G. V. Zhutaevaz, M. R. Tarasevich, M. V. Radina, and I. S. Chernyshova
Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
Received July 01, 2008
Abstract—The electrochemical behavior of composite materials based on phenyl substituted cobalt porphyrins
and Nafion is studied. Several cobalt porphyrins with presumably predictable variation of their hydro-
philic/hydrophobic properties due to different donor and acceptor substituents in the para position of phenyl
rings are synthesized and studied. It is shown that introduction of Nafion into a system with acceptor substitu-
ents results in a significant acceleration of the model oxygen reduction reaction. This allows assuming that a
bond between a proton of the Nafion sulfogroup with the porphyrin active center is most probable in this very
group of porphyrins, which facilitates the protonation step required for activation of the oxygen molecule. A
certain correlation is found between the model reaction of oxygen electroreduction (halfwave potential, reac-
tion rate constant) and Hammett constant varying as dependent on the nature of peripheric substituents.
Key words: phenyl substituted cobalt porphyrins, Nafion, oxygen reduction
DOI: 10.1134/S1023193509090146
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