Efficient microwave absorption achieved through in situ construction of core-shell CoFe₂O₄@mesoporous carbon hollow spheres

Utilizing of cobalt ferrite (CoFe₂O₄) with good chemical stability and magnetic loss ability to prepare composites with a special structure can effectively improve the material's absorbing performance. Herein, introducing CoFe₂O₄ magnetic particles into the hollow mesoporous carbon material through an unsophisticated in-situ preparation method, the author of the research has synthesized the CoFe₂O₄@ mesoporous carbon hollow spheres (MCHS) with core-shell structure. The content of MCHS and cobalt ferrite CoFe₂O₄ and the size of the pores can be changed to coordinate the magnetic loss and dielectric loss. In light of previous researches of the same author, the minimum reflection loss (RL_min) of CoFe₂O₄@MCHS composites occurs as -29.7 dB when the microwave frequency is modulated to 5.8 GHz. Besides, the effective absorption bandwidth (EAB) emerges as 3.7 GHz, with the thickness being 2.5 mm and the filling rate being 30%. The good electromagnetic wave (EMW) absorption performance is generated by the special core-shell structure and exceptional impedance matching. The results show that tweaking the ratio of MCHS and CoFe₂O₄, the impedance match absorbing properties of CoFe₂O₄@MCHS composites are altered. Corresponding absorption mechanism has been discussed within the paper. This method provides a feasible solution to prepare core-shell structure microwave absorbents and is much promising for practical use.