Gold nanoparticles hybridizing molybdenum disulfide nanosheets for sensitive surface-enhanced Raman scattering

Coin-metal@semiconductor nanohybrids have attracted extensive attention in surface-enhanced Raman scattering (SERS) detection, aiming to achieve the synergistic effect of electromagnetic enhancement mechanism (EM) and chemical enhancement mechanism (CM). In this work, positively charged thin-layered molybdenum disulfide nanosheets (MoS₂NSs) and negatively charged gold nanoparticles (AuNPs) were synthesized, which were further fabricated into MoS₂NSs@AuNPs via electrostatic interactions and Au-S bonding. The approach is quite rapid, cost-effective, and environmentally friendly, and the resulting MoS₂NSs@AuNPs exhibited an outstanding SERS enhancement factor of up to 2.33 × 10⁸ for crystal violet due to the synergistic effect of EM and CM. Furthermore, the fabricated SERS substrate demonstrated long-term stability, maintaining about 80% of SERS activity even after storage for two months, and excellent reproducibility, with a relative standard deviation of 5.20%. Remarkably, this SERS-active nanohybrid enabled rapid and highly sensitive detection of thiram residues in apple juice, achieving satisfactory recoveries of 82.6-110.7% and an impressively low limit of quantification of 50 µg/L. This work not only presents a novel strategy for designing high-performance SERS nanomaterials but also highlights their promising applications in food safety monitoring and environmental analysis.