Microporous Oxide-Based Surface-Enhanced Raman Scattering Film for Quadrillionth Detection of Mercury Ion (II)

• Main Authors: Sripansuang Tangsuwanjinda, Yu-Yu Chen, Ching-Hsiang Lai, Guan-Ting Jhou, Yu-Wei Chiang, Hsin-Ming Cheng
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Processes
• Subjects: surface-enhanced Raman scattering; mercuric (II) ion; zinc oxide; porous oxide
• Online Access: https://www.mdpi.com/2227-9717/9/5/794

A variety of chemical sensing materials and procedures for conveniently detecting mercuric ion (II) (Hg²⁺) have been extensively explored. The detection challenges for accomplishing a simple, fast, and low investment procedure at the ultrasensitive level are ongoing. Herein we report a quadrillionth level for detecting Hg²⁺ by the surface-enhanced Raman scattering (SERS) technique. There is an interaction of silver nanoparticles decorated on a zinc-oxide tetrapod structure and coated on FTO glass (Ag@ZnO-FTO) with an organic ligand. 4,4′-Dipyridyl (DPy) performed as being chemisorbed by Ag nanoparticles interacting with a pyridine ring to produce plasmonic hot spots for SERS. The morphology of the surface and porous structure of the tetrapod becomes the powerful platform for enhanced SERS performance of DPy detection. In the absence of the augmentative electrolyte, the enhancement factor for DPy is more than 10⁷. The inhibiting of the aggregation between Ag and DPy was present following the appearance of Hg²⁺, demonstrated by the quenching of the SERS signal from the DPy molecules. The capability to reproduce and the selectivity of the sensing by DPy were both demonstrated. In addition, the applications for detecting Hg²⁺ in natural water and beverages were successfully detected. These results demonstrated the SERS sensors had the potential for detecting Hg²⁺ in practical use.