Abstract: Phthalocyanine-2,9,16,23-tetracarboxylic acid cobalt complex(1)and phthalocyanine-2,9, 16, 23-tetracarboxyl tetrachloride cobalt complex(2) were synthesized.The glassy carbon electrodes coated with polyethylpyridine film or polyaniline film were made by electrochemical methods.Chemically modified electrodes(CMEs)were prepared by precipitation of 1 from its solution to the electrode coated with the polyethylpyridine film or electrode coated with the polyaniline film, and by precipitation of 2 from its solution to the electrode coated with polyaniline film.Catalytic activities and lifetime of these CMEs were investigated to electroreduction dioxygen in aqueous solution with cyclic voItammogram.ElectrodeⅠcoated with 1 and polyethylpyridine showed activity in 0.2 mol/Lpotassiumchloride aqueous solution.ElectrodeⅡcoated with 1 and polyaniline was the same active as electrode Ⅲ coated with 2 and polyaniline in 1.0 mol/Lhydrogen sulfate aqueous solution which was active during a long continuous operation.Ⅲ had a longer life thanⅠand Ⅱ.

Key words: Cobaltphthalocyanine-2,9,16,23-tetracarboxylic acid, Electrode modified with two films of polymer, Electroreduction