Electrochemical Behavior of Carbonate Ion in the LiF^|^ndash;NaF^|^ndash;Li2CO3 System

Li, Liangxing; Shi, Zhongning; Gao, Bingliang; Xu, Junli; Hu, Xianwei; Wang, Zhaowen

doi:10.5796/electrochemistry.82.1072

Cited by 28 publications

(15 citation statements)

References 28 publications

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“…17,18 Analogously the evolution of CO and CO 2 gases should have affected on the "electro-deoxidation" processes.…”

Section: -16mentioning

confidence: 99%

“…This led to a local increase in the current density of the actual cathode and to the formation of calcium. The latter then reacted with the carbon-containing ions dissolved in the melt to form ultrafine carbon 17,18 on the holes of the alumina tube.…”

Section: Electrolysis Tests-formation Of Camentioning

confidence: 99%

“…[13][14][15][16] The latter interact with calcium dissolved in the melt or diffuse to the cathode with subsequent direct discharge to ultrafine carbon. 17,18 Analogously the evolution of CO and CO 2 gases should have affected on the "electro-deoxidation" processes. [1][2][3][4][5] Finally, the presence of carbon in the melt changes its physical-chemical properties, significantly impacting the electrolysis parameters.…”

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confidence: 99%

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Reduction of Solid Al₂O₃with Electrolysis of CaCl₂-Based Melt

Suzdaltsev¹,

Khramov²,

Zaikov³

et al. 2017

J. Electrochem. Soc.

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Cyclic and square-wave voltammetry methods are used to investigate the mechanism of the cathode process on molybdenum in a CaCl 2 -CaF 2 melt at 750 • C. It is shown that calcium reduces on an inert cathode in the form of its solution in catholyte at potentials more positive than are required for metallic calcium formation. The presence of Al 2 O 3 in the catholyte increases currents of calcium reduction on the forward cathodic wave at potentials more positive than are required for metallic calcium formation. A decrease in the ohmic resistance between the anode and cathode is observed to have been caused by the appearance of electronic conduction during the calcium cathodic reduction in the studied melt. A mechanism for the reduction of Al 2 O 3 in the catholyte during electrolysis of the CaCl 2 -CaF 2 melt, including Ca + subions and calcium cathode formation and the secondary reduction of Al 2 O 3 , is proposed. In order to demonstrate the supposed mechanism for the Al 2 O 3 reduction, the electrolysis tests were performed in two laboratory-scale electrolyzers with different separation type of anolyte and catholyte. Since Chen and Fray's seminal paper published in 2000 1 , over a thousand publications have been devoted to the further development and improvement of direct electroreduction or "electro-deoxidation" of metal oxides in CaCl 2 -based melts. However, despite this significant attention from researchers from all over the world, 2-5 this promising method is yet to be meaningfully applied at an industrial scale. This is likely to be due to several important mechanisms in the metal oxide reductions remaining to be adequately explained. Thus, in our previous theoretical research, 6 we have shown that non-conductive crystal oxides can be reduced by calcium solution (in a form of Ca, Ca + or CaCl) in its chloride. 7-10 The latter can be formed at the inert cathode during electrolysis or due to introduction of calcium metal into the melt. Dissolution of alkali or alkaline earth metal in their halides reveals the nature of such melts, which are representative of ion-electron liquids. 7,8 Therefore, the nature of the melts under study enables using the innovative method only in electrolysis lab tests. Moreover, the presence of calcium (in a form of solution or metal phase) in the molten calcium chloride leads to the appearance of electronic conduction that causes a side reaction of calcium oxidation in the anolyte and at the anode. 11,12Since the principal anode material used (as mentioned in most papers [1][2][3][4][5] ) is graphite, the discharge of oxygen-containing ions on graphite is accompanied by the formation of anode gases (CO, CO 2 ) which dissolves in the CaCl 2 -melts in the form of carbonate ions. 13-16The latter interact with calcium dissolved in the melt or diffuse to the cathode with subsequent direct discharge to ultrafine carbon. 17,18 Analogously the evolution of CO and CO 2 gases should have affected on the "electro-deoxidation" processes.1-5 Finally, the presence of carbon in the melt chang...

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“…17,18 Analogously the evolution of CO and CO 2 gases should have affected on the "electro-deoxidation" processes.…”

Section: -16mentioning

confidence: 99%

Section: Electrolysis Tests-formation Of Camentioning

confidence: 99%

mentioning

confidence: 99%

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Reduction of Solid Al₂O₃with Electrolysis of CaCl₂-Based Melt

Suzdaltsev¹,

Khramov²,

Zaikov³

et al. 2017

J. Electrochem. Soc.

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“…According to the Arrhenius law, a small diffusion coefficient, as observed here, can be attributed to the high activation energy of surface migration. 56,57 As has been shown in our previous work, 15 the surface migration of the neutral Pb species on free-standing graphene requires overcoming highenergy barriers of about 100 meV, which can be explained by the fact that the Pb species tend to reside on bridge sites avoiding the hollow site positions (the centres of the hexagonal rings) on graphene. All experimental details yield atomistic insights into the location of the Pb deposits on graphene.…”

Section: Electrodeposition Of Lead: Chronopotentiometric Stripping Anmentioning

confidence: 69%

Lead (Pb) interfacing with epitaxial graphene

Shtepliuk

Vagin

Ivanov

et al. 2018

Phys. Chem. Chem. Phys.

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Here, we report the electrochemical deposition of lead (Pb) as a model metal on epitaxial graphene fabricated on silicon carbide (Gr/SiC). The kinetics of electrodeposition and morphological characteristics of the deposits were evaluated by complementary electrochemical, physical and computational methods. The use of Gr/SiC as an electrode allowed the tracking of lead-associated redox conversions. The analysis of current transients passed during the deposition revealed an instantaneous nucleation mechanism controlled by convergent mass transport on the nuclei locally randomly distributed on epitaxial graphene. This key observation of the deposit topology was confirmed by low values of the experimentally-estimated apparent diffusion coefficient, Raman spectroscopy and scanning electron microscopy (SEM) studies. First principles calculations showed that the nucleation of Pb clusters on the graphene surface leads to weakening of the interaction strength of the metal-graphene complex, and only spatially separated Pb adatoms adsorbed on bridge and/or edge-plane sites can affect the vibrational properties of graphene. We expect that the lead adatoms can merge in large metallic clusters only at defect sites that reinforce the metal-graphene interactions. Our findings provide valuable insights into both heavy metal ion electrochemical analysis and metal electroplating on graphene interfaces that are important for designing effective detectors of toxic heavy metals.

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“…Based on the Arrhenius' law, the following eqn (4) shows relationship between the diffusion coefficients and the activation energy. 35,36…”

Section: Chronoamperometrymentioning

confidence: 99%