Self-Assembly Three-Dimensional Porous Carbon Networks for Efficient Dielectric Attenuation

Highly efficient hierarchically porous carbon-silica composite for sub-terahertz stealth and shielding applications

The development of future 6G communication systems necessitates advanced materials for efficient electromagnetic interference shielding in the sub-terahertz frequency range. This study presents the preparation, porosimetry analysis, compositional and electromagnetic characterization of a highly efficient hierarchically porous carbon-silica composite suitable for shielding and stealth applications in this frequency regime. The composite, fabricated using a mixture of carbon powder and tetraethoxysilane, possesses a highly porous structure with high surface area, which facilitates multiple reflections and scattering of electromagnetic waves. Electromagnetic characterization was conducted using a free-space semi-optical method at 140-220 GHz, focusing on reflection-only measurements due to the sample's large thickness. The results demonstrate that the composite exhibits a qualified bandwidth of 83% over the measured frequency band, with a maximum reflection loss of 35 dB at 187 GHz. Furthermore, measurements demonstrate that electromagnetic power within the sample's volume is effectively attenuated. The composite's shielding efficiency due to reflection is on average 0.26 dB across the band, highlighting its potential for high frequency EMI shielding and stealth applications.

Exploring the efficacy and future potential of polypyrrole/metal oxide nanocomposites for electromagnetic interference shielding: a review

With recent advancements in technology, the emission of electromagnetic radiation has emerged as a significant issue due to electromagnetic interferences. These interferences include various undesirable emissions that can degrade the performance of equipment and structures. If left unresolved, these complications can create extra damage to the security operations and communication systems of numerous electronic devices. Various studies have been conducted to address these issues. In recent years, electrically conductive polypyrrole has gained a unique position because of its many advantageous properties. The absorption of microwaves and the electromagnetic interference (EMI) shielding characteristics of electrically conductive polypyrrole can be described in relation to its great electrical conductivity with strong relaxation and polarization effects due to the existence of strong bonds or localized charges. In the present review, advancements in electromagnetic interference shielding with conjugated polypyrrole and its nanocomposites with metal oxides are discussed and correlated with various properties such as dielectric properties, magnetic properties, electrical conductivity, and microwave adsorption properties. This review also focuses on identifying the most suitable polypyrrole-based metal oxide nanocomposites for electromagnetic interference shielding applications.

Combination strategy of large interlayer spacing and active basal planes for regulating the microwave absorption performance of MoS2/MWCNT composites at thin absorber level

Recently, molybdenum disulfide (MoS₂)/carbon has become a promising candidate for efficient microwave absorption. However, it is still challenging to simultaneously optimize the synergy of impedance matching and loss capability at the level of a thin absorber. Here, a new adjustment strategy is proposed by changing the concentration of precursor l-cysteine for MoS₂/multi-walled carbon nanotubes (MWCNT) composites to unlock the basal plane of MoS₂ and expand the interlayer spacing from 0.62 nm to 0.99 nm, leading to improved packing of MoS₂ nanosheets and more active sites. Therefore, the tailored MoS₂ nanosheets exhibit abundant sulfur-vacancies, lattice-oxygen, more metallic 1T-phase, and higher surface area. Such sulfur-vacancies and lattice-oxygen promote the electronic asymmetric distribution at the solid-air interface of MoS₂ crystals and induce stronger microwave attenuation through interface/dipole polarization, which is further verified by first-principles calculations. In addition, the expansion of the interlayer spacing induces more MoS₂ to deposit on the MWCNT surface and increases the roughness, improving the impedance matching and multiple scattering. Overall, the advantage of this adjustment method is that while optimizing impedance matching at the thin absorber level, composite still maintains a high attenuation capacity, which means enhancing the attenuation performance of MoS₂ itself offsets the weakening of the composite's attenuation ability caused by the decrease in the relative content of MWCNT components. Most importantly, adjusting impedance matching and attenuation ability can be easily implemented by separate control of l-cysteine content. As a result, the MoS₂/MWCNT composites achieve a minimum reflection loss value of -49.38 dB and an effective absorption bandwidth of 4.64 GHz at a thickness of only 1.7 mm. This work provides a new vision for the fabrication of thin MoS₂-carbon absorbers.

