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1

Adsorptionof Urea on the Gold Electrode and Air/Solution Interface

Jurkiewicz-Herbich M.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 9

1513-1524

EN

The adsorption of urea on gold from aqueous 1MLiClO4 has been determined from measurements of cyclic voltammetry and electrochemical impedance spectroscopy. The film pressure and the Gibbs excess are determined as functions of urea concentrations and potential. The standard free energy of adsorption is a quadratic function of charge with maximum adsorption occurring at a charge of +6 mi C cm-2. These data are interpreted in terms of the partially oriented urea dipoles (with the CO group directed towards the metal) and the contribution of water dipoles.

2

Efekty powierzchniowej struktury metali w procesach elektrochemicznych

Sobkowski J., Jurkiewicz-Herbich M.

Wiadomości Chemiczne

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2004

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[Z] 58, 5-6

449--476

EN

It is known that both the nature and structure of a metal have a great influence on electrochemical processes. Interpretation of a mechanism of electrochemical reactions that occur on polycrystalline electrodes is often complicated because of their heterogeneous structure consisting of randomly distributed monocrystals on the surface. To avoid this problem, electrodes with well defined surfaces are commonly used in electrochemical experiments. In this paper, effects of the surface structure of a metallic electrode on properties of the double layer of the metal/solution interface, electrosorption and also on the electrochemical reactions has been reviewed. The presented data refer mainly to the basic planes of monocrystalline electrodes of face-centered cubic system. In first three chapters problems of the double layer structure of monocrystalline electrodes, the correlation of the potential of zero charge and work function, and the competition of a substrate and water molecules in the electrosorption process in relation to the hydrophilicity of metals are discussed. In chapters 4 and 5 the influence of the surface structure on the adsorption of organic molecules, strongly and weakly interacting with the electrode surface, is reviewed. It was shown that the surface concentration of adsorbate depends not only on the number of adsorption sites (assumed as the surface atom density) but also on the geometry of adsorbed molecule as well as on the kind and size of the supporting electrolyte anions. The latter play a very important role when the interaction of an adsorbed molecule and a metal is weak. Chapter 6 concerns the role of the electrode surface structure in the hydrogen ion discharge and also underpotential deposition of ions. The relationship between electrocatalytic properties of an electrode and its surface structure is presented in chapter 7. The kinetics of oxidation of methanol and formic acid at different planes of the platinum electrode and various products of the reduction of carbon oxide on copper monocrystalline electrodes are given as examples.

3

Surface-Enhanced Raman Spectroscopy and Electrochemical studies of 4-Phenylpyridine Adsorption at the Silver/Solution Interface

Bukowska J., Calvo M., Jurkiewicz-Herbich M., Jackowska K.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 8

1151-1162

EN

The adsorption of 4-phenylpyridine (4-PhPy) on silver was examined using conventional electrochemical techniques: cyclic voltammetry, impedance measurements and surface enhanced Raman spectroscopy (SERS) in a wide range of electrode potentials. Electrochemical results indicate a weaker adsorption of 4-PhPy molecules on Ag than on Au electrode, but considerably stronger than adsorption of pyridine. For saturated solutions the Raman results point out the reorientation of the 4-PhPy molecules from more flat configuration at potentials more positive than -0.7 V vs SCE, to more perpendicular one at more negative potentials. This reorientation may be connected with the formation of stable surface complexes at potentials more positive than -0.7 V and of molecular stacks at more negative electrode potentials.

4

Adsorption of L-histidine from aqueous solutions on the mercury electrode and air/solution interface

Słojkowska R., Jurkiewicz-Herbich M.

Polish Journal of Chemistry

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1999

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vol. 73 nr 3

527-539

EN

The differential capacitance characteristics of (Hg/0.1 mol dm-3KF and Hg/0.1 mol dm-3 LiClO4 interfaces were studied in the presence of L-histidine (His). The strongest adsorption of His on yhe mercury electrode was observed in solutions at pHł8. Probably, it results from the strong interactions between mercury and His molecules possessing in these solutions one or two deprotonated nitrogen atoms in the imidazole ring. Quantitative analysis of the data was possible for the alkaline solutions only. The anomalies observed in the course of C-E curves in the neutral or acidic solutions are discussed. Adsorption of His on a free surface is very weak. Practically it results from the salting-out effect, because, in the case of the solutions without the electrolyte, the His molecules do not adsorb at this interface.

5

Adsorption of tyrosine on Ag(110) and Ag(111) surfaces

Miłkowska M., Jurkiewicz-Herbich M.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 6

1096-1105

EN

The adsorption of tyrosine at Ag(110) and Ag(111) single crystal electrodes has been studied in aqueous solutions of 0.1 M LiClO4. The standard Gibbs energies of adsorption Delta G(0)-ads, at the potential of maximum adsorption and the interaction parameters, A, using Frumkin's isotherm were calculated. The orientation of the adsorbed tyrosine molecules is different on Ag(111) and Ag(110) electrodes. At Ag(111) the molecules adsorb flat with the benzene ring parallel to the electrode, whereas at Ag(110) electrode the orientation is propably vertical with OH group tawards the metal. The origin of that differences is propably the different atomic structure of both electrodes.