Fabrication and characterization of the Fe 3 O 4 @SiO 2 -rGO nanocomposite: a catalyst for multi-component reactions.

A novel nanocomposite is synthesized by covalently modifying reduced graphene oxide (rGO) with Fe 3 O 4 @SiO 2 nanoparticles. Fe 3 O 4 was synthesized using a co-precipitation method, and SiO 2 was then coated onto the Fe 3 O 4 via a sol-gel method. Graphene oxide was synthesized using the Hummers' method. Furthermore, a hydrothermal method was applied to create the Fe 3 O 4 @SiO 2 -GO composite, and a simple reduction was used to obtain three-dimensional (3D) Fe 3 O 4 @SiO 2 -rGO core-shell spheres. XRD, FTIR, FE-SEM, VSM, BET, TGA, and Raman analyses were used to characterize the prepared nanocomposites. X-Ray diffraction (XRD) and Raman spectra reveal that the nanostructures consist of highly crystallized cubic Fe 3 O 4 , amorphous SiO 2 , and rGO sheets stacked in a disordered fashion. Field emission scanning electron microscopy (FE-SEM) characterization indicates that the form of the Fe 3 O 4 @SiO 2 core-shell structures is spherical, with an average size of about 25 nm. Magnetic hysteresis loops reveal the super-paramagnetic behavior of the samples at room temperature. All of the results obtained confirm the synthesis of high-quality nanocomposites, which can be a good candidate for use as a catalyst in multi-component reactions.