LiF-CaF2-BaF2-ZrO2熔盐中Zr4+在钨电极上的电化学还原机理

LiF-CaF₂-BaF₂-ZrO₂熔盐中Zr⁴⁺在钨电极上的电化学还原机理

摘要: 以LiF-CaF₂-BaF₂为熔盐体系, ZrO₂为原料, 1 373 K条件温度下利用循环伏安法, 计时电位法, 计时电流法, 研究锆离子在钨电极上的电化学过程，对不同ZrO₂含量0.5 %，0.7 %，0.9 %的熔盐体系进行电化学分析，研究结果表明：Zr⁴⁺在钨电极上还原是通过两步得电子反应, 即Zr⁴⁺+2e→Zr²⁺，Zr²⁺+2e→Zr，相对参比电极铂还原峰分别为0.9 V和1.2 V，析出过程是受扩散控制的准可逆反应. 1 373 K时Zr⁴⁺在LiF-CaF₂-BaF₂-ZrO₂熔盐中的扩散系数D为6.7×10^-6 cm²/s.

Abstract: The electrochemical process of Zr⁴⁺ on the tungsten electrode at the temperature of 1 373 K was studied through the methods of cyclic voltammetry, chronopotentiometry and chronoamperometry when LiF-CaF₂-BaF₂was taken as the molten salt system, and ZrO₂ as the raw material.This paper has carried out an electrochemical analysis for molten salt with different ZrO₂ contents of 0.5 %, 0.7 %, 0.9 %. The results show that the electrochemical reduction of Zr⁴⁺on the tungsten electrode is caused by two electrode reactions, namely Zr⁴⁺+2e→Zr²⁺ and Zr²⁺+2e→Zr. As a result, platinum reduction peak of the relative reference electrode is 0.9 V and 1.2 V respectively, which proves that this process is a quasi-reversible reaction controlled by diffusion. The diffusion coefficient of Zr⁴⁺ in the molten salt is 6.7×10^-6 cm²/s at 1 373 K.