930d . .

TY  - JOUR
AU  - Marković, NM
AU  - Grgur, Branimir
AU  - Lucas, CA
AU  - Ross, PN
PY  - 1997
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/130
AB  - A new type of flame-annealing method has been developed for the preparation of surfaces having either fcc(110)-(1x1) or fcc(110)-(1 x 2) symmetry. In situ X-ray scattering studies show that both the Pt(110)-(1 x 2) and Pt(110)-(1 x 1) surfaces are stable in the potential region between 0 and 1.0 V. Adsorption of CO on the (1 x 2) surface in solution does not induce the (1 x 2)-- gt (1 x 1) transition that is observed in UHV upon adsorption of CO. Nominally identical saturation coverages of hydrogen (H-upd) and COad are observed on the two surfaces, implying that two H-upd atoms or two COad molecules are adsorbed per unit cell of the reconstructed (1 x 2) surface. A significant increase in the interatomic spacing between the first and second layer of the reconstructed (1 x 2) surface occurs upon hydrogen adsorption to full coverage. Occupation of subsurface sites for H-upd are inferred from this result. The (1 x 2) surface is found to have a much higher catalytic activity for the electro-oxidation of CO; the anodic oxidation of either COad or dissolved COgas occurs at approximate to 0.3 V lower potential on the (1 x 2) than the (1 x 1) surface.
PB  - Elsevier Science Bv, Amsterdam
T2  - Surface Science
T1  - Surface electrochemistry of CO on Pt(110)-(1x2) and Pt(110)-(1x1) surfaces
EP  - L814
IS  - 1-3
SP  - L805
VL  - 384
DO  - 10.1016/S0039-6028(97)00252-5
ER  - 

@article{
author = "Marković, NM and Grgur, Branimir and Lucas, CA and Ross, PN",
year = "1997",
abstract = "A new type of flame-annealing method has been developed for the preparation of surfaces having either fcc(110)-(1x1) or fcc(110)-(1 x 2) symmetry. In situ X-ray scattering studies show that both the Pt(110)-(1 x 2) and Pt(110)-(1 x 1) surfaces are stable in the potential region between 0 and 1.0 V. Adsorption of CO on the (1 x 2) surface in solution does not induce the (1 x 2)-- gt (1 x 1) transition that is observed in UHV upon adsorption of CO. Nominally identical saturation coverages of hydrogen (H-upd) and COad are observed on the two surfaces, implying that two H-upd atoms or two COad molecules are adsorbed per unit cell of the reconstructed (1 x 2) surface. A significant increase in the interatomic spacing between the first and second layer of the reconstructed (1 x 2) surface occurs upon hydrogen adsorption to full coverage. Occupation of subsurface sites for H-upd are inferred from this result. The (1 x 2) surface is found to have a much higher catalytic activity for the electro-oxidation of CO; the anodic oxidation of either COad or dissolved COgas occurs at approximate to 0.3 V lower potential on the (1 x 2) than the (1 x 1) surface.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Surface Science",
title = "Surface electrochemistry of CO on Pt(110)-(1x2) and Pt(110)-(1x1) surfaces",
pages = "L814-L805",
number = "1-3",
volume = "384",
doi = "10.1016/S0039-6028(97)00252-5"
}

Marković, N., Grgur, B., Lucas, C.,& Ross, P.. (1997). Surface electrochemistry of CO on Pt(110)-(1x2) and Pt(110)-(1x1) surfaces. in Surface Science
Elsevier Science Bv, Amsterdam., 384(1-3), L805-L814.
https://doi.org/10.1016/S0039-6028(97)00252-5

Marković N, Grgur B, Lucas C, Ross P. Surface electrochemistry of CO on Pt(110)-(1x2) and Pt(110)-(1x1) surfaces. in Surface Science. 1997;384(1-3):L805-L814.
doi:10.1016/S0039-6028(97)00252-5 .

Marković, NM, Grgur, Branimir, Lucas, CA, Ross, PN, "Surface electrochemistry of CO on Pt(110)-(1x2) and Pt(110)-(1x1) surfaces" in Surface Science, 384, no. 1-3 (1997):L805-L814,
https://doi.org/10.1016/S0039-6028(97)00252-5 . .