ADSORPTION CHARACTERISTICS BY A RADIOCHEMICAL METHOD ON SMOOTH ELECTRODE SURFACES

The determination of adsorbate surface concentration and its dependenc e on fundamental electrochemical variables is of paramount importance in studies of electrode processes, electrocatalysis and corrosion. In this paper we review the current status of a radiotracer method that p ermits measurements of adsorbate surface concentrations on surfaces of smooth solid electrodes of a convenient size and thickness. Several e xamples are presented of the most representative measurements carried out with polycrystalline platinum, gold and copper electrodes, and wit h platinum single-crystal electrodes. We discuss the interdependences between surface concentrations and voltammetric currents, and provide detailed characteristics of the molecular adsorption of pyridine and t he anionic adsorption of sulfate on a clean and an admetal-covered ele ctrode surfaces. We also report on a new all-glass cell design that fa cilitates cleaning and a convenient observation of the cell interior d uring measurements. We believe that the performance of this method, an d the cell design concepts, have been verified to the point that the t echnique can now be recommended for broader use, especially in applied electrochemistry where coverage measurements are essential and the ne ed for a spectroscopic focus is less apparent. However, since possibil ities for joint radioanalytical and spectroscopic measurements are num erous, the resulting complementary interpretation may contribute equal ly effectively to both fundamental and applied electrochemical surface science.