Hollow Engineering of Core-Shell Fe3O4@MoS2 Microspheres with Controllable Interior toward Optimized Electromagnetic Attenuation

The development of electromagnetic wave absorbing materials with broadband absorption and thin thickness still confronts huge challenges in addressing the aggravating problem of electromagnetic pollution. Herein, hollow core-shell Fe3O4@MoS2 microspheres with controllable interior and tunable shell are constructed to precisely regulate the corresponding electromagnetic attenuation. The results demonstrate that hollow Fe3O4 microspheres exhibit strong absorption in C-X bands owing to their strong ferromagnetic resonance. Upon structural regulation, hollow core-shell Fe3O4@MoS2 microspheres not only ensure outstanding electromagnetic wave absorption intensity at thin thickness, but also endow broadband absorption characteristics. Benefiting from the cooperative merits of manipulated Fe3O4 interior and controllable MoS2 shells, the as-synthesized microspheres display obvious interface polarization, defect/dipole polarization and multiple scatterings, thereby resulting in improved impedance matching and attenuation capability. Especially for Fe3O4@MoS2-2, the strongest reflection loss is -69.01 dB at 2.66 mm and the effective absorption bandwidth reaches 8.40 GHz when the thickness is 3.0 mm. This study systematically investigates the balance relationship between core-shell structures and absorption attenuation, and simultaneously provides a referable strategy to regulate the electromagnetic wave absorption by structural optimization.