Partial charge transfer reactions in electrochemical kinetics

Lorenz, W.J.; Salié, G.

doi:10.1016/s0022-0728(77)80102-2

Cited by 85 publications

(18 citation statements)

References 208 publications

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“…This different spectral response between species in solution versus in the metal-adsorbed state may reflect diminished distinction between P−O−H···O and P−O···H−O bonding at the interface. Previous studies on the vibrational spectra of phosphates in solution and crystals have shown similar proton-transfer equilibria. , Also, partial charge transfer upon adsorption leading to decreased electrostatic repulsion , could be an additional reason that hydrogen bonding increases for adsorbed anions.…”

Section: Discussionmentioning

confidence: 79%

Surface-Enhanced Raman Spectroscopy of Phosphate Anions: Adsorption on Silver, Gold, and Copper Electrodes

1997

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The adsorption of phosphate anions on Ag, Au, and Cu electrodes from H2O and D2O solutions has been studied by means of surface-enhanced Raman spectroscopy (SERS). The interpretation of the spectra based on the solution Raman data and frequency shifts upon solution H2O/D2O exchange are presented. The prominent band at 1070−1100 cm-1, observed from adsorbed PO4 3- and HPO4 2- ions, exhibits downshifts of about 10 cm-1 in D2O solutions and has been assigned to the asymmetric P−O stretching mode. The corresponding asymmetric deformation mode has been assigned to the band located at ∼570 cm-1 which shows an upshift of 9−15 cm-1 in D2O solutions. Monodentate surface coordination of the PO4 3- and HPO4 2- ions is proposed. The dependence of the relative intensity of the internal modes on electrode potential was interpreted in terms of the migration of P−O groups from the surface as potential became more negative. Spectroscopic evidence was found for chemisorption of H2PO4 - ion on the Cu electrodes, but no such evidence was found in the cases of the Au and Ag electrodes. The adsorbed H2PO4 - ion on Cu showed an intense band at ∼907 cm-1 which was assigned to the symmetric stretching mode of the P−OH groups, based primarily on the considerable frequency downshift (∼11 cm-1) and peak broadening (∼15 cm-1) in D2O solutions. The formation of a P−O−P bond in the adsorbed state on Cu electrodes in acidic solutions is suggested. The force constants derived from experimental metal−oxygen frequencies are compared for the three electrodes, and the following strength order has been estimated: k(Cu−O‘) > k(Au−O‘) > k(Ag−O‘).

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Section: Discussionmentioning

confidence: 79%

Surface-Enhanced Raman Spectroscopy of Phosphate Anions: Adsorption on Silver, Gold, and Copper Electrodes

1997

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“…The experimental quantity is the thermodynamic coefficient l = -F-'ido/dYh = (dn/dE)r (10) which represents the average number of unit charges supplied to the electrode from the external circuit when one molecule of a species is adsorbed at constant potential.275,276 A comprehensive review of experimental methods discusses the determination of l as well as its interpretation, leading to a partial charge-transfer coefficient. 277 An alternative approach278 sets out clearly the components of the apparent charge-transfer coefficient l: l = gz -A(1 -g) + /cad -j>kw (11) Here A is the fraction of the charge lost by the ion of charge originally ze, g is a geometric factor expressing the fraction of the double-layer potential drop crossed by the ion, «ad is the contribution of the dipole of the adsorbing species, and k" is that of each of the v water molecules it displaces. There is a further contribution to l if the thickness of the double layer changes.…”

Section: Chapman Resultsmentioning

confidence: 99%

The electrical double layer: recent experimental and theoretical developments

Parsons¹

1990

Chem. Rev.

397

270

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“…Therefore, the oxidation currents of A2 (in the potential range +0.5 to +0.7V) are caused by any palladium species or palladium complexes respectively. Since palladium is not oxidized to higher oxidation states (oxidation number Y > +2) at these potentials, the oxidation state of the surface bound palladium is Y < $2 and the formation of surface bound palladium is accompanied by a reduction or (according to the concept of partial charge transfer reactions [24]) a partial charge transfer from the electrode to the palladium. This is confirmed by the observation that the currents flowing during polarization of the electrode to 0 V, +O.…”

Section: Surface Bound Palladiummentioning

confidence: 99%

Voltammetric study of the immobilization of palladium at the surface of carbon paste electrodes

1996

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The immobilization of palladium at the surface of unmodified carbon paste electrodes is studied by cyclic voltammetry. Some features of the voltammetric behavior of palladium(1i) at carbon paste electrode in chloride solution are elucidated. Through pretreatment at 0 V (vs. Ag/ AgCI) palladium is bound at the surface of the carbon paste. The amount immobilized depends on the composition of the solution, polarization time, electrode potential and stirring. During an anodic scan the surface-bound palladium is oxidized at about +0.6 V; the wellshaped peaks can be utilized for the determination of the immobilized Pd. The detection limit is about 5 x M Pd2+ after 5 min polarization at 0 V (vs. Ag/AgCl) with stirring (base electrolyte 1 M KCI, pH 5.5). The rather complicated influence of hydrogen ions on the reactions at the palladium/carbon surface is discussed. Palladium and hydrogen can be "deposited" simultaneously at the carbon paste surface through cathodic polarization. Electrode reactions related to the observed peaks are suggested.

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Partial charge transfer reactions in electrochemical kinetics

Cited by 85 publications

References 208 publications

Surface-Enhanced Raman Spectroscopy of Phosphate Anions: Adsorption on Silver, Gold, and Copper Electrodes

Surface-Enhanced Raman Spectroscopy of Phosphate Anions: Adsorption on Silver, Gold, and Copper Electrodes

The electrical double layer: recent experimental and theoretical developments

Voltammetric study of the immobilization of palladium at the surface of carbon paste electrodes

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