Plasmonic 3D Semiconductor–Metal Nanopore Arrays for Reliable Surface-Enhanced Raman Scattering Detection and In-Site Catalytic Reaction Monitoring

It is urgent to develop a rapid, reliable, and in-site determination method to detect or monitor trace amounts of toxic substances in the field. Here, we report an alternative surface-enhanced Raman scattering (SERS) method coupled with a portable Raman device on a plasmonic three-dimension (3D) hot spot sensing surface. Plasmonic Ag nanoparticles (AgNPs) were uniformly deposited on 3D TiO2 nanopore arrays as a sensitive SERS substrate, and further coated with graphene oxide (GO). We demonstrate the plasmon-induced SERS enhancement (5.8-fold) and the improvement of catalytic activity by incorporation of plasmonic AgNPs into the 3D TiO2 nanopore arrays. The modification of GO on the TiO2–Ag nanopore array further increases by a 6.2-fold Raman enhancement compared to TiO2–Ag while maintaining good uniformity (RSD 2–Ag–GO substrate shows powerful quantitative detection potential for drug residues in fish scales via a simple scrubbing method, and the limit of detection (LOD) for crystal violet (CV) was 10–8 M. The SERS substrate also showed detection practicability of pesticide residues in banana peel with an LOD of 10–7 M. In addition, our TiO2–Ag–GO substrate exhibits excellent SERS self-monitoring performance for catalytic reduction of multiple organics in NaBH4 solution, and the substrate shows good recyclability of 6 cycles. Such a 3D TiO2–Ag–GO substrate is a promising SERS substrate with good sensitivity, uniformity, and reusability, and may be utilized for further miniaturization for point of analytical applications