Research on chemically modified electrodes: Part XX. Catalysis of dioxygen reduction at the electrochemically polymerized iron protoporphyrin film electrode

Abstract

The electrocatalytic reduction of dioxygen and its kinetic process at the electrochemically polymerized iron protoporphyrin film glassy carbon electrode (Poly(FePP)/GC) in various pH buffer solutions has been studied by cyclic voltammetry and rotating disk and ring-disk electrode voltammetry. At limiting current potentials, the Poly(FePP)/GC electrode is able to catalyze the four-electron reduction of dioxygen to water in different pH buffer solutions. The mechanism of the catalysis may include a process whereby dioxygen molecules penetrate into the polymerized film and are catalyzed by active bimetal centers. The surface of the Poly(FePP)/GC electrode has been analyzed by ESCA. It is shown that the deactivation of the electrode for dioxygen reduction probably is due to the loss of central metal ions on the porphyrin rings.