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Grinevitch, V.V.; Резніченко, В. А.; Model, M.S.; Kuznetsov, S. A.; Polyakov, E. G.; Stangrit, P.T.

doi:10.1023/a:1003443811387

Cited by 21 publications

(18 citation statements)

References 11 publications

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“…A linear relationship between the current and reciprocal square root of time was obtained (Figure 7). Accordingly the cathodic current can be expressed by the Cottrell's equation (31) It 1/2 = nFD 1/2 Nb(V) AC/π 1/2 [7] From the slope of the corresponding plot (Figure 7), the diffusion coefficient of Nb(V) at 1073 K was obtained as 1.32⋅10 -5 cm 2 s -1 . The diffusion coefficient of Nb(IV) determined by chronoamperometry 1.82⋅10 -5 cm 2 s -1 was larger than for Nb(V).…”

Section: Resultsmentioning

confidence: 99%

Electrochemistry of the Nb(V)/Nb(IV) Redox Couple in the KCl-K₂NbF₇ Melt

Popova¹,

Kuznetsov²

2010

ECS Trans.

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The electrochemistry of the Nb(V)/Nb(IV) redox couple in the KCl-K 2 NbF 7 melt has been studied at 1073-1173 K on glassy carbon and platinum electrodes by transient electrochemical techniques. The diffusion coefficients of Nb(V) and Nb(IV) were determined by linear sweep voltammetry, chronopotentiometry and chronoamperometry. The values obtained by these methods at the different substrates are also in a good agreement. Diffusion coefficients decreased when niobium oxidation state increased, while the activation energies for diffusion increased. The standard rate constants of charge transfer (k s ) on platinum and glassy carbon electrodes for Nb(V)/Nb(IV) redox couple were calculated on the basis of cyclic voltammetry data at a sweep rate 0.75 < ν ≤ 2.0 V s -1 , where a mixed diffusion and electron-transfer control was observed. It was found that k s increased with increasing temperature and values of k s obtained at platinum electrode were higher than at a glassy carbon electrode. The values of the standard rate constants testify that the redox process Nb(V) + e -↔ Nb(IV) proceeds quasi-reversibly, mostly under diffusion control.

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Section: Resultsmentioning

confidence: 99%

Electrochemistry of the Nb(V)/Nb(IV) Redox Couple in the KCl-K₂NbF₇ Melt

Popova¹,

Kuznetsov²

2010

ECS Trans.

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“…In recent years, the behavior of oxygen, especially of oxygen-containing niobium species, in electrochemical processes has drawn the attention of many researchers [28][29][30][31][32][33][34]. This fact is apparent: oxygen is one of the most harmful impurities in niobium and adversely affects the mechanical and electrophysical properties of all refractory metals.…”

Section: Creation Of New Materialsmentioning

confidence: 99%

“…Thus, we have considered the cathodic behavior of oxygen in the melts, which initially contained oxygen-free niobium complex anions NbF 7 2and gradually obtained more and more niobium monooxofluoride anions, evidently NbOF 5 2or NbOF 6 3- [34], generated by NbO anode dissolution. The final point of such monitoring should be the situation when all niobium in the melt is represented by these ions, with no initial niobium fluoride anions.…”

Section: S a Kuznetsovmentioning

confidence: 99%

Electrochemistry of refractory metals in molten salts: Application for the creation of new and functional materials

Kuznetsov

2009

Pure and Applied Chemistry

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The processes of refractory metal complex electroreduction in transition from chloride to chloride-fluoride and oxofluoride melts have been studied. Decrease of the stage number of process complex electroreduction to metal and the possibility of a large number of electrons transferred in a single electrochemical stage on increasing the melt basicity has been established. It was shown that decreasing the stage number of electrode processes can be achieved by the change in anion composition (the first coordination sphere) and, in a number of cases, by the change in the cation composition (the second coordination sphere). With the melt basicity increase, a transition from reversible processes of the complex to metal discharge irreversible ones is observed, as a rule. The knowledge of electrode and chemical reactions accompanying the electroreduction of refractory metals and the study of the processes of alloy formation allow us to obtain novel niobium compounds and functional materials.

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“…However, how to employ a hydrothermal synthesis method to synthesize a five coordinated niobium oxide fluoride compound and explore its coordination mode, which remains largely unexplored. Few of reported five coordinated niobium oxide fluoride compounds were synthesized by the reactions of conventionally [10][11][12].…”

Section: Introductionmentioning

confidence: 99%