Ceramic Carbon Electrode Modified with Redox Probe and Salt Solution in Hydrophobic Polar Solvent

Ceramic carbon electrode modified with redox probe and salt solution in hydrophobic polar solvent was prepared and studied. The electrode consisting of graphite powder, homogeneously dispersed in hydrophobic silicate matrix, was prepared from the mixture of methyltrimethoxysilane based sol and graphite powder by sol-gel method. Then it was immersed in t-butylferrocene and tetrabutylammonium perchlorate solution in nitrobenzene. The electrode properties were investigated by cyclic voltammetry and chronoamperometry in KNO3 solutions of different concentration. Linear polarization of the electrode towards positive potentials results in peak shaped symmetric voltammogram originating from electrooxidation of t-butylferrocene. The peak current is few times larger than that obtained when organic phase does not contain salt. It is also proportional to the concentration of the redox probe in organic phase and salt in aqueous phase, whereas the midpeak potential is almost not affected by these factors. The reasons of these effects are discussed.