3D core-shell FeO@SiO@MoS composites with enhanced microwave absorption performance.

In this work, a 3D ternary core-shell FeO@SiO@MoS composite is synthesized by a hydrothermal technique and a modified Stöber method, where magnetic FeO@SiO microsphere with the core of raspberry-like FeO nanoparticles is completely coated by the flower-like MoS. Herein, the electromagnetic parameters of the composites are effectively tuned by the combination of magnetic FeO with dielectric SiO and MoS. The obtained ternary composites exhibit remarkable enhancement of microwave absorption. The measurement results indicate that the minimum reflection loss (RL) of FeO@SiO@MoS 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 FeO particles and FeO@SiO 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.