Facile fabrication of carbon microspheres decorated with B(OH)₃ and α-Fe₂O₃ nanoparticles: Superior microwave absorption

We demonstrate that novel three-dimensional (3D) B(OH)₃ and α-Fe₂O₃ nanoparticles decorated carbon microspheres (B(OH)₃/α-Fe₂O₃-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1-3μm and decorated B(OH)₃ and α-Fe₂O₃ nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)₃/α-Fe₂O₃-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2-18GHz. They have a minimum reflection loss (RL) value of -52.69dB at a thickness of 3.0mm, and the effective absorption bandwidth for RL less than -10dB is as large as 5.64GHz. The enhanced microwave absorption performance arises from the synergy of the impedance matching caused by the B(OH)₃ nanoparticles, dielectric loss as well as the enhancement of multiple reflection among 3D α-Fe₂O₃ nanocrystals. These results provide a new strategy to tune electromagnetic properties and enhance the capacity of high-efficient microwave absorbers.