g-C3N4/TiO2-Xheterojunctionwithhigh-efficiencycarrierseparationandmultiplechargetransferpathsforultrasensitiveSERSsensing

The combination of interface engineering and defect engineering is a promising strategy for developing new semiconducting surface-enhanced Raman scattering （SERS） substrate.Herein,an organic/inorganic hybrid g-C3N4/TiO2-Xheterojunction with synchronous generation of strong interface effect and abundan surface oxygen vacancy （OV） defect was prepared by a simple sol-hydrothermal procedure with a help of urea.Due to the improved substrate-to-molecule charge transfer （CT） from joint contribution of high efficiency carrier separation induced by strong interface coupling effect and multiple CT paths derived from abundant surface OV,g-C3N4/TiO2-Xsubstrate exhibits greatly enhanced SERS effect for non-resonan4-mercaptobenzoic acid （4-MBA） probe.The enhancement factor of g-C3N4/TiO2-Xsubstrate for 4-MBA i as high as 5.57×10～6,and the substrate exhibits ultra-high stability and excellent spectral reproducibility More meaningfully,the developed g-C3N4/TiO2-Xheterojunction can be used to execute an ultrasensitive detection for antibiotic residues in real water system,even comprehensive evaluation of multi-componen residues.