Oxygen electrosorption on Ag(111) and Ag(110) electrodes in NaOH solution

Abstract

The first stages of the anodic oxidation of Ag(111) and Ag(110) electrodes in NaOH solution were studied by potential sweep voltammetry and ellipsometry. It was found that in the potential region studied, dissolution of silver species and electrosorption of oxygen occur. The (110) face is much more reactive to oxygen than the (111) face. On Ag(ll0) oxygen is reversibly adsorbed via a process of random deposition. The half-width of the adsorption peak indicates attractive lateral interactions in the chemisorbed layer.

Quick-Scanning EXAFS in the Reflection Mode as a Probe for Structural Information of Electrode Surfaces with Time Resolution: An in Situ Study of Anodic Silver Oxide Formation

“…Cyclic voltammetry generally features two major anodic and two cathodic peaks which can be related to the formation and the reduction of Ag 2 O and AgO, respectively (e.g., refs −3). During the initial stages of the anodic oxidation of silver, an AgOH monolayer is formed, , followed by a thin primary Ag(I) oxide overlayer of monolayer coverage, which grows with increasing electrode potential. , While the secondary silver(I) oxide formed at more anodic potentials reveals a structure very similar to that of crystalline Ag 2 O, the short-range order structure of this primary oxide is strongly disordered, as shown by a previous extended X-ray absorption fine structure (EXAFS) study . EXAFS explores the modulations in the X-ray absorption spectrum that extend from approximately 40 eV above the X-ray absorption edge up to about 1000 eV or more.…”

In Situ STM Study of the Surface Structure, Dissolution, and Early Stages of Electrochemical Oxidation of the Ag(111) Electrode

“…The nucleation and growth of the anodic oxides have been followed with potentiostatic transient techniques. − ,, In situ ellipsometry and Raman spectroscopy suggest the initial specific adsorption of OH - followed by the formation of Ag 2 O in the underpotential range of oxidation, i.e., below the Nernst equilibrium potential for the 3D growth of the oxide. − ,,, These findings have been confirmed by detailed studies applying X-ray photoelectron spectroscopy (XPS) and in situ grazing incidence X-ray absorption spectroscopy (GIXAS) on polycrystalline samples. − ,, A phase transformation in the adsorbed hydroxide layer was proposed to account for the underpotential cyclic voltammograms obtained on Ag(111) and Ag(100) single-crystal surfaces. , The generation of surface and subsurface hydroxide and oxide-like species was proposed from an XPS study of the thermal stability of emerged Ag(111) surfaces. ,, …”

“…The polarization curves of Ag in alkaline aqueous solutions show 2 main sets of anodic/cathodic peaks, A1/C1 and A2/C2, attributed to the formation and reduction of Ag(I) and Ag(II) oxides according to reactions 1 and 2, respectively: These surface reactions and their initial stages have been the subject of several electrochemical and surface analytical studies. − …”

Hydroxide Adsorption on Ag(110) Electrodes: An in Situ Second Harmonic Generation and ex Situ Electron Diffraction Study

“…The electrochemical behavior of Ag surfaces in alkaline electrolytes has been extensively investigated in the potential region of oxide formation with a variety of techniques, including electrochemical measurements, Raman spectroscopy, ellipsometry, electrochemical quartz crystal microbalance, and extended X-ray absorption fine structure spectroscopy . It has been proposed that a monolayer of Ag 2 O is formed, which then grows into a multilayer oxide film.…”