Search

• Plate-like BaFe 12 O 19 @ZnFe 2 O 4 /MWCNTs nanocomposites were successfully fabricated via a facile method. • MWCNTs formed conductive networks in the ternary hybrids. • The exchange coupling between BaFe 12 O 19 and ZnFe 2 O 4 could widen the absorption band. • RL min reaches to −42.3 dB at 8.2 GHz and −10 dB bandwidth reaches 3.6 GHz. In order to reduce the radiation and interference of electromagnetic waves, rational assembly of dielectric materials and magnetic materials is becoming a promising strategy to produce highly efficient microwave absorbers. Herein, a novel kind of ternary nanocomposites, multi-wall carbon nanotubes decorated plate-like BaFe 12 O 19 @ZnFe 2 O 4 (BaFe 12 O 19 @ZnFe 2 O 4 /MWCNTs), was fabricated via a two-step method. Plate-like BaFe 12 O 19 was prepared firstly as a template for the growth of ZnFe 2 O 4 layer, forming a core-shell structure. MWCNTs dispersed between BaFe 12 O 19 @ZnFe 2 O 4 particles and ZnFe 2 O 4 microspheres, forming three-dimensional (3D) conductive networks. The careful design of the structure and the combination of the dielectric material with the hard-soft magnetic material caused excellent impedance matching and multiple loss mechanisms, which endow the ternary hybrids with remarkable microwave absorption performance. The minimum reflection loss reaches −42.3 dB at 8.2 GHz with a layer thickness of 2.5 mm, and the effective bandwidth is 3.6 GHz (from 12.5 GHz to 16.1 GHz) with a layer thickness of 1.5 mm. [ABSTRACT FROM AUTHOR]

Highlights • Highly porous carbon decorated with Co nanoparticles were synthesized. • The rambutan-like composites exhibite excellent microwave absorption property. • The pyrolysis temperature is the main factor for the composites. Abstract Nanoporous carbon (NPC) composites embedded with magnetic nanoparticles have been widely studied for applications in microwave absorption. Herein, highly porous rambutan-like carbon composites decorated with controllable carbon nanotubes (CNTs) and Co nanoparticles were synthesized through a thermal decomposition of Co-doped zeolitic imidazolate frameworks-8 (ZIF-8) under different temperatures. The MOF-derived carbon nanocomposites with the cobalt content accounting for 30% of the total mass of cobalt and zinc, carbonized at 700 °C, exhibited excellent microwave absorption property of −30.2 dB. Characterizations exhibit that the in-situ generated Co nanoparticles are uniformly embedded into NPC matrix, which are surrounded by highly graphitized CNTs. The research presents a facile and promising route for rapid mass production of metal-doped NPC/CNTs composites for high-efficiency microwave absorption. [ABSTRACT FROM AUTHOR]