Electrochemical reduction of oxygen: an alternative method to prepare active CoN4 catalysts

An alternative method for preparing active catalysts for oxygen reduction with similar a performance as heat treated cobalt porphyrin on carbon is presented. The catalysts were prepared from cobalt acetate, carbon black and a nitrogen donor. Several nitrogen donors were investigated. The best results were obtained with 2,5-dimethylpyrrole. In this case the activity of the heat treated cobalt porphyrin could be matched. EXAFS indicated that similar active sites were found on both types of catalyst, although in the alternative catalyst some metallic cobalt is also present