Electrostatic Self-Assembly of Ti 3 C 2 T x MXene and Gold Nanorods as an Efficient Surface-Enhanced Raman Scattering Platform for Reliable and High-Sensitivity Determination of Organic Pollutants.

A reliable surface-enhanced Raman scattering (SERS) substrate composed of 2D MXene (Ti3C2Tx) nanosheets and gold nanorods (AuNRs) is designed and fabricated for sensitive detection of organic pollutants. The AuNRs are uniformly distributed on the surface of the 2D MXene nanosheets due to the strong electrostatic interactions forming abundant SERS hot spots. The MXene/AuNRs SERS substrate exhibits high sensitivity and excellent reproducibility in the determination of common organic dyes such as rhodamine 6G (R6G), crystal violet (CV), and malachite green (MG). The detection limits are 1 × 10-12 M, 1 × 10-12 M, and 1 × 10-10 M and relative standard deviations (RSD) determined from 13 areas on each sample are 18.1%, 10.1%, and 15.6%, respectively. In the determination of more complex organic pesticides and pollutants, the substrate also shows excellent sensitivity and quantitative detection and the detection limits for thiram and diquat of 1 × 10-10 M and 1 × 10-8 M, respectively, are much lower than the contaminant levels stipulated by the US Environmental Protection Agency. The MXene/AuNRs composite constitute an efficient SERS platform for reliable and high-sensitivity environmental analysis and food safety monitoring.