An electrochemical and radiotracer investigation on lead dioxide: Influence of the deposition current and temperature

The properties of electrodeposited PbO2 are sensibly influenced by deposition current and temperature. In particular, tritium radiotracer measurements have demonstrated that protons are incorporated in the bulk of the oxide film and on its surface. The degree of hydration increases with increasing current and decreases with temperature, and is related to the morphological characteristics of the oxide such as roughness measured by changes of the double layer capacity. Conversely, the amount of hydrogen has negligible effects on the number of free carriers evaluated from Mott-Schottky plots. The hydration degree of the surface seems to be an important factor influencing electrocatalytic processes at high potentials such as O2 evolution and O3 formation. On less hydrated, more crystalline PbO2 surfaces the first process is inhibited, and accordingly, the second is favored.