Characterization and application of anion exchange polymer membranes with non-platinum group metals for fuel cells

Abstract

An investigation of the carbon-supported iron phthalocyanine (Fe-Pc) catalyst for oxygen reduction reaction (ORR) in alkaline media and in hydrogen fuel cells is described. The non-noble metal Fe-Pc catalyst is shown to be a promising alternative to platinum for ORR in alkaline media, with onset potentials of ca. 15 mV higher and double the mass activity than that of Pt. The catalyst also showed lower peroxide generation at lower voltages than Pt when tested at a rotating ring disc electrode. The effect of various parameters such as catalyst loading, catalyst layer thickness, fabrication technique, and ionomer on a hydrogen fuel cell performance using an alkaline electrolyte membrane made by radiation grafting is described. Peak power densities of the fuel cell with Pt/C oxygen reduction catalysts were greater than 100 mW/cm at 60 °C using air. The performance of the fuel cell with the Fe-Pc catalyst was inferior to that with the Pt catalyst giving approximately half the peak power density initially due to the thicker catalyst layer and instability in the quaternary ammonium environment. However, the performance of the Fe-Pc catalyst under fuel cell conditions was found to fall with time due to an interaction of the catalyst with the ion-exchange group of the membrane and the ionomer used in the catalyst layer.