Highly dispersed Co/Co9S8 nanoparticles encapsulated in S, N co-doped longan shell-derived hierarchical porous carbon for corrosion-resistant, waterproof high-performance microwave absorption

It is highly desirable, but challenging to develop multifunctional electromagnetic wave (EMW) absorbing material for practical applications in some harsh environments. Herein, we successfully embedded highly dispersed Co/Co₉S₈ nanoparticles into a three-dimensional (3D) honeycomb porous carbon skeleton (the carbon skeleton is derived from longan shell-derived S, N co-doped porous carbon) as a multifunctional material with outstanding EMW absorption properties, hydrophobicity and corrosion resistance. Its superior versatility is attributed to synergistic effects of the S and N dopants, large specific surface area, abundant carbon defects, and 3D porous characteristics. Minimal reflection loss (RL_min) and efficient absorption bandwidth (EAB) of the optimized material as EMW absorbers can achieve -59.9 dB and 6.8 GHz at a thickness of 2.7 mm, respectively, which are superior to most of the reported carbon-based absorbents. Meanwhile, theoretical simulations of the radar scattering cross section (RCS) further confirm that this multifunctional material has outstanding EMW attenuation performance and actual application potential. In addition, the material possesses strong hydrophobicity (124°) and anti-corrosion properties, expanding the scope of potential applications of microwave absorbers. Therefore, this work provides an effective development strategy for the design of anti-corrosion, super-hydrophobic, and high-performance EMW absorbing materials.

Facile synthesis of Fe3O4 nanoparticles/reduced graphene oxide sandwich composites for highly efficient microwave absorption

Component regulation and microstructure design are two effective strategies to adjust electromagnetic parameters and improve the microwave absorption performance of materials. In this study, a facile synthesis strategy consisting of ultrasonic dispersion, blast drying, and roasting is proposed to build a sandwich-like graphene-based absorbent, in which Fe₃O₄ nanoparticles with adjustable content are sandwiched uniformly between reduced graphene oxide nanosheets. The sandwich structure can form multiple interfaces, prevent the aggregation of nanoparticles, facilitate interface polarization, and endow the material with multiple electromagnetic loss mechanisms, which is very beneficial for impedance matching and microwave attenuation. Notably, the effective absorption bandwidth achieves 5.7 GHz, and the minimum reflection loss value is -49.9 dB. In addition, the synthesis process is simple and suitable for large-scale production and possible industrial applications. Thus, this facile route to fabricate sandwich-like graphene-based absorbents provides new ideas and approaches for designing new graphene-based nanocomposites.

Combining thin-film microextraction and surface enhanced Raman spectroscopy to sensitively detect thiram based on 3D silver nanonetworks

By coupling thin-film microextraction (TFME) with surface enhanced Raman scattering (SERS), a facile method was developed for the determination of thiram in the complex matrix (orange juice or grape peel). The substrate of TFME was made by self-assembling silver sol on the silicon wafer to form a three-dimensional (3D) silver nanonetwork structure, without adding any template, which was used for TFME and SERS detection, respectively. The substrate exhibits high reproducibility with a relative standard deviation of about 7.32 % in spot and spot SERS intensity. The SERS signal intensity at a shift of 1384 cm^-1 and the thiram concentration showed good linearity in the range of 0.01-5 µg/L and the linear correlation coefficient was 0.9912. The detection limit for thiram was found to be 0.01 µg/L. The TFME-SERS method was applied for the determination of thiram in fruit juice and the results were obtained very well. Therefore, this method is expected to play a role in the detection of trace pollutants.

