3D Fe3O4@Au@Ag nanoflowers assembled magnetoplasmonic chains for in situ SERS monitoring of plasmon-assisted catalytic reactions

Abstract

One-dimensional (1D) assembled magnetoplasmonic nanochains (MPNCs) were fabricated using Fe₃O₄@Au core–shell nanoparticles (NPs) via a magnetic field induced assembly. With the help of a silver growth solution, the 3D Fe₃O₄@Au@Ag nanoflowers assembled magnetoplasmonic chains (Fe₃O₄@Au@Ag NAMPCs) were prepared via an in situ reduction method. A heterogeneous epitaxial growth mechanism was proposed to explain the growth process of the Fe₃O₄@Au@Ag NAMPCs. The Fe₃O₄@Au@Ag NAMPCs possessed large numbers of hot spots within the highly ordered structure and were used as a SERS substrate to enhance the sensitivity, uniformity and reproducibility of Raman signals. Subsequently, the Fe₃O₄@Au@Ag NAMPCs, integrating a heterogeneous catalysis and in situ SERS detection, was assessed to monitor the catalytic reduction of 4-nitrothiophenol (4-NTP) to p,p′-dimercaptoazobenzene (DMAB).