Titanium carbide MXene/silver nanostars composite as SERS substrate for thiram pesticide detection

Two-dimensional transition metal carbonitrides, Ti₃C₂T_x MXene nanosheets, have drawn much attention due to their unique optical properties. These materials have huge potential to be employed as surface-enhanced Raman scattering (SERS) substrates. Herein, to combine the benefits of metal nanoparticles and MXene as SERS substrates, we prepared composite SERS films with different volume ratios composed of Ti₃C₂T_x MXene with silver nanostars (AgNs) as a promising SERS substrate for detection of pesticides. These SERS films were prepared via a drop-casting technique. The SERS activities of the MXene/AgNs composites were evaluated through detection of the thiram pesticide. MXene/AgNs exhibited the highest SERS intensity compared to MXene or AgNs substrate alone. Sampling from 20 different areas and samples of the substrate gave very consistent SERS signals. The MXene/AgNs substrate shows good stability for 1 month when stored in a small transparent container with silica gel. The MXene/AgNs SERS substrate exhibits excellent sensitivity able to detect thiram concentrations as low as 10⁻⁸ M which also having low a relative standard deviation (RSD) value for reproducibility and stability over a significant period.