SHORT-TIME PULSE VOLTAMMETRIC STUDIES OF FAST HETEROGENEOUS ELECTRON-TRANSFER REACTIONS

The use of short time pulse voltammetry for the measurement of fast heterogeneous electron transfer kinetics has been examined. Pulse times as short as 5 mus were used to study oxidation of ferrocene and anthracene at 5 mum radius Pt electrodes in acetonitrile and dichloromethane. The only correction of the experimental voltammograms was a subtraction of background currents, smaller than 10% of the total cur-rents measured. The kinetic parameters were obtained by a direct comparison of the experimental voltammograms with those calculated by using a model for a quasi-reversible electrode reaction. The results of the analysis did not provide statistical evidence for the need of correction of the data for ohmic potential drop. The standard rate constants (uncorrected for double-layer effects) for FeCp2 in acetonitrile and dichloromethane were found to be 1.23+/-0.31 cm s-1 and 0.35+/-0.09 cm s-1 respectively. For anthracene in acetonitrile and dichloromethane, k(s) was determined to be 0.73+/-0.37 and 0.20+/-0.05 cm s-1.