Facile Synthesis of MFe2O4/RGO (M = Ni, Co) Nanocomposites and Their Application in the Reduction of 4-Nitrophenol

In this study, magnetic MFe2O4 (MFO, M = Ni, Co)/RGO heterogeneous catalysts have been synthesized by a facile solvothermal method. To characterize their morphological, structural, magnetic, and optical properties, the materials were analyzed by complementary chemical-physical methods. Moreover, the obtained results were compared with those obtained from pristine MFe2O4 and individual synthesized RGO. The MFO/RGO composites are composed of thin RGO layers and approximatively spherical aggregates of small crystalline MFO nanoparticles. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride was applied to access the catalytic activity of the synthesized composites. Among these synthesized materials, NiFe2O4/RGO was highly active in this reaction. The combination of RGO layers and NiFe2O4 nanoparticles is assumed to be responsible for its high activity. Furthermore, NFO/RGO was catalytically active for six cycles adding fresh 4-nitrophenol (4-NP) to the reaction mixture.