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
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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.
Keywordsbromate-anion Br2/Br− redox couple comproportionation redox-mediating autocatalysis convective diffusion kinetic layer
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- 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
- 3.Tanaka, Y., Chapter in: Ion exchange membranes. Fundamentals and applications (Second Edition), Elsevier B.V., 2015.Google Scholar
- 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
- 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
- 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.Nernst, W., Theorie der Reaktionsgeschwindiglceit in heterogenen Systemen, Z. Phys. Chem., 1904, vol. 47, p. 52.Google Scholar
- 11.Nernst, W, and Merriam, E.S., Zur Theorie des Rest-stroms, Z. Phys. Chem, 1905, vol. 53, P. 235.Google Scholar
- 12.Levich, V.G., Physicochemical Hydrodynamics, Englewood Cliffs, NJ: Prentice-Hall, 1962.Google Scholar
- 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.Cussler, E.L., Diffusion: Mass Transfer in Fluid Systems, Second ed., New York: Cambridge University Press, 1997.Google Scholar
- 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