Three-Dimensional Pt-on-Au Bimetallic Dendritic Nanoparticle: One-Step, High-Yield Synthesis and Its Bifunctional Plasmonic and Catalytic Properties

Pt-based bimetallic dendritic nanoparticles (NPs) with noncompact nanobranches show great potential as catalysts for reducing Pt consumption, providing a high surface area and facilitating the enhanced performance in the catalytic applications. However, developing a one-step route to synthesize such dendritic NPs with a well-defined morphology at room temperature is still a great challenge and has been rarely reported. Herein, we report a one-step, room-temperature, and aqueous route for the synthesis of Pt-on-Au bimetallic dendritic NPs with noncompact nanobranches (denoted as BDNNNs) in high yield (similar to 100%). These BDNNNs have many big gaps available among the Pt nanobranches, which are important for providing a high electrochemical surface area. Methanol was selected as a model molecule for studying the electrocatalytic performance of BDNNNs. Interestingly, it is found that BDNNNs have a higher electrochemically active area than Au@Pt core/shell NPs with a rough surface and thus lead to higher catalytic activity for methanol oxidation. Moreover, for BDNNNs, the surface plasmonic resonance (SPR) peak of the Au core can be observed even when many Pt nanobranches are supported on the Au core because of the noncompact Pt nanobranches, which is important for in situ spectroscopic (such as surface-enhanced Raman scattering) characterization of catalytic reactions.