Fabrication of core–shell-like bimetallic SERS substrates with inter-coordination effect for catalysis of p-mercaptoaniline

Abstract

The present study discusses the core–shell structures of Au@Ag prepared by a seed-growth method. The morphology and composition of Au@Ag nanoparticles were analyzed, indicating that they were successfully prepared. By studying the surface-enhanced Raman scattering spectra (SERS) of p-mercaptoaniline (PATP) molecules adsorbed on Au@Ag substrates, it was found that PATP molecules could be oxidized to form p-mercaptoazobenzene (DMAB) on Au@Ag substrates, indicating that the gold–silver bimetallic nanomaterials could catalyze the PATP molecules with excellent enhancement effect and stability. In order to further study the enhancement effect of the Au@Ag substrate, the electric field strength of Au nanoparticles and Au@Ag nanoparticles was simulated by using the finite difference time domain (FDTD) method, which showed that the SERS enhancement effect of Au@Ag nanoparticles was more significant as well as consistent with the experimental results. This work provides a reference for further preparation of efficient and stable bimetallic SERS substrates.