In situ deposition of α-Co nanoparticles on three-dimensional nitrogen-doped porous graphene foams as microwave absorbers

Three-dimensional (3D) porous microstructures in graphene-based composites have been a promising strategy to reinforce their electromagnetic wave absorption performance. Herein, the 3D super-light nitrogen-doped porous graphene foams (GFs) embedded with α-Co nanoparticles (N-MGF@Co) have been constructed through in situ simultaneous deposition of α-Co on graphene sheets. Their crystalline structure, chemical composition, morphology and magnetic properties were characterized by XRD, XPS, SEM/EDS, TEM and VSM. The electromagnetic wave (EMW) absorption properties of N-MGF@Co composites with different α-Co proportions were investigated in detail. Compared with the two-dimensional hierarchical graphene-based hybrids, the obtained 3D super-light N-doped porous magnetic graphene foams exhibited much better EMW absorption properties in terms of both the effective absorption bandwidth (EAB) and minimum reflection loss (RLmin). Interestingly, EMW absorption nanoparticles properties of the as-prepared samples can be tuned by varying proportions of α-Co and the thickness of absorbers layer. The results indicate that the 3D porous magnetic graphene foams could be potential candidates for lightweight and high performance EMW absorption materials.