Epitaxial Growth of Heterogeneous Metal Nanocrystals: From Gold Nano-octahedra to Palladium and Silver Nanocubes

The construction of functional noble metal nanocrystals has received increasing interest because their unique optical, magnetic, and catalytic properties can be tuned by controlling the size, shape, chemical composition, surface and interfacial structure,1,2 and they have potential applications such as in catalysis, biodiagnostics, plasmonics, and surface-enhanced Raman spectroscopy.3,4 Very recently, the special attention has been paid on the shape-controlled synthesis of binary metallic heterostructures through epitaxial growth of second (third) metal over the seed metal.5–7 As a new and very important achievement, Yang and co-workers rationally designed and used cubic Pt nanocrystals as seeds for the conformal shape-controlled epitaxial overgrowth of Pd and the anisotropic growth of Au.8 They also showed that lattice mismatch (0.77 % for Pt/Pd versus 4.08 % for Pt/Au) plays a critically important role in the overgrowth of the secondary metal and high lattice mismatc