On-site Gas Sensing by Surface-Enhanced Raman Scattering

Title : On-site Gas Sensing by Surface-Enhanced Raman Scattering

Abstract:

Ag nanorods coated with an ultrathin HfO₂ shell (AgNRs@HfO₂) were prepared for the synthesis of a versatile, robust, and easily recyclable surface-enhanced Raman scattering (SERS) substrate. This substrate maximizes the high melting point of HfO₂ shell and thus ensures the plasmonic efficiency of AgNRs. Therefore, it possesses extraordinary thermal stability and SERS activity, which could act as a reusable and cost-effective SERS detector. After SERS detection, the regeneration of AgNRs@HfO₂ was achieved by annealing the substrate within several seconds. This procedure led to the thermal release of adsorbed molecules and resulted in a refreshed substrate for subsequent measurements. The composite substrate maintained its SERS efficiency well during multiple “detection−heating” cycles, exhibiting good stability and recyclability. Furthermore, in addition to revealing the feasibility of SERS sensing in liquids, AgNRs@HfO₂ also provided continuous real-time monitoring of gas targets at ultralow concentrations. This work provides a robust and renewable SERS sensor with advantages of high sensitivity, stability, cost effectiveness, and easy operation, which can be implemented for both aqueous and gaseous analyte detection and is thus an intriguing candidate for practical applications in environmental, industrial, and homeland security sensing fields.

Audience take away:

• Localized surface plasmon resonance (LSPR) of metallic nanostructures
• Surface-enhanced Raman scattering (SERS) for trace level sensing
• Fabrication of thermally stable metallic nanostructures

Biography:

Dr. Zhang studied Materials Science and Engineering at Tsinghua university, China, and received his BS, MS and Ph.D. degrees in 1991, 1993 and 1995, respectively. He then stayed as an Alexander von Humboldt research fellow and STA research fellow in Germany and Japan and a postdoctoral researcher in the US from 1996 to 2001. He is now a full professor at School of materials Science and Engineering, Tsinghua university.