Ex Situ X-ray Photoelectron Spectroscopy Study of the Interface between a Ag(111) Electrode and an Alkaline Electrolyte. 1. Influence of the Electrode Potential on the Adsorption of Oxygen Species

A Ag(111) single-crystal electrode emersed from the NaF + NaOH electrolyte (pH 11) under the anodic polarization has been studied ex situ by means of X-ray photoelectron spectroscopy. The oxidation of the electrode starts at −0.6 V vs Hg/HgO (ca. 1 V negative to the reversible potential of Ag2O phase formation) and manifests itself by the appearance of different surface and bulk oxygen-containing species. These are surface OH groups (OHads), surface oxide-like species ( ), and bulk OH groups (OHbulk). The OHbulk exhibit high thermal stability in a vacuum but can be efficiently removed from the electrode via cathodic polarization.