Use of a Metal-Containing Plasma Polymer Coating to Prepare a Prussian Blue Surface Modified Electrode

Graphite electrodes are surface modified by coating them in a glow-discharge plasma chamber with iron pentacarbonyl (the resulting deposit is called an iron-containing plasma deposit) or iron pentacarbonyl and ethane in a 1:1 molar ratio (the resulting deposit is called an iron-containing plasma polymer). Both modified electrodes have surface bound redox-active iron centers that are characterized by cyclic voltammetry. Either of these surface modified electrodes may be further modified by electrochemical reaction with hexacyanoferrate to form surface adherent Berlin green, Prussian blue, and Everitt's salt, which may be interchanged reversibly by changing the potential of the electrode. Well-defined cyclic voltammograms [formula-omitted] are obtained in neutral aqueous solution by using the Prussian blue surface modified working electrode. Surface adherence of the Prussian blue persists over several thousand cycles. Concentrations of surface adherent redox-active Prussian blue increase to as high as 2 X 10-7 mol/cm2 with increased nominal coatings of iron-containing plasma polymer or iron-containing plasma deposit on the graphite electrode surface. The Prussian blue modified electrode is permeable to both K+ and Na+ ions, and the kinetics of the oxidation-reduction processes at the electrode surface are controlled by diffusion of the electrolyte cation in and out of the lattice. Experiments with mixed electrolytes in aqueous solution demonstrate a cation preference in the order K+ > Na+ >> Li+. © 1983, American Chemical Society. All rights reserved.

Duke Scholars

Author Alvin L. Crumbliss Chemistry