A Highly Stable Silver Nanoparticle Loaded Magnetic Nanocomposite as a Recyclable Catalysts

The broad application of organic dyes such as 4-nitrophenol (4-NP), rhodamine 6G (R6G), and methylene blue (MB) as raw materials in the manufacture of dyes, explosives, pesticides, preservatives, and pharmaceuticals caused serious damage to the environment, particularly aquatic ecosystems. In this study, silver nanoparticles decorated ZnO/Fe3O4 (Ag/ZnO/Fe3O4) nanocomposite was used as a catalyst to reduce 4-NP, R6G, and MB in the presence of sodium borohydride as a reducing agent. Silver nanoparticles decorated ZnO/Fe3O4 composite was synthesized via a simple and inexpensive chemical reduction method. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and X-ray diffraction (XRD) were used to characterize the particles. The surface-enhanced Raman spectroscopy (SERS) activity of the nanocomposites due to AgNPs was used to monitor catalytic reactions with detailed spectral features using SERS. Thus, the catalytic transformation of 4-nitrothiophenol (4-NTP) into 4-aminothiophenol (4-ATP) was traced using SERS. The magnetic property of the nanocomposites enables its repeated use. Easy recovery of the particles from the reaction solution was achieved and run for fifteen cycles with no significant loss of its efficiency.