3D core-shell Fe3O4@SiO2@MoS2 composites with enhanced microwave absorption performance

In this work, a 3D ternary core–shell Fe3O4@SiO2@MoS2 composite is synthesized by a hydrothermal technique and a modified Stöber method, where magnetic Fe3O4@SiO2 microsphere with the core of raspberry-like Fe3O4 nanoparticles is completely coated by the flower-like MoS2. Herein, the electromagnetic parameters of the composites are effectively tuned by the combination of magnetic Fe3O4 with dielectric SiO2 and MoS2. The obtained ternary composites exhibit remarkable enhancement of microwave absorption. The measurement results indicate that the minimum reflection loss (RL) of Fe3O4@SiO2@MoS2 composites reaches −62.98 dB at 1.83 mm with the effective absorption bandwidth (RL < −10 dB) of 5.76 GHz (from 11.28 to 17.04 GHz) at 1.92 mm, much higher than those of pure Fe3O4 particles and Fe3O4@SiO2 microsphere. It is believed that the improved performances come from the specific structural design and the plentiful interfacial construction. Further, the synergistic effect of the dielectric and magnetic loss as well as the promoted impedance matching also help to enhance the microwave absorption of the composites. The microwave absorption behavior of the composites conforms to the quarter-wavelength cancellation theory. Our study offers an effective and promising strategy in the structural design and interfacial construction of the novel magnetic/dielectric composites with high-efficiency microwave absorption.