COMPONENTS FOR PEM FUEL-CELL SYSTEMS USING HYDROGEN AND CO CONTAININGFUELS

Proton exchange membrane fuel cells (PEMFC) show a significant perform ance drop in CO containing hydrogen as fuel gas in comparison to pure hydrogen. The lower performance is due to CO adsorption at the anode t hus poisoning the hydrogen oxidation reaction. Two approaches to impro ve the cell performance are discussed. First, the use of improved elec trocatalysts for the anode, such as PtRu alloys, can significantly enh ance the CO tolerance. On the other hand, CO poisoning of the anode co uld be avoided by the use of non-electrochemical methods. For example, the addition of liquid hydrogen peroxide to the humidification water of the cell leads to the formation of active oxygen by decomposition o f H2O2 and the oxidation of CO. In such a way a complete recovery of t he CO free cell performance is achieved for H-2/100 ppm CO. (C) 1998 E lsevier Science Ltd. All rights reserved.