Platinum Overgrowth on Gold Multipod Nanoparticles: Investigation of Synergistic Catalytic Effects in a Bimetallic Nanosystem

Abstract

Highly ordered heteronanostructures can be synthesized by overgrowth of a secondary material on the as-prepared seed nanocrystal. The unique morphology of seed nanocrystals directs the shape of the secondary structure, which is exploited to develop structure-controlled composite nanomaterials. Herein, we report a facile and controllable synthetic strategy toward noble star-shaped bimetallic nanostructures. Gold multipod nanoparticle (GMN) core-platinum shell nanoparticles (GMN@Pt NPs) are successfully synthesized through the overgrowth of Pt on the surface of GMN seeds. Due to the structural uniqueness of GMNs, GMN@Pt NPs show bimetallic core-shell geometries, which have surface roughness and star-shaped multi-branches with sharp edges and tips. The island nucleation and growth of individual Pt particles to form a shell provide larger surface areas and plenty of defects on the bimetallic nanocrystals. GMN@Pt NPs with optimized Pt shells show much higher catalytic activities in 4-nitrophenol reduction and ethanol electrooxidation than those of GMNs or Pt nanoparticles, mainly due to the synergistic effects of the bicomponent nanosystem.