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.

A series of inkjet printing processes have been studied using graphene-based inks. Under optimized conditions, using water-soluble single-layered graphene oxide (GO) and few-layered graphene oxide (FGO), various high image quality patterns could be printed on diverse flexible substrates, including paper, poly(ethylene terephthalate) (PET) and polyimide (PI), with a simple and low-cost inkjet printing technique. The graphene-based patterns printed on plastic substrates demonstrated a high electrical conductivity after thermal reduction, and more importantly, they retained the same conductivity over severe bending cycles. Accordingly, flexible electric circuits and a hydrogen peroxide chemical sensor were fabricated and showed excellent performances, demonstrating the applications of this simple and practical. The results show that graphene materials—which can be easily produced on a large scale and possess outstanding electronic properties—have great potential for the convenient fabrication of flexible and low-cost graphene-based electronic devices, by using a simple inkjet printing technique.