Electrochemical redox reaction at silicate based electrode–silicate based electrolyte interface

Abstract

The electrochemical redox reactions of ferrocene or ferrocenedimethanol were studied at silicate based electrode–silicate based electrolyte interface. The electrode was prepared from methyltrimethoxysilane sol and graphite particles. The electrolyte consists of silicate matrix obtained from tetramethoxysilane with embedded redox probe and salt solution in propylene carbonate or water. It was prepared with electrodes immersed before gelation occurred. Stable slow scan peak shaped voltammograms were obtained after tens of days elapsed after gel formation. Their shape depends on whether electrode is immersed in liquid electrolyte, sol and gel. For organic solvent based gels the weak dependence of the magnitude of the peak current on time elapsed after gelation, whereas for aqueous based system its substantial decrease is observed. On the results of potential step experiments some features typical for spherical diffusion as well as these indicating penetration of the electrode matrix by organic solvent were observed.