Preparation of Heat-treated Iron-Phthalocyanine Cathode Catalysts and their Active Sites Evaluation for Oxygen Reduction Reaction in Alkaline Media

摘要

A heat-treated iron-phthalocyanine cathode catalyst was used to oxygen reduction reaction (ORR) in alkaline media. Heat-treatment temperature was determined by thermogravimetric analysis. Physicochemical characterizations of the electrocatalysts were performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The electrochemical activities of the catalysts were examined for ORR in alkaline media using rotating disk electrode (RDE) system. Acid treatment of ironphthalocyanine was conducted to assess the role of metal in the nitrogen-containing non-noble metal catalyst. Durability studies were carried out by means of an accelerated durability test of 4000 voltametric cycles. ORR activities were higher when the catalysts were treated at lower temperature. As a result of the XPS and ORR tests, the transition metal itself is not an active site for ORR. Nitrogen appeared to be the active site of heattreated iron phthalocyanines for ORR in alkaline media.