The kinetics of oxide growth and oxygen evolution during potentiostatic polarization of lead in H2SO4 electrolytes—investigations on the temperature dependence
✍ Scribed by Timo Laitinen; Jürgen P. Pohl
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- English
- Weight
- 743 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0013-4686
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✦ Synopsis
The growth of oxide layers on lead in sulfuric acid solutions in the PbO, potential region is consistent with a parabolic growth law. This is in agreement with a model, according to which the growth rate is determined by the transport of oxygen through the layer. During oxide growth gaseous oxygen is also evolved at the PbO,*lectrolyte phase boundary. In this work the kinetics of oxide growth and of oxygen evolution were studied in the temperature range 15-50°C in different H,SO, concentrations. As a result of the experiments the activation energies for the rate determining step of the transport of oxygen through the layer and of oxygen evolution on PbO, were determined. The kinetic data for oxygen evolution are in agreement with the assumption that the rate determining step of the reaction is localized on the oxide surface. The kinetic data for oxide growth show that the transport properties of the layer strongly depend on the experimental conditions (electrode potential, pH) under which ihe layer is formeci. Potentiostatic polarization of lead in H,SO, electrolytes