Electroactive ceramic carbon electrode impregnated with n-alkanes

The carbon ceramic electrodes impregnated with n-alkanes (hexane, decane or hexadecane) containing redox probe (decamethylferrocene) were prepared. The electrodes consist of graphite powder, homogeneously dispersed in hydrophobic silica matrix. The matrix was obtained from organically modified silicate - methyltrimethoxysilane by sol-gel process. After gelation and drying it was filled with n-alkane by immersion. The properties of the electrode were investigated by cyclic voltammetry and chronoamperometry in aqueous halide solution. The width of potential window depends to some extent on anion present in aqueous phase. Approximately symmetric cyclic voltammograms, which can be attributed to the reversible electrochemical oxidation-reduction of decamethylferrocene within the organic phase were obtained with the electrode modified with redox probe solution. The shape, magnitude and position on the potential scale depends on the organic solvent and the salt present in aqueous phase. The reasons of this behavior were discussed. It has been concluded that the mechanism of the electrode process involves electron transfer between graphite particle and the redox probe in the organic phase, followed by anion transfer from the aqueous phase. It probably occurs at three phase junction. The similarities between the response of the studied electrode and that of ensemble of ultramicroelectrodes were also found.