Microwave absorption enhancement of porous C@CoFe₂O₄ nanocomposites derived from eggshell membrane

As the rapid development of electronic devices and wireless communication tools, it is urgent to design and fabricate low-cost, lightweight and effective electromagnetic absorption materials to solve electromagnetic interference of electromagnetic wave. Herein, a feasible and low-cost method has been developed to synthesize an effective carbon-based microwave absorber. The hierarchically porous structures derived from eggshell membrane (ESM) and the anchored CoFe₂O₄ nanoparticles (NPs) helped the C/CoFe₂O₄ nanocomposites perform a favor for strengthening electromagnetic absorption capability. The porous C@CoFe₂O₄ nanocomposites achieves the maximum reflection loss value of −49.6 dB at 9.2 GHz with 30% loading in the paraffin matrix. Detailed investigation reveals that the porous structure as well as strong synergetic effect between porous carbon matrix and magnetic nanoparticles can effectively improve the impedance matching condition and attenuation ability of the nanocomposites, leading to a high microwave absorption performance. In addition, the simulation results indicate that the radar cross section (RCS) of a strong metal scattering sources at different degrees can be significantly reduced after coating with C@CoFe₂O₄ nanocomposites. These achievements light the way to prepare low-cost and sustainable microwave absorbents with excellent electromagnetic wave absorbing performances, utilizing the wasted eggshell membrane biomasses as precursors.