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

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 stateof-the-art Pt/C catalyst.Cell reversal testing by simulation of fuel starvation reveals that the durability of IrRu₂/C(~7 h) significantly exceeds that of the conventional Pt/C catalyst(~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.

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

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 (～ 7 h) significantly exceeds that of the conventional Pt/C catalyst (～ 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.