Room temperature fabrication of an RGO–Fe3O4 composite hydrogel and its excellent wave absorption properties

Abstract

As a result of their lightweight properties and high dielectric loss, graphene and their composites have attracted great attention for potential applications in wave absorption. Herein, we report room temperature conditions for the synthesis of a 3D composite hydrogel composed of reduced graphene oxide nanosheets and Fe₃O₄ nanoparticles (RGO–Fe₃O₄). The experimental results show that the composite has an interconnected 3D porous network with micrometer-sized pores, and that the Fe₃O₄ nanoparticles with a small size of about 5–10 nm are uniformly dispersed onto the thin graphene nanosheets. The as-prepared RGO–Fe₃O₄ composite hydrogel shows excellent microwave absorbability compared with previously reported nanocomposites based on graphene and Fe₃O₄. The obtained composite with a coating layer thickness of only 2.5 mm exhibits a maximum absorption of −47.9 dB at 10.1 GHz. In particular, the product with a coating layer thickness of only 2.0 mm shows a bandwidth of 5.3 GHz (from frequency of 11.3–16.6 GHz) corresponding to reflection loss at −10 dB (90% absorption). Additionally, the fabrication method is simple, low cost and easily done on a large scale. This further confirms that nanoscale Fe₃O₄ particles on graphene networks give the composite hydrogel the ability to realize practical applications for wave absorption.