A General and High-Yield Galvanic Displacement Approach to Au-M (M=Au, Pd, and Pt) Core-Shell Nanostructures with Porous Shells and Enhanced Electrocatalytic Performances

In this work, we utilize the galvanic displacement synthesis and make it a general and efficient method for the preparation of Au?M (M=Au, Pd, and Pt) coreshell nanostructures with porous shells, which consist of multilayer nanoparticles. The method is generally applicable to the preparation of Au?Au, Au?Pd, and Au?Pt coreshell nanostructures with typical porous shells. Moreover, the Au?Au isomeric coreshell nanostructure is reported for the first time. The lower oxidation states of AuI, PdII, and PtII are supposed to contribute to the formation of porous coreshell nanostructures instead of yolk-shell nanostructures. The electrocatalytic ethanol oxidation and oxygen reduction reaction (ORR) performance of porous Au?Pd coreshell nanostructures are assessed as a typical example for the investigation of the advantages of the obtained coreshell nanostructures. As expected, the Au?Pd coreshell nanostructure indeed exhibits a significantly reduced overpotential (the peak potential is shifted in the positive direction by 44 mV and 32 mV), a much improved CO tolerance (If/Ib is 3.6 and 1.63 times higher), and an enhanced catalytic stability in comparison with Pd nanoparticles and Pt/C catalysts. Thus, porous Au?M (M=Au, Pd, and Pt) coreshell nanostructures may provide many opportunities in the fields of organic catalysis, direct alcohol fuel cells, surface-enhanced Raman scattering, and so forth.