Temperature effects on the kinetics of a PbO2 electrosynthesis process in an alkaline bath

An electrochemical investigation of temperature on the electrosynthesis of lead dioxide in alkaline solutions was performed using a rotating disk electrode (RDE). In the Pb(II)-containing alkaline solution, the reaction taking place at 0.6 V-SCE is under the mixed control of ionic transport and charge transfer. The Koutechy-Levich equation was used to calculate the kinetics of the PbO2 electrodeposition process at 0.6 V-SCE. The results indicate that temperature has a positive influence on the diffusion of Pb(II). Moreover, temperature has a positive influence on the apparent heterogeneous rate constant of Pb(II) oxidation reactions within a temperature range of 25-40 degrees C. XRD and SEM results show that PbO2 synthesized in the alkaline solution consists of pure alpha phase within a temperature range of 25-45 degrees C. The intensity of the (200) crystallographic plane shows the same variation in the calculated apparent heterogeneous rate constant k of the PbO2 electrodeposition process. The deposits are composed of rounded nanocrystallites when the temperatures of solutions are lower than 40 degrees C, but the deposits synthesized at 40 degrees C and 45 degrees C exhibit rod-like crystallites.