Fabrication of porous graphene-Fe3O4 hybrid composites with outstanding microwave absorption performance

Graphene is a promising lightweight microwave absorption (MA) absorber, but the limited dielectric loss and nonmagnetic characteristic have impeded its further applications. Through the structure modification, porous (1-2.5 μm) graphene was successfully prepared via a simple pyrolysis process, and the minimum reflection loss (RL) value reached −48 dB at 9.8 GHz, which demonstrated that porous graphene (PG) showed outstanding MA performance than the ordinary graphene (OG). In order to strengthen the magnetic loss, and then boost the impedance matching, Fe3O4 nanoparticles (∼10 nm) were deposited uniformly on the surface of PG via in situ precipitation to synthesize porous graphene-Fe3O4 (PG-Fe3O4) composites. It was found that the as-prepared PG-Fe3O4 composites showed especially high MA performance, and the minimum RL of −53.0 dB was achieved at 5.4 GHz with the thickness of 6.1 mm. The absorption bandwidth of RL less than −10 dB was from 12.6 to 18.0 GHz (5.4 GHz) with a thin thickness of 2.7 mm. The excellent MA properties of PG-Fe3O4 composites were the consequence of the perfect impedance matching, porous structure as well as the multi-polarization. These results demonstrated that the PG-Fe3O4 composites with excellent MA properties and lightweight should be promising absorbers for practical applications.