Induced Crystallization-Controllable Nanoarchitectonics of 3D-Ordered Hierarchical Macroporous Co@N-Doped Carbon Frameworks for Enhanced Microwave Absorption

The construction of ordered hierarchical porous structures in metal-organic frameworks (MOFs) and their derivatives is highly promising to meet the low-density and high-performance demands of microwave absorption materials. However, traditional methods based on sacrificial templates or corrosive agents inevitably suffer from the collapse of the microporous framework and the accumulation of nanoparticles during the carbonization transformation, resulting in the deteriorating impedance match, which greatly limits the incident and attenuation of microwaves. Herein, an induced crystallization and controllable nanoarchitectonics strategy is employed to replace traditional growing-etching methods and successfully synthesize carbonized 3D-ordered macroporous Co@N-doped carbon (3DOM Co@NDC) based on the 3D-ordered template. The obtained 3D-ordered macroporous structure ensures the stable growth of hybrid carbon frameworks and CoC nanoparticles without collapse, preserves abundant interfaces for both the incident and attenuation performance, so as to significantly improve the impedance matching and absorption properties compared to conventional MOFs derivatives. The minimum reflection loss of 3DOM Co@NDC is -57.36 dB at the thickness of 1.9 mm, and the effective bandwidth is 7.36 GHz at 1.6 mm. Moreover, the innovative strategy to prepare 3D-ordered hierarchical macroporous structures opens up a new avenue for advanced MOFs-derived absorbers with excellent performance.

Facile Synthesis of Metal Oxide Decorated Carbonized Bamboo Fibers with Wideband Microwave Absorption

Aiming at the disadvantages of high cost, complex processes, low yield, and narrow bandwidth of carbon-based microwave absorbing materials, this paper provides a novel and efficient method for synthesizing metal oxide/carbonized bamboo fibers using renewable natural bamboo fibers as a carbon source. The results suggested that the metal oxides such as NiO and Fe₃O₄ were uniformly dispersed on the carbonized bamboo fibers and proved that the dielectric component NiO and magnetic component Fe₃O₄ can significantly improve the microwave absorption performance of the carbonized bamboo fibers. As expected, the NiO/carbonized bamboo fibers showed excellent microwave absorption performance due to the appropriate complex permittivity, high impedance matching, and attenuation coefficient. A wide effective bandwidth of 6.4 GHz with 2.2 mm thickness is achieved, covering the entire Ku-band. Remarkably, the reflection loss (RL) values less than -10 dB covered the whole X-band at a thickness of 3.0 mm. This work reveals the potential of carbonized bamboo fibers-based composite as an economic and broadband microwave absorbent and offers a new strategy for designing promising microwave absorption materials.

Self assembled three dimensional β-Cu2V2O7 hierarchical flower decorated porous carbon: An efficient electrocatalyst for flutamide detection in biological and environmental samples

The serious situation mandates the use of anticancer drugs, which protect people all over the world from the growth of prostate cancer. In particular, excessive dosage and erroneous discharge of flutamide concentration cause make environmental pollution on the surface of the wastewater. In this study, the highly sensitive and selective electrochemical approach based on copper vanadium oxide decorated porous carbon (denoted as β-Cu₂V₂O₇/PC) composite modified glassy carbon electrode (GCE) has been developed and it was applied for sensitive detection of anticancer drug flutamide (FTM). Moreover, using the co-precipitation method, the flower-like β-Cu₂V₂O₇ hierarchical microstructure was synthesized, and through the wet chemical process, the β-Cu₂V₂O₇/PC composite was obtained. The resultant product was characterized by XRD, FTIR, RAMAN, XPS and structural morphology established by FESEM analysis. Besides that, the electrochemical characterization and properties were analyzed by cyclic voltammetry (CV) and amperometric (i-t) techniques. The β-Cu₂V₂O₇/PC/RDGCE had two linear ranges at 0.01-2.11 μM and 2.31-30.81 μM. The lower limits of detection and sensitivity were found at 0.62 nM (S/N = 3), and 24.33 μA μM^-1 cm^-2 respectively. The practicability test was applied for the determination of FTM in urine, blood serum and environmental aquatic fluid with satisfactory recovery obtained.

