Chemically modified carbon fibre electrodes part II. Characterization of trimethylsilanized carbon fibres by reduction of adsorbed o-nitrophenol

Abstract

Bulk-functionalized carbon fibres [1], i.e. distorted carbon fibres with a high concentration of oxygen-containing functional groups not only on their surface but also in their bulk, were tested as a precursor for the preparation of chemically modified carbon electrodes. Reactivity and concentration of the functional groups were characterized by trimethylsilanization as a model reaction. Trimethylsilanized areas are highly hydrophobic—they can be discriminated from non-modified areas via electrochemical reduction of strongly adsorbed o-nitrophenol (o-NPh). It is concluded that trimethylsilanized electrodes based on bulk-functionalized carbon fibres are not only covered with o-NPh on their surface but also contain it on “internal sites”. In contrast, conventional high-temperature surface oxidation of carbon fibres and subsequent trimethylsilanization is not very effective, as this modification technique is mainly restricted to the few edge-sites of the graphite-like carbon layers.