Electroreduction of molecular oxygen on poly-iron-tetraaminophthalocyanine modified electrodes

Abstract

In this work we have investigated the electrocatalytic activity for O2 reduction of monomeric (FePcTA) and polymeric (poly-FePcTA) iron tetraaaminophthalocyanine, deposited on glassy carbon. The activity of the electropolymerized ligand (poly-H2PcTA) was also investigated. Its activity is much lower than the activity of both monomeric and polymeric FePcTA. The electropolymerized FePcTA is more active and stable for O2 reduction than the monomeric species. In contrast to other Fe-phthalocyanines, poly-FePcTA only catalyzes the two-electron reduction of O2 to peroxide. Both monomeric and polymeric Fe species seem to form an adduct with oxygen and this causes a gradual deactivation, However at pH 5.85, using sodium perchlorate as electrolyte, the polymer does not lose its activity for O2 reduction.