Anodic oxidation of copper in concentrated sulfuric acid solutions

Copper oxidation in 1-10 M sulfuric acid solutions is studied using cyclic voltammetry and x-ray diffraction methods., Copper passivation is shown to be caused by the formation of a resistive porous layer of copper(l) oxide via an electrochemical mechanism. The primary product of the electrode reaction is unstable and, depending on the acid concentration, either enters chemical reactions with electrolyte components or is oxidized electrochemically to give copper(II) oxide.