Dendritic alloy shell Au@AgPt yolk sensor with excellent dual SERS enhancement and catalytic performance for in-situ SERS monitoring reaction

In situ monitoring of the changes of reactants on the metal catalyst surface/interface, capture, and identification of intermediate species and products are very important for revealing catalytic pathways, mechanisms, and designing high-performance catalysts. A novel Au@AgPt yolk structure with ternary metallic composition and dendritic alloy shell was synthesized, which had dual catalytic and surface-enhanced Raman spectroscopy (SERS) performance to meet the demand of in-situ SERS monitoring reaction. The key factors for the formation of this special structure are the Ag-Pt mole ratio (n(Ag: Pt)) and surfactant types. The yolk structure with the most optimal catalytic and SERS performance (n(Ag: Pt)=1:1) was screened out for in-situ SERS monitoring. The classic 4-NTP reduction to 4-ATP model was first used to verify the excellent SERS and catalytic dual-functional properties of the Au@AgPt yolk structure. Importantly, this yolk structure was further used to detect plasmon-induced halogenated benzene dehalogenated coupling reaction, and the results show that the hot electrons generated by Au@AgPt NPs could trigger C-X (X = Cl, Br) bond fracture to form the C-C bond under continuous laser irradiation, which provided an effective way for C-X bond activation in organic synthesis.