Bimetal-doped core-shell carbon derived from nickel-cobalt dual-ligand metal-organic framework for adjustable strong microwave absorption

Metal-organic framework materials (MOF) have become a new generation of microwave absorption (MA) materials. However, it is still challenging to design an appropriate microstructure that can efficiently adjust the microwave absorbing characteristics. Herein, a novel bimetal-doped core-shell carbon derived from nickel-cobalt dual-ligand MOF has been successfully prepared. By changing the ratio of the second ligand, the morphology can change from sea urchin-like to rod-like and petal-like shapes, thereby regulating the final wave absorption performance of MOF derivatives. The Bi-MOF-1 exhibited strong microwave absorption (up to -70.70 dB), while Bi-MOF-2 presented broad effective absorption bandwidth (5.92 GHz). The analyses indicated that the excellent impedance matching can be attributed to the double-layer magnetic loss and multiple dielectric loss of the core-shell structure. This work provides a feasible approach for the design and preparation of functional composite structures based on MOF derivatives with controllable microwave absorbing properties.

Rationally designed structure of mesoporous carbon hollow microspheres to acquire excellent microwave absorption performance

In this study, we used a novel and facile hard-template etching method to manufacture mesoporous carbon hollow microspheres (MCHMs). We prove that the dielectric ability and microwave absorption of MCHMs can be adjusted by structural characteristics. When the average particle size of MCHMs is 452 nm, the paraffin composite material mixed with 10 wt% MCHMs can achieve a maximum reflection loss value of -51 dB with a thickness of 4.0 mm at 7.59 GHz. When the average particle size of MCHMs is 425 nm, the effective absorption bandwidth of the paraffin composite material mixed with 10 wt% MCHMs can achieve a broad bandwidth of 7.14 GHz with a thickness of 2.5 mm. Compared with other microwave absorbers, MCHMs possess high microwave absorption capacity and broad microwave absorption bandwidth with as low as a 10 wt% filler ratio. This excellent microwave absorption performance is due to the internal cavity and the mesoporous shell of MCHMs. By rationally designing the structure of MCHMs, excellent microwave absorption performance can be acquired. Meanwhile, this design concept based on a rational design of spherical structure can be extended to other spherical absorbers.

Carbon Fibers Embedded with Aligned Magnetic Particles for Efficient Electromagnetic Energy Absorption and Conversion

Harvesting electromagnetic (EM) energy from the environment and converting it into useful micropower is a new and ideal way to eliminate EM radiation and while providing power for microelectronic devices. The key material of this technology is broadband, ultralight, and ultrathin EM-wave-absorbing materials, whose preparation remains challenging. Herein, a high magnetic field (HMF) strategy is proposed to prepare a biomass-derived CoFe/carbon fiber (CoFe/CF) composite, in which CoFe magnetic particles are aligned in CFs, creating magnetic coupling and fast electron transmission channels. The graphitization degree of CFs is improved via the "migration catalysis" of CoFe particles under HMF. The HMF-derived CoFe/CF shows a largely broadened EM wave absorption bandwidth under ultralight and ultrathin conditions (1.5 mm). Its absorption bandwidth increases 5-10 times compared with conventional CoFe/CF that has randomly distributed CoFe particles and surpasses the reported analogues. A device model for EM energy absorption and reuse is designed based on the HMF-derived CoFe/CF membrane, which exhibits a 300% higher capability than conventional CoFe/CF membrane in converting EM energy to thermal energy. This work offers a new strategy for the design and fabrication of broadband, ultrathin, and ultralight EM wave absorption materials and demonstrates a potential conversion approach of the waste EM energy.

