(525c) Synthesis of Freestanding Metal-Platinum Core-Shell Structure with Well Defined Facets As Electro-Catalyst for the Oxygen Reduction Reaction

Electro-catalytic oxygen reduction reaction (ORR) has drawn considerable attention because of its slow kinetics and the need for better electro-catalysts with decreased Pt content for proton exchange membrane fuel cells (PEMFCs). One promising approach to solving these problems is to design catalysts with little amount of Pt supported on suitable metal nanomaterials [1].

Here, we report the design and synthesis of freestanding metal-platinum core-shell nanostructures with well defined facets via a simple solution based method. Pd nanocrystal is synthesized by polyol method and used as core for Pt overlayer growth. The surface morphology and composition of the catalyst is characterized by the SEM and TEM techniques. The surface of the nanostructure is bound mainly by [111] and [110] planes. Rotating disk electrode measurements are carried out to analyze the ORR kinetics and activities of the catalysts. Preliminary results suggest that controlling the morphology of Pt nanostructures can improve their catalytic properties and increase their activity both on specific and mass basis compared to the commercially used Pt/C and the first generation catalyst Pt black. The new type of catalysts has a great potential in fuel cell applications. Better performance is expected by optimization of Pt shell thickness. Other substrate can be considered to further reduce the cost of the catalyst.