Study of the chlorine anion interaction with surface of the gold electrode by GRS spectroscopy under electric polarization

L.V. Sitnikov, I. D. Zakirianova, E. V. Kirillova

ABSTRACT:

The GRS spectra in the systems: Au/KCl aqueous solution and Au/CsCl aqueous solution have been obtained in situ under a reversible electric polarization. It was revealed that at low anodic potentials the chloride ion adsorbs on the electrode surface in a KCl solution in the form of complex ions [ AuCl4 ] and [ AuCl2]. With further potential increase the [AuCl4 ] concentration increases as on the surface as in the electrolyte bulk due to the anodic reaction of gold dissolution. In the CsCl solution, at low electrode polarization in the area of the reversible adsorption, the complex [AuCl2] was a dominant group on the gold electrode surface, whereas the complex [AuCl4] was not detected. When the potential increases a salt phase Cs2Au2Cl6 is formed on the electrode; the [AuCl4] ions are not present in the bulk. A cell design allows for a comprehensive study of properties of the interface metal/electrolyte at elevated temperatures and in aggressive media, especially in salt melts.

KEYWORDS:

 specific adsorption, gold, alkali metal halides, spectroscopy of giant Raman scattering