Carbon-Based MOF Derivatives: Emerging Efficient Electromagnetic Wave Absorption Agents
TL;DR: This review summarizes progresses and highlights strategies of MOF derivatives for efficient electromagnetic wave absorption, and summarizes the relevant theories and evaluation methods, and categorized the state-of-the-art research progresses in EMW absorption field.
Abstract: To tackle the aggravating electromagnetic wave (EMW) pollution issues, high-efficiency EMW absorption materials are urgently explored. Metal–organic framework (MOF) derivatives have been intensively investigated for EMW absorption due to the distinctive components and structures, which is expected to satisfy diverse application requirements. The extensive developments on MOF derivatives demonstrate its significantly important role in this research area. Particularly, MOF derivatives deliver huge performance superiorities in light weight, broad bandwidth, and robust loss capacity, which are attributed to the outstanding impedance matching, multiple attenuation mechanisms, and destructive interference effect. Herein, we summarized the relevant theories and evaluation methods, and categorized the state-of-the-art research progresses on MOF derivatives in EMW absorption field. In spite of lots of challenges to face, MOF derivatives have illuminated infinite potentials for further development as EMW absorption materials.
Highlights:
1 In terms of components and structures, this review summarizes progresses and highlights strategies of MOF derivatives for efficient electromagnetic wave absorption.2 We also systematically delineate relevant theories and points out the prospects and current challenges.
Citations
More filters
TL;DR: In this article , comprehensive views toward dielectric loss mechanisms including interfacial polarization, dipolar polarization, conductive loss, and defect-induced polarization are provided, and in-depth losses and mechanisms regulation strategies instead of regular components compositing are summarized to provide inspiring thoughts toward simple and effective EM wave attenuation behavior modulation.
Abstract: Electromagnetic (EM) wave absorbing materials play an increasingly important role in modern society for their multi‐functional in military stealth and incoming 5G smart era. Dielectric loss EM wave absorbers and underlying loss mechanism investigation are of great significance to unveil EM wave attenuation behaviors of materials and guide novel dielectric loss materials design. However, current researches focus more on materials synthesis rather than in‐depth mechanism study. Herein, comprehensive views toward dielectric loss mechanisms including interfacial polarization, dipolar polarization, conductive loss, and defect‐induced polarization are provided. Particularly, some misunderstandings and ambiguous concepts for each mechanism are highlighted. Besides, in‐depth dielectric loss study and novel dielectric loss mechanisms are emphasized. Moreover, new dielectric loss mechanism regulation strategies instead of regular components compositing are summarized to provide inspiring thoughts toward simple and effective EM wave attenuation behavior modulation.
246 citations
TL;DR: In this article , the copper sulfide wrapped by reduced graphene oxide (CuS@rGO) was synthesized via thermal reduction ways (hydrothermal, ascorbic acid reduction) and freeze-drying strategy.
Abstract: Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot, which is still a problem to be solved. Herein, the copper sulfide wrapped by reduced graphene oxide to obtain three-dimensional (3D) porous network composite aerogels (CuS@rGO) were synthesized via thermal reduction ways (hydrothermal, ascorbic acid reduction) and freeze-drying strategy. It was discovered that the phase components (rGO and CuS phases) and micro/nano structure (microporous and nanosheet) were well-modified by modulating the additive amounts of CuS and changing the reduction ways, which resulted in the variation of the pore structure, defects, complex permittivity, microwave absorption, radar cross section (RCS) reduction value and infrared (IR) emissivity. Notably, the obtained CuS@rGO aerogels with a single dielectric loss type can achieve an ultrabroad bandwidth of 8.44 GHz at 2.8 mm with the low filler content of 6 wt% by a hydrothermal method. Besides, the composite aerogel via the ascorbic acid reduction realizes the minimum reflection loss (RLmin) of - 60.3 dB with the lower filler content of 2 wt%. The RCS reduction value can reach 53.3 dB m2, which effectively reduces the probability of the target being detected by the radar detector. Furthermore, the laminated porous architecture and multicomponent endowed composite aerogels with thermal insulation and IR stealth versatility. Thus, this work offers a facile method to design and develop porous rGO-based composite aerogel absorbers with radar-IR compatible stealth.
114 citations
TL;DR: In this article , the copper sulfide wrapped by reduced graphene oxide (CuS@rGO) was synthesized via thermal reduction ways (hydrothermal, ascorbic acid reduction) and freeze-drying strategy.
