Electrochemical synthesis of Co–Pr intermetallic compounds by the co-reduction of Co(II) and Pr(III) ions in a molten LiCl–KCl eutectic

For effective recovery of the fission element Pr from spent nuclear fuel (SNF) by using molten salt electrolysis technology, the electrochemical behavior of Pr(III) on inert Mo electrode in the molten LiCl–KCl system was investigated by cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques, indicating that the reduction of Pr(III) on the Mo electrode is a one-step reaction process with three electrons. Subsequently, electrochemical methods were used to reveal and calculate the kinetic and thermodynamic parameters of the Pr(III) ion reduction process. The co-reduction reaction of Pr(III) and Co(II) ions was explored, and five different Co_xPr_y intermetallic compounds were detected. Meanwhile, only one Co₂Pr intermetallic compound was obtained by galvanostatic and potentiostatic electrolysis with the best electrochemical parameters, and the thermodynamic properties of the Co₂Pr intermetallic compound were calculated at different temperatures. The co-reduction product was verified using X-ray diffraction (XRD), and the composition was determined by scanning electron microscopy (SEM) with energy spectrum analysis (EDS) and X-ray photoelectron spectroscopy (XPS). In addition, the produced Co₂Pr intermetallic compound has magnetic properties with a saturation magnetization of 10.3 emu/g.