Syntheses of Sub-30 nm Au@Pd Concave Nanocubes and Pt-on-(Au@Pd) Trimetallic Nanostructures as Highly Efficient Catalysts for Ethanol Oxidation

Designed manipulation of the morphology of metallic nanostructures containing Pd and/or Pt represents a challenge in the search of highly efficient precious metal catalysts. We provide herein the first selective synthesis of narrowly sized small (21 nm) Au@Pd concave nanocubes enclosed with high-index Pd facets by deposition of Pd atoms on truncated-octahedral Au seeds. Moreover, further controlled deposition of Pt onto these Au@Pd concave nanocubes produces sub-30 nm trimetallic Pt-on-(Au@Pd) nanostructures having jagged Pt-rich surfaces. The as-prepared Au@Pd and Pt-on-(Au@Pd) nanostructures are found highly active and fairly stable when employed as anode catalysts for ethanol electrooxidation, their activity normalized to the mass of Pd or Pd plus Pt being 7–9 times higher than conventional Pd black catalyst. These data may echo the importance of innovative small multimetallic nanostructures for highly efficient catalysts that depend critically on use of precious metals, for applications in energy, environmental, and chemical technologies.