High-sensitivity SERS sensor leveraging three-dimensional Ti3C2Tx/TiO2/W18O49 semiconductor heterostructures for reliable detection of trace micro/nanoplastics in environmental matrices

The proliferation of micro/nanoplastics (MNPs) has emerged as a pivotal environmental issue, largely due to their potential for human exposure. Consequently, the development of sensitive and efficient detection methodologies is paramount for elucidating their environmental footprint. Here, we report a novel three-dimensional (3D) surface-enhanced Raman scattering (SERS) sensor, which integrate Ti 3 C 2 T x /TiO 2 /W 18 O 49 semiconductor heterostructure, for the rapid and sensitive detection of MNPs in environmental matrices. The sensor's unique layered architecture and efficient charge transfer mechanism endow it with high sensitivity. It has demonstrated remarkable detection capabilities, achieving a sensitivity of 10 −8  M for Rhodamine 6G (R6G), equating to an enhancement factor (EF) of 2.33 × 10 6 . This level of sensitivity allows for the detection of polystyrene (PS) microplastics at concentration as low as 25 μg/mL, with a relative standard deviation (RSD) of 12.58 %, signifying superior reproducibility. Moreover, the sensor's fingerprinting capabilities enable the identification of a variety of MNPs, including polyethylene (PE) and polyethylene terephthalate (PET), thus facilitating the analysis of complex MNPs mixtures. The sensor's applicability to real-world samples was confirmed through the quantitative detection of PS microplastics in rainwater, soil, and industrial wastewater, with a detection limit of 25 μg/mL and exhibiting good linearity. It is concluded that the 3D SERS sensor is a promising tool for the rapid and precise detection of MNPs across diverse environmental matrices. The advent of this technology marks a significant leap forward in environmental analysis, providing a robust method for the monitoring of MNPs pollution.