Reduced graphene oxide decorated with carbon nanopolyhedrons as an efficient and lightweight microwave absorber

Graphene-based composites are becoming a new kind of microwave absorbers that can overcome the challenges related to the performance and light weight in electromagnetic pollution precaution. Herein, a series of reduced graphene oxide decorated with carbon nanopolyhedrons (CNPs/rGO) composites have been successfully fabricated through in situ pyrolysis of ZIF-8/GO hybrids. It is found that GO can restrain the growth of ZIF-8 crystals and produce small-size CNPs after high-temperature pyrolysis, and CNPs will suppress the re-stacking of rGO nanosheets. More importantly, the coupling of CNPs and rGO not only generates the desirable synergistic effects, but also accounts for the profitable interfacial polarization. Therefore, the electromagnetic parameters and microwave absorption properties of these composites can be rationally modulated in terms of the amount of GO. The optimized CNPs/rGO composite exhibits strong reflection loss [-66.2 dB (6.2 GHz, 2.89 mm)] and broad qualified bandwidth (over -10 dB in 3.2-18.0 GHz with integrated absorber thickness of 1.0-5.0 mm), which are superior to many graphene-based composites with high-density magnetic components. Electromagnetic analysis reveals that good attenuation ability and impedance matching are responsible for its excellent performance. It is believed that these results may inspire the design of lightweight microwave absorbers in the future.