Magnetic and Conductive Ni/Carbon Aerogels toward High-Performance Microwave Absorption

Abstract

Novel magnetic and conductive Ni/carbon aerogels have been successfully fabricated through an autocatalytic reduction process. The resultant Ni/carbon aerogels have nanoporous structure with high specific surface area, low densities, appropriate electrical conductivities and controllable magnetization. Due to these special attributes, the aerogel composites are demonstrated to be a great microwave absorbent possessing strong and controllable EM absorption with ultrathin thickness. Only with filler loading of 10 wt % in the wax, a minimum RL of −57 dB is found at 13.3 GHz with the thickness of 2 mm. Even with the thickness of 1.5 mm, the Ni/carbon aerogel-3 composite can exhibit the low RL min value of −32 dB and wide effective EM absorption bandwidth of 4.0 dB. The synergistic effect of the medium dielectric loss, weak magnetic loss and good impedance match, accounts for the high microwave absorption performance.

Nanoporous Ni with High Surface Area for Potential Hydrogen Storage Application

“…Then, a two-step chemistry process was employed to fabricate the Ni aerogel ( Figure 1 ). Ni nanoparticles were chemically deposited on the surface of SiO 2 aerogel templates by an autocatalytic reduction process [ 21 , 29 ]. During the reduction process, Pd particles were first deposited on the surface of the SiO 2 aerogel as the catalytic agent.…”

Magnetic aerogel: an advanced material of high importance

“…131 In order to fabricate a magnetic aerogel for photocatalytic degradation Rhodamine B dye core-shell Fe 3 O 4 @TiO 2 particles were dispersed in silica aerogel by using the sol-gel approach and hydrothermal drying process. The obtained composite Removal of uoride from water 69 Oil spoilage and other environmental contaminants removal 73,79,81,88,95,96 Adsorption of As(III) at optimized conditions 136 Oils and organic solvents removal from water surface 104,135 Organic pollutants 109 Adsorption of As(V) 41,114 As a highly effective microwave absorber 132 Microwave absorbing material 28,42,122,124,140,141 Data storage applications and other military purposes 90…”

“…These all properties made it an efficient microwave absorbing material with excellent performance (RL −57 dB at 13.3 GHz). 28 Magnetic aerogel with different additives including magnetic iron oxide, cobalt, and nickel foam was synthesized by mixing the pre-synthesized modified polyurethane sponges and the precursors of above additives, followed by the heat treatment in inert atmosphere. The carbon matrix of the aerogel was obtained by calcination of polyurethane grafted with polyelectrolyte layers and metal acrylate.…”

“…1, opens up fascinating possibilities for applications in several elds like environmental remediation, catalysis, magnetic eld-assisted chemical reactions, controlled drug delivery applications, microwave absorption, electromagnetic interference (EMI) shielding, radiotherapy, catalysis, magnetic high-density storage devices, and devising therapeutic and sensing types of equipment. [20][21][22][23][24][25][26][27][28][29] The use of different types of drying techniques are done in order to achieve aerogels of the desired characteristics as it has also been reported for cryogels that the drying processes are noted to have a great effect on the nal morphological, structural and physical characteristics of the materials. 30 The microwave absorption capability, drug delivery application, catalytic ability, mechanical properties, and re-usability of the pristine aerogels can be improved by making their composites.…”

A Novel Radiation Method for Preparing MnO2/BC Monolith Hybrids with Outstanding Supercapacitance Performance

“…With the rapid increase of global energy demand and the depletion risk of fossil fuels, developing alternative sustainable, affordable, efficient and clean energy has become very urgent in recent decades [ 1 , 2 ]. Among energy storage devices, supercapacitors (or ultracapacitors) have attracted intense interest because of their high energy density, safe operation, super-high service life and great power density [ 3 , 4 , 5 ].…”