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

Abstract

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 (1–2.5μm) graphene was successfully prepared via a simple pyrolysis process, and the minimum reflection loss (RL) value reached −48dB at 9.8GHz, 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 (∼10nm) 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 −53.0dB was achieved at 5.4GHz with the thickness of 6.1mm. The absorption bandwidth of RL less than −10dB was from 12.6 to 18.0GHz (5.4GHz) with a thin thickness of 2.7mm. 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.