A Review on Metal-Organic Framework-Derived Porous Carbon-Based Novel Microwave Absorption Materials

The development of microwave absorption materials (MAMs) is a considerable important topic because our living space is crowed with electromagnetic wave which threatens human's health. And MAMs are also used in radar stealth for protecting the weapons from being detected. Many nanomaterials were studied as MAMs, but not all of them have the satisfactory performance. Recently, metal-organic frameworks (MOFs) have attracted tremendous attention owing to their tunable chemical structures, diverse properties, large specific surface area and uniform pore distribution. MOF can transform to porous carbon (PC) which is decorated with metal species at appropriate pyrolysis temperature. However, the loss mechanism of pure MOF-derived PC is often relatively simple. In order to further improve the MA performance, the MOFs coupled with other loss materials are a widely studied method. In this review, we summarize the theories of MA, the progress of different MOF-derived PC‑based MAMs, tunable chemical structures incorporated with dielectric loss or magnetic loss materials. The different MA performance and mechanisms are discussed in detail. Finally, the shortcomings, challenges and perspectives of MOF-derived PC‑based MAMs are also presented. We hope this review could provide a new insight to design and fabricate MOF-derived PC-based MAMs with better fundamental understanding and practical application.

Constructing Ni12P5/Ni2P Heterostructures to Boost Interfacial Polarization for Enhanced Microwave Absorption Performance

Heterostructures with a rich phase boundary are attractive for surface-mediated microwave absorption (MA) materials. However, understanding the MA mechanisms behind the heterogeneous interface remains a challenge. Herein, a phosphine (PH₃) vapor-assisted phase and structure engineering strategy was proposed to construct three-dimensional (3D) porous Ni₁₂P₅/Ni₂P heterostructures as microwave absorbers and explore the role of the heterointerface in MA performance. The results indicated that the heterogeneous interface between Ni₁₂P₅ and Ni₂P not only creates sufficient lattice defects for inducing dipolar polarization but also triggers uneven spatial charge distribution for enhancing interface polarization. Furthermore, the porous structure and proper component could provide an abundant heterogeneous interface to strengthen the above polarization relaxation process, thereby greatly optimizing the electromagnetic parameters and improving the MA performance. Profited by 3D porous heterostructure design, P400 could achieve the maximum reflection loss of -50.06 dB and an absorption bandwidth of 3.30 GHz with an ultrathin thickness of 1.20 mm. Furthermore, simulation results confirmed its superior ability (14.97 dB m² at 90°) to reduce the radar cross section in practical applications. This finding may shed light on the understanding and design of advanced heterogeneous MA materials.

Extending effective microwave absorbing bandwidth of CoNi bimetallic alloy derived from binary hydroxides

Effectively broadening microwave absorbing frequency of pure magnetic substances remains a huge challenge. Herein, micro-perspective structures can be controlled through a calcination route. Satisfactorily, the composites prepared at the calcination temperature of 900 °C exhibit excellent microwave attenuation performance with a broad working frequency and appropriate paraffin filling ratio. Remarkably, the composites can reach an extremely high reflection loss (RL) value of - 49.79 dB, and the extended effective working frequency range (RL < - 10 dB) of 6.84 GHz can also be obtained. Superb magnetic loss, admirable dielectric loss, sufficient dipole polarization, as well as superior impedance matching should be band together for obtaining ideal microwave absorbers. The CoNi hydroxides derived bimatallic alloy composites were fabricated via a cost-effective and facile synthesis process, and this work aroused inspirations of designing high-performance microwave absorbers for mataining the sustainable development.

