Redox reactions at titanium electrodes covered with doped passive films

The rate of electron transfer reactions at titanium electrodes covered with thin platinum-doped passive films was investigated. The doping enhances the current considerably. It is suggested that the platinum atoms in the film serve as intermediate states in an electronic resonance-tunnelling mechanism. The corresponding model calculations show a satisfactory agreement with the experimental data. From these calculations the energy levels of the platinum states in the film are estimated.