Enhanced Electromagnetic Wave Absorption of Three-Dimensional Porous Fe₃O₄/C Composite Flowers

Magnetite (Fe 3 O 4 )/carbon (C) composite flowers with an average size of 4–6 μm were prepared through a facile route including a solvothermal approach and a carbon reduction process. The resultant Fe 3 O 4 /C composites are porous and exhibit a three-dimensional (3D) flower-like morphology with the core–shell Fe 3 O 4 @C nanoparticles hybridized by amorphous carbon sheets. The epoxy resin composites containing 50 wt % 3D porous Fe 3 O 4 /C composite flowers display an optimal reflection loss (RL) value of −54.6 dB at 5.7 GHz at a thin thickness of 4.27 mm and the effective bandwidth with RL < −10 dB reaches 6.0 GHz at a thickness of 2.1 mm. These enhanced EM wave absorption performances are attributed to the synergistic effects of Fe 3 O 4 and carbon as well as the structural advantages, e.g., three-dimensional structure with large surface area, porous and core–shell structures of Fe 3 O 4 /C flowers. These results suggest the 3D porous Fe 3 O 4 /C composite flowers designed here can serve as ideal candidates for high-performance EM wave absorption.