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Russian Journal of Electrochemistry

, Volume 55, Issue 5, pp 458–466 | Cite as

Bromate-Anion Electroreduction at Rotating Disc Electrode under Steady-State Conditions: Comparison of Numerical and Analytical Solutions for Convective Diffusion Equations in Excess of Protons

  • A. E. AntipovEmail author
  • M. A. VorotyntsevEmail author
  • D. V. Konev
  • E. M. Antipov
Article
  • 1 Downloads

Abstract

The article contains results of numerical analysis of convective-diffusion transport equations for the components of the bromate anion electrochemical reduction process at rotating disk electrode via the redox-mediator autocatalysis (EC″) mechanism. The problem is solved taking into account the difference in the diffusion coefficients of the components. It is assumed that the concentration of protons inside the solution is constant, including the diffusion layer, due to its high value compared to the concentration of bromate-anions. Comparison of the obtained results with the predictions of an approximate analytical study of the same system (Vorotyntsev, M.A., Antipov, A.E., Electrochim. Acta, 2017, vol. 246, p. 1217) confirms the adequacy of the developed analytical approach to the calculating of both the concentration profiles of the system’s components (with the exception of the case of very thick diffusion layer) and the current density for a wide range of external parameters: the solution composition, rate of the comproportionation reaction, the convection intensity (the electrode rotation velocity) and the passing current.

Keywords

bromate-anion Br2/Br redox couple comproportionation redox-mediating autocatalysis convective diffusion kinetic layer 

