NaCl-KCl-NaF-WO3熔盐体系W6+的电化学行为

Electrochemical behavior of W6+ in NaCl-KCl-NaF-WO3 molten salt system

  • 摘要: 实验以NaCl-KCl-NaF为电解质体系,WO3为原料,利用循环伏安法、计时电位法、计时电流法和方波伏安法, 研究温度为973 K时钨离子在钨电极上的电化学过程.结果表明:W(Ⅵ)离子的还原过程分2步进行,第1步还原过程为两电子转移,电极反应方程式为W6++2e-→W4+; 第2步还原过程为四电子转移过程,电极反应方程式为W4++4e-→W,且都为准可逆反应. W(Ⅵ)离子在钨电极上的还原过程受扩散控制,扩散系数为1.05×10-9 cm2/s.

     

    Abstract: The electrochemical reduction mechanism of W6+ on the tungsten electrode at 973 K was studied by the methods of cyclic voltammetry, chronopotentiometry, chronoamperometry and square wave voltammetry, and by using NaCl-KCl-NaF and WO3 as molten salt and raw material respectively. The results show that the reduction process of W(Ⅵ) ion is carried out in two steps: the first one is a two-electron transfer process, and the electrode reaction equation is W6+ + 2e-→W4+; the second one is a four-electron one, and the electrode reaction equation is W4+ + 4e-→W. The two depositing processes of tungsten ion are both quasi-reversible reactions. The reduction process of W(Ⅵ) ion on the tungsten electrode is controlled by diffusion whose coefficient is 1.05×10-9 cm2 /s.

     

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