Magnetic modulation of core@shell MoS2-based flower-like multicomponent nanocomposites to improve microwave attenuation

Structural, Magnetic, and Electrical Investigations of PVA/Ni Ferrite/(MoS2)x Nanocomposites

Transition metal sulfides (TMDs) possess exceptional dielectric properties and a narrow band gap, rendering them highly efficient as electromagnetic absorbing materials. Among these TMDs, the two-dimensional MoS2 nanosheet has received significant attention in research. However, the quest for new absorbers no longer finds satisfaction in solitary absorption mechanisms. This article introduces a successful method for creating PVA/NiFe2O4/(MoS2)x nanocomposites via a straightforward sol-gel technique, wherein porous amorphous NiFe2O4 microspheres are integrated into MoS2 nanosheets. The investigation uncovers that the incorporation of MoS2 results in an enhanced complex permittivity, facilitating the attainment of a desirable permittivity level. The PVA/NiFe2O4/(MoS2)x nanocomposite absorber exhibits an incredibly low reflection loss (RL) of -16.75 dB at a mere thickness of 1 mm, achieved through the cooperative interaction of dielectric and magnetic loss, along with the advantages of the structure and composition. Consequently, the PVA/NiFe2O4/(MoS2)x nanocomposites effectively absorb electromagnetic waves. Therefore, it is posited that MoS2-based composites hold great promise as highly effective microwave absorbers, boasting strong absorption intensity and a wide absorption frequency range, given the exceptional performance of the as-fabricated PVA/NiFe2O4/(MoS2)x nanocomposites.

Facile preparation and high microwave absorption of flower-like carbon nanosheet aggregations embedded with ultrafine Mo2C

Rational regulation of microstructure and components is vital for excellent microwave absorption performance. In this study, we report flower-like carbon nanosheet architectures embedded with ultrafine Mo₂C as a microwave absorber, prepared via simple carbothermal reduction using Mo-polydopamine as the precursor. We found that the particle size of the obtained Mo₂C/C composites could be simply tailored by the added ammonium molybdate content in the initial solution for the preparation of the Mo-polydopamine precursor. This helped tailor the BET surface area, which significantly impacts microwave absorption performance. The sample with a BET surface area of 173.31 m²g^-1 displayed high-efficiency microwave absorption, and the effective absorbing band reached up to 7.04 GHz (10.96-18 GHz) with the matching thickness of 2.9 mm at relatively low filler loading (only 10 wt%). Thus, the excellent microwave absorption performance and simple preparation process of the flower-like Mo₂C@C composites are promising for applications requiring lightweight and broadband microwave absorption.