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The process of Ag2O formation has been investigated in 0.1M, 0.3 M, 1.0Mand 2.0 M NaOH solutions on polycrystalline Ag electrodes by cyclic voltammetry potentiostatic pulse and SEM techniques. The SEM micrographs of the chemically polished Ag surface and the surface after oxide formation revealed considerable roughening of the Ag surface after Ag2O formation and reduction. The roughening was more pronounced at higher NaOH concentrations, indicating that only the first cycle or pulse applied on a freshly polished Ag electrode should be considered in mechanistic studies of Ag2O formation. In the given range of NaOH concentrations, it was shown that the process is not controlled simply by the diffusion of the reacting species.Anucleation phenomenon was clearly detected in all the examined solutions. The SEM micrographs confirm that the two anodic peaks, present on the voltammograms of Ag2O formation correspond to two types of oxide film, i.e., non-homogeneously and homogeneously distributed ones. Potentiostatic formation of the oxide at potentials corresponding to the first and second anodic peak yielded simple cubic Ag2O but of very different grain size.

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Copper electrodeposition from copper acid solutions containing PEG and NaCl has been investigated onto Cu(111), Cu(100) and polycrystalline copper electrodes using polarization and EIS measurements. The adsorption of sulphate and chloride anions, and PEG molecules, was investigated onto Cu(111) and Cu(100) by cyclic voltammetry and differential capacitance measurements. Differential capacitance vs. potential curves recorded onto Cu(100) in solutions containing 0.1 M H2SO4, 0.1 M H2SO4 + 10-3 M PEG and 0.1MH2SO4 + 10-3MPEG + 10-3MNaCl confirm that ?specific adsorption? of PEG molecules occurs in the absence of NaCl in the solution, in the potential region of copper electrodeposition, e.g., between -1.0 V and -0.5 V vs. SSE. In the presence of chloride ions, the adsorption of PEG molecules is suppressed and there is no evidence of adsorption of neutral PEG molecules. It is shown that hysteresis, appearing on the polarization curves of copper electrodeposition, is not a consequence of competition between inhibition provided by the Cl-PEG/Cu2+/Cu+/Cu interface and the catalytic effects of Cl-MPSA/Cu2+/Cu+/Cu interaction, because hysteresis is present in the solution containing only PEG and NaCl, e.g., in the absence of MPSA. EIS measurements confirm the simultaneous occurrence of two processes during copper electrodeposition: deposition of copper by discharge of Cu2+ ions and ?specific adsorption? and discharge of some heavily charged species, most probably containing Cu, PEG and Cl.

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