Electrodeposition of Tb on Mo and Al electrodes: Thermodynamic properties of TbCl3 and TbAl2 in the LiCl-KCl eutectic melts

The kinetics process of a Pb(ii)/Pb(0) couple and selective fabrication of Li-Pb alloys in LiCl-KCl melts

The electrode reaction of Pb(ii) and co-reduction of Li(i) and Pb(ii) were investigated on a tungsten electrode in LiCl–KCl eutectic melts by a range of electrochemical techniques. From cyclic voltammetry and square wave voltammetry measurements, the reduction of Pb(ii) was found to be a one-step diffusion-controlled reversible process with the exchange of 2 electrons. The diffusion coefficients of Pb(ii) were computed, and they obey the Arrhenius law. Using the linear polarization technique, the kinetic parameters, such as exchange current intensity (j₀), standard rate constant (k⁰) and charge transfer resistance (R_ct) for the Pb(ii)/Pb(0) couple on a tungsten electrode were studied at different temperatures, and the activation energy is 27.32 kJ mol⁻¹, smaller than the one for diffusion of Pb(ii), which further confirmed that the reduction of Pb(ii) was controlled by diffusion. A depolarisation effect for Li(i) reduction was observed from the results of cyclic voltammetry, square wave voltammetry and chronopotentiometry due to the formation of Li–Pb alloys by co-reduction of Li(i) and Pb(ii). Furthermore, five Li–Pb intermetallic compounds, LiPb, Li₈Pb₃, Li₃Pb, Li₁₀Pb₃ and Li₁₇Pb₄ characterized by scanning electronic microscopy and X-ray diffraction, were selectively prepared by potentiostatic electrolysis on a tungsten electrode and galvanostatic electrolysis on a liquid Pb electrode, respectively.

Five Li–Pb intermetallic compounds are selectively prepared according to their deposition potentials and characterized by XRD and SEM.

Electrolytic extraction of dysprosium and thermodynamic evaluation of Cu-Dy intermetallic compound in eutectic LiCl-KCl

The electrochemical reduction of dysprosium(iii) was studied on W and Cu electrodes in eutectic LiCl–KCl by transient electrochemical methods. Cyclic voltammogram and current reversal chronopotentiogram results demonstrated that dysprosium(iii) was directly reduced to dysprosium (0) on the W electrode through a single-step process with the transfer of three electrons. Electrochemical measurements on the Cu electrode showed that different Cu–Dy intermetallics are formed. Moreover, the thermodynamic properties of Cu–Dy intermetallic compounds were estimated by open circuit chronopotentiometry in a temperature range of 773–863 K. Using the linear polarization method, the exchange current density (j₀) of dysprosium in eutectic LiCl–KCl on the Cu electrode was estimated, and the temperature dependence of j₀ was studied to estimate the activation energies associated with Dy(iii)/Cu₅Dy and Dy(iii)/Cu_9/2Dy couples. In addition, potentiostatic electrolysis was conducted to extract dysprosium on the Cu electrode, and five Cu–Dy intermetallic compounds, CuDy, Cu₂Dy, Cu_9/2Dy, Cu₅Dy and Cu_0.99Dy_0.01 were identified by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. Meanwhile, the change of dysprosium(iii) concentration was monitored using inductively coupled plasma-atomic emission spectrometry, and the maximum extraction efficiency of dysprosium was found to reach 99.2%.

The electrochemical reduction of dysprosium(iii) was studied on W and Cu electrodes in eutectic LiCl–KCl by transient electrochemical methods.

Electrochemical formation and thermodynamic properties of Tb–Bi intermetallic compounds in eutectic LiCl–KCl

The electrochemical formation and thermodynamic properties of Tb–Bi intermetallic compounds were investigated on a Bi film electrode in eutectic LiCl–KCl.

Electroreduction-based Tb extraction from Tb4O7 on different substrates: understanding Al–Tb alloy formation mechanism in LiCl–KCl melt

This work presents the electroreduction of Tb(iii) ions, and formation mechanisms of Al–Tb alloys in molten chlorides by applying different types of cathodes: Mo, Al and Al-coated Mo.

Electrochemical behavior of La(iii) on liquid Bi electrode in LiCl–KCl melts. Determination of thermodynamic properties of La–Bi and Li–Bi intermetallic compounds

Electrochemical behavior of La(iii) was studied on liquid Bi electrode. Thermodynamic properties of five La–Bi intermetallic compounds and Li₃Bi were calculated from emf measurements.