Tuning the structure and plasmonic properties of Pt–Au triangular nanoprisms: From deposition to etching

Because of the strong electromagnetic field at the corners and more tunable surface plasmon resonance (SPR) bands in the visible and infrared regions, gold triangular nanoprisms can be applied to more fields. Compared with monometallic nanomaterials, polymetallic nanomaterials are composed of multiple metals and possess many special optical properties. Recently, structurally novel Pt-based polymetallic nanostructures have attracted much attention due to their superior catalytic performance. In this study, gold triangular nanoprisms were prepared by the seed growth method. By adjusting the amount of seeds, gold triangular nanoprisms of different sizes were formed. By changing the concentration of Cetyltrimethylammonium Bromide (CTAB) and Cetyltrimethylammonium chloride (CTAC), the purification process of gold triangular nanoprisms was adjusted to make gold triangular nanoprisms more uniform. The synthesis of Pt-Au triangular nanoprisms and the switching between etching and deposition dominated in the reaction is controlled by adjusting the volume of AgNO₃, H₂PtCl₆, and the size of gold triangular nanoprisms. At relatively high H₂PtCl₆ concentrations, the etching process dominates; at lower H₂PtCl₆ concentrations, the etching process is restrained. Due to the good catalytic performance of Pt itself and the rough surface-induced Surface-Enhanced Raman Scattering (SERS) improvement of the nanoparticles, the application of Pt-Au triangular nanoprisms in the fields of catalysis and SERS is proposed.