Highly efficient surface-enhanced Raman scatting performance of the Na2Ti3O7-Au chip for facile thiram or malachite green sensing

Thiram and malachite green (MG) are widely used in daily life, but their excessive residues, as highlighted by the World Health Organization (WHO), pose significant health risks. In this study, Na₂Ti₃O₇ nanosheets (NTSs) with a 3D cross-linked morphology were prepared by hydrothermal synthesis and magnetron sputtering for rapid detection of thiram and MG. NTS-Au composites demonstrated excellent surface-enhanced Raman scattering (SERS) activity, with an enhancement factor (EF) of 1.43 × 10⁷. Notably, the NTS-Au composites showed excellent reproducibility and a good linear relationship in the concentration range of 10⁻³ to 10⁻⁸ M, achieving limits of detection (LODs) of 4.07 × 10⁻¹⁰ for thiram and 1.82 × 10⁻⁹ M for MG. The remarkable sensitivity arises from the unique nanosheet structure, which enables multiple reflections of electromagnetic waves. This light-trapping effect enhances resonance absorption, promoting charge transfer (CT) and exciton enhancement. This study provides a novel approach for the rapid and sensitive detection of thiram and MG.