High-sensitivity detection of thiram by collaborative enhancement of surface-enhanced Raman scattering substrates based on Ti3C2Tx-supported nanocomposites inlaid with four-concave-faced hollow silver nanocubes.

Distinct from conventional MXene-supported Ag SERS substrates, Ti3C2Tx-supported four-concave-faced hollow silver nanocubes (FCFH AgNCs) integrating concave surfaces and internal cavities were developed for thiram detection. Silver nanocubes were synthesized by the polyol method and transformed through HAuCl4-mediated etching into a series of nanostructures, including six-concave-faced AgNCs, FCFH AgNCs, and AgNC frameworks. Among them, FCFH AgNCs showed the strongest SERS activity, indicating that hollow-concave structure was most favorable for hotspot generation. After assembly with Ti3C2Tx via electrostatic interaction, the resulting Ti3C2Tx-FCFH AgNCs substrate exhibited enhanced Raman performance with an enhancement factor of 3.75 × 106 and improved signal uniformity by reducing the coffee-ring effect. The optimized substrate enabled thiram detection over 1 × 10-10 to 1 × 10-4 mol/L, with a detection limit of 0.3 × 10-10 mol/L, and showed good reproducibility, stability, and anti-interference ability, providing an effective strategy for pesticide residue detection and food safety monitoring and analysis.