▎ 摘　　要

In this paper, graphene oxide/Fe3O4 (GO/Fe3O4) nanocomposites were prepared by using co-precipitation method at low temperature. The formation of the GO/Fe3O4 nanocomposites was confirmed by X-ray diffraction (XRD), Energy dispersive X-ray analysis and Fourier transform infrared analysis. The morphology and particle size of the GO/Fe3O4 nanocomposites were investigated by Transmission electron microscopy (TEM) and Scanning electron microscopy. The grain size of the Fe3O4 nanoparticles was estimated about 10-20 nm from XRD. Also, the particle size of the Fe3O4 nanoparticles (according to TEM image) was found to be smaller than 20 nm. Finally magnetite property of the GO/Fe3O4 nanocomposites was studied by vibrating sample magnetometer (VSM) and Mossbauer spectroscopy. The VSM and Mossbauer results were confirmed each other and shown the magnetite property decrease by decreasing the Fe3O4 amount of samples. Also, catalytic activity of the GO/Fe3O4 nanocomposites has been tested for the reduction of methylene blue at room temperature. It was found that the GO/Fe3O4 nanocomposites are highly active and recyclable catalysts and due to the magnetic separability can be recovered and reused several times without marked loss of activity.