Controlled synthesis of dendritic Au@Pt core-shell nanomaterials for use as an effective fuel cell electrocatalyst.

We report the controlled synthesis of dendritic Au@Pt core-shell nanomaterials. The size and morphology of the Au cores and the Pt shell thickness of the Au@Pt core-shell nanostructures could be easily tuned. It was found that the directing agent and the reducing agent play critical roles in the synthesis of dendritic Au@Pt core-shell nanomaterials. For comparison purposes, conventional Au@Pt core-shell nanoparticles and monometallic Pt nanoparticles were also synthesized by the successive reduction method. Transmission electron microscopy (TEM) observations demonstrated the dendritic surface of the products obtained. The UV-visible (UV-vis) spectroscopy results and a comparison of the average diameter between the dendritic Au@Pt and conventional Au@Pt confirmed the relatively loose Pt shells around Au cores for the dendritic Au@Pt. The as-prepared dendritic Au@Pt showed enhanced electrocatalytic activity for methanol oxidation in acid medium, compared to the conventional Au@Pt and monometallic Pt.