Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Excellent microwave absorption properties based on a composite of one dimensional Mo₂C@C nanorods and a PVDF matrix.

ABSTRACT: MoO₃ nanowires were synthesized by a wet chemical process and then coated by glucose, and finally successfully turned into Mo₂C@C nanorods by carbonation reaction. An excellent absorption strength of -39.0 dB and absorption bandwidth of 12.2 GHz in the thickness range of 2.0-5.0 mm were achieved by the Mo₂C@C/PVDF with 10% filler content, derived from effective Debye dipolar relaxation processes. It is expected that the composite can be applied as a novel and desirable microwave absorber.

SUBMITTER: Li CQ

PROVIDER: S-EPMC9066012 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Excellent microwave absorption properties based on a composite of one dimensional Mo2C@C nanorods and a PVDF matrix.

Li Chao-Qin CQ Shen Xun X Ding Ruo-Cheng RC Wang Guang-Sheng GS

RSC advances 20190709 37

MoO3 nanowires were synthesized by a wet chemical process and then coated by glucose, and finally successfully turned into Mo2C@C nanorods by carbonation reaction. An excellent absorption strength of -39.0 dB and absorption bandwidth of 12.2 GHz in the thickness range of 2.0-5.0 mm were achieved by the Mo2C@C/PVDF with 10% filler content, derived from effective Debye dipolar relaxation processes. It is expected that the composite can be applied as a novel and des ...[more]

PMID: 35521326

Similar Datasets

Preparation of porous Fe2O3 nanorods-reduced graphene oxide nanohybrids and their excellent microwave absorption properties.

Project description:In this paper, α-Fe2O3 nanoparticles (NPs)-reduced graphene oxide (RGO), α-FeOOH nanorods (NRs)-RGO and porous α-Fe2O3 NRs-RGO could be selectively synthesized by hydrothermal method. The investigations indicated that the obtained α-Fe2O3 NPs, α-FeOOH NRs and porous α-Fe2O3 NRs were either attached on the surface of RGO sheets or coated uniformly by the RGO sheets. And the as-prepared nanohybrids exhibited excellent microwave absorption performance, which was proved to be ascribed to the quarter-wavelength matching model. The optimum reflection loss (RL) values for α-Fe2O3 NPs-RGO, α-FeOOH NRs-RGO and porous α-Fe2O3 NRs-RGO were ca. -32.3, -37.4 and -71.4 dB, respectively. Moreover, compared to the obtained α-Fe2O3 NPs-RGO and α-FeOOH NRs-RGO, the as-prepared porous α-Fe2O3 NRs-RGO nanohybrids exhibited enhanced microwave absorption properties because of their special structure and synergetic effect. The possible enhanced microwave absorption mechanisms were discussed in details. Our results confirmed that the geometrical morphology had a great influence on their microwave absorption properties, which provided a promising approach to exploit high performance microwave absorbing materials.

| S-EPMC5593864 | biostudies-literature

C/Co3O4/Diatomite Composite for Microwave Absorption.

Project description:Transition metal oxides have been widely used in microwave-absorbing materials, but how to improve impedance matching is still an urgent problem. Therefore, we introduced urea as a polymer carbon source into a three-dimensional porous structure modified by Co3O4 nanoparticles and explored the influence of different heat treatment temperatures on the wave absorption properties of the composite. The nanomaterials, when calcined at a temperature of 450 °C, exhibited excellent microwave absorption capabilities. Specifically, at an optimized thickness of 9 mm, they achieved a minimum reflection loss (RLmin) of -97.3 dB, accompanied by an effective absorption bandwidth (EAB) of 9.83 GHz that comprehensively covered both the S and Ku frequency bands. On the other hand, with a thickness of 3 mm, the RLmin was recorded as -17.9 dB, with an EAB of 5.53 GHz. This excellent performance is attributed to the multi-facial polarization and multiple reflections induced by the magnetic loss capability of Co3O4 nanoparticles, the electrical conductivity of C, and the unique three-dimensional structure of diatomite. For the future development of bio-based microwave absorption, this work provides a methodology and strategy.

| S-EPMC11434343 | biostudies-literature

NiS2@rGO Nanosheet Wrapped with PPy Aerogel: A Sandwich-Like Structured Composite for Excellent Microwave Absorption.

