Much enhanced electromagnetic wave absorbing properties from the synergistic effect of graphene/γ-graphyne heterostructure in both gigahertz and terahertz band ranges

Exploring advanced electromagnetic wave (EMW) absorbers is one of the most feasible ways to solve the increasing electromagnetic pollution in both military and civil fields. In this work, γ-graphyne (γ-GY) is synthesized by a mechanochemical route using CaC2 and hexabromobenzene (PhBr6). Then three-dimensional (3D) reduced graphene oxide/γ-GY (RGO/GY) heterostructures are prepared through facile solvothermal self-assembly and subsequent thermal reduction. The influences of calcination temperature and the content of γ-GY of the composite on EMW absorption performance are fully investigated. The minimum reflection loss (RL) value of the RGO/GY composite foam is −71.73 dB at 10.48 GHz with the matching thickness of 3.54 mm, and the effective absorption bandwidth (EAB) less than −10 dB is 7.36 GHz. Moreover, excellent terahertz (THz) absorption property is also obtained at 0.2–1.6 THz. The RL of 84.08 dB is acquired, and the EAB covers 100% of the entire measured bandwidth. In addition, the composite is also a promising anticorrosive EMW absorber. This work provides encouraging findings, which are also instructive for the potential advantages of graphyne-based materials as highly efficient EMW absorbers in both gigahertz and terahertz band ranges.