Graphene-enhanced microwave absorption properties of Fe3O4/SiO2 nanorods

Fe3O4/SiO2/graphene composite composed of Fe3O4/SiO2 core–shell nanorods and graphene nanosheets were synthesized by a facile wet chemical method. Structure and morphology studies reveal that the Fe3O4/SiO2 nanorods with porous structure and large aspect ratio are densely wrapped by the graphene nanosheets. By changing the graphene content, the electromagnetic properties of the Fe3O4/SiO2/graphene composite can be well tuned. When the weight ratio of Fe3O4/SiO2 to graphene reaches an appropriate value, excellent microwave absorption performance is achieved due to the large electromagnetic losses and good impedance matching. The Fe3O4/SiO2/graphene composite with graphene content of 5 wt.% shows the minimum reflection loss of −27.1 dB at 12.2 GHz when the coating layer thickness is only 1.5 mm.