Project description:To reduce electromagnetic pollution as well as increase the accuracy of high-precision electronic equipment, more attention has been paid to new electromagnetic wave (EMW) absorbing materials, which have the advantages of strong absorption, wide absorption bands, and a narrow thickness. In this study, a novel ternary type of the NiS2@rGO/polypyrrole (PPy) sandwich-like structured composites was synthesized via a facile two-step method, in which the hydrothermal method was used to prepare NiS2@rGO binary composites and then the in situ polymerization method was used to synthesize the PPy, which acted as the outer layer of the sandwich-like structure. The morphologies and electromagnetic absorption performance of the NiS2@rGO/PPy were measured and investigated. A sample with 6 wt% NiS2@rGO/PPy loading paraffin-composite obtained an outstanding reflection loss (RL) of -58.7 dB at 16.44 GHz under a thickness of 2.03 mm. Simultaneously, the effective electromagnetic wave absorption bandwidth for RL < -10 dB, which covered 7.04 to 18.00 GHz (10.96 GHz), was achieved by changing the thickness of the absorber from 2.0 to 3.5 mm. The results not only suggest that the NiS2@rGO/PPy composite has excellent performance in the field of EMW absorption but also prove that the novel sandwich-like structure can contribute to appropriate impedance matching through multiple relaxation and interfacial polarization processes.

| S-EPMC6630302 | biostudies-literature

Construction of one-dimensional MoO2/NC heteronanowires for microwave absorption.

Project description:A combination of a special micro-nanostructure and multiple components has been proven as an effective strategy to strengthen the microwave attenuation capacity. In this work, one-dimensional MoO2/N-doped carbon (NC) nanowires with a heterostructure have been successfully prepared by utilizing mild in situ chemical oxidative polymerization and pyrolysis treatment. After compounding them with a thermoplastic polyurethane (TPU) matrix, the flexible composites exhibit tunable wave absorbing performance by modulating the filler loading of MoO2/NC heteronanowires. Experimental results demonstrate that the minimum reflection loss value of the MoO2/NC-TPU hybrid is up to -35.0 dB at 8.37 GHz under a thickness of only 2.3 mm with 40 wt% filler amounts. Moreover, the effective absorption bandwidth enables 3.26 GHz to be achieved (8.49-11.75 GHz) when the thickness changes to 2.0 mm, covering almost the whole X-band. Meanwhile, when the filler loading becomes 30 wt%, dual-absorption peaks appear. The relevant absorption mechanism is mainly attributed to the dielectric loss including strong dipolar/interfacial polarizations, Debye relaxation loss and multiple reflection and scattering.

| S-EPMC8981422 | biostudies-literature

Two-Dimensional Cr5Te8@Graphite Heterostructure for Efficient Electromagnetic Microwave Absorption.

Project description:Two-dimensional (2D) transition metal chalcogenides (TMCs) hold great promise as novel microwave absorption materials owing to their interlayer interactions and unique magnetoelectric properties. However, overcoming the impedance mismatch at the low loading is still a challenge for TMCs due to the restricted loss pathways caused by their high-density characteristic. Here, an interface engineering based on the heterostructure of 2D Cr5Te8 and graphite is in situ constructed via a one-step chemical vapor deposit to modulate impedance matching and introduce multiple attenuation mechanisms. Intriguingly, the Cr5Te8@EG (ECT) heterostructure exhibits a minimum reflection loss of up to - 57.6 dB at 15.4 GHz with a thin thickness of only 1.4 mm under a low filling rate of 10%. The density functional theory calculations confirm that the splendid performance of ECT heterostructure primarily derives from charge redistribution at the abundant intimate interfaces, thereby reinforcing interfacial polarization loss. Furthermore, the ECT coating displays a remarkable radar cross section reduction of 31.9 dB m2, demonstrating a great radar microwave scattering ability. This work sheds light on the interfacial coupled stimulus response mechanism of TMC-based heterogeneous structures and provides a feasible strategy to manipulate high-quality TMCs for excellent microwave absorbers.

| S-EPMC10733264 | biostudies-literature

Excellent microwave absorption property of Graphene-coated Fe nanocomposites.

Project description:Graphene has evoked extensive interests for its abundant physical properties and potential applications. It is reported that the interfacial electronic interaction between metal and graphene would give rise to charge transfer and change the electronic properties of graphene, leading to some novel electrical and magnetic properties in metal-graphene heterostructure. In addition, large specific surface area, low density and high chemical stability make graphene act as an ideal coating material. Taking full advantage of the aforementioned features of graphene, we synthesized graphene-coated Fe nanocomposites for the first time and investigated their microwave absorption properties. Due to the charge transfer at Fe-graphene interface in Fe/G, the nanocomposites show distinct dielectric properties, which result in excellent microwave absorption performance in a wide frequency range. This work provides a novel approach for exploring high-performance microwave absorption material as well as expands the application field of graphene-based materials.

| S-EPMC3852363 | biostudies-other

Enhanced Wave Absorption and Mechanical Properties of Cobalt Sulfide/PVDF Composite Materials.

