Cyclic Voltammetry of Platinum in Weakly-acidic Aqueous Solutions

Abstract

The electrolytic behavior of platinum in weakly-acidic aqueous solutions containing Na₂SO₄, NaNO₃, KNO₃ or KCl as electrolyte was investigated by means of cyclic voltammetry. The voltammograms obtained in these solutions were greatly different from those usually observed for strongly-acidic, neutral and alkaline solutions. Particularly, one reversible couple of oxidation-reduction currents was observed at about -0.5 V vs. SCE during the potential sweep of a platinum electrode in weakly-acidic solution. The appearence of this reversible wave which is attributable to the discharge of hydrogen ion under diffusion control was found to depend on the potential sweep range, sweep rate, kind of electrolyte, pH value and so on. A brief discussion was made on the suitable pretreatment methods of the electrode for evaluating the electrode reactions in these systems.