A metallic molybdenum dioxide with high stability for surface enhanced Raman spectroscopy

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Semiconductors are explored as Surface-Enhanced Raman Spectroscopy (SERS) substrates due to their plasmonic properties.
• Instability, oxidation, and decomposition under laser irradiation or corrosive conditions limit semiconductor SERS substrate performance.
• Noble metals like gold and silver are effective but costly SERS substrates.

Purpose of the Study:

• To investigate metallic molybdenum dioxide (MoO₂) as a novel, stable SERS substrate.
• To evaluate MoO₂'s efficacy in detecting trace amounts of high-risk chemicals.
• To assess the stability and performance of MoO₂ under harsh conditions.

Main Methods:

• Fabrication and characterization of metallic MoO₂.
• Utilized MoO₂ as a SERS substrate for detecting bisphenol A (BPA), dichlorophenol (DCP), and pentachlorophenol (PCP).
• Assessed substrate stability through high-temperature exposure and strong acid/alkali etching.

Main Results:

• Achieved a minimum detectable concentration of 10⁻⁷ M for target analytes.
• Obtained a maximum enhancement factor of 3.75 × 10⁶, comparable to noble metals.
• Demonstrated exceptional oxidation resistance up to 300°C in air and stability against strong acids and alkalis.

Conclusions:

• Metallic MoO₂ is a promising, robust SERS substrate material.
• MoO₂ offers high sensitivity and stability, outperforming many existing metal oxide SERS substrates.
• This material presents a cost-effective and durable alternative to noble metal SERS substrates for detecting hazardous chemicals.