Origin of the electrocatalytic properties for oxygen reduction of some heat-treated polyacrylonitrile and phthalocyanine cobalt compounds adsorbed on carbon black as probed by electrochemistry and x-ray absorption spectroscopy

Abstract

Electrochemical and X-ray absorption techniques have been used to determine the influence of heat treatment in electrocatalytic activity for O 2 reduction for two cobalt catalysts. The catalysts are cobalt phthalocyanine (catalyst 1) and polyacrylonitrile +cobalt acetate (catalyst 2) adsorbed on carbon black and heat treated at several temperatures. A maximum for the catalytic activity was obtained for PcCo at 850 o C and for the PAN+Co catalyst at 950 o C with subsequent decrease. The results obtained by XANES and EXAFS data clearly show that metallic cobalt aggregates with different size are synthetized in the range of increased activity