Recyclable Ag-Deposited TiO(2) SERS Substrate for Ultrasensitive Malachite Green Detection

[Image: see text] An ultrasensitive Ag-deposited TiO(2) flower-like nanomaterial (FLNM) surface-enhanced Raman scattering (SERS)-active substrate is synthesized via a hydrothermal method, and Ag nanoparticles (NPs) are deposited through electron beam evaporation. Malachite green (MG), which is widely used in aquaculture, is employed to assess the surface-enhanced Raman scattering (SERS) properties of TiO(2)/Ag FLNMs. They exhibit ultrasensitivity (limit of detection (LOD) of MG reaches 4.47 × 10(–16) M) and high reproducibility (relative standard deviations (RSDs) are less than 13%); more importantly, the TiO(2)/Ag FLNMs are recyclable, as enabled by their self-cleaning function due to TiO(2) photocatalytic degradation. Their recyclability is achieved after three cycles and their potential application is examined in the actual system. Finite difference time domain (FDTD) simulations and the charge-transfer (CT) mechanism further prove that the excellent SERS properties originate from localized surface plasmon resonance (LSPR) of Ag NPs and the coupling field between Ag and TiO(2) FLNMs. Therefore, TiO(2)/Ag FLNMs show promising application in aquaculture.