Fabrication of a highly dispersed Pdcore@Ptshell electrocatalyst for the oxygen reduction reaction

Abstract

Core-shell nanostructures have been widely investigated to improve the electrocatalytic performance of platinum. However, organic precursors, surfactants or high temperature are usually necessary during the preparation procedure. Unfortunately, these requirements limit the application of these methods on a large scale. Herein, a Pd core @Pt shell nanostructure was fabricated through the reduction of K 2 PtCl 4 by dissociated hydrogen at room temperature without the assistance of either a surfactant or a high-boiling point solvent. The shell thickness of this nanostructure was successfully controlled by varying the amount of K 2 PtCl 4 ; core-shell nanoparticles with a shell thickness of 0.45, 0.75 and 0.90 nm were obtained, as determined by TEM. The remarkable crystallinity and epitaxial growth of the Pd core @Pt shell nanostructure were revealed by HRTEM and EDS. According to ICP and XPS, surface segregation of Pt was established. The impressive ORR performance was attributed to the weak adsorption strength of the OH ads species, which resulted from the electron transfer impact between the Pd core and Pt shell . The facile and clean preparation method can be used to prepare other core-shell nanostructures under a mild atmosphere. Highly dispersed Pd core @Pt shell nanoparticles are successfully prepared via a facile and clean method at room temperature without the assistance of high-boiling point surfactant or solvent in one pot. The Pd core @Pt shell displays remarkable ORR performance and stability.