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 . .