Pd@Pt Core−Shell Nanostructures with Controllable Composition Synthesized by a Microwave Method and Their Enhanced Electrocatalytic Activity toward Oxygen Reduction and Methanol Oxidation

Abstract

Three-dimensional Pd@Pt core−shell nanostructures with controllable shape and composition were synthesized by using a one-step microwave heating method. The nanostructures with the morphology, structure, and composition being easily controlled through adjusting the molar ratio between Pt and Pd precursor were characterized by transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), X-ray powder diffraction (XRD), and energy-dispersive X-ray (EDX) techniques. In addition, the electrocatalytic characteristics of these prepared Pd@Pt electrocatalysts with different Pd/Pt molar ratio for oxygen electro-reduction reaction (ORR) and methanol electro-oxidation reaction (MOR) were systematically investigated by voltammetry. The results show that Pd@Pt electrocatalysts exhibit higher catalytic activity than pure Pd and pure Pt catalysts for both the ORR and MOR, and the highest activity is obtained at the Pd@Pt electrocatalyst with a Pd/Pt molar ratio of 1:3. This result demonstrates that a higher performance of ORR and MOR could be realized at the novel core−shell electrocatalyst while Pt utilization also could be diminished. This method may open a general approach for the shape-controlled synthesis of bimetallic Pt−M nanocatalysts, which can be expected to have promising applications in fuel cells.