Self-Cleaning Surface Enhanced Raman Spectroscopy (SERS) Platform: Hierarchical Au/Titanium (IV) Oxide/Au Nanoarchitecture for the Ultrasensitive and Recyclable Determination of Antibiotics

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for the rapid, real-time monitoring of trace aquatic pollutants. However, a major challenge persists in the development of SERS substrates capable of simultaneously determining and degrading pollutants. Herein, a highly sensitive Au/TiO₂/Au sandwich-structured substrate was fabricated that exhibited excellent SERS performance with an enhancement factor (EF) of 1.05 × 10⁷. Limits of detection (LODs) as low as 1.42 × 10⁻⁷ M for ofloxacin (OFL) and 1.26 × 10⁻⁹ M for trimethoprim (TMP) were achieved. Notably, the substrate retained stable SERS activity even after five consecutive detect-degrade cycles. By integrating plasmonic enhancement (for SERS detection) with photocatalytic degradation (for pollutant removal), this dual-functional platform demonstrated high reproducibility, with a relative standard deviation (RSD) below 6%, and long-term stability, retaining 60% of its initial SERS intensity after 60 days of storage. The strategy reported herein provides a practical approach for the simultaneous determination and degradation of antibiotics in aqueous matrices.