Porous Pd Layer-Coated Au Nanoparticles Supported on Carbon: Synthesis and Electrocatalytic Activity for Oxygen Reduction in Acid Media

Abstract

This paper reports the simple synthesis and characterization of carbon-supported Pd layer-coated Au nanoparticles (AuPd/C). A series of AuPd/C with various Pd/Au weight percentage ratios were prepared by the spontaneous deposition of a Pd shell on a Au nanoparticle core using different Pd precursor concentrations (0.5, 5, 10, 20 mM PdCl2). Au nanospheres encapsulated by the porous Pd shells are confirmed by transmission electron microscopy (TEM), UV–vis absorption spectroscopy, and scanning TEM. The catalytic activity of the AuPd/C for the oxygen reduction reaction (ORR) was investigated by rotating disk electrode voltammetry in 0.5 M H2SO4. In particular, a AuPd/C with a Pd/Au ratio of 0.61 shows superior ORR activity along with satisfactory stability and methanol tolerance under acidic conditions.