Electrochemical Behavior of Zr（Ⅳ） on Mo Electrode in LiCl-KCl Molten Salt

In this presentation, the electrochemical behaviors of ZrCl₄ on the Mo electrode in the LiCl-KCl molten salt have been investigated by various techniques,including-cyclic-voltammetry,square-wave-voltammetry, and chronopotentiometry etc. The reduction mechanism of Zr(Ⅳ) on the Mo electrode has been discussed, and the diffusion coefficient of Zr(Ⅱ) and the apparent standard potential of Zr(Ⅱ)/Zr(0) have been calculated. The results show that the reduction mechanism of Zr(Ⅳ) on the Mo cathode is that Zr(Ⅳ)+2e=Zr(Ⅱ); Zr(Ⅱ)+2e=Zr(0) or Zr(Ⅱ)+e+Cl^-=ZrCl; ZrCl+e=Zr(0)+Cl^-, and the oxidation process of Zr on the anode is: Zr(0)-2e=Zr(Ⅱ) and Zr(Ⅱ)-2e=Zr(Ⅳ). The CV of LiCl-KCl-ZrCl₄ indicate that the reduction process Zr(Ⅱ)/Zr(0) is reversible and controlled by diffusion. The dependence of diffusion coefficients of Zr(Ⅱ) in the LiCl-KCl molten salt with temperature is ln D=-6724/T-2.95 and the activation energy is E_a=55.9 kJ/mol. The relationship of apparent standard potential of Zr(Ⅱ)/Zr(0) is E^Θ*_{Zr(Ⅱ)/Zr(0)}=-2.695+9.33×10^-4T.