ELECTROREDUCTION OF OXYGEN AND HYDROGEN-PEROXIDE ON IRON TETRA(P-METHOXYPHENYL)PORPHYRIN DISPERSED ON CARBON-BLACK

Redox-conversions (CVA) and electroreduction reactions of O-2 and H2O2 (RRDE) in aqueous solutions pH 0.3 - 14) on iron tetra(p-methoxypheny l)porphyrin, FeTMPP, dispersed on carbon black, are analyzed. It is co ncluded that there are two types of active sites: FeTMPP molecules ads orbed on oxygen-containing functional groups of the carbon carrier and FETMPP ''free'' molecules, whose electrochemical behavior is similar to their behavior in a solution. On molecules of the first type, elect roreduction of O-2 proceeds to H2O2 with the acceleration in the stage O-2 + H+ + e --> HO2.. On molecules of the second type after the redo x-conversion of the central ion Fe(III)/Fe(II), the consecutive four-e lectron process of O-2 electroreduction to H2O occurs with the interme diate formation of H2O2, which is reduced at the instant of its format ion.