KINETICS OF IRON DEPOSITION ON A ROTATING PLATINUM DISK ELECTRODE

The kinetics of iron deposition from acid solutions under steady-state conditions have been studied using a rotating platinum disk electrode. The data obtained in the pH range between 1. 8 and 3. 8 can be explained on the basis of two reaction mechanisms. The noncatalyzed mechanism is applicable at pH less than equivalent to 2. 4, while the catalyzed one is applicable at pH greater than equivalent to 3. 3. In between there is a transition from one mechanism to the other. Measurements of electrochemical reaction order as a function of the pH indicate the existence of the catalyzed mechanism at pH greater than equivalent to 3. 3. In this pH-range the ferrous ion discharge takes place in the charge transfer region of the HER and consequently the pH at the electrode surface is the same as in the bulk of the solution. These results are in good agreement with an earlier investigation on the iron deposition on a rotating gold disk electrode.