Multifunctional magnetic Fe3O4/Cu2O-Ag nanocomposites with high sensitivity for SERS detection and efficient visible light-driven photocatalytic degradation of polycyclic aromatic hydrocarbons (PAHs).

[Display omitted] • Fe 3 O 4 /Cu 2 O-Ag nanocomposites (NCs) were designed and synthesized successfully. • We realized integration of SERS detection and photocatalytic degradation for PAHs. • Effect of Ag contents on SERS and catalytic activity of Fe 3 O 4 /Cu 2 O-Ag was studied. • SERS detection limit of Fe 3 O 4 /Cu 2 O-Ag towards PAHs was as low as 10-9 to 10-10 M. • Photocatalytic mechanism of PAHs degradation by Fe 3 O 4 /Cu 2 O-Ag was proposed. Polycyclic aromatic hydrocarbons (PAHs) with carcinogenic, teratogenic and mutagenic properties are persistent organic pollutants in the environment. Herein, the novel multifunctional Fe 3 O 4 /Cu 2 O-Ag nanocomposites (NCs) have been established for ultra-sensitive surface-enhanced Raman scattering (SERS) detection and visible light-driven photocatalytic degradation of PAHs. Fe 3 O 4 /Cu 2 O-Ag NCs with different amounts of Ag nanocrystals were synthesized, and the effect of Ag contents on SERS performance was studied by finite-difference time-domain (FDTD) algorithm. The synergistic interplay of electromagnetic and chemical enhancement was responsible for excellent SERS sensitivity of Fe 3 O 4 /Cu 2 O-Ag NCs. The limit of detection (LOD) of optimal SERS substrates (FCA-2 NCs) for Nap, BaP, Pyr and Ant was as low as 10-9, 10-9, 10-9 and 10-10 M, respectively. The SERS detection of PAHs in actual soil environment was also studied. Moreover, a simple SERS method was used to monitor the photocatalytic process of PAHs. The recovery and reuse of Fe 3 O 4 /Cu 2 O-Ag NCs were achieved through magnetic field, and the outstanding SERS and photocatalytic performance were still maintained even after eight cycles. This magnetic multifunctional NCs provide a unique idea for the integration of ultra-sensitive SERS detection and efficient photocatalytic degradation of PAHs, and thus will have more hopeful prospects in the field of environmental protection. [ABSTRACT FROM AUTHOR]