Facile Synthesis of Porous Hexapod Ag@AgCl Dual Catalysts for In Situ SERS Monitoring of 4-Nitrothiophenol Reduction

Abstract

Controllable morphological metal catalytic materials have always been a focus in research. In the previous work, hexapod AgCl was successfully synthesized. In this paper, hexapod Ag@AgCl microstructures with diverse Ag contents are prepared through NaBH4 reduction. They are characterized by scanning electron microscopy (SEM) and the element distribution is proved by an energy dispersive X-ray spectrometer (EDS). They are porous dendritic microstructures with a large specific surface area and a rough surface, which display high catalytic performance and surface-enhanced Raman spectroscopy (SERS) activity. Furthermore, the hexapod Ag@AgCl microstructure is devoted as a dual catalyst to monitor the reduction of 4-nitrothiophenol (4-NTP) to 4-aminothiophenol (4-ATP) in situ using SERS. Ultraviolet–visible (UV–Vis) spectroscopy was employed to evaluate the catalytic performance of the hexapod Ag@AgCl microstructures. The consequences show that the velocity of reaction became faster with a corresponding increase in silver content and the reaction mechanism was cleared. In addition to preparing a good catalyst, this work also promotes the combination of micro-nano materials and spectroscopy technology.

Keywords

• Ag@AgCl microstructure
• in situ monitoring
• surface-enhanced Raman spectroscopy
• 4-nitrothiophenol reduction