Small Au nanoparticles to be modified with decavanadate for sensitive and stable SERS detection

Area of Science:

• Materials Science
• Spectroscopy
• Nanotechnology

Background:

• Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for trace analysis.
• The performance of SERS is highly dependent on the properties of plasmonic substrates.
• Polyoxovanadates offer unique electronic properties that can potentially enhance plasmonic substrates.

Purpose of the Study:

• To combine the electronic properties of polyoxovanadates with the plasmonic properties of gold nanoparticles (Au NPs).
• To develop a more stable and sensitive SERS substrate for trace determination.
• To investigate the interaction between decavanadate (V10) and Au NPs.

Main Methods:

• Modification of citrate-capped gold nanoparticles (cit-Au NPs) with decavanadate (V10) via ligand displacement.
• Control of V10 structure through pH adjustment.
• Characterization using X-ray photoelectron spectroscopy (XPS) and SERS.
• Stability testing in various solvent environments and over time.
• Evaluation of SERS enhancement and sensitivity for target analytes.

Main Results:

• V10-Au NPs exhibited a higher absolute zeta potential and enhanced stability in a CH3OH/H2O solvent mixture compared to cit-Au NPs.
• The V10-Au NPs maintained their SERS activity and coffee ring effect during evaporation even after 60 minutes of soaking.
• The modified nanoparticles demonstrated stability over 5 days at pH 4.8.
• High sensitivity was observed for cationic dye molecules and antibiotics, with detection limits down to μg·L−1.

Conclusions:

• The V10-Au NPs serve as a stable and effective SERS substrate.
• This approach enables sensitive detection of low-concentration cations and monitoring of polyoxometalate morphology.
• The study provides a foundation for advanced applications of SERS in chemical analysis and materials science.