Kinetics of Redox Couples at Solid Electrodes*): I‐Ferro‐Ferricyanide System in Nearly Neutral Media on Polycristalline Spinel Manganites MeMn2O4 (Me = Cu, Ni and Al) Thermally Deposited on Platinum Grids

The charge transfer kinetics of the redox couple Fe(CN)64‐/Fe(CN)63‐ is studied on three polycristalline spinel oxides, the resistivity of which increases in the order: CuMn2O4, NiMn2O4, and AlMn2O4. The electrode is a vibrating grid on which the oxides have been thermally deposited. A diffusion overvoltage is observed on CuMn2O4 and NiMn2O4, with currents of the same order of magnitude as on Pt. A reaction overvoltage is observed on AlMn2O4, with currents which are two orders of magnitude smaller. In all cases the cathodic current is partially inhibited.