On the Origin of the Errors of i_k as Estimated from K-L Equation in Rotating Disk Electrode System

Authors

Wei CHEN
Ling-wen LIAO
Zheng-da HE
Yan-xia CHENFollow

Corresponding Author

Yan-xia CHEN(yachen@ustc.edu.cn)

Abstract

Rotating disk electrode system is mainly used to study the kinetics of reactions whose reactants have very low solubility in the electrolyte. For an irreversible reaction, Koutecky-Levich equation (K-L Eq.) is frequently used to deduce the kinetic current i_k). Since K-L Eq. is derived based on the assumption that a system should conform the steady-state diffusion conditions, the data recoded from the actual system which deviates from such a condition, great error may be induced for the i_k estimated. In this work, polarization curves for oxygen reduction reaction at polycrystalline Pt electrode recorded in solutions with various O₂ concentrations and under various electrode rotation speeds have been analyzed systematically. Our analysis reveals that an error of 30% may be introduced by extrapolation to infinite rotation speed in solution with low O₂ concentration or by including the data recorded under very slow electrode rotation speeds. The origins of the error and the ways to avoid such error are discussed.

Graphical Abstract

Keywords

gas electrode reaction, rotating disk electrode, Koutecky-Levich equation, diffusion, mmass transport, oxygen reduction reaction

DOI Link

https://doi.org/10.13208/j.electrochem.131167

Publication Date

2014-10-28

Online Available Date

2014-06-03

Revised Date

2014-05-27

Received Date

2014-01-15

Recommended Citation

Wei CHEN, Ling-wen LIAO, Zheng-da HE, Yan-xia CHEN. On the Origin of the Errors of i_k as Estimated from K-L Equation in Rotating Disk Electrode System[J]. Journal of Electrochemistry, 2014 , 20(5): 131167.
DOI: 10.13208/j.electrochem.131167
Available at: https://jelectrochem.xmu.edu.cn/journal/vol20/iss5/15