Electrochemical and thermodynamic studies on the molten salt electrodeposition of Ce on W electrode and liquid Zn electrode

The recovery of cerium via molten salt electrolysis with the liquid zinc (Zn) cathode is considered a highly promising strategy for rare earth resource recycling. To reveal the electrochemical reduction of cerium (Ce) ions and the alloy formation process on the Zn electrode, in this work, multiple electrochemical methods were adopted to study the electrode reactions and thermodynamic properties during the Ce deposition process at high temperatures. A concentration-dependent test of the co-deposition reaction indicated that the alloying behaviour of reduced Ce was affected by ion concentration. The electrochemical results showed that four Ce Zn alloys were formed in the electrode reaction. The Gibbs free energy of alloy formation was determined. Furthermore, in order to understand the reaction kinetics on the liquid electrode and the thermodynamic behaviour of the reduced Ce in the electrode, the exchange current density and activity coefficient during electrodeposition were determined by Tafel analysis and coulometric titration, respectively. The temperature dependence of both exchange current density and activity coefficient was further revealed