Platinum-free electrocatalysts for Oxygen Reduction Reaction

At present, platinum and its alloys are the best cathode catalysts for oxygen reduction in PEM fuel cells. However, since this metal is scarce and expensive, there is a strong effort to find alternative catalysts. Catalysts based on iron and cobalt ions seem to be a good and promising alternative to platinum [1]. Moreover, in the literature it is underlined the importance of the nature and behaviour of the catalyst support. Activated carbons can be used to support catalysts and electrocatalysts in many chemical and electrochemical processes. This is due to their structural and morphological features (high surface area and microporosity), high adsorption power and complex surface chemistry. Improved performances of these materials are desirable and can be obtained by modifying the nature and number of the native functional groups of the carbon surface and by introducing new surface species, as metal centres. In this work we present some results about electrochemical oxygen reduction onto amine-modified activated carbon also bearing metal cations (Co, Fe). Different - diamines were used. Catalysts characterisation was carried out by physical, chemical and electrochemical methods. Results are given in terms of the influence that amines and metal centres exert on the onset of oxygen reduction potential and oxygen reduction currents. [1] F. Charreteur, F. Jaouen, S. Ruggeri, J.-P. Dodelet, Electrochim. Acta, 53 (2008) 2925.