Investigation on the Kinetics of Electroreduction Processes at Dark TiO2 and SrTiO3 Single Crystal Semiconductor Electrodes

The cathodic dark current at n‐type Nb‐doped and electrodes in , Fe +3 , or aqueous solution was measured as a function of applied voltage, concentration of oxidizing agent, and p H. Two distinct current regimes were observed, differing by their Tafel slopes and by their concentration dependence. The most marked feature of the results was the saturation of the current as a function of concentration in the high current‐density region. The experimental data were interpreted on the basis of a model involving electron transfer through surface states.