Preparation and characterization of multifunctional Fe^sub 3^O^sub 4^-coated Ag nanocomposites for catalytic reduction of 4-nitrophenol

In this study, a core-satellite nanocomposite, termed Ag@Fe3O4 consisting of Ag particles as the inner core and many superparamagnetism Fe3O4 nanoparticles (NPs) as the outer surface, synthesized by a facile and efficient polyol method. The Ag@Fe3O4 nanocomposites were characterized using X-ray diffraction, X-ray photoelectron spectroscopy and Transmission electron microscopy measurements. The results indicated that Ag particles were successfully coated with Fe3O4 NPs and showed excellent conversion efficiency of more than 99% within 8 min in the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Furthermore, the magnetically functionalized Ag nanocomposites could be easily recovered with an external magnet, which retained good activity and stability after five cycles.