Facile synthesis of bifunctional Fe3O4/Au nanocomposite and their application in catalytic reduction of 4-nitrophenol

In this paper, we report a simple, facile and efficient method to synthesize the bifunctional Fe3O4/Au nanocomposites by the direct reduction of HAuCl4 in the presence of carboxylate functionalized Fe3O4 particles which are prepared by a modified solvothermal approach. This facile synthesis route avoids the use of toxic reagent and further surface modification on the Fe3O4 surface. The obtained bifunctional Fe3O4/Au nanocomposites are characterized by HRTEM, EDX, XRD, UV–vis, and SQUID. The results indicate that every as-prepared Fe3O4/Au nanocomposites contain numerous Au nanoparticles with an average size of 6 nm around Fe3O4 spheres (260 nm). The bifunctional Fe3O4/Au nanocomposites exhibit high saturation magnetization (58 emu/g) and high performance in catalytic reduction of 4-nitrophenol (0.05 mg of catalyst with conversion of 95% in 8 min). Furthermore, the Fe3O4/Au catalysts show convenient magnetic separability and good reusability.