Core-shell catalysts consisting of nanoporous cores for oxygen reduction reaction.

A comprehensive experimental study was conducted on the dealloying of PdNi6 nanoparticles under various conditions. A two-stage dealloying protocol was developed to leach >95% of Ni while minimizing the dissolution of Pd. The final structure of the dealloyed particle was strongly dependent on the acid used and temperature.

Synthesis and characterization of 9 nm Pt-Ni octahedra with a record high activity of 3.3 A/mg(Pt) for the oxygen reduction reaction.

Nanoscale Pt-Ni bimetallic octahedra with controlled sizes have been actively explored in recent years owning to their outstanding activity for the oxygen reduction reaction (ORR). Here we report the synthesis of uniform 9 nm Pt-Ni octahedra with the use of oleylamine and oleic acid as surfactants and W(CO)6 as a source of CO that can promote the formation of {111} facets in the presence of Ni. Through the introduction of benzyl ether as a solvent, the coverage of both surfactants on the surface of resultant Pt-Ni octahedra was significantly reduced while the octahedral shape was still attained.

Pt monolayer on porous Pd-Cu alloys as oxygen reduction electrocatalysts.

We demonstrate the synthesis of a core-shell catalyst consisting of a Pt monolayer as the shell and porous/hollow Pd-Cu alloy nanoparticles as the core. The porous/hollow Pd-Cu nanoparticles were fabricated by selectively dissolving a less noble metal, Cu, using an electrochemical dealloying process. The Pt mass activity for the oxygen reduction reaction of a Pt monolayer deposited on such a porous core is 3.