Preparation and electrocatalytic activity of palladium–platinum core–shell nanoalloys protected by a perfluorinated sulfonic acid ionomer

Abstract Palladium–platinum nanoalloys with a core–shell and nano-network structure were successfully synthesized by a hydrogen sacrificial protective method in an aqueous solution directly using a perfluorinated sulfonic acid (PFSA) ionomer as a protecting agent. The structure, local composition and electrocatalytic activity for the oxygen reduction reaction of the Pd/Pt/PFSA nanoalloys were investigated by transmission electron microscopy (TEM), aberration corrected scanning transmission electron microscopy (Cs-STEM), energy-dispersive X-ray spectrometry (EDS) and voltammetry. The core–shell structure was completed without contaminating reducing agents, organic solvents, useless protecting agents and a mediator. The Pd/Pt/PFSA core–shell nanoalloys realized a high electrochemical surface area and better electrocatalytic mass-activity for the oxygen reduction reaction than the Pt/PFSA nanoparticles.