A UV-VISIBLE STUDY OF THE ELECTROPOLYMERIZATION OF COTAPP AT VITREOUSCARBON AND INVESTIGATION OF ITS CATALYTIC ACTIVITY TOWARDS THE ELECTROREDUCTION OF DIOXYGEN

Cobalt tetra(o-aminophenyl)porphyrin (CoTAPP) was electropolymerized f rom an acetonitrile solution containing 0.1 M (CoTAPP), at a vitreous carbon electrode, leading to a polymer film, poly(CoTAPP). UV-visible differential reflectance spectra (UVDRS) were recorded respectively. d uring the electropolymerization process and during the oxygen reductio n reaction (orr) at a poly(CoTAPP) electrode. Comparison between the U V-visible spectra of the poly(CoTAPP) electrode, recorded under N-2 an d under O-2 in a 0.5 M H2SO4 solution, shows dearly the band associate d with the charge-transfer process between the central metal ion and t he complex ligand. The initial reduced state corresponding to the acti ve state for the oxygen reduction reaction was confirmed to be Co(II) species. (C) 1998 Elsevier Science S.A. All rights reserved.