Multifunctional Ir-Ru alloy catalysts for reversal-tolerant anodes of polymer electrolyte membrane fuel cells

Abstract

To address the problem of fuel starvation in fuel-cell electric vehicles, which causes cell voltage reversal and results in cell failure when repeated continuously, we developed a reversal-tolerant anode (RTA) to promote water oxidation in preference to carbon corrosion. Graphitized carbon-supported Ir-Ru alloys with different compositions are employed as RTA catalysts in an acidic polyol solution and are shown to exhibit composition-dependent average crystallite sizes of < 5.33 nm. The adopted approach allows the generation of relatively well-dispersed Ir-Ru alloy nanoparticles on the carbon support without severe agglomeration. The activity of IrRu2/C for the hydrogen oxidation reaction is 1.10 times that of the state-of-the-art Pt/C catalyst. Cell reversal testing by simulation of fuel starvation reveals that the durability of IrRu2/C (similar to 7 h) significantly exceeds that of the conventional Pt/C catalyst (similar to 10 min) and is the highest value reported so far. Thus, the developed Ir-Ru alloy catalyst can be used to fabricate practical RTAs and replace Pt catalysts in the anodes of polymer electrolyte membrane fuel cells. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.