Au-Bi₂Se₃ hybrid nanosheets with enhanced SERS activity for detecting polystyrene plastics

Polystyrene (PS) plastics were potentially present in consumer products through the use of plastics packaging. The migration and enduring presence for bioaccumulation posed significant threats to human health and the environment. It was significant to develop a simple and reliable approach for sensitive PS plastics detection. In this study, Au-Bi₂Se₃ hybrid nanosheets (NSs) were designed and utilized as SERS probes for the detection of PS plastics. The electron transfer from Bi₂Se₃ to AuCl₄^- induced the formation of Au NPs on the surface of thin Bi₂Se₃ NSs. Au-Bi₂Se₃ hybrid NSs were found to display enhanced SERS activity by using PS plastics as Raman tags. Besides the unique electromagnetic enhanced mechanism from Au NPs, the introduction of Bi₂Se₃ supported the Dirac plasmon polaritons in electromagnetic modes, and Bi₂Se₃ with high dielectric constants inhibited the decay of electromagnetic waves. Au-Bi₂Se₃ hybrid NSs engineered SERS sensor achieved stable and sensitive detection of PS plastics in essence liquid. Different sized PS plastics ranging from 89.3 nm to 1.48 μm were detected with the LODs of ppm levels. These findings highlight the potential of Au-Bi₂Se₃ hybrid NSs as effective and universal SERS substrates for detecting different sized plastics in real samples.