Multifunctional Organic–Inorganic Hybrid Aerogel for Self‐Cleaning, Heat‐Insulating, and Highly Efficient Microwave Absorbing Material

Hollow Engineering to Co@N-Doped Carbon Nanocages via Synergistic Protecting-Etching Strategy for Ultrahigh Microwave Absorption

Currently, electromagnetic (EM) pollution poses severe complication toward the operation of electronic devices and biological systems. To this end, it is pertinent to develop novel microwave absorbers through compositional and structural design. Porous carbon (PC) materials demonstrate great potential in EM wave absorption due to their ultralow density, large surface area, and excellent dielectric loss ability. However, the large-scale production of PC materials through low-cost and simple synthetic route is a challenge. Deriving PC materials through biomass sources is a sustainable, ubiquitous, and low-cost method, which comes with many desired features, such as hierarchical texture, periodic pattern, and some unique nanoarchitecture. Using the bio-inspired microstructure to manufacture PC materials in mild condition is desirable. In this review, we summarize the EM wave absorption application of biomass-derived PC materials from optimizing structure and designing composition. The corresponding synthetic mechanisms and development prospects are discussed as well. The perspective in this field is given at the end of the article.

/pdf/biomass-derived-porous-carbon-based-nanostructures-for-a8l3dt0sju.pdf

Biomass-Derived Porous Carbon-Based Nanostructures for Microwave Absorption

Achieving superior electromagnetic wave absorbers through the novel metal-organic frameworks derived magnetic porous carbon nanorods

Graphene and MXene Nanomaterials: Toward High-Performance Electromagnetic Wave Absorption in Gigahertz Band Range

Rational construction of a profitable microstructure in carbon-based electromagnetic composites is becoming a promising strategy to reinforce their microwave absorption performance. Herein, the microstructure design is innovatively coupled with a metal–organic frameworks (MOFs)-derived method to produce hollow Co/C microspheres (Co/C-HS). The resultant composites combine the advantages of hollow microstructures and good chemical homogeneity. It is found that the pyrolysis temperature plays an important role in determining the electromagnetic properties of these hollow Co/C microspheres, where high pyrolysis temperature will increase relative complex permittivity and decrease relative complex permeability. When the pyrolysis temperature is 600 °C, the sample (Co/C-HS-600) will show improved impedance matching and good attenuation ability, and thus an excellent microwave absorption performance with strong reflection loss (−66.5 dB at 17.6 GHz) and wide response bandwidth (over −10 dB, 3.7–18.0 GHz) can be a...

MOFs-Derived Hollow Co/C Microspheres with Enhanced Microwave Absorption Performance

Rational design of the microstructure of functional materials provides a new opportunity to improve their performance. However, it is always difficult to construct desirable microstructures in magnetic metals due to their strong magnetic interactions. Herein, we demonstrate the successful synthesis of three-dimensional flower-like Ni microspheres (FNMs) through a simple two-step process, in which flower-like Ni(OH)2 microspheres are firstly prepared by a hydrothermal route and then are reduced under a high-temperature H2/N2 atmosphere. The as-prepared FNMs are composed of cross-linked nanoparticles directed by their precursor. Compared with commercial and home-made Ni powder, FNMs exhibit enhanced conductivity and dielectric loss ability, as well as significantly improved impedance matching. As a result, FNMs exhibit good microwave absorption properties, including a strong reflection loss (−56.8 dB at 15.8 GHz) and a broad qualified frequency range (2.5–18.0 GHz) with thicknesses ranging from 5.0 to 1.0 mm and a thin matching thickness of 1.12 mm. Such an excellent performance is substantially superior to those of Ni-based materials derived from various elaborate strategies. It is believed that our work may inspire the controlled synthesis of conventional magnetic metal materials with enhanced microwave absorption properties in the future.

Facile synthesis of 3D flower-like Ni microspheres with enhanced microwave absorption properties

Binary dielectric composites are viewed as a kind of promising candidate for conventional magnetic materials in the field of microwave absorption. Herein, we demonstrate the successful fabrication ...

Space-Confined Synthesis of Core–Shell BaTiO3@Carbon Microspheres as a High-Performance Binary Dielectric System for Microwave Absorption

Carbides/carbon composites are becoming a new kind of microwave absorption (MA) materials with great potential in chemical stability and light weight, as well as enhanced performance. Herein, we design a series of Mo2C/C composites through a simple pyrolysis of Mo-substituted ZIF-8 (Mo/ZIF-8). It is found that the transformation of zeolitic imidazolate frameworks into carbon polyhedrons is accompanied by the in situ formation of ultrasmall Mo2C nanoparticles (Mo2C NPs) less than 5.0 nm. The molar ratio of 2-methylimidazole to molybdic acid (MIM/Mo) presents a significant effect on the relative content of Mo2C NPs but not on their average size. The uniform distribution of Mo2C NPs in carbon polyhedrons overcomes the poor chemical homogeneity in conventional carbides/carbon composites. More importantly, Mo2C NPs modulate the dielectric loss of these composites effectively. On one hand, they moderately weaken the contribution from conductivity loss and dipole orientation polarization; on the other hand, they...

Chaolong Li

Papers

MOFs-Derived Hollow Co/C Microspheres with Enhanced Microwave Absorption Performance

Facile synthesis of 3D flower-like Ni microspheres with enhanced microwave absorption properties

Space-Confined Synthesis of Core–Shell BaTiO3@Carbon Microspheres as a High-Performance Binary Dielectric System for Microwave Absorption

Ultrasmall Mo2C Nanoparticle-Decorated Carbon Polyhedrons for Enhanced Microwave Absorption