Abstract: Developing ultrabroad radar-infrared compatible stealth materials has turned into a research hotspot, which is still a problem to be solved. Herein, the copper sulfide wrapped by reduced graphene oxide to obtain three-dimensional (3D) porous network composite aerogels (CuS@rGO) were synthesized via thermal reduction ways (hydrothermal, ascorbic acid reduction) and freeze-drying strategy. It was discovered that the phase components (rGO and CuS phases) and micro/nano structure (microporous and nanosheet) were well-modified by modulating the additive amounts of CuS and changing the reduction ways, which resulted in the variation of the pore structure, defects, complex permittivity, microwave absorption, radar cross section (RCS) reduction value and infrared (IR) emissivity. Notably, the obtained CuS@rGO aerogels with a single dielectric loss type can achieve an ultrabroad bandwidth of 8.44 GHz at 2.8 mm with the low filler content of 6 wt% by a hydrothermal method. Besides, the composite aerogel via the ascorbic acid reduction realizes the minimum reflection loss (RLmin) of - 60.3 dB with the lower filler content of 2 wt%. The RCS reduction value can reach 53.3 dB m2, which effectively reduces the probability of the target being detected by the radar detector. Furthermore, the laminated porous architecture and multicomponent endowed composite aerogels with thermal insulation and IR stealth versatility. Thus, this work offers a facile method to design and develop porous rGO-based composite aerogel absorbers with radar-IR compatible stealth.
99 citations
TL;DR: In this paper, the molar ratios of Fe3+ to Zn2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites, i.e., the obtained composites had the optimal electromagnetic attenuation performance, and the minimum reflection loss achieved −79.0dB with a matching thickness of 2.76mm and effective absorption bandwidth was as high as 5.8GHz under a thin thickness of 1.8mm and low filling ratio of 20.0
Abstract: Developing strong absorption and broadband microwave absorbers derived from metal-organic frameworks (MOFs) still remains a big challenge in the field of microwave absorption. Herein, iron zinc bimetallic metal-organic frameworks/reduced graphene oxide (FeZn-MOFs/RGO) precursors derived ferroferric oxide/carbon (Fe3O4/C) decorated graphene composites were fabricated via a solvothermal and carbonization two-step strategy. It was found that the morphology of carbon frameworks could be regulated from the traditional regular octahedron to the pomegranate shape by simply adjusting the molar ratios of Fe3+ to Zn2+ in the precursors. Moreover, results revealed that the molar ratios of Fe3+ to Zn2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites. Significantly, the obtained composites with the molar ratio of Fe3+ to Zn2+ of 1:2 presented the optimal electromagnetic attenuation performance, i.e. the minimum reflection loss achieved −79.0 dB with a matching thickness of 2.76 mm and effective absorption bandwidth was as high as 5.8 GHz under a thin thickness of 1.8 mm and low filling ratio of 20.0 wt%. Additionally, the potential microwave dissipation mechanisms were illuminated. Therefore, our results would shed light on the development of high-efficiency and broadband microwave absorbing composites derived MOFs.
70 citations
TL;DR: In this article , the molar ratios of Fe 3+ to Zn 2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites and the potential microwave dissipation mechanism was proposed.
Abstract: Developing strong absorption and broadband microwave absorbers derived from metal-organic frameworks (MOFs) still remains a big challenge in the field of microwave absorption. Herein, iron zinc bimetallic metal-organic frameworks/reduced graphene oxide (FeZn-MOFs/RGO) precursors derived ferroferric oxide/carbon (Fe 3 O 4 /C) decorated graphene composites were fabricated via a solvothermal and carbonization two-step strategy. It was found that the morphology of carbon frameworks could be regulated from the traditional regular octahedron to the pomegranate shape by simply adjusting the molar ratios of Fe 3+ to Zn 2+ in the precursors. Moreover, results revealed that the molar ratios of Fe 3+ to Zn 2+ had notable effects on the electromagnetic parameters and microwave attenuation capacity of attained composites. Significantly, the obtained composites with the molar ratio of Fe 3+ to Zn 2+ of 1:2 presented the optimal electromagnetic attenuation performance, i.e. the minimum reflection loss achieved −79.0 dB with a matching thickness of 2.76 mm and effective absorption bandwidth was as high as 5.8 GHz under a thin thickness of 1.8 mm and low filling ratio of 20.0 wt%. Additionally, the potential microwave dissipation mechanisms were illuminated. Therefore, our results would shed light on the development of high-efficiency and broadband microwave absorbing composites derived MOFs. • Fe 3 O 4 /C decorated graphene composites derived from bimetallic MOFs were prepared. • Morphology of carbon frameworks evolved from octahedron to pomegranate shape. • Microwave absorption was regulated by adjusting the molar ratios of Fe 3+ to Zn 2+ . • Strong absorption, broad bandwidth, thin thickness and low loading were achieved. • The potential microwave dissipation mechanism of attained composites was proposed.
69 citations
References
More filters
TL;DR: This study reports an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation and reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions.
