Exchange current density of Th4+|Th couple in LiCl-KCl eutectic

Abstract Exchange current density ( i ∘ ) of thorium in LiCl-KCl eutectic at tungsten(inert) and liquid cadmium electrodes is reported in the present work. A cadmium electrode was designed in our laboratory for estimating i ∘ of thorium in liquid cadmium. Cyclic voltammetry of thorium at tungsten electrode was associated with a cathodic peak at −1.59 V at 773 K attributed to Th 4+ |Th redox couple. Cathodic peaks corresponding to Th 4+ |ThCd 11 and Th 4+ |ThCd 5 couples at −1.31 V and −1.38 V, respectively (at 773 K) were observed in the cyclic voltammograms of thorium at liquid cadmium electrode. i ∘ of thorium in LiCl-KCl eutectic at tungsten electrode (cathodic polarization) estimated by Tafel and Allen-Hickling methods were compared with those estimated from the cyclic voltammograms of LiCl-KCl-ThCl 4 . i ∘ at tungsten electrode was found to be higher than that at liquid cadmium electrode. The temperature dependence of i ∘ was studied to estimate the activation energy associated with Th 4+ |Th couple at tungsten, liquid cadmium (cathodic polarization) and dissolution of thorium (anodic polarization). The compositional dependence of i ∘ of thorium at tungsten electrode was also addressed. This is the first report on the i ∘ of thorium in LiCl-KCl eutectic.