Anodic Iridium Oxide Films: XPS‐Studies of Oxidation State Changes and

The anodic oxidation of iridium and evolution on iridium oxide films in has been investigated using x‐ray photoelectron spectroscopy. The binding energy of the O 1s level decreases with anodic polarization of the electrode while the relative amount of oxygen compared to iridium remains constant. The XPS results are consistent with a model of subsequent deprotonation of the anodic iridium oxide upon anodic polarization. A reaction path for evolution and corrosion on iridium oxide is proposed. Valence band spectra of the oxide surfaces confirm the proposed model.