Journal of Electroanalytical Chemistry, Vol.441, No.1-2, 153-160, 1998
Studies of ferrocene derivative diffusion and heterogeneous kinetics in polymer electrolyte by using microelectrode voltammetry
The heterogeneous electron transfer rate constants (k(s)) of seven ferrocene derivatives were estimated using cyclic voltammograms under mixed spherical/semi-infinite linear diffusion and steady-state voltammetry at a microdisk electrode in polymer electrolyte. The k(s) and diffusion coefficient (D) are both 100 to 1000-fold smaller in polymer solvent than in monomeric solvents, and the D and k(s) decrease with increasing polymer chain length. The results conform to the difference of viscosity (eta) or relaxation time (tau(L)) for these different solvents. The k(s) and D increase with increasing temperature, and the activation barriers of the electrode reaction are obtained. The influences of the substituting group in the ferrocene ring on k(s) and D are discussed. The k(s) are proportional to the D of the ferrocene derivatives, which indicates that solvent dynamics control the electrode reaction.
Keywords:SOLID-STATE VOLTAMMETRY;POLY(ETHYLENE OXIDE);MICRODISK ELECTRODES;SOLVENT DYNAMICS;RADICAL-ANION;VOLTAMMOGRAMS;DEPENDENCE;TRANSPORT;INTERFACE