The surface of a Pt electrode has been examined as a function of applied potential with reflection-adsorption infrared spectroscopy and linear sweep voltammetry. In a 1 M HClO4 solution, adsorbed hydronium was present on the surface at potentials less than 0 V vs. Ag/AgCl. Adsorbed hydronium reduced CO adsorption, and caused an upward shift in the CO stretching frequency. At potentials greater than 0.5 V, OH adsorbed on the surface. The hydroxyl groups blocked CO adsorption on the electrode surface. Anodic oxidation occurs at potentials above 1.2 V in 1 M HClO4 with the formation of a partially hydrated platinum hydroxide surface layer. The thickness of the surface layer increased with increasing applied potential. Adsorption on the Pt electrode from 1 M NaOH solutions resembled that observed with acid solution. However, anodic oxidation of the Pt electrode in basic solution produced a surface film with less incorporated water than was observed in acid solution.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Chemical Engineering(all)