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1.
Artículo en Inglés | MEDLINE | ID: mdl-38959083

RESUMEN

Aerogel-based composites, renowned for their three-dimensional (3D) network architecture, are gaining increasing attention as lightweight electromagnetic (EM) wave absorbers. However, attaining high reflection loss, broad effective absorption bandwidth (EAB), and ultrathin thickness concurrently presents a formidable challenge, owing to the stringent demands for precise structural regulation and incorporation of magnetic/dielectric multicomponents with synergistic loss mechanisms within the 3D networks. In this study, we successfully synthesized a 3D hierarchical porous Fe3O4/MoS2/rGO/Ti3C2Tx MXene (FMGM) composite aerogel via directional freezing and subsequent heat treatment processes. Owing to their ingenious structure and multicomponent design, the FMGM aerogels, featured with abundant heterogeneous interface structure and magnetic/dielectric synergism, show exceptional impedance matching characteristics and diverse EM wave absorption mechanisms. After optimization, the prepared ultralight (6.4 mg cm-3) FMGM-2 aerogel exhibits outstanding EM wave absorption performance, achieving a minimal reflection loss of -66.92 dB at a thickness of 3.61 mm and an EAB of 6.08 GHz corresponding to the thickness of 2.3 mm, outperforming most of the previously reported aerogel-based absorbing materials. This research presents an effective strategy for fabricating lightweight, ultrathin, highly efficient, and broad band EM wave absorption materials.

2.
ACS Nano ; 18(17): 11449-11461, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38644575

RESUMEN

Bimetallic alloy nanoparticles have garnered substantial attention for diverse catalytic applications owing to their abundant active sites and tunable electronic structures, whereas the synthesis of ultrafine alloy nanoparticles with atomic-level homogeneity for bulk-state immiscible couples remains a formidable challenge. Herein, we present the synthesis of RuxCo1-x solid-solution alloy nanoparticles (ca. 2 nm) across the entire composition range, for highly efficient, durable, and selective CO2 hydrogenation to CH4 under mild conditions. Notably, Ru0.88Co0.12/TiO2 and Ru0.74Co0.26/TiO2 catalysts, with 12 and 26 atom % of Ru being substituted by Co, exhibit enhanced catalytic activity compared with the monometallic Ru/TiO2 counterparts both in dark and under light irradiation. The comprehensive experimental investigations and density functional theory calculations unveil that the electronic state of Ru is subtly modulated owing to the intimate interaction between Ru and Co in the alloy nanoparticles, and this effect results in the decline in the CO2 conversion energy barrier, thus ultimately culminating in an elevated catalytic performance relative to monometallic Ru and Co catalysts. In the photopromoted thermocatalytic process, the photoinduced charge carriers and localized photothermal effect play a pivotal role in facilitating the chemical reaction process, which accounts for the further boosted CO2 methanation performance.

3.
Adv Sci (Weinh) ; 11(19): e2400403, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38483033

RESUMEN

Improving interface connectivity of magnetic nanoparticles in carbon aerogels is crucial, yet challenging for assembling lightweight, elastic, high-performance, and multifunctional carbon architectures. Here, an in situ growth strategy to achieve high dispersion of metal-organic frameworks (MOFs)-anchored cellulose nanofibrils to enhance the interface connection quality is proposed. Followed by a facile freeze-casting and carbonization treatment, sustainable biomimetic porous carbon aerogels with highly dispersed and closely connected MOF-derived magnetic nano-capsules are fabricated. Thanks to the tight interface bonding of nano-capsule microstructure, these aerogels showcase remarkable mechanical robustness and flexibility, tunable electrical conductivity and magnetization intensity, and excellent electromagnetic wave absorption performance. Achieving a reflection loss of -70.8 dB and a broadened effective absorption bandwidth of 6.0 GHz at a filling fraction of merely 2.2 wt.%, leading to a specific reflection loss of -1450 dB mm-1, surpassing all carbon-based aerogel absorbers so far reported. Meanwhile, the aerogel manifests high magnetic sensing sensibility and excellent thermal insulation. This work provides an extendable in situ growth strategy for synthesizing MOF-modified cellulose nanofibril structures, thereby promoting the development of high-value-added multifunctional magnetic carbon aerogels for applications in electromagnetic compatibility and protection, thermal management, diversified sensing, Internet of Things devices, and aerospace.

4.
Sci Adv ; 10(11): eadl6498, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38478599

RESUMEN

Designing a functional, conductive metal-organic framework (cMOF) is highly desired. Substantial efforts have been dedicated to increasing the intralayer conjugation of the cMOFs, while less dedication has been made to tuning the interlayer charge transport of the metal-organic nanosheets for the controllable dielectric property. Here, we construct a series of conductive bimetallic organic frameworks of (ZnxCu3-x) (hexahydroxytriphenylene)2 (ZnCu-HHTP) to allow for fine-tuned interlayer spacing of two-dimensional frameworks, by adjusting the ratios of Zn and Cu metal ions. This approach for atomistic interlayer design allows for the finely control of the charge transport, band structure, and dielectric properties of the cMOF. As a result, Zn3Cu1-HHTP, with an optimal dielectric property, exhibits high-efficiency absorption in the gigahertz microwave range, achieving an ultra-strong reflection loss of -81.62 decibels. This study not only advances the understanding of the microstructure-function relationships in cMOFs but also offers a generic nanotechnology-based approach to achieving controllable interlayer spacing in MOFs for the targeted applications.

5.
Small ; 20(11): e2307647, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37890470

RESUMEN

The exploitation of advanced electromagnetic functional devices is perceived as the effective prescription to deal with environmental contamination and energy deficiency. From the perspective of observing and imitating nature, pine branch-like zirconium dioxide/cobalt nanotubes@nitrogen-doped carbon nanotubes are synthesized victoriously through maneuverable electrospinning process and follow-up thermal treatments. In particular, introducing carbon nanotubes on the surface of hollow nanofibers to construct hierarchical architecture vastly promoted the material's dielectric properties by significantly augmenting specific surface area, generating abundant heterogeneous interfaces, and inducing the formation of defects. Supplemented by the synergistic effect between each constituent, ultra-strong attenuation capacity and perfect impedance matching characteristics are implemented simultaneously, and jointly made contributions to the splendid microwave absorption performance with a minimum reflection loss of -67.9 dB at 1.5 mm. Moreover, this fibrous absorber also exhibited promising potential to be utilized as a green and efficient electromagnetic interference shielding material when the filler loading is enhanced. Therefore, this design philosophy is destined to inspire the future development of energy conversion and storage devices, and provide theoretical direