Preparation And Properties Of Fe₃O₄@Carbon/Graphene Oxide Composites By Hydrothermal Method

Fe3O4@carbon(Fe3O4@C) composites are being researched in many fields, especially adsorption and electrochemical application while facing several problems with low adsorption capacity, slow adsorbing rate and low electrochemical capacity. As a new carbon material, graphene owes excellent physical and chemical properties and large specific surface area. In order to obtain new composites, graphene oxide was added based on the Fe3O4@C composites, thus enhancing their relevant properties.In this paper, Fe3O4@carbon/graphene oxide composites (Fe3O4@C/GO) were prepared, and the properties were characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), specific surface area and pore analyzer(BET).(1) Fe3O4@C/GO composites (Fe3O4@C/Gl, Fe3O4@C/G2 and Fe3O4@C/G3) were synthesized by hydrothermal method with Fe3O4 nanoparticles prepared by coprecipitation, soluble starch and graphene oxide(GO) under the condition of different mass ratios of GO to Fe3O4(0.3,0.8 and 1.2). Fe3O4 was coated by carbon based starch and anchored on the graphene sheets firmly with excellent distribution. The structure of the materials was stable containing large amounts of oxygen-containing groups. The composites gained excellent magnetic property, higher specific surface area and pore volume compared to Fe3O4@C.(2)In order to investigate the adsorption properties of Fe3O4@C/GO composites, Rhodamine B(RhB), methylene blue(MB) and copper ion were used as adsorbates. The saturated adsorption capacities of composites towards dyes increased with the increase of GO content, initial dyes concentration or absorbing temperature. Furthermore, the adsorption rate of the composite was more quick when higher amount of GO was used. The composites had good recycle performance because of their excellent saturation magnetization. The composite with mass ratio of GO to Fe3O4 being 0.8 had the best adsorption properties when comparing composites adsorbing Cu2+with different mass ratio of GO to Fe3O4. The suitable temperature also had significant influence on the adsorption process.(3)The electrochemical properties of Fe3O4@C/GO composites were evaluated by using it as an anode material in lithium-ion batteries, which consisted of constant current charge-discharge and rate performance. The composite with mass ratio of GO to Fe3O4 being 1.2 presented good electrochemical properties. When the composite was treated at 500?, its cycle stability performanced better and structure had no change.