Nanoarrayed Ag-anchored MoS₂ heterostructure platforms: Emerging tools for ultrasensitive pesticide detection and removal of hazardous dyes

Molecular sensing plays a crucial role in food safety because ensuring food quality and safety is essential for protecting public health. However, the use of surface-enhanced Raman spectroscopy (SERS) for food safety monitoring is still hindered because of considerable fluctuations in Raman intensity associated with the detection of low concentrations of harmful additives. To overcome this issue, novel 2D/0D MoS₂ nanoflakes decorated with Ag nanoparticles (MoS₂NFs@Ag) were successfully developed and employed as a reusable dual-functional SERS platform for both sensitive detection in real samples and outstanding photodegradation. The as-fabricated 2D/0D MoS₂ NFs@Ag substrates exhibit excellent SERS performance for various analyte molecules, including crystal violet (CV), methylene blue (MB), and the fungicide thiabendazole (TBZ) pesticide, which is widely used in modern agriculture to prevent fungal diseases in fruits and vegetables. For CV and MB, broad linear detection ranges from 10^-6 - 10^-12 M were achieved, with enhancement factors (EFs) of 9.5 × 10¹⁰ and 4.8 × 10¹⁰ for CV and MB, respectively, at a limit of detection of 10^-12 M. The developed SERS platform enabled ultrasensitive detection of dye contaminants in real water samples and TBZ residues in apple and orange juice, achieving a detection limit of 10^-11 M. It also exhibited excellent photocatalytic activity, degrading over 95% of CV and MB under UV irradiation. Furthermore, the Raman signal remained stable after 50 days of ambient storage. This work presents a rapid, robust, and highly sensitive SERS-based sensing platform for practical monitoring of food contaminants and environmental pollutants.