A novel and facile-to-synthesize three-dimensional honeycomb-like nano-Fe3O4@C composite: Electromagnetic wave absorption with wide bandwidth

The three-dimensional honeycomb-like nano-Fe3O4@C (HcFe(3)O(4)@C) composite and the three-dimensional honeycomb-like porous carbon (HcC) were prepared through a two-step colloidal template method. The HcFe(3)O(4)@C composite material shows a three-dimensional multilayer honeycomblike structure with a uniform pore diameter of 100 nm, while the HcFe3O4@C composite exhibits enhanced absorbing properties with a low Fe3O4 content(28.95%). HcFe(3)O(4)@C composite display an optimal reflection loss (RL) value of -46.4 dB at 9.6 GHz at a thin thickness of 3.5 mm, and a wide absorption bandwidth of 5.04 GHz. These enhanced EM wave absorption performances are attributed to the synergistic effects of Fe3O4 and carbon as well as the structural advantages, such as multiple reflections of electromagnetic waves in the three-dimensional honeycomb structure and interface polarization caused by Fe3O4 nanoparticles and carbon layer. The work herein reported provides a new route for preparing ferrite-carbon based absorbers with honeycomb-like nanostructures. (C) 2020 Elsevier Ltd. All rights reserved.