Growth of Fe3O4 nanosheet arrays on graphene by a mussel-inspired polydopamine adhesive for remarkable enhancement in electromagnetic absorptions

Fe3O4 nanosheet arrays grown on both surfaces of graphene can be achieved by combining a mussel-inspired polydopamine adhesive and ethylene glycol-mediated process. Polydopamine is utilized not only as an efficient linker molecule that binds Fe3O4 nanosheets to the graphene, but also as a carbon source during heat treatment to yield the three dimensional (3D) graphene@carbon@Fe3O4 nanosheet arrays architecture. After the growth of Fe3O4 nanosheet arrays with accompanying reduction of graphene oxide into graphene, the 3D architecture exhibits outstanding microwave absorption properties. The simulated value of maximum reflection loss can reach -52.8 dB at 9.5 GHz with a sample thickness of 2.7 mm. The improved absorption capacity arises from the synergy of dielectric loss and magnetic loss, as well as the enhancement of multiple interfaces among graphene, carbon and Fe3O4 nanosheets. Furthermore, the synthesis strategy presented here can be expended as a facile approach to synthesizing related graphene-based 3D nanostructures for functional design and applications.