Electrochemical studies on the comproportionation reaction between Zr(0) and Zr(IV) in molten LiCl-KCl eutectic salt

Abstract

The electrochemical behavior of Zr was investigated by a unique comproportionation reaction between Zr(0) and Zr(IV) in molten LiCl-KCl eutectic salt. Based on the quantitative analysis by X-ray photoelectron spectroscopy and square wave voltammetry, the unknown Zr ion, which is the product of comproportionation reaction, is revealed as Zr(III) rather than Zr(II), whose existence was reported in all literatures. Additionally, the complicated redox behavior of Zr in molten LiCl-KCl eutectic salt has been revisited by cyclic voltammetry based on the knowledge of comproportionation reaction. The cyclic voltammogram of LiCl-KCl-ZrCl4 system provides a significant discrepancy by changing the experimental condition such as the working electrode. Lastly, the chronoamperometric electrodeposition is attempted, and the deposited product is analyzed with X-ray diffractometry in order to investigate the reduction mechanism of Zr species. In accordance with experimental results, the expected reaction for the major oxidation peaks on cyclic voltammogram is suggested and compared with that in other literatures.