3D heterostructure of graphene@Fe3O4@WO3@PANI: Preparation and excellent microwave absorption performance

•Sandwich quaternary composite of graphene@Fe3O4@PANI@WO3 was fabricated using hydrothermal method and chemical oxidation polymerization.•The maximum RL value of graphene@Fe3O4@PANI@WO3 composite is up to −46.7 dB at 9.4 GHz with a thickness of 4 mm.•The absorbing bandwidth (<−10 dB) is about 1.8 GHz (from 12.4 to 14.2 GHz) at only 1.5 mm.

The sandwich quaternary composite of graphene@Fe3O4@PANI decorated with WO3 particles was successfully synthesized using simple hydrothermal method and chemical oxidation polymerization. The microstructure, chemical composition and morphology of the samples were investigated in detail. The spherical Fe3O4 and WO3 nanoparticles with an average diameter of 300-500 nm and 50-150 nm, respectively, were distributed between graphene@PANI layers. The as-prepared samples were made into cylinder shape with a paraffin matrix to obtain electromagnetic parameters by a vector network analyzer at 2-18 GHz. The electromagnetic wave absorbing performances of graphene@Fe3O4@PANI@WO3 composite are significantly enhanced compared with graphene@Fe3O4, graphene@Fe3O4@PANI, with the maximum absorption as high as −46.7 dB for a coating of 4 mm and the maximum absorbing bandwidth (≤10 dB) of 1.8 GHz (from 12.4 to 14.2 GHz) at only 1.5 mm. The results demonstrate that the sandwich structure composite with improving microwave absorption properties can be used as a promising absorber in weakening electromagnetic wave irradiation.

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