La,S-CeO₂/Ag-based reusable SERS substrate for simultaneous detection of multiple hazardous molecules

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Surface-enhanced Raman scattering (SERS) requires highly sensitive and reusable substrates for effective analyte detection.
• Developing composite materials with tailored properties is crucial for enhancing SERS performance.

Purpose of the Study:

• To create a high-performance, reusable SERS substrate using a three-dimensional, bowtie-like La, S co-modified CeO2/Ag composite.
• To evaluate the substrate's sensitivity, reproducibility, stability, and self-cleaning capabilities for pollutant detection.

Main Methods:

• Fabrication of a three-dimensional, bowtie-like La, S co-modified CeO2/Ag composite.
• Characterization of the composite's structure and SERS performance using Congo red (CR) as a model analyte.
• Testing the substrate's ability to detect various pollutants (tetracycline, thiram) in spiked lake water.
• Assessing the substrate's reusability through integrated photocatalytic self-cleaning cycles.

Main Results:

• The substrate achieved a low detection limit of 10⁻¹¹ M for CR, with an enhancement factor of 4.3 × 10⁷.
• Excellent reproducibility (RSD = 3.25%) and long-term stability (retaining ~90% activity after three months) were observed.
• The composite effectively detected tetracycline (10⁻¹¹ M) and thiram (10⁻¹⁰ M) in spiked lake water.
• After five detection-degradation cycles, SERS signals for CR and thiram retained ~83% and ~76% activity, respectively, demonstrating excellent reusability.

Conclusions:

• The La, S co-modified CeO2/Ag composite serves as a high-performance, reusable SERS substrate.
• Synergistic enhancement from the unique architecture and optimized electronic structure contributes to superior performance.
• The integrated photocatalytic self-cleaning function enables excellent reusability, making it suitable for environmental monitoring and analytical science.