Abstract: Quantum electrodynamics (resulting from the merger of quantum mechanics and relativity theory) has provided a clear understanding of phenomena ranging from particle physics to cosmology and from astrophysics to quantum chemistry. The ideas underlying quantum electrodynamics also influence the theory of condensed matter, but quantum relativistic effects are usually minute in the known experimental systems that can be described accurately by the non-relativistic Schrodinger equation. Here we report an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation. The charge carriers in graphene mimic relativistic particles with zero rest mass and have an effective 'speed of light' c* approximately 10(6) m s(-1). Our study reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions. In particular we have observed the following: first, graphene's conductivity never falls below a minimum value corresponding to the quantum unit of conductance, even when concentrations of charge carriers tend to zero; second, the integer quantum Hall effect in graphene is anomalous in that it occurs at half-integer filling factors; and third, the cyclotron mass m(c) of massless carriers in graphene is described by E = m(c)c*2. This two-dimensional system is not only interesting in itself but also allows access to the subtle and rich physics of quantum electrodynamics in a bench-top experiment.
18,958 citations
TL;DR: In this paper, the locus of the dielectric constant in the complex plane was defined to be a circular arc with end points on the axis of reals and center below this axis.
Abstract: The dispersion and absorption of a considerable number of liquid and dielectrics are represented by the empirical formula e*−e∞=(e0−e∞)/[1+(iωτ0)1−α]. In this equation, e* is the complex dielectric constant, e0 and e∞ are the ``static'' and ``infinite frequency'' dielectric constants, ω=2π times the frequency, and τ0 is a generalized relaxation time. The parameter α can assume values between 0 and 1, the former value giving the result of Debye for polar dielectrics. The expression (1) requires that the locus of the dielectric constant in the complex plane be a circular arc with end points on the axis of reals and center below this axis.If a distribution of relaxation times is assumed to account for Eq. (1), it is possible to calculate the necessary distribution function by the method of Fuoss and Kirkwood. It is, however, difficult to understand the physical significance of this formal result.If a dielectric satisfying Eq. (1) is represented by a three‐element electrical circuit, the mechanism responsible...
8,409 citations
TL;DR: Metal-organic framework (MOF-5), a prototype of a new class of porous materials and one that is constructed from octahedral Zn-O-C clusters and benzene links, was used to demonstrate that its three-dimensional porous system can be functionalized with the organic groups and can be expanded with the long molecular struts biphenyl, tetrahydropyrene, pyrene, and terphenyl.
Abstract: A strategy based on reticulating metal ions and organic carboxylate links into extended networks has been advanced to a point that allowed the design of porous structures in which pore size and functionality could be varied systematically. Metal-organic framework (MOF-5), a prototype of a new class of porous materials and one that is constructed from octahedral Zn-O-C clusters and benzene links, was used to demonstrate that its three-dimensional porous system can be functionalized with the organic groups –Br, –NH2, –OC3H7, –OC5H11, –C2H4, and –C4H4 and that its pore size can be expanded with the long molecular struts biphenyl, tetrahydropyrene, pyrene, and terphenyl. We synthesized an isoreticular series (one that has the same framework topology) of 16 highly crystalline materials whose open space represented up to 91.1% of the crystal volume, as well as homogeneous periodic pores that can be incrementally varied from 3.8 to 28.8 angstroms. One member of this series exhibited a high capacity for methane storage (240 cubic centimeters at standard temperature and pressure per gram at 36 atmospheres and ambient temperature), and others the lowest densities (0.41 to 0.21 gram per cubic centimeter) for a crystalline material at room temperature.
6,922 citations
5,393 citations
TL;DR: The Zr-MOFs presented in this work have the toughness needed for industrial applications; decomposition temperature above 500 degrees C and resistance to most chemicals, and they remain crystalline even after exposure to 10 tons/cm2 of external pressure.
Abstract: Porous crystals are strategic materials with industrial applications within petrochemistry, catalysis, gas storage, and selective separation Their unique properties are based on the molecular-scale porous character However, a principal limitation of zeolites and similar oxide-based materials is the relatively small size of the pores, typically in the range of medium-sized molecules, limiting their use in pharmaceutical and fine chemical applications Metal organic frameworks (MOFs) provided a breakthrough in this respect New MOFs appear at a high and an increasing pace, but the appearances of new, stable inorganic building bricks are rare Here we present a new zirconium-based inorganic building brick that allows the synthesis of very high surface area MOFs with unprecedented stability The high stability is based on the combination of strong Zr−O bonds and the ability of the inner Zr6-cluster to rearrange reversibly upon removal or addition of μ3-OH groups, without any changes in the connecting carbox
4,958 citations