Radiotracer study of the adsorption of urea on platinized platinum electrodes in the presence of different ions and organic compounds

Abstract

Radiotracer study of the adsorption of C-14 labelled urea on platinized platinum electrodes was carried out under different experimental conditions. The potential and concentration dependence was studied at low concentrations (10 −5–10 −3 mol dm −3) using M HClO 4 supporting electrolyte. An anion-like adsorption behaviour was observed. The effect of different inorganic (HCl, H 2SO 4, H 3PO 4) and organic (oxalic, glyoxalic acids, etc.) additives was studied. Both C-14 labelled urea and Cl-36 labelled HCl were used for the study of the simultaneous adsorption of Cl − ions and urea. A decrease of the adsorption of urea was observed in the presence of the different anions. The extent of the decrease was connected with the adsorbability of the anions considered. The effect of oxalic acid on the adsorption was similar to that of anions. Chemisorption of alcohols and oxo compounds prevents the adsorption of urea. The increase of the urea adsorption with increasing potential indicates the oxidation of chemisorbed species. It has been shown that periodical changes in the urea adsorption may be observed in the course of potential oscillations occurring during galvanostatic oxidation of organic compounds.