High performance carbon supported palladium catalyst in anodes of proton exchange membrane fuel cell

Abstract

Carbon support palladium catalyst (Pd/C) were prepared by borohydride method and characterized by XRD, TEM and EDX and then used to prepare anodes and cathodes for performance evaluation in single cell. For comparison were also used anodes and cathodes prepared with the commercial platinum catalyst (Pt/C), which allowed verifying the efficiency of using Pd/C in cathodes, anodes or both electrodes. It was found similar performance at room temperature, even at the cathode; however, the temperature rise was kinetically favorable to oxygen reduction reaction of cathodes with Pt/C which was not observed for Pd/C cathodes. Moreover, Pd/C anodes showed maximum performance of 83 % related to Pt/C at 85 °C, a behavior that was virtually constant at all temperatures studied and that justifies the application of palladium on fuel cell anodes to platinum replacement on the cost and nature reserves perspectives. The characterization confirmed the palladium FCC crystal structure, a mean particle size of 4.4 nm, presence of some agglomerates and the synthesis method efficiency that resulted in metallic loading of 19.88 % for a nominal load of 20.0 %. The performance achieved by the standards used in MEAs preparation at IPEN and the standards evaluation adopted resulted in a performance higher than reported in the literature motivating this publication.