ZnO Nanorod-Based Microflowers Decorated with Fe₃O₄ Nanoparticles for Electromagnetic Wave Absorption

Abstract

It is of great significance to improve the electromagnetic wave absorption performance of absorbing materials for application in critical fields using different techniques to design a unique structure. Three-dimensional (3D) ZnO nanorods with unique microflower-like structures and high-performance microwave absorption were successfully synthesized via the hydrothermal route and annealing process, which were modified with sphere-like Fe 3 O 4 nanoparticles. The composites display an outstanding microwave absorption property with different contents of Fe 3 O 4 nanoparticles and the mass ratio of ZnO/Fe 3 O 4 to paraffin is 3:2. The best reflection loss (RL) value can reach −36.2 dB at 9.35 GHz with an absorber thickness of only 2.7 mm and the corresponding absorption bandwidth is 4.02 GHz (6.81−10.83 GHz) in the range of 2−18 GHz when the composites contain 11.3 wt % Fe 3 O 4 as the filler. A mechanism is proposed and discussed to further understand the absorption behavior of composites. This work demonstrates a promising synthetic route to design thin, economical, and wide-bandwidth stable microwave-absorbing materials with outstanding microwave absorption performance.

Nickel Iron Layered Double Hydroxide Nanostructures Composited with Carbonyl Iron Powder for Microwave Absorption

“…To visually judge the electromagnetic wave absorption performance of all samples, the reflection loss (RL) value based on transmission line theory can be calculated by the following equation: , .25ex2ex RL 0.25em ( dB ) = 20 log true| Z in − Z 0 Z in + Z 0 true| Z in = Z 0 μ r ε r tanh true( j 2 π italicfd c μ normalr ε normalr true) where ε r and μ r represent the complex permittivity and complex permeability, respectively; f stands for frequency; c stands for the speed of light; and d stands for thickness …”

Marine polysaccharide-based electromagnetic absorbing/shielding materials: design principles, structure, and properties

“…23 As representatives of magnetic and conductive materials, Fe 3 O 4 and CNTs are widely used in the field of EMW absorption by virtue of their extraordinary magnetic loss, dielectric loss, and conductive loss. 155–158 There are a large number of oxygen-containing functional groups (–COOH and –OH) and defects on the surface of the oxidized CNTs, 159 which not only anchor the magnetic Fe 3 O 4 particles tightly on the surface of CNTs and generate multi-interfacial heterostructures that contribute to interfacial polarization, but also produce abundant dipoles that contribute to relaxation loss with Fe 3 O 4 and several defects as polarization centers. 160 The 3D porous conductive network combining the advantages of SA and CNTs, and the effective multi-interface heterostructures constructed between the two types of magnetic particles and the derived carbon skeletons can be obtained by crosslinking Ni 2+ with the SA–Fe 3 O 4 /CNTs hybrid matrix and carbonizing.…”

High performance flexible electromagnetic interference shielding material realized using ZnO nanorod decorated polyvinylidene fluoride (PVDF)-MXene composite nanofibers

“…For example, various nanostructures, such as Fe 3 O 4 NP-coating on ZnO NRs, aerogels, 3D metal-organic frameworks (MOFs), and porous carbon, have been adopted and demonstrated enhanced EMI SE. [20][21][22][23] Therefore, to realize high-performance MXene-based NF EMI shielding materials, different performance enhancement methods should be seamlessly adopted.…”