Well-defined coreeshell goldepalladium@palladium nanocrystals (AuPd@Pd) are facilely prepared by a
simple and green wet-chemical method at 25 C. A Good’s buffer, 2-[4-(2-hydroxyethyl)-1-piperazinyl]
ethanesulfonic acid (HEPES), is used as a reducing agent and a shape-directing agent, while there is no
template, seed, organic solvent, or surfactant involved. The AuPd@Pd nanocrystals are uniformly
dispersed on graphene nanosheets by ultrasonication, resulting in the formation of graphene supported
AuPd@Pd (G-AuPd@Pd). The as-prepared nanocomposites exhibit the improved catalytic activity, good
tolerance, and better stability for oxygen reduction reaction (ORR) and methanol oxidation reaction
(MOR) in alkaline media, compared with the G-Pd and commercial Pd black catalysts. The as-developed
method may provide a promising pathway for large-scale fabrication of AuPd-based catalysts.