The heat treatment of Co tetraphenylporphyrin chem. modified glassy C electrode was described. The modified electrode by heat treatment [(PCo/GO)h] shows a considerable catalytic activity and stability for O reduction The catalytic activity is still maintained after 3000 circles of cyclic voltammetric scans (100 meV/s) in O saturated 0.05 mol/L H2SO4. The effects of heat treatment temperature from 500 to 1000?on the preparation and catalytic activity of the modified electrode were studied. Using UV-visible spectroscopy the possible structure of products by heat treatment on electrode surface were analyzed. The electrocatalytic and dynamic behaviors for reduction of O at the electrode were investigated by cyclic voltammetry and by rotating disk electrode resp. The rate constant of O reduction at (PCo/GC)h electrode in 0.05 mol/L H2SO4 was measured. The catalytic reduction of O to H2O2 at the electrode is a 2-electron irreversible process.

Key words: OXYGEN, HEAT-TREATMENT, COBALT COMPLEX, REDUCTION REACTION, ROTATION ELECTRODES, DISK ELECTRODES, CARBON ELECTRODES, CHEMICAL MODIFIED ELECTRODE, ELECTRO-CATALYSIS, GLASS ELECTRODE