Mesoporous semiconducting TiO₂ with rich active sites as a remarkable substrate for surface-enhanced Raman...

Area of Science:

• Materials Science
• Nanotechnology
• Spectroscopy

Background:

• Surface-enhanced Raman scattering (SERS) is a powerful analytical technique.
• Semiconductor titanium dioxide (TiO2) shows promise for SERS, but practical applications are limited by low sensitivity.
• Existing TiO2 SERS substrates require improvement in surface performance and detection limits.

Purpose of the Study:

• To develop a novel strategy for enhancing the SERS activity of TiO2 nanoparticles.
• To improve the sensitivity and stability of TiO2-based SERS substrates.
• To investigate the potential of mesoporous TiO2 for high-performance SERS detection.

Main Methods:

• Fabrication of mesoporous TiO2 frameworks via reductive calcination of polymer-coated TiO2 nanocrystals.
• Utilizing 4-mercaptobenzoic acid (4-MBA) as a probe molecule for SERS detection.
• Comparing SERS enhancement on mesoporous TiO2 versus ordinary TiO2 nanoparticle substrates.

Main Results:

• Mesoporous TiO2 substrates exhibited significantly larger SERS enhancement for 4-MBA compared to ordinary TiO2 NPs.
• The enhanced SERS activity is attributed to abundant surface active sites and improved charge transfer.
• A detection limit of 1 × 10^-8 mol L^-1 for 4-MBA was achieved, surpassing other semiconductor substrates and rivaling noble metal substrates.
• The mesoporous TiO2 substrates demonstrated high stability and self-cleaning properties, enabling repeated use.

Conclusions:

• The developed mesoporous TiO2 framework represents a significant advancement in SERS-active substrate technology.
• This approach overcomes the limitations of conventional TiO2 SERS substrates, offering high sensitivity and stability.
• The mesoporous TiO2 substrates show great potential for various SERS applications, including chemical sensing and molecular detection.