Project description:A cobalt sulfide/PVDF(Polyvinylidene Fluoride) composite was prepared by a simple blending method, and the microstructure of the composite was investigated through X-ray diffraction, scanning electron microscopy, and field emission scanning electron microscopy. Increased absorption properties at frequencies ranging from 2 GHz to 18 GHz were studied, and the mechanical properties were investigated via tensile tests and finite element method simulations. The results indicated that the cobalt sulfide/PVDF composites exhibited strong microwave absorption intensities (-43 dB at 6.6 GHz) with a low filler loading (5.0 wt%). The elastic modulus increased with the cobalt sulfide mass fraction. Cobalt sulfide could improve the mechanical properties of the composite, especially in the lengthwise direction.

| S-EPMC6642107 | biostudies-literature

Ultra-High Electromagnetic Absorption Property of One-Dimensional Carbon-Supported Ni/Mo2C and Polyvinylidene Fluoride.

Project description:A novel one-dimensional carbon-supported Ni/Mo2C (Ni/Mo2C-C) nanocomposite with excellent electromagnetic wave absorption properties was successfully synthesized by annealing NiMoO4@PDA directly, and then the (Ni/Mo2C-C)/polyvinylidene fluoride (PVDF) composites were fabricated using a simple blending and hot-molding technique. An excellent reflection loss (RL) of -55.91 dB at 9.28 GHz with a low filler loading (15 wt%) and effective bandwidth (RL < -10 dB) of 14.12 GHz in the thickness range of 1.5-5.0 mm was obtained. Dielectric loss is considered to be the dominant mechanism of (Ni/Mo2C-C)/PVDF, which was confirmed by the Debye relaxation process and attenuation theory.

| S-EPMC6595158 | biostudies-literature

Multicaloric effect in a multiferroic composite of Gd5(Si,Ge)4 microparticles embedded into a ferroelectric PVDF matrix.

Project description:The coupling between electric, magnetic and elastic features in multiferroic materials is an emerging field in materials science, with important applications on alternative solid-state cooling technologies, energy harvesting and sensors/actuators. In this direction, we developed a thorough investigation of a multiferroic composite, comprising magnetocaloric/magnetostrictive Gd[Formula: see text]Si[Formula: see text]Ge[Formula: see text] microparticles blended into a piezo- and pyroelectric poly(vinylidene) fluoride (PVDF) matrix. Using a simple solvent casting technique, the formation and stabilization of PVDF electroactive phases are improved when the filler content increases from 2 to 12 weight fraction (wt.%). This effect greatly contributes to the magnetoelectric (ME) coupling, with the ME coefficient [Formula: see text] increasing from 0.3 V/cm.Oe to 2.2 V/cm.Oe, by increasing the amount of magnetic material. In addition, magnetic measurements revealed that the ME-coupling has influenced the magnetocaloric effect via a contribution from the electroactive polymer and hence leading to a multicaloric effect. These results contribute to the development of multifunctional systems for novel technologies.

| S-EPMC6892869 | biostudies-literature

Hierarchical Ti3C2Tx@ZnO Hollow Spheres with Excellent Microwave Absorption Inspired by the Visual Phenomenon of Eyeless Urchins.

Project description:Ingenious microstructure design and rational composition selection are effective approaches to realize high-performance microwave absorbers, and the advancement of biomimetic manufacturing provides a new strategy. In nature, urchins are the animals without eyes but can "see", because their special structure composed of regular spines and spherical photosensitive bodies "amplifies" the light-receiving ability. Herein, inspired by the above phenomenon, the biomimetic urchin-like Ti3C2Tx@ZnO hollow microspheres are rationally designed and fabricated, in which ZnO nanoarrays (length: ~ 2.3 μm, diameter: ~ 100 nm) as the urchin spines are evenly grafted onto the surface of the Ti3C2Tx hollow spheres (diameter: ~ 4.2 μm) as the urchin spherical photosensitive bodies. The construction of gradient impedance and hierarchical heterostructures enhance the attenuation of incident electromagnetic waves. And the EMW loss behavior is further revealed by limited integral simulation calculations, which fully highlights the advantages of the urchin-like architecture. As a result, the Ti3C2Tx@ZnO hollow spheres deliver a strong reflection loss of - 57.4 dB and broad effective absorption bandwidth of 6.56 GHz, superior to similar absorbents. This work provides a new biomimetic strategy for the design and manufacturing of advanced microwave absorbers.

| S-EPMC8938554 | biostudies-literature