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^⊝*_Zr(II)/Zr(0) = -2.695 + 9.33 × 10^-4 T. (authors)