Sandwich structures of graphene@Fe₃O₄@PANI decorated with TiO₂ nanosheets for enhanced electromagnetic wave absorption properties

The novel sandwich structures of graphene@Fe₃O₄@PANI decorated with TiO₂ nanosheets were firstly successfully prepared by simple hydrothermal method and in situ polymerization. VSM results reveal that the nanocomposites have a superparamagnetic behavior. Structure and morphology were characterized by X-ray diffraction, transmission electron microscopy, and field-emission scanning electron microscopy. Electron microscopy images show that TiO₂ nanosheets are mostly grown upright on the top of graphene@Fe₃O₄@PANI support with a random orientation, and form hierarchical structures. Electromagnetic (EM) wave absorption properties of graphene@Fe₃O₄@PANI@TiO₂ nanosheets containing 50wt% paraffin were investigated in the frequency region of 2-18 GHz. The maximum reflection loss of the nanocomposites is up to -41.8 dB at 14.4 GHz with a thickness of 1.6 mm, and the absorption bandwidth of R_L < -10 dB is almost up to 3.5 GHz. Thus, the enhanced EM wave absorption properties of graphene@Fe₃O₄@PANI@TiO₂ nanosheets can be used as promising EM wave absorbers.