An efficientfficient, controllable and facile two-step synthesis strategy: Fe3O4@RGO composites with various Fe3O4 nanoparticles and their supercapacitance properties

An efficient, controllable, and facile two-step synthetic strategy to prepare graphene-based nanocomposites is proposed. A series of Fe 3 O 4 -decorated reduced graphene oxide (Fe 3 O 4 @RGO) nanocomposites incorporating Fe 3 O 4 nanocrystals of various sizes were prepared by an ethanothermal method using graphene oxide (GO) and monodisperse Fe 3 O 4 nanocrystals with diameters ranging from 4 to 10 nm. The morphologies and microstructures of the as-prepared composites were characterized by X-ray diffraction, Raman spectroscopy, nitrogen adsorption measurements, and transmission electron microscopy. The results show that GO can be reduced to graphene during the ethanothermal process, and that the Fe 3 O 4 nanocrystals are well dispersed on the graphene sheets generated in the process. The analysis of the electrochemical properties of the Fe 3 O 4 @RGO materials shows that nanocomposites prepared with Fe 3 O 4 nanocrystals of different sizes exhibit different electrochemical performances. Among all samples, Fe 3 O 4 @RGO prepared with Fe 3 O 4 nanocrystals of 6 nm diameter possessed the highest specific capacitance of 481 F/g at 1 A/g, highlighting the excellent capability of this material. This work illustrates a promising route to develop graphene-based nanocomposite materials with a wide range of potential applications.