Highly Sensitive, Uniform, and Reusable Surface-Enhanced Raman Scattering Substrate with TiO₂ Interlayer between Ag...

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Developing sensitive and reusable substrates is crucial for surface-enhanced Raman scattering (SERS).
• Reduced graphene oxide (rGO) offers a 2D platform, TiO2 provides photocatalysis, and Ag nanoparticles enhance SERS signals.
• Existing substrates often face challenges with sensitivity, uniformity, or reusability.

Purpose of the Study:

• To create a highly sensitive, uniform, and reusable SERS substrate using a Ag/TiO2/rGO nanocomposite.
• To investigate the synergistic effects of TiO2 interlayer on SERS performance.
• To demonstrate the substrate's reusability through photocatalytic degradation of analytes.

Main Methods:

• A two-step solvothermal process was employed to deposit TiO2 nanoparticles and Ag nanoparticles successively onto reduced graphene oxide (rGO).
• Characterization of the Ag/TiO2/rGO nanocomposite was performed.
• SERS measurements were conducted using 4-aminothiophenol (4-ATP) as a probe molecule to evaluate sensitivity, uniformity, and enhancement factor.
• Photocatalytic degradation and reusability tests were performed under UV irradiation.

Main Results:

• The Ag/TiO2/rGO nanocomposite exhibited significantly enhanced SERS sensitivity compared to Ag/rGO.
• The detection limit for 4-ATP was lowered from 10(-10) M to 10(-14) M.
• The enhancement factor increased from 1.27 × 10(10) to 3.46 × 10(12) with good uniformity (RSD ≈ 10%).
• The substrate demonstrated excellent reusability, retaining its SERS performance after five reuse cycles via photocatalytic cleaning.

Conclusions:

• The Ag/TiO2/rGO nanocomposite is a highly promising SERS substrate with superior sensitivity, uniformity, and reusability.
• The TiO2 interlayer effectively suppresses rGO's intrinsic Raman signals, boosting overall sensitivity.
• The photocatalytic property of TiO2 enables efficient analyte removal, facilitating substrate reuse for sustainable sensing.