Diffusion Coefficient of Ho3+at Liquid zinc Electrode and Co-reduction Behaviors of Ho3+ and Zn2+ on W Electrode in the LiCl-KCl Eutectic

Abstract

In this work, the diffusion coefficients of Ho3+ at the Zn pool electrode and the Zn film electrode were firstly studied. Both semi-differential and semi-integral techniques were employed to analysis the cyclic voltammetry (CV) curves for the determination of the diffusion coefficients. The results showed that diffusion coefficients at Zn pool electrode and the Zn film electrode were close to each other by semi-differential technique. In addition, the co-reduction behaviors of Ho3+ and Zn2+ on W electrode were also investigated to determine the reactions of Ho with the Zn electrode. It was found that HoxZny intermetallic compounds would be formed by the co-reduction process, and the compositions of these HoxZny intermetallic compounds were estimated by the accumulated coulomb numbers of the relative anodic peaks on the CV curves. Moreover, electrodeposition of Ho3+ was carried out on both the inert W electrode and the liquid zinc electrode. X-ray diffraction (XRD) results showed that Ho2Zn17 and HoZn3 were obtained on the W electrode by the co-reduction process, whilst Ho2Zn17 was gained at the liquid zinc electrode by underpotential-deposition process. The microstructures of the intermetallic compounds were characterized by scanning electron microscopy (SEM).