Advertisement

Journal of Applied Electrochemistry

, Volume 17, Issue 1, pp 33–48 | Cite as

Kinetics and mechanism of anodic oxidation of chlorate ion to perchlorate ion on lead dioxide electrodes

  • N. Munichandraiah
  • S. Sathyanarayana
Papers

Abstract

The kinetics and mechanism of anodic oxidation of chlorate ion to perchlorate ion on titanium-substrate lead dioxide electrodes have been investigated experimentally and theoretically. It has been demonstrated that the ionic strength of the solution has a marked effect on the rate of perchlorate formation, whereas the pH of the solution does not influence the reaction rate. Experimental data have also been obtained on the dependence of the reaction rate on the concentration of chlorate ion in the solution at constant ionic strength. With these data, diagnostic kinetic criteria have been deduced and compared with corresponding quantities predicted for various possible mechanisms including double layer effects on electrode kinetics. It has thus been shown that the most probable mechanisms for anodic chlorate oxidation on lead dioxide anodes involve the discharge of a water molecule in a one-electron transfer step to give an adsorbed hydroxyl radical as the rate-determining step for the overall reaction.

Keywords

Ionic Strength Perchlorate Chlorate Anodic Oxidation Transfer Step 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Nomenclature

β

anodic energy transfer coefficient

φ2

potential of outer Helmholtz plane with respect to solution

φM

potential of metal with respect to solution

ɛ

dielectric constant of solution

ɛ2

permittivity of free space

θ

faradaic efficiency for anodic chlorate oxidation

A

adsorbed intermediate in Reaction 2

B

bulk species in Reaction 2

cA

concentration of A at outer Helmholtz plane

cB

concentration of B at outer Helmholtz plane

cB0

concentration of B in bulk

cClO3/0

concentration of ClO 3 in bulk

cClO4/0

concentration of ClO 4 in bulk

E

electrode potential corrected for ohmic drop

Ea

electrode potential as measured against reference electrode

Es0

standard electrode potential of Reaction 2

Ez

potential of zero charge of the anode in test solution

F

Faraday constant

f

F/(RT)

It

current at anode

IOER

current used for oxygen evolution reaction at anode

I

current used for chlorate oxidation (=ItIOER) at anode

it

It/anode area

iOER

IOER/anode area

i

I/anode area

J

total concentration of (uni-univalent) electrolytes in solution

K2

integral capacitance of compact part of double layer

Ks

standard rate constant for Reaction 2, corrected for double layer effects

ns

number of electrons involved in Reaction 2

p

∂ln(−i)/∂lnc ClO3 /0

qM

charge density on metal surface

Q1

quantity of electricity passed in given time interval

QOER

quantity of electricity required for oxygen evolution reaction in given time interval

Rω

ohmic resistance between anode and Luggin tip

R

gas constant

r

∂ln(−i)/∂lnJ

s

∂ln(−i)/∂ pH

T

absolute temperature

t

∂ln(−i)/∂E

u

(ɛɛ2RT/2π)1/2

V

volume of gases evolved in given time interval

VH

volume of hydrogen evolved in given time interval

ZB

charge on species B

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    W. Oechsli,Z. Elekrochem. 9 (1903) 807.Google Scholar
  2. [2]
    C. W. Bennett and E. L. Mack,Trans. Electrochem. Soc. 29 (1916) 323.Google Scholar
  3. [3]
    N. V. S. Knibbs and H. Palfreeman,Trans. Faraday Soc. 16 (1920) 402.Google Scholar
  4. [4]
    K. Sugino and S. Aoyagi,J. Electrochem. Soc. 103 (1956) 166.Google Scholar
  5. [5]
    T. Osuga, S. Fujii, K. Sugino and T. Sekine,116 (1969) 203.Google Scholar
  6. [6]
    K. C. Narasimham, S. Sundararajan and H. V. K. Udupa,108 (1961) 798.Google Scholar
  7. [7]
    Yung-Chao Chu and Shih-Hsiung Chin,Chem. Abs. 67 (1967) 7479e.Google Scholar
  8. [8]
    M. P. Grotheer and E. H. Cook,Electrochem. Technol. 6 (1968) 221.Google Scholar
  9. [9]
    O. de Nora, P. Gallone, C. Traini and G. Meneghini,J. Electrochem. Soc. 116 (1969) 146.Google Scholar
  10. [10]
    A. J. Bard and L. R. Faulkner, ‘Electrochemical Methods: Fundamentals and Applications’, John Wiley, New York (1980) p. 28.Google Scholar
  11. [11]
    H. Wroblawa, Z. Kovac and J. O'M. Bockris,Trans. Faraday Soc. 61 (1965) 1523.Google Scholar
  12. [12]
    P. Delahay, ‘Double Layer and Electrode Kinetics’, Interscience Publishers, New York (1965).Google Scholar
  13. [13]
    J. P. Carr, N. A. Hampson and R. Taylor,J. Electroanal. Chem. 27 (1970) 109.Google Scholar
  14. [14]
    N. Munichandraiah and S. Sathyanarayana,J. Appl. Electrochem. 17 (1987) 22.Google Scholar
  15. [15]
    A. I. Vogel, ‘A Text Book of Quantitative Inorganic Analysis’, 3rd edn, The English Language Book Society and Longmans Green & Co. Ltd, London (1961) p. 313.Google Scholar
  16. [16]
    D. J. Pietrzyk and C. W. Frank, ‘Analytical Chemistry’, Academic Press, New York (1979) p. 557.Google Scholar
  17. [17]
    S. Sathyanarayana, unpublished results.Google Scholar

Copyright information

© Chapman and Hall Ltd 1987

Authors and Affiliations

  • N. Munichandraiah
    • 1
  • S. Sathyanarayana
    • 1
  1. 1.Department of Inorganic and Physical ChemistryIndian Institute of ScienceBangaloreIndia

Personalised recommendations