The Electrochemical Behavior of Tellurium Tetrachloride in LiCl-KCl Eutectic Molten Salt at 450 ºC

Abstract

Cyclic voltammetry CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy measurements were carried out in 1 and 5 wt% TeCl 4 containing LiCl-KCl eutectic molten salt at 450 °C using tungsten and glassy carbon as working electrodes. Reduction of Te(IV) to Te(0) occurred in three steps at potentials more negative than −0.4 V Ag/AgCl . The Te(0) was further reduced to Te 2− at more negative potentials. Formation of Te 2− was observed at potentials more negative than −2.2 V Ag/AgCl . Diffusivities of Te 4+ , Te 2+ , and Te 2− and their formal potentials were estimated from the CV data. The diffusion coefficients of Te 4+ , Te 2+ and Te 2− were 0.9 × 10 −5 , 3.8 × 10 −5 , and 1.5 × 10 −5 cm 2 s −1 , respectively in the 1 wt% TeCl 4 containing LiCl-KCl molten salt. The diffusivity of Te species generally decreased with increase in the concentration of TeCl 4 .