Study on the exchange current density of lanthanide chlorides in LiCl-KCl molten salt

Lim, Keun Hong; Yun, Jong-Il

doi:10.1016/j.electacta.2018.10.104

Cited by 37 publications

(22 citation statements)

References 38 publications

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“…Among them, the exchange current density expresses an important parameter of charge transfer kinetics in the reaction process. The Butler–Volmer equation, including major variables such as exchange current density and transfer coefficient, is applied to simulate and evaluate the electrolytic refining process . It is assumed that, in the absence of material transfer, charge transfer kinetics is described by deriving the following Butler–Volmer equation − as follows: j = j 0 [ exp true( α italicnF italicRT true) η − exp true( prefix− ( 1 − α ) italicnF italicRT true) η ] where j represents the net current density, j 0 stands for the exchange current density, η is the overpotential, and α denotes the charge transfer coefficient.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical Extraction of Fission Element Samarium from Molten NaCl-2CsCl Eutectic Salt Using the Liquid Gallium Cathode

Zhang

Jiang

et al. 2023

ACS Sustainable Chem. Eng.

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The effective extraction of neutron poison samarium from nuclear waste to prevent reactions with metallic uranium is crucial for the sustainable development of nuclear energy. The electrochemical recovery of samarium on the liquid gallium cathode from the NaCl-2CsCl molten salts has been investigated by a variety of electrochemical techniques, and its electrochemical reduction properties and kinetic parameters have been provided. It was revealed that the reduction reaction on the Mo cathode of Ga(III) to Ga(0) and Sm(III) to Sm(II) is a two-step and one-step reaction process, respectively, and both reactions are reversible. The diffusion coefficients of Ga(III)/Ga(II) and Sm(III)/Sm(II) were identified, and the activation energies were 20.07 and 42.96 kJ mol −1 , respectively. Simultaneously, the codeposition mechanism of Ga(III) and Sm(III) on the Mo cathode was systematically investigated, and the potential and types of formation of binary intermetallic compounds were explored. Subsequently, it was determined that there are two main reaction processes for Sm(III) on the liquid Ga cathode, and the deposition potential of Sm becomes more positive due to the formation of the alloy. The exchange current density values of Sm(III)/Sm(Ga) obtained by both linear polarity (LP) and Tafel techniques increased with temperature, meanwhile the charge transfer resistance decreased, as well as the transfer coefficient. In addition, the apparent electrode potential of Sm(III)/Sm(Ga) was also calculated. Based on the electrochemical analysis, the fission element Sm was deposited on the liquid Ga cathode by potentiostatic electrolysis at a suitable potential, and the alloy products were verified by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. Ultimately, the highest separation efficiency of Sm on the liquid Ga cathode reached 92.43% according to the analysis of inductively coupled plasma atomic emission spectrometry (ICP-AES) results.

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Section: Resultsmentioning

confidence: 99%

Electrochemical Extraction of Fission Element Samarium from Molten NaCl-2CsCl Eutectic Salt Using the Liquid Gallium Cathode

Zhang

Jiang

et al. 2023

ACS Sustainable Chem. Eng.

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“…Therefore, the exchange current density i 0 on the glassy carbon electrode in the bath was studied by LSV. The Butler-Volmer [23,24] equation was applied at very low cathode overpotential, which can be simpli ed to Eq. ( 2), Take the logarithm of both sides of Eq.…”

Section: Exchange Current Densitymentioning

confidence: 99%

Preparation and electrochemical behavior of amorphous Co-Mo coating with high content of Mo

Tian

et al. 2022

Preprint

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At present, alloy materials have been widely used as wear-resistant coatings due to good mechanical properties. In this paper, electrodeposition was used to prepare the Co-Mo coating. The electrochemical behavior of the deposition of alloy and the phase composition, morphology, composition and property of the coating have been studied. The study of process parameters found that when the concentration of Na2Mo4 is 0.05mol/L, the concentration of C6H5Na3O7 is 0.15mol/L, the pH of the solution is 7, and the temperature is 50℃, the content of Mo in Co-Mo coating is 39.56%, and the microhardness reaches the maximum value of 503HV. The study of electrochemical behavior found that when the concentration of Na2Mo4 is 0.05mol/L, the concentration of C6H5Na3O7 is 0.15mol/L, the pH of the solution is 7 and the temperature is 50℃, the most positive deposition potential, maximum exchange current density and minimum charge transfer impedance were obtained, which explained why the best performance coating can be obtained under this condition.

