Photochemical synthesis of Ag/Au/AgCl heterostructure from Ag nanowires as a reusable SERS substrate for ultrasensitive detection of analgesics and antibiotics

Abstract The composite nanostructure composed of semiconductors and noble-metals have received widespread attention in the field of surface-enhanced Raman scattering (SERS). Herein, one-dimensional (1D) silver/gold/silver-chloride nanowires (Ag/Au/AgCl NWs) are prepared using the facile hydrothermal and photoreduction processes for the SERS detection of antibiotics and analgesics. The nanometer-scale interparticle gaps in the Ag/Au/AgCl heterostructure have been produced and the hotspots are provoked to enhance the SERS signal of target molecules by boosting the synergistic action of the heterostructure. The Ag/Au/AgCl heterostructure offers high sensitivity, good uniformity and high reproducibility. Meanwhile, the SERS substrate based on the Ag/Au/AgCl heterostructure is studied for the determination of paracetamol (PCT) and furazolidone (FZD) with the wide linear ranges of 10-1 M ~ 10-10 M and 10-1 M ~ 10-9 M. Their corresponding limits of detection (LOD) are as low as 2.8 × 10-12 M and 1.9 × 10-11 M, respectively. The separate and multiplex detection of PCT and FZD by the Ag/Au/AgCl heterostructure have been performed. Furthermore, the Ag/Au/AgCl heterostructure is successfully applied to determine the PCT and the FZD in the human urine samples with satisfactory results. To ensure the self-reviving ability of Ag/Au/AgCl heterostructure, the photodegradation of PCT and FZD molecules has been conducted and analyzed. The SERS substrate based on the semiconductor/noble-metal heterostructure with the self-reviving capability paves the way for the accurate detection of biologically important molecules like antibiotics and analgesics at the ultralow-level concentrations.