With reference to the United States Los Alamos National Laboratory’s report about a new class of composite catalysts Co-PPy-C (PPy, polypyrrole) which were applied to the oxygen electrode of fuel cells, the Co-PAn-C (PAn, polyaniline) composite catalysts were boldly put forward and successfully prepared, which probably had the oxygen reduction activity. It was found that this composite had obvious catalytic performance, and reached the current density of 128 mA•cm^－2 at the potential －0.2 V (vs. Hg/HgO), and its performance was relatively stable. The catalytic mechanism of ORR (oxygen reduction reaction) on Co-PAn-C was preliminarily studied. The probably existent Co-N sites in the structure influenced the adsorption and desorption processes of oxygen and the reaction intermediates.

Key words: fuel cell, oxygen reduction, metal porphyrin, electrocatalysis