A novel synthesis of magnetic and photoluminescent graphene quantum dots/MFe2O4 (M = Ni, Co) nanocomposites for catalytic application

In recent year, the research is focused on the nanostructured catalyst with increase physiochemical properties. Herein, Different magnetic nanocomposites of graphene quantum dots (GQD) and MFe2O4 (M = Ni, Co) with intrinsic photoluminescent and ferromagnetic properties were synthesized by a convenient co-precipitation method. The structure, morphology, and properties of these nanocomposites as well as the catalytic activity of the nanocomposites for the reduction of p-nitrophenol were investigated. The catalytic activity was found to be in the order of NiFe2O4/GQD > CoFe2O4/GQD > NiFe2O4 > CoFe2O4. The sample NiFe2O4/GQD exhibited the best catalytic activity with an apparent rate constant of 3.56 min(-1) and a reduction completion time to p-aminophenol of 60 s. The catalysts can be reused by a magnetic field and display good stability, which can be recycled for six successive experiment with a conversion percentage of more than 95%. These results demonstrate that the nanocomposite NiFe2O4/GQD is an efficient catalyst for the reduction of p-nitrophenol compound. Also, the new nanocomposites have shown a significant reduction in the direct and indirect energy bandgaps when compared to pure GQD and the corresponding magnetic metal oxides. (C) 2018 Elsevier B.V. All rights reserved.