Affordable Access

Publisher Website

Voltammetric study of electrocatalysis for dioxygen reduction by trinuclear rutheniumammine complex confined in a polymer membrane

Electrochimica Acta
Publication Date
DOI: 10.1016/s0013-4686(02)00360-2
  • Oxygen Reduction
  • Electrocatalysis
  • Molecular Catalysis


Abstract Electrocatalytic O 2 reduction was studied using a modified electrode coated with a Nafion membrane (Nf) dispersing a trinuclear ruthenium ammine complex ([(NH 3) 5Ru IIIORu IV(NH 3) 4ORu III(NH 3) 5]Cl 6, Ru-red). When measuring cyclic voltammogram under O 2 atmosphere (at 0.5 mV s −1), catalytic currents due to O 2 reduction were found to develop below −0.2 V (vs. Ag/AgCl). Since Ru-red undergoes irreversible decomposition into the mononuclear complexes via the reduced state (Ru III–Ru III–Ru III) (∼−0.1 V), it is suggested that the electrocatalysis originates from the decomposed species (initial active species: Ru II(NH 3) 5(OH 2) and Ru II(NH 3) 4(OH 2) 2) rather than from the Ru-red. Although the present electrocatalyst was also applied to H 2O 2 reduction system, the catalytic activity was found to be poor from the voltammetric behavior. It appeared that the kinetics of the electrocatalysis is much faster in the O 2 reduction than in the H 2O 2 one. A selective and direct catalysis for O 2 reduction into H 2O was suggested from a ring–disk voltammogram to take place by an aggregate of the mononuclear ruthenium complexes in the polymer matrix. In addition, it was found that electrocatalytic O 2 reduction involves a slow kinetic process, so that factors affecting the overall kinetics were discussed in terms of the catalysis mechanism.

There are no comments yet on this publication. Be the first to share your thoughts.