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

Using Bi2Fe4O9 microplatelets as precursors, we developed a facile etching strategy for three-dimensional porous Bi2Fe4O9 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 Bi2Fe4O9 fragments and graphene to form the rGO/porous Bi2Fe4O9 composite. The porous Bi2Fe4O9 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 Bi2Fe4O9 composite not only utilize efficiently the high conductivity and specific surface area of graphene, but only the hierarchical architectures of porous Bi2Fe4O9 microspheres. The results show that the rGO/porous Bi2Fe4O9 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.