Kinetic aspects of the electrodissolution of zinc in bromate-containing alkaline solutions

摘要

The effect of bromate ions on the anodic behavior of zinc electrodes in potassium hydroxide solutions has been investigated experimentally using the rotating disk electrode technique. The total dissolution current was observed to decrease with the increasing concentration of the bromate ions. The experiments also showed that the potential required for the onset of passivation increased anodically with the addition of potassium bromate but rapidly reached a stable value that depended on the hydrodynamic condition. The Tafel slope became smaller with the introduction of potassium bromate. Based on the experimental results, a kinetic model describing the dissolution process was developed and tested. Good agreement between the experimental results and the model predictions supports our hypothesis that the reduction of bormate proceeds in parallel with the anodic dissolution of a zinc electrode in alkaline electrolyte solutions.