Cu(i)-mediating Pt reduction to form Pt-nanoparticle-embedded Nafion composites and their electrocatalytic O2 reduction

Abstract

A Cu⁺ ion-mediating Pt reduction used to prepare nanoparticle Pt-embedded Nafion (NF(Pt_nano)) composites with well-dispersed and protective agent-free Pt nanocrystals with narrow particle size (∼2.1 nm) distribution is described. Cu⁺ accumulated in Nafion via the electrochemical reduction of Cu²⁺ serves as a movable mediator to reduce PtCl₄²⁻ to Pt. The NF(Pt_nano) composites were probed as a function of composition and particle size distribution using powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electrochemical characterization. The Pt nanoparticles distributed in the Nafion film electrically communicate with the electrode without any mediators or carbon support. The highly catalytic performance of the NF(Pt_nano) composite as a potential electrocatalytic material for facilitation of the oxygen reduction reaction (ORR) was demonstrated. The electrocatalytic activity of Pt-embedded Nafion catalysts for ORR was investigated with cyclic voltammetry and rotating disc electrode (RDE) voltammetry experiments.