Cu2O and CuO Films Produced by Chemical and Anodic Oxidation on the Surface of Copper Foil

Abstract

The processes underlying the chemical and anodic oxidation of the surface of copper foil have been studied by X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. It has been shown that, in the case of anodic oxidation, at a given process duration (τ) the composition and density of initially forming Cu(OH)₂ films depend not only on the current density (j_a) but also on whether or not the electrolyte is stirred. A Cu₂O film with an optimal, coral-like structure has been produced by the anodic oxidation of copper foil for τ = 10 min at j_a = 5 mA/cm² without stirring, followed by the thermal reduction of the Cu(OH)₂ in a nitrogen atmosphere for 1 h at 500°C. In the case of the chemical oxidation of the copper foil surface, similar Cu₂O films with a coral-like structure can also be produced by the thermal reduction of initially forming Cu(OH)₂ at 500°C for 1 h.