Oxide layers developed on copper electrodes in Cu(II) solutions containing ligands

Different electrochemical and spectrometric methods are applied to study the development, composition, electrochemical and photoelectrochemical properties of oxide layers formed in Cu(II) solutions containing ligands. Layers containing Cu2O may be formed if reasonable conditions (certain concentrations of Cu2+ ions and solution pH values) are established. The rate of this process depends mainly on the degree of complexation of the solution: the less stable the complexes of Cu(II) formed, the more intensive is oxidation of copper that occurs. Oxide layers may be reduced cathodically, exhibiting characteristic current peaks. They possess properties typical both of p- and n-type semiconductors and are sensitive toward optical perturbation. The photoresponses can be used for the detection of Cu2O on the electrode surface. Oxide layers are liable to photocorrosion and can be destroyed under optical illumination.