Self-precipitated metal-doped titanate nanofiber substrates for surface-enhanced Raman scattering of organic analytes

Background: Surface-enhanced Raman scattering (SERS) has emerged as a powerful technique for trace-level detection by leveraging localized surface plasmon resonance (LSPR) to amplify weak Raman signals. Although noble metal-modified TiO₂ shows great potential as a SERS substrate, conventional modification methods such as photodeposition and wet chemistry are often time-consuming, costly, and multi-step. We developed a straightforward hydrothermal synthesis to fabricate Au-doped titanate nanofibers with in-situ self-precipitated Au nanoparticles to overcome these limitations. This method offers a scalable and efficient platform for enhancing SERS performance broadly applicable to environmental and industrial pollutant monitoring. Methods: Various titanate nanofibers with different incorporated metal ions were synthesized via a hydrothermal method. Self-precipitated Au nanoparticles are uniformly integrated onto sodium titanate fibers to enhance surface plasmon resonance behavior. Comprehensive characterization, including synchrotron X-ray diffraction, XPS, UV–Vis, Raman spectroscopy, and photo-assisted Kelvin probe force microscopy (photo-KPFM) are employed to confirm successful nanoparticle integration and assess plasmonic enhancement. Significant findings: The Au doped titanate substrate demonstrates superior SERS performance, achieving an analytical enhancement factor (AEF) of 185,000 for methylene blue detection at concentrations as low as 3.0 × 10⁻⁹ g/cm². The findings establish Au-doped titanate nanofibers as a scalable, sensitive platform for organic pollutant detection with potential applications in environmental monitoring and analytical sensing.