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

•The bifunctional Fe3O4/Au nanocomposites are synthesized by a facile method.•The direct reduction of Au on carboxylate functionalized Fe3O4 is used.•This method avoids the use of toxic reagent and further surface modification on Fe3O4.•Nanocomposites show great high catalytic reactivity and reusability.

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.

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