Abstract: Tetraphenylporphyrin and its cobalt complex were synthesized under different conditions and characterized by infrared spectroscopy and 1H nuclear magnetic resonance. The influences of catalyst, solvent, and temperature on the yield of tetraphenylporphyrin were investigated. The effect of heat treatment on structure of cobalt tetraphenylporphyrin at different temperatures was investigated using X-ray photoelectron spectroscopy. Cathodic polarization curves of air electrode loaded with cobalt tetraphenylporphyrin were measured to evaluate the performance of heat-treated catalysts. The results showed that using p-nitrobenzoic acid as catalyst and nitrobenzene as solvent, the yield of tetraphenylporphyrin was about 32% at 200 ℃. The moiety Co[KG-45x]-[KG-20x]N4 of cobalt tetraphenylporphyrin was in a critical state under 600 ℃ heat treatment but was destroyed partly at 800 ℃. Thus the catalytic activity of cobalt tetraphenylporphyrin heat-treated at 600 ℃ was higher than that heat-treated at 800 ℃.

Key words: cobalt, tetraphenylporphyrin, heat treatment, air electrode, electrocatalysis, oxygen reduction