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References

  1. 1.
    Tolmachev, Y.V., Piatkivskyi, A., Ryzhov, V.V, Konev, D.V, and Vorotyntsev, M.A., Energy cycle based on a high specific energy aqueous flow battery and its potential use for fully electric vehicles and for direct solar-to-chemical energy conversion, J. Solid State Electrochem., 2015, vol. 19, p. 2711.CrossRefGoogle Scholar
  2. 2.
    Tolmachev, Yu.V. and Vorotyntsev, M.A., Fuel Cells with Chemically Regenerative Redox Cathodes, Russ. J. Electrochem., 2016, vol. 50, p. 403–411.CrossRefGoogle Scholar
  3. 3.
    Tanaka, Y., Chapter in: Ion exchange membranes. Fundamentals and applications (Second Edition), Elsevier B.V., 2015.Google Scholar
  4. 4.
    Trushkina, O.A., Fedorovich, N.V., and Botuchova, G.N., Hidden limiting currents for electroreduction of the second group anions, Russ. J. Electrochem., 1995, vol. 32, p. 857.Google Scholar
  5. 5.
    Skunik, M. and Kidesza, P.J. Phosphomolybdate-modified multi-walled carbon nanotubes as effective mediating systems for electrocatalytical reduction of bromate, Anal. Chim. Acta, 2009, vol. 631, p. 153.CrossRefGoogle Scholar
  6. 6.
    Vorotyntsev, M.A., Konev, D.V, and Tolmachev, Y.V., Electroreduction of halogen oxoanions via autocatalytic redox mediation by halide anions: novel EC” mechanism. Theory for stationary 1D regime, Electrochim. Acta, 2015, vol. 173, p. 779.CrossRefGoogle Scholar
  7. 7.
    Vorotyntsev, M.A., Antipov, A.E., and Konev, D.V., Bromate anion reduction: novel autocatalytic (EC”) mechanism of electrochemical processes, Its implication for redox flow batteries of high energy and power densities, Pure Appl. Chem., 2017, vol. 89.  https://doi.org/10.1515/pac-2017-0306
  8. 8.
    Antipov, A.E. and Vorotyntsev, M.A., Bromate anion electroreduction on inactive RDE under steady-state conditions. Numerical study of ion transport processes and comproportionation reaction, Russ. J. Electrochem., 2016, vol. 52, p. 925.CrossRefGoogle Scholar
  9. 9.
    Antipov, A.E., Vorotyntsev, M.A., Tolmachev, Y.V. et al., Electroreduction of bromate anion in acidic solutions at the inactive rotating disc electrode under steady-state conditions: Numerical modeling of the process with bromate anions being in excess compared to protons, Doklady, Phys. Chem, 2016, vol. 468, p. 141.CrossRefGoogle Scholar
  10. 10.
    Nernst, W., Theorie der Reaktionsgeschwindiglceit in heterogenen Systemen, Z. Phys. Chem., 1904, vol. 47, p. 52.Google Scholar
  11. 11.
    Nernst, W, and Merriam, E.S., Zur Theorie des Rest-stroms, Z. Phys. Chem, 1905, vol. 53, P. 235.Google Scholar
  12. 12.
    Levich, V.G., Physicochemical Hydrodynamics, Englewood Cliffs, NJ: Prentice-Hall, 1962.Google Scholar
  13. 13.
    Vorotyntsev, M.A. and Antipov, A.E., Bromate electroreduction from acidic solution at rotating disc electrode. Theory of steady-state convective-diffusion transport, Electrochim. Acta, 2017, vol. 246, p. 1217.CrossRefGoogle Scholar
  14. 14.
    Antipov, A.E. and Vorotyntsev, M.A., Bromate anion electroreduction on RDE under steady state conditions in excess of protons: numerical solution of the convection-diffusion equations with equal diffusion coefficients of components, Russ. J. Electrochem., 2017, vol. 54, p. 62.CrossRefGoogle Scholar
  15. 15.
    Cortes, C.E.S. and Faria, R.B., Revisiting the kinetics and mechanism of bromate-bromide reaction, J. Brazilian Chem. Soc., 2001, vol. 12, p. 775.CrossRefGoogle Scholar
  16. 16.
    Cortes, C.E.S. and Faria, R.B., Kinetics and mechanism of bromate-bromide reaction catalyzed by acetate, Inorg. Chem., 2004, vol. 43, p. 1395.CrossRefGoogle Scholar
  17. 17.
    Schmitz, G., Kinetics of the bromate-bromide reaction at high bromide concentrations, Int. J. Chem. Kinet., 2007, vol. 39, p. 1721.CrossRefGoogle Scholar
  18. 18.
    Pugh, W., The stability of bromic acid and its use for the determination of bromide in bromates and in chlorides, Trans. Roy. Soc. S. Afr., 1932, vol. 20, p. 327.CrossRefGoogle Scholar
  19. 19.
    Vorotyntsev, M.A. and Antipov, A.E., Reduction of bromate anion via autocatalytic redox-mediation by Br2/Br redox couple. Theory for stationary 1D regime. Effect of different Nernst layer thicknesses for reactants, J. Electroanal. Chem., 2016, vol. 779, p. 146.CrossRefGoogle Scholar
  20. 20.
    Bruno, T.J. and Lide, D.R., CRC Handbook of Chemistry and Physics, 97th Edition, ed. Haynes, W.M., Boca Raton, FL: CRC Press, 2015.Google Scholar
  21. 21.
    Cussler, E.L., Diffusion: Mass Transfer in Fluid Systems, Second ed., New York: Cambridge University Press, 1997.Google Scholar
  22. 22.
    Antipov, A.E. and Vorotyntsev, M.A., Maximum current density for bromate anion electroreduction on RDE: asymptotic behavior for large diffusion layer thicknesses, Russ. J. Electrochem., 2018, vol. 54 (in press).Google Scholar

Copyright information

© Pleiades Publishing, Ltd. 2019

Authors and Affiliations

  1. 1.Mendeleev University of Chemical TechnologyMoscowRussia
  2. 2.Lomonosov Moscow State UniversityMoscowRussia
  3. 3.Institute of Problems of Chemical PhysicsRussian Academy of SciencesChernogolovka, Moscow oblastRussia
  4. 4.UMR 6302 CNRS-Université de BourgogneDijonFrance

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