Using the potentiodynamic polarization curves to study the photoelectrochemical effect of cuprite on the corrosion of pristine copper

Purpose This paper aims to clarify the photoelectrochemical effect of cuprite (as the main corrosion products of copper) on the corrosion of pristine copper. Design/methodology/approach A cuprite layer with p -type semiconductor characteristic was electrodeposited on pristine copper; the corrosion promotion effect of cuprite on copper under AM1.5 (100 mW/cm² simulated sunlight) illumination was determined via potentiodynamic polarization test. Findings Photo-induced electrons tend to transport to electrolyte side for the reduction of dissolved oxygen, whereas the holes are more apt to deprive the electrons by oxidizing the Cu atoms to Cu I and Cu II ions. Both the anodic and cathodic processes of Cu corrosion were enhanced under illumination, especially for the anodic process. Originality/value A drawback of semi-logarithmic polarization curve for revealing the actual photo electrochemical effect on the corrosion characterization is proposed; a method of current subtraction at identical overpotential between the currents derived from illumination and darkness is proposed as well.