Platinum Nanoparticle-Supported Electrocatalysts Functionalized by Carbonization of Protic Ionic Liquid and Organic Salts

A novel approach involving a carbonization process of a protic ionic liquid (PIL) and organic salt (POS) is used to functionalize Pt-nanoparticle-supported carbon electrocatalysts for oxygen reduction reaction. The catalyst prepared using PIL N,N-diethyl-N-methylammonium hydrogen sulfate ([DEMA][HSO4]) and POS diphenylammonium hydrogen sulfate ([DPA][HSO4]) has a high long-term stability of catalytic performance because the Pt nanoparticles on the catalyst are well encapsulated with the carbonized PIL/POS mixture. Although the carbonization process enlarges the Pt nanoparticles and consequently reduces mass activity, surprisingly it realizes a high specific activity more than four times as much as a commercially available Pt nanoparticle electrocatalyst.