Electrochemical Behaviors of Ce(III) in Molten AlCl3-NaCl under Various Contents of Fluoride

Abstract

The electrochemical behavior of CeCl3 was investigated in molten AlCl3-NaCl melt with various concentrations of fluoride anions using molybdenum electrode at a temperature of 473 K. Transient electrochemical techniques, such as cyclic voltammetry and square wave voltammetry, were performed to reveal the diffusion coefficients of the electroactive species and reduction steps. Results suggest that there are two steps for Ce(III) ion reduction in molten AlCl3-NaCl: Ce(III)→Ce(II) and Ce(II)→Ce. The reduction processes shifted to Ce(III)→Ce when NaF was added in the melt in increasing amount. The molar ratio of fluoride ions and cerium (F/Ce ratio) was employed as a parameter to illustrate the influence of fluoride anions. The diffusion coefficient of electroactive species were determined in AlCl3-NaCl melt at 473 K by using square wave voltammetry.