On the interaction of oxygen with platinum

The cyclic voltammograms were obtained on both bright polycrystalline Pt and Pt---O alloy bead electrodes in both 2 N H₂SO₄ and 1 N HF solutions saturated with purified N₂. The samples were scanned between 0 and 1500 mV vs nhe at rates from 100 to 17 mV s⁻¹. In rigorously purified systems, the chief effect of polarizing Pt above 1 V is the charging of Pt with dissolved oxygen. Such a Pt--- O alloy has different electrochemical properties than Pt. On Pt there are two adsorption and desorption sites for hydrogen and possibly two adsorption sites for sulfate ions. A third hydrogen desorption site exists on Pt---O alloy.