A green fabrication and variable temperature electromagnetic properties for thermal stable microwave absorption towards flower-like Co₃O₄@rGO/SiO₂ composites

High efficiency and thermal stability are two key factors of ideal electromagnetic attenuation materials, which are becoming desired owing to more complex modern service environment. Herein, a new type of high-temperature microwave absorber, flower-like Co₃O₄@rGO/SiO₂ composite is synthesized by a generic and green fabrication route. It possesses stable microwave absorption (MA) performance in the temperature range from 353 K to 473 K. Particularly, the optimal reflection loss (RL) reaches −52.6 dB with thickness of 1.78 mm at the temperature of 353 K, and maximum bandwidth (RL ≤ −10 dB) of samples can cover the entire X-band (8.2–12.4 GHz) at the thickness of ∼2.00 mm. The excellent high-temperature MA performance can be ascribed to the synergistic effect of the introduced magnetic loss and conduction loss, as well as the multiple polarizations loss of three-dimensional (3D) hierarchical structures. Our work confirms that 3D hierarchical Co₃O₄@rGO/SiO₂ sample can provide a novel pathway for designing high-temperature microwave absorbers in the future.