Graphene multilayered sheets assembled by porous Bi2Fe4O9 microspheres and the excellent electromagnetic wave absorption properties

Using Bi 2 Fe 4 O 9 microplatelets as precursors, we developed a facile etching strategy for three-dimensional porous Bi 2 Fe 4 O 9 microspheres with reduced graphene oxide (rGO) multilayered sheets for high-performance electromagnetic (EM) absorbing material. In a solution of N,N dimenthyl formamide (DMF), hydrazine and methyl mercaptoacetate, the precursors synchronously were subjected to a dissolution-recrystallization/reduction process to obtain a hybrid of numerous Bi 2 Fe 4 O 9 fragments and graphene to form the rGO/porous Bi 2 Fe 4 O 9 composite. The porous Bi 2 Fe 4 O 9 microspheres with an mean diameter of 500 nm were uniformly assembled on the graphene multilayered sheets without obvious aggregation. Such three-dimensional structure rGO/porous Bi 2 Fe 4 O 9 composite not only utilize efficiently the high conductivity and specific surface area of graphene, but only the hierarchical architectures of porous Bi 2 Fe 4 O 9 microspheres. The results show that the rGO/porous Bi 2 Fe 4 O 9 composite exhibits a maximum reflection coefficient of −71.88 dB at 13.8 GHz with a sample thickness of only 2.0 mm and an effective absorption bandwidth (reflection loss below −10 dB) of 4.24 GHz, greatly superior to the present graphene-based metallic oxide composite. The strategy paves an efficient way for designing new candidate for lightweight electromagnetic wave (EMW) absorbing materials.