ELECTROCHEMICAL-BEHAVIOR OF COPPER-OXIDE GRAPHITE PASTE ELECTRODES INHYDROCHLORIC-ACID SOLUTIONS

Solid-phase voltammetry was used to investigate the cathodic and anodi c reactions of Cu2O and CuO in graphite paste electrodes in 0.05 to 1. 0 M HCl solutions. It was shown that copper oxides are reduced by thre e different mechanisms, two of them occurring in the solid phase. The third, ionic mechanism is complicated by complex formation (in the cas e of Cu2O) or chloride ion adsorption (in the case of CuO). The effect ive transfer coefficients of the cathodic processes were determined. T he electrochemical reactions of the copper oxide reduction products an d the anodic oxidation of Cu2O were studied. Schemes of electrode reac tions explaining the experimental observations were proposed.