Theory of coupled electrochemical and chemical reactions, response to a potential step

Journal Article · Mon Dec 01 04:00:00 EST 1986 · J. Electrochem. Soc.; (United States)

DOI:https://doi.org/10.1149/1.2108462· OSTI ID:6800347

Lessner, P; Winnick, J; Mc Larnon, F R; Cairns, E J

The equations and assumptions that allow the derivation of the analytic form of the current transient for a small potential step are discussed. The equations are generalized so that they are applicable to the electrode reaction: s/sub o/O + ne in equilibrium s/sub r/R where s/sub o/ and s/sub r/ are not necessarily equal. Then a system with a homogeneous reaction in solution coupled to the electrode reaction is considered. The treatment includes the case of a solution-phase homogeneous reaction that takes place at a rate comparable to that of the heterogeneous reaction. The current response to a potential step in the linear overpotential region is solved numerically for both a first-order homogeneous reaction and a homogeneous reaction involving dissociation-dimerization. Using this model the exchange current density and diffusion parameter of the heterogeneous reaction can be determined as can the rate constants of the homogeneous reaction. It is shown that there is a range of parameters wherein the electrode current response is most sensitive to the values of the homogeneous rate constants. The results for the two homogeneous kinetic models are qualitatively similar but differ quantitatively.

• Research Organization: Applied Science Div., Lawrence Berkeley Lab. and Dept. of Chemical Engineering, Univ. of California, Berkeley, CA 94720
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6800347
• Journal Information: J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 133:12; ISSN JESOA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
CURRENT DENSITY
DIFFUSION
DIMERIZATION
DISSOCIATION
ELECTRIC POTENTIAL
ELECTRICAL TRANSIENTS
ELECTROCHEMISTRY
ELECTRODES
EQUATIONS
KINETICS
MATHEMATICAL MODELS
POLYMERIZATION
REACTION KINETICS
TRANSIENTS
VOLTAGE DROP