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

Abstract

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.