Pt-Nanoparticle-Supported Carbon Electrocatalysts Functionalized with a Protic Ionic Liquid and Organic Salt

Pt-nanoparticle-supported carbon catalysts for the electrochemical oxygen reduction reaction produced using a Pt-nanoparticle-monodispersed ionic liquid (IL) show better durability than a commercially available catalyst due to the small amount of IL between the Pt nanoparticles and the carbon support. In this study, to add further functionality to the catalysts prepared with the Pt-nanoparticle-monodispersed IL, a protic organic salt, diphenylammonium hydrogen sulfate ([DPA][HSO4]), and a protic ionic liquid, N, N-diethyl-N-methylammonium hydrogen sulfate ([DEMA][HSO4]), are employed for catalyst preparation. Interestingly, the mass activity and durability of the resulting catalyst are significantly enhanced by the addition of an electrochemically polymerizable [DPA][HSO4] to the Pt-nanoparticle-monodispersed [DEMA][HSO4] because of the formation of a conducting polymer, poly(diphenylamine), between the Pt nanoparticles and the carbon support during potential cycling.