Radioactive Labeling Study of Sulfate/Bisulfate Adsorption on Smooth GoldElectrodes

摘要

Adsorption of sulfate/bisulfate anions was studied on a smooth gold electrode bythe use of the radioactive labeling method. Adsorption is reversible with respect to the bulk concentration of adsorbate and the electrode potential. The chemical component in adsorption is weak, as assessed from an almost linear relationship between surface concentration and the electrode potential. This indicates that the surface attachment occurs predominantly through electrostatic interactions between the surface and the ions, which were concluded to be bisulfate anions. Processing the radiochemical information using the Bennes adsorption isotherm yields basic thermodynamic magnitudes, such as standard Gibbs energy of adsorption and the interaction energy. Their analysis reveals that in the studied bulk concentration range a strong interionic repulsion limits the uptake of anions to ca. 30% of a maximum coverage. Keywords: Reprints, Au, Electrochemical adsorption, Radiochemical research, Isotherms, Chemical reactions. (JG)