Real time observation of the anodic dissolution of copper in NaCl solution with the digital holography

Abstract

There are three possible cases of the initial electro-dissolution reactions of bare copper in acid/neutral chloride media. Two of them involve the direct formation of a cuprous chloride species from the metal, while the other, the dissolution of copper as cuprous ion. In the present work, the digital holography has been employed with an attempt to identify the actual mechanism through observing the dynamic changes of the diffusion layer at the electrode/electrolyte interface during the anodic processes of copper in 0.5 mol dm −3 NaCl solution. On the basis of the phase distribution reconstructed from the holograms, the dynamic changes of concentration field within the diffusion layer of the process can be obtained. The results confirm that, at the initial stage, the cuprous ion is formed first, which then reacts to produce the cuprous chloride and/or cuprous chloride complexes.