Ni2P-Graphite Nanoplatelets Supported Au-Pd Core-Shell Nanoparticles with Superior Electrochemical Properties

Nanoparticles of Au-Pd with core-shell structure were synthesized through the coreduction of HAuCl4 and Na2PdCl4 in aqueous media by using cetyltrimethylammonium chloride as a reducing agent. The morphology and structure of the core-shell NPs were confirmed by transmission electron microscopy, X-ray diffraction, and UV-vis spectroscopy. We further demonstrate that the core-shell structure is formed as a synergistic result of low interfacial energy and small lattice mismatch between Au and Pd, different redox potentials of PdCl42-/Pd and AuCl4-/Au, and low reduction rates of HAuCl4 and Na2PdCl4. The catalyst of Au-Pd core-shell nanoparticles supported on Ni2P-graphite nanoplatelets (Au@Pd/Ni2P-GNPs) exhibits a noticeably higher activity than Pd and Pt catalysts in electrochemical ethanol oxidation. Moreover, we show that the activity and stability of Au-Pd core-shell for ethanol oxidation can be significantly enhanced using Ni2P nanoparticles as a cocatalyst. The prepared Au@Pd/Ni2P-GNPs catalyst exhibits a current density of 1.348 A mg(metal)(-1), which is 2.1 times as high as that of Au@Pd/GNPs without Ni2P nanoparticles deposited.