Electrochemical Behavior of Platinum in 0.5M Hydrochloric Acid in the Potential Range 0.0 to 1.0 Volt vs. Saturated Calomel Electrode

The electrochemical reactions of a platinum electrode were studied in 0.5M hydrochloric acid supporting electrolyte. Using the rotating ring-disk electrode, the presence of an impurity having all the electrochemical properties of the Cu(M)/Cu(l) couple was established in the supporting electrolyte. It was shown that the previously reported electrochemical oxidation of a platinum electrode at +0.3 to +0.6 V vs. the SCE is actually the oxidation of adsorbed Cu(l). This Cu(l) is adsorbed when the electrode is potentiostated at zero volt in a hydrochloric acid supporting electrolyte containing trace Cu(ll). In 0.5M hydrochloric acid supporting electrolyte no oxidation of the platinum electrode is observed at potentials less than +0.6 V.