Advancements in recyclable photocatalytic semiconductor substrates for SERS detection in food safety applications

Surface-enhanced Raman scattering (SERS) technique is widely used in the field of food detection due to its rapidity, non-destructiveness and high sensitivity. However, non-recyclable substrates are limited in their practical detection application owing to high-cost and environmental pollution. Therefore, it is crucial to design SERS substrates that are recyclable and highly sensitive. Semiconductors with photocatalytic degradation capabilities have become attractive materials for the detection of contaminated residues in complex food matrices due to their high photocatalytic efficiency and environmental friendliness. Nevertheless, relevant research advances in this field have not been reviewed. In this review, the basic principles of SERS and semiconductor photocatalysis are introduced. The various constituent structures of semiconductors used for SERS substracts are described, including pure semiconductors, semiconductor-Ag/Au hybrid structures, and semiconductor-transition metal/semiconductor heterostructures. Then, the application of recyclable substrates for SERS detection of pesticides, dyes, antibiotics, heavy metals and other contaminants in agri-food products is then elaborated. Finally, the limitations and prospects of recyclable SERS substrates are presented. Photocatalytic semiconductors are potential candidates for the preparation of highly sensitive and recoverable SERS substrates. However, the development of recyclable SERS substrates for real sample detection remains a challenging scientific problem. Future research should focus on preparing novel photocatalytic semiconductor heterojunctions, investigating substrate interface catalytic processes and exploring the effects of complex food substrates on substrate recycling performance to improve the versatility of substrates and make them practical tools for the detection of food contaminants in the agri-food industry.