The corrosion of copper as a tool in the investigation of the reaction kinetics

The copper electrode reaction kinetics have been studied in acid CuSO, solutions. Dissolved oxygen was used to remove the reaction intermediate Cu⁺ from the electrode. This shifted the equilibrium potentials of the two partial reactions in an opposite direction allowing a somewhat unusual interpretation of impedance measurements. The charge transfer resistance of the Cu²⁺ → Cu⁺ reaction was always higher than that of the Cu⁺ → Cu reaction. In the neighbourhood of the open circuit potential an additional “surface step” in the latter reaction made it rate-controlling. The slow diffusion of cuprous ions was manifested in an inductive impedance component in this region.