Surface plasmonics of nanomaterials has been one of the main research themes in nanoscience. Spherical and elongated nanoparticles show their corresponding unique optical features mainly depending on the physical dimensions. Here we successfully synthesized Au nanorings having Pt framework (Pt@Au nanorings) with high uniformity through wet-chemistry. The synthetic strategy consisted of serial reactions involving site-selective growth of Pt on the rim of Au nanoplates, subsequent etching of Au nanoplates, followed by regrowth of Au on the Pt rim. In this synthetic method, Au(3+) ions exhibited dual functionality as an etchant and a metal precursor. The resultant product, Pt@Au nanorings, exhibited unique localized surface plasmon resonance (LSPR) bands originating from the Au shell. The inner Pt skeleton turns out to be important to hold structural stability.
