Controlling Shape and Plasmon Resonance of Pt-Etched Au@Ag Nanorods

Abstract

Pt-based catalysts with novel structure have been attracted great attention due to their outstanding performance. In this work, H2PtCl6 was used as both precursor and etching agent, to realize the shape-controlled synthesis of Pt-modified Au@Ag nanorods (NRs). During the synthesis, the as-prepared Ag shell played a crucial role in both protecting the Au NRs from being etched away by PtCl62- and leading to an unusual growth mode of Pt component. The site-specified etching and/or growth depended on the concentration of H2PtCl6, where high-yield core-shell structure or dumbbell-like structure could be obtained. The shape-controlled synthesis also led to a tunable longitudinal surface plasmon resonance from ca. 649 to 900 nm. Meanwhile, the core-shell Pt-modified Au@Ag NRs showed approximately 4-fold enhancement in catalytic reduction reaction of p-nitrophenol than the Au NRs, suggesting the great potential for photocatalytic reaction.