Core-shell nanostructures have been widely investigated to improve the electrocatalytic perfor-mance of platinum. However, organic precursors, surfactants or high temperature are usually nec-essary during the preparation procedure. Unfortunately, these requirements limit the application of these methods on a large scale. Herein, a Pdcore@ Pt shell nanostructure was fabricated through the reduction of fcPtCU by dissociated hydrogen at room temperature without the assistance o f either a surfactant or a high-boiling point solvent. The shell thickness of this nanostructure was successfully controlled by varying the amount of fcPtCU; core-shell nanoparticles with a shell thickness of 0.45, 0.75 and 0.90 nm w ere obtained, as determined by TEM. The remarkable crystallinity and epitaxial growth of the Pdcore@ 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 OHads species, which resulted from the electron transfer impact between the Pdcore and Ptshell. The facile and clean preparation method can be used to prepare other core-shell nanostructures under a mild atmosphere.
