Pt nanocrystal evolution in the presence of Au(III)-salts at room temperature: spontaneous formation of AuPt heterodimers

Room temperature synthesis of AuPt heterodimers is reported using a simple protocol. The role of oleylamine and Pt NCs in the reduction and nucleation of Au has been investigated. There are two unique aspects in this synthesis. Firstly, the synthesis was conducted at room temperature, which enabled the heterodimer growth to progress at a slower rate and thus allowed monitoring of the Au nucleation process. Secondly, these conditions allowed epitaxial growth with no crystal modification at the Au-Pt interphase. The presence of Pt NC seeds markedly accelerated the reaction, serving both as nucleation platforms and as an initial catalytic reducer of the Au ions in solution. The growth of Au on Pt NCs was monitored at different times by UV-vis, HRTEM and XRD.