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

Abstract

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 °C. XRD and SEM results show that PbO₂ synthesized in the alkaline solution consists of pure α phase within a temperature range of 25–45 °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 °C, but the deposits synthesized at 40 °C and 45 °C exhibit rod-like crystallites.