Catalysis of Electrochemical Reactions at Redox Polymer Coated Electrodes. Mediation of the Fe(III)/Fe(II) Oxido-Reduction by a Polyvinylpyridine Polymer Containing Coordinatively Attached Bisbipyridine Chlororuthenium Redox Centers.

The (Ru(bpy)/sub 2/Cl-poly(4-vinylpyridine)) redox polymer catalyzes the oxidation of Fe(II) into Fe(III) in 1 M HCl in a quite efficient manner both in terms of current and potential. Quite substantial portions of the film thickness are active in the catalytic system. Providing a good example of the interest of redox polymer coatings in the catalysis of electrochemical reactions as a result of the three-dimensional dispersion of the reacting centers. The polymer is also able to catalyze, although to a lesser extent, the reduction of Fe(III) to Fe(II) in the same medium in spite of the fact that the standard potential of the Ru(III)/Ru(II) couple is positive to that of the Fe(III)/Fe(II) couple. Analysis of the experimental data and the optimization of the catalytic efficiency by means of previously developed kinetic models demonstrate the validity of these models both in terms of the limiting currents and half-wave potentials featuring the catalytic process.