CHARGE TRANSFER RATE CONSTANTS FOR THE REDUCTION OF COBALTOCENIUM AT ACCUMULATED N-SI ELECTRODES

摘要

A theoretical description of heterogeneous charge transfer rate constants has been developed for accumulated semiconductor electrodes in contact with outer sphere redox couples. Analysis of the rate constants using a Fermi Golden Rule formalism in a nonadiabatic electron transfer framework has facilitated a theoretical comparison between the rate constants of metal; and accumulated semiconductor electrodes in contact with a common electrolyte-redox couple solution. Chronoamperometric measurements of n-Si electrodes in contact with CH3OH-cobaltocenium (CoCp(2))(+)-CoCp(2) have been performed to investigate these predictions experimentally. A standard rate constant, k(0), of (2-4) x 10(-2) cm s(-1) was obtained for n-Si/CH3OH-CoCp(2)(+/0) contacts, while the CoCp(2)(+/0) redox couple was found to be electrochemically reversible (k(0) > 0.1 cm s(-1)) at Hg electrodes under the same conditions. [References: 84]