Recyclable Au@R-Fe3O4/g-C3N4 Substrates for Rapid SERS Detection and Degradation of Multiple Pollutants

Developing a Surface-enhanced Raman spectroscopy (SERS) method with excellent detecting ability, good recyclability and analyzing multiple pollutants rapidly are critical for evaluation of water quality in emergency pollution affairs. While constructing a multifunctional substrate with these characteristics to realize the application of SERS in water quality monitoring remains a challenge. In this work, a reusable Au@R-Fe3O4/g-C3N4 SERS substrate is prepared by loading Au nanoparticles (Au NPs) on Fe3O4 nanorings (R-Fe3O4) and the formed Au@R-Fe3O4 is further combined with g-C3N4 nanosheets through a simple electrostatic assembly method. The Au@R-Fe3O4/g-C3N4 nanocomposite presents multifunction of magnetic enrichment, SERS signal enhancement, multiple pollutants analyzing, and photocatalytic activity, which achieves quantitative detection of rhodamine B (RhB), tetracycline hydrochloride (TC), and 4-chlorophenol (4-CP), with detection limits of 5.30 × 10-9, 7.50 × 10-8, 7.69 × 10-8 mol/L, respectively. Furthermore, the recyclable detection capability of Au@R-Fe3O4/g-C3N4 for multi components is demonstrated by the strong SERS signal after 9 cycles of “detection-degradation” processes. Combined with good uniformity and stability, this SERS method based on Au@R-Fe3O4/g-C3N4 substrate provides a new strategy for the multi-pollutants detection and degradation in water environment.