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“…21−24 Electrochemical investigations of lanthanides exhibiting an accessible Ln(III/II) couple also reveal fast, reversible electron transfer characteristics through cyclic voltammetry (CV) and suggest that electron transfer is dominated by outer-sphere effects. 24,25 Further, they demonstrate that the Cl − ligand has a strong stabilizing effect on the Ln III oxidation states and is reflected as a negative shift in their reduction potentials. 21 These influences of the salt electrolyte environment were corroborated by MacInnes et al who found that the molten salt cation polarization strength played a significant role in the stability of lanthanide chloride anionic complexes due to outer-sphere coordination effects.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In molten chloride salts, lanthanides such as Nd, Eu, Ce, and Ho are observed to exist predominantly in their Ln(III) oxidation state and form octahedrally coordinated LnCl 6 3– anionic complexes as measured by spectrophotometric techniques. − The octahedral coordination complex has also been demonstrated in a variety of RTIL systems such as in the chloroaluminate melt and a variety of chloride-doped hydrophobic RTILs. − Electrochemical investigations of lanthanides exhibiting an accessible Ln(III/II) couple also reveal fast, reversible electron transfer characteristics through cyclic voltammetry (CV) and suggest that electron transfer is dominated by outer-sphere effects. , Further, they demonstrate that the Cl – ligand has a strong stabilizing effect on the Ln III oxidation states and is reflected as a negative shift in their reduction potentials . These influences of the salt electrolyte environment were corroborated by MacInnes et al who found that the molten salt cation polarization strength played a significant role in the stability of lanthanide chloride anionic complexes due to outer-sphere coordination effects .…”

Section: Introductionmentioning

confidence: 99%

Room-Temperature Ionic Liquid Cation Effects on the Structure and Stability of Anionic Lanthanide Complexes

Unger

Jensen

2023

Inorg. Chem.

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Room-temperature ionic liquids (RTILs) are a subset of molten salts that are liquids at room temperature and may offer an elegant, low-temperature route to predicting the properties of solvated metal complexes in their high-temperature analogues. This work studied the chemistry of chloride anion-containing RTILs to determine their similarity to inorganic molten chloride salts. The behaviors of complexes of Mn, Nd, and Eu were evaluated in a variety of chloride RTILs by absorption spectrophotometry and electrochemistry to elucidate trends in cation effects on the coordination geometry and redox properties of the solvated species. Spectrophotometric data indicated the metals are present as anionic complex (e.g., MnCl 42− and NdCl 6 3−) analogous to those observed in molten chloride salts. Strongly polarizing, charge-dense RTIL cations induced distortions to the symmetry of these complexes, resulting in lower oscillator strengths and red-shifted energies for the observed transitions. Cyclic voltammetry experiments were used to characterize the Eu(III/II) redox couple producing diffusion coefficients on the order of 10 −8 cm 2 s −1 and heterogeneous electron transfer rate constants ranging between 6 × 10 −5 and 2 × 10 −4 cm s −1 . The E 1/2 potentials for Eu(III/II) were also found to shift positively with increasing cation polarization power, stabilizing the Eu(II) oxidation state by removing electron density from the metal center over chloride bond networks. Both the optical spectrophotometry and electrochemistry results suggest that the polarization strength of an RTIL cation plays a major role in the geometry and stability of a metal complex.

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Study on the exchange current density of lanthanide chlorides in LiCl-KCl molten salt

Cited by 37 publications

References 38 publications

Electrochemical Extraction of Fission Element Samarium from Molten NaCl-2CsCl Eutectic Salt Using the Liquid Gallium Cathode

Electrochemical Extraction of Fission Element Samarium from Molten NaCl-2CsCl Eutectic Salt Using the Liquid Gallium Cathode

Preparation and electrochemical behavior of amorphous Co-Mo coating with high content of Mo

Room-Temperature Ionic Liquid Cation Effects on the Structure and Stability of Anionic Lanthanide Complexes

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