OXYGEN REDUCTION IN ACID-MEDIA - EFFECT OF HEAT-TREATMENT ON THE ACTIVITY OF CO NAPHTHALOCYANINE (2,3)-ISOMER IMPREGNATIONS ON CARBON-BLACKAND THE LIFE TEST COMPARISON WITH THE (1,2)-ANALOG ISOMER MIXTURE

O-2 reduction has been investigated using rotating disc electrode and voltammetric techniques for naphthalocyanine CoNPc(2,3) impregnations supported on two kinds of carbon blacks according to the same procedur e as that described by A. Biloul, O. Contamin, G. Scarbeck, M. Savy, B . Palys, J. Riga and J. Verbist, J. Electroanal. Chem., 365 (1994) 239 . Samples were also characterized by Fourier transform IR and X-ray ph otoelectron spectroscopy techniques which indicate a bilayer structure . An optimized thermal treatment yielded initial activities almost ide ntical with those of the NPcCo(1,2) isomer mixture. However, after a 1 0 day stay in acidic solutions, the activities dropped in all cases an d became comparable with those corresponding to non-thermally treated samples. Thus the isomer structural effect is relatively minor with Co NPc.