Highly effective antibacterial zeolitic imidazolate framework-67/alginate fibers

Antibacterial fibers have great potential in many applications including wound dressings, surgical gowns, and surgical sutures, and play an important role in our daily life. However, the traditional fabrication method for the antibacterial fibers shows high cost, complexity, and inferior antibacterial durability. Herein, we report a facile and scalable fabrication of highly effective antibacterial alginate (SA) composite fibers through blend spinning of zeolitic imidazolate framework-67 (ZIF-67) particles and SA. The fabricated ZIF-67@SA composite fibers show high tensile strength and initial modulus. More importantly, the ZIF-67@SA composite fibers demonstrate excellent antibacterial properties, and the antibacterial efficiency reaches over 99% at ultralow ZIF-67 loading (0.05 wt%). In addition, the ZIF-67@SA fibers show good antibacterial durability even after five laundering cycles. The excellent antibacterial performance of the ZIF-67@SA fibers is attributed to the synergistic effects of the highly effective antibacterial ZIF-67 particles, swelling of alginate, and immobilization of ZIF-67 particles both inside and outside the fiber surface. This work may shed light on the antibacterial mechanism of metal organic frameworks and pave the way for the development of high-performance antibacterial textiles.

Assembling Nano-Microarchitecture for Electromagnetic Absorbers and Smart Devices

Smart devices, nowadays, are inspiring the infinite vitality and possibilities of intelligent life, such as self-power electromagnetic (EM) nanogenerator and microsensor, smart window, thermally-driven EM absorber, interstellar energy deliverer, and so on. Herein, the latest and most impressive works of 3D nano-micro architectures and their smart EM devices are highly focused on. The most key information, including assembly strategy and mechanism, EM response, and approach-structure-function relationship, is extracted and well-organized with profundity and easy-to-understand approach. The merit and demerit are revealed by comparison. What's more, the brightest and most cutting-edge smart EM devices constructed by 3D nano-micro architectures are reported as highlights, and the device principles are deeply dissected. Finally, a profound and top comment on the fast-growing field as well as challenges are proposed, and the future directions are predicted intelligently.

Bimetallic MOF-derived hollow ZnNiC nano-boxes for efficient microwave absorption

In this work, we report the facile synthesis of a hollow ZnNiC nano-box using a hollow ZnNi-MOF as the sacrificial template through a one-step pyrolysis process. Remarkably, the as-prepared hollow ZnNiC/paraffin composite exhibited a minimum reflection loss (RLmin) of -66.1 dB at 15.3 GHz and effective absorption bandwidth of 4.4 GHz with a thickness of 1.6 mm.

Confining Tiny MoO2 Clusters into Reduced Graphene Oxide for Highly Efficient Low Frequency Microwave Absorption

Herein, a supermolecular-scale cage-confinement pyrolysis strategy is proposed to build two dielectric electromagnetic wave absorbents, in which MoO₂ nanoparticles are sandwiched uniformly between porous carbon shells and reduced graphene oxide (RGO). Both sandwich structures are derived from hybrid hydrogels doped by two different crosslinkers (with/without oxygen bridge), which can precisely confine Mo source (e.g., PMo₁₂ ). Without adding magnetic components, both absorbents exhibit excellent low frequency absorption performance in combination with electrically tunable ability and enhanced reflection loss value, which is superior over other relative 2D dielectric absorbers and satisfies the requirements of portable electronics. Notably, introducing oxygen bridges in the crosslinker generates a more stable confining configuration, which in turn renders its corresponding derivative exhibiting an extra multifrequency electromagnetic wave absorption trait. The intrinsic electromagnetic wave adjustment mechanism of the ternary hybrid absorbent is also explored. The result reveals that the elevated electromagnetic wave absorbing property is attributed to moderate attenuation constant and glorious impendence matching. The cage-confinement pyrolysis route to fabricate 2D MoO₂ -based dielectric electromagnetic wave absorbents opens a new path for the design of electromagnetic wave absorbents used in multi/low frequency.

Preparation of CTCNFs/Co9S8 hybrid nanofibers with enhanced microwave absorption performance

A three-step synthesis strategy has been applied to the preparation of Co₉S₈-loaded tubular carbon nanofibers (CTCNFs/Co₉S₈ hybrid nanofibers) with excellent microwave absorbing ability. Firstly, tubular polymer nanofibers (TPNFs) are synthesized using the confined self-condensation method that we developed. Afterwards, TPNFs are converted into surface carboxylated tubular carbon nanofibers (CTCNFs) by carbonization and subsequent acidification processes. Finally, a hydrothermal method is used for the controllable growth of Co₉S₈ nanoparticles on CTCNFs, and a series of CTCNFs/Co₉S₈ hybrid nanofibers with different Co₉S₈ loading are obtained. The prepared CTCNFs/Co₉S₈ hybrid nanofibers possess abundant effective interface and defect dipoles, which will lead to stronger polarization. Using the strategy of enhancing dielectric loss, the microwave dissipation ability of CTCNFs/Co₉S₈ hybrid nanofibers has been significantly improved, showing an excellent low-frequency absorbing performance with a minimum reflection loss of -46.81 dB@5.3 GHz. In addition, the composition, structure and properties of nanofibers have been systematically characterized. The Co₉S₈ loading on CTCNFs and the filler content of CTCNFs/Co₉S₈ hybrid nanofibers in matrix are studied and optimized. The microwave attenuation mechanism is also explained.

Periodic Three-Dimensional Nitrogen-Doped Mesoporous Carbon Spheres Embedded with Co/Co3O4 Nanoparticles toward Microwave Absorption

Although various bio-inspired materials with outstanding mechanical, acoustic, and optic properties have been developed, bio-inspired materials for microwave absorption applications are rarely reported. Herein, under the inspiration of the opal structure, for the first time, a kind of Co@Co₃O₄/nitrogen-doped (N-doped) mesoporous carbon sphere (Co@Co₃O₄/NMCS) with a periodic three-dimensional structure toward microwave absorption application was designed and synthesized. The microwave absorption performance was optimized with respect to the content of Co@Co₃O₄ nanoparticles. Co@Co₃O₄/NMCS with ∼20 wt % Co@Co₃O₄ achieves a reflection loss of -53.8 dB at 5.7 GHz. The simulated radar cross section demonstrated that the Co@Co₃O₄/NMCS can efficiently suppress the strong electromagnetic scattering from a metal groove structure, which further reveals its excellent absorbing performance. These periodic porous structures of N-doped mesoporous carbon spheres combined with the magnetic Co@Co₃O₄ nanoparticles contribute to the excellent microwave-absorbing performance.

Environment-Stable CoxNiy Encapsulation in Stacked Porous Carbon Nanosheets for Enhanced Microwave Absorption

Magnetic/dielectric@porous carbon composites, derived from metal-organic frameworks (MOFs) with adjustable composition ratio, have attracted wide attention due to their unique magnetoelectric properties. In addition, MOFs-derived porous carbon-based materials can meet the needs of lightweight feature. This paper reports a simple process for synthesizing stacked CoxNiy@C nanosheets derived from CoxNiy-MOFs nanosheets with multiple interfaces, which is good to the microwave response. The CoxNiy@C with controllable composition can be obtained by adjusting the ratio of Co2+ and Ni2+. It is supposed that the increased Co content is benefit to the dielectric and magnetic loss. Additionally, the bandwidth of CoNi@C nanosheets can take up almost the whole Ku band. Moreover, this composite has better environmental stability in air, which characteristic provides a sustainable potential for the practical application.

MOF-derived yolk–shell Ni/C architectures assembled with Ni@C core–shell nanoparticles for lightweight microwave absorbents

The yolk–shell Ni/C microspheres assembled by Ni@C core–shell nanoparticles with excellent microwave absorption performance can be simply fabricated by decomposition of a Ni-based metal–organic framework (Ni-MOF).