Preparation of Graphene Aerogel with High Mechanical Stability and Microwave Absorption Ability via Combining Surface Support of Metallic-CNTs and Interfacial Cross-Linking by Magnetic Nanoparticles

The preparation of graphene aerogel by hydrothermal or chemical reduction has been one of the hot topics of research. But in the process of assembly, the random weak connection of GO flakes leads to irreversible deformation under compression, and the mechanical stability of aerogel based on graphene is one of its drawbacks that is hard to overcome. Here, a novel method to prepare graphene aerogel with high mechanical stability was proposed via combining surface support brought by metallic-CNT networks and interfacial cross-linking of GO sheets achieved by nanoparticle selective absorption. Thoroughly dispersed metallic-CNTs absorbed on the basal plane of GO flakes formed continuous network structures, which not only improve the mechanical performance of flakes but also provide steric effects to impel the adsorption of metallic oxide magnetic nanoparticles concentrated on the edge of GO flakes, thereby guaranteeing the interfacial connection of adjacent rGO flakes by nanoparticle cross-linking. Meanwhile, the surface and interface reinforce approach can greatly improve the electrical conductivity and mechanical stability of composites. Owing to the light weight, abundant interface, high electrical conductivity, combined with the superparamagnetic properties brought by the magnetic nanoparticles, composite aerogel with high mechanical stability and excellent microwave absorption was achieved, of which the effective absorption bandwidth of the aerogel is 4.4–18 GHz and the maximum value can reach −49 dB. This approach could not only be used to prepare microwave absorption materials with light weight and high performance but also be meaningful to enlarge the construction and application of carbon-based materials.