Effect of temperature on surface processes at the Pt(111)-liquid interface: Hydrogen adsorption, oxide formation, and CO oxidation
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.
Source:
Journal of Physical Chemistry B, 1999, 103, 40, 8568-8577Publisher:
- Amer Chemical Soc, Washington
DOI: 10.1021/jp991826u
ISSN: 1089-5647
WoS: 000083151400022
Scopus: 2-s2.0-0000897494
Institution/Community
Tehnološko-metalurški fakultetTY - 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 . .