Controlled Synthesis and Microwave Absorption Property of Chain-Like Co Flower

Abstract

Chain-like Co flower is synthesized by simply modulating the reaction conditions via a facile liquid-phase reduction method. The morphology evolution process and transformation mechanism from particle to flower and finally to chain-like flower have been systematically investigated. [001] is the preferred growth orientation due to the existence of easy magnetic axis. The microwave loss mechanism can be attributed to the synergistic effect of magnetic loss and dielectric loss, while magnetic loss is the main loss mechanism. In addition, the special microstructure of chain-like Co flower may further enhance microwave attenuation. The architectural design of functional material morphology is critical for improving its property toward future application.

Improved electromagnetic wave absorption of Co nanoparticles decorated carbon nanotubes derived from synergistic magnetic and dielectric losses

“…Over the past few years, the electromagnetic (EM) wave absorbing materials, applicable in the gigahertz frequency range, have attracted a growing research interest due to their extensive applications in electronic equipment or integrated electronics such as computers, communication devices, and electronic toll collection. Since radiations from an EM wave could cause serious environmental pollution and harm to human health, [1][2][3][4][5][6][7][8][9][10][11][12] great efforts have been made to develop high-efficiency EM absorbents by utilizing the magnetic loss or dielectric loss of the materials. Although a variety of strategies have been explored by the combination of magnetic and dielectric losses to improve EM absorbing performances, it is still a challenge to obtain more efficient EM absorption materials that possess strong absorption, are light weight, have a thin thickness, and cover a wide absorption frequency range.…”

Synthesis of Highly Uniform Nickel Multipods with Tunable Aspect Ratio by Microwave Power Control

“…Enhancing tip growth requires control of surface energy, which can be achieved by ligand binding or potentially selective heating. MW heating can give rise to selective heating due to the fact that MW absorption by a nanoparticle is size- and shape-dependent. ,, The interaction of the MW field will be largest at sharp edges, reflecting the properties of the dielectric absorption process. ,,− In systems exhibiting overgrowth, this may lead to selective heating of the tips and potentially increased reduction rates at the overgrowth sites owing to the lightning rod effect, − leading to enhanced anisotropic growth at the superheated tips as hypothesized in Figure . Of course, under continuous MW absorption, as the nanoparticle reaches thermal equilibrium, this effect will be diminished, leading to the reported spherical shapes.…”

“…MW power cycling as a tool in MW chemistry has been suggested by organic chemists to enhance yield of reactions and in materials synthesis to manipulate heating rates. Although the fundamental physics are well understood and the lightning rod effect has been shown to enhance electromagnetic shielding, ,,− the use in MW synthesis has not been explored.…”

Facile preparation and excellent microwave absorption properties of an RGO/Co0.33Ni0.67 lightweight absorber

“…In contrast, the tan d 3 values of the RGO/Co 0.33 Ni 0.67 composites are higher than their tan d m values, demonstrating that the dielectric loss is regarded as the main loss mechanism aer combining with RGO. 32 The dielectric loss usually derives from nature resonance, electronic polarization and electronic conductivity. 26,33 For the RGO/Co 0.33 Ni 0.67 composites, the Co 0.33 Ni 0.67 and residual defects and groups of the RGO act as polarized scattering center which can absorb the electromagnetic energy.…”