Improving Oxygen Reduction Performance by Using Protic Poly(Ionic Liquid) as Proton Conductors.

Improving catalytic performance of the oxygen reduction reaction (ORR) of Pt/C catalysts is essential for reducing Pt-loading and the according cost of proton exchange membrane fuel cells (PEMFCs). Herein, we report a new conceptual design of catalyst layers to improve the ORR performance of Pt/C catalysts by replacing perfluorosulfonated ionomers with protic poly(ionic liquid) as a proton conductor. The specific activity of the designed catalyst at 0.9 V under acidic conditions is over three times higher than that of catalyst using Nafion as the proton conductor. Furthermore, the durability test reveals that the introduction of protic poly(ionic liquid) ionomers can protect Pt nanoparticles against aggregation during potential cycles, but it is less durable than Nafion because of the nature of hydrocarbons. Nevertheless, we believe that replacing perfluorosulfonated ionomers with protic poly(ionic liquid) as proton conductors could be a promising strategy to design an efficient cathode for low Pt-loading PEMFCs.