MOFs-derived multi-chamber carbon microspheres with enhanced microwave absorption

Microstructure is playing a more and more important role in upgrading the performance of microwave absorption materials (MAMs) nowadays. Herein, we demonstrate the successful synthesis of multi-chamber carbon microspheres (MCCMs) with abundant interior cavities. The reflection loss (RL) characteristics of MCCMs and the effect of microstructure on electromagnetic properties have been discussed thoroughly. It is found that compared with the solid carbon microspheres, MCCMs possess reinforced dielectric loss and attenuation ability towards incident electromagnetic waves, and in contrast to hollow carbon microspheres, the unique multi-chamber architecture endows MCCMs with better impedance matching characteristic. More importantly, it is proved that the consolidated multiple reflection effect originated from multi-chamber microstructure can contribute to reinforced attenuation ability and optimized impedance matching characteristic simultaneously. In consequence, MCCMs exhibit enhanced microwave absorption properties, including the minimum RL intensity of similar to 28.5 dB at 10.2 GHz with the thickness of 2.0mm and the widest effective absorption bandwidth of 5.7 GHz with the thickness of 1.8 mm. It is believed that these results will provide some practical significance for high-performance MAMs based on carbon-related materials with profitable microstructure. (C) 2019 Elsevier Ltd. All rights reserved.