Kinetic parameters for anodic oxidation of hypochlorite ion on Pt and Pt oxide electrodes in alkaline solution

Kinetic parameters for the anodic oxidation of hypochlorite ion have been determined by means of normal pulse voltammetry by using a platinum disk as the working electrode. By using the working electrode that formed an oxide film by electrochemical pretreatment, the effect of the lattice oxygen of the surface oxide on the reaction was also examined. The measurement results were analyzed by the classical method, and then the analytical results were evaluated by digital simulation. The normal pulse voltammogram of the hypochlorite ion showed quasi-reversible oxidation waves. The apparent rate constant was calculated to be 5.0–8.1 × 10−4 cm s−1, depending on the electrode surface state. At the low-concentration range of <4.0 mg Cl dm−3, the oxidation current was concentration dependent at the cathodically polarized electrode, while it became independent after the anodic polarization.