Multifunctional magnetic sphere-MoS@Au hybrid for surface-enhanced Raman scattering detection and visible light photo-Fenton degradation of aromatic dyes.

A ternary hybrid, MNPs-MoS@Au, composed of gold nanoparticles (AuNPs) grown on a magnetic sphere (MNPs)-MoS microflower composite (MNPs-MoS) was proposed for surface-enhanced Raman scattering (SERS) detection and visible-light photo-Fenton degradation of aromatic dyes. The hybrid was prepared by sequential solvothermal growth of MNPs and MoS, and electroless deposition of AuNPs. A comparison of results revealed that the synergy among these components endowed the hybrid with a much higher SERS enhancement ability than MNPs, or MNPs@MoS. The dosage of HAuCl and MNPs-MoS to prepare the hybrid greatly influenced the SERS activity of the hybrid. Under optimized conditions, quantitative SERS analysis of dyes including CV, MG, and MB was performed with a low detection limit (1 pM, 0.15 nM and 1 nM for CV, MG, and MB, respectively) and adequate reproducibility (RSDs were less than 6% and 11% for CV and MG, respectively). The hybrid could also serve as a visible light-active photo-Fenton catalyst for efficient degradation of aromatic dyes, and the decolorization of 20 mg/L RhB was 90% in 40 min in the presence of HO because of a synergy mechanism among components confirmed by comparison experiment and first-order kinetics study. The multifunctional material prepared here possesses great values in SERS analysis, environmental monitoring, and restoration.