Composite electrocatalysts for molecular O-2 reduction in alkaline solution with higher activity than a pyrolyzed mixture of cobalt tetramethoxy-phenylphorphyrin (CoTMPP)+carbon black were synthesized by pyrolyzing a mixture Of CoCO3 + TMPP + carbon black in an inert atmosphere. Maximum activation was observed at 800 degreesC. Neither Co3O4 + TMPP nor CoCO3 + TMPP, both mixed with carbon black after pyrolysis, showed better activity than pyrolyzed CoTMPP + carbon black at 900 degreesC, which points to the presence of carbon as a crucial factor during pyrolysis. Various Co/TMPP mole ratio and CoCO3/carbon weight ratio were tested. Maximum activity was observed with 1/1 mole ratio and 5% weight ratio, respectively. (C) 2003 Elsevier Science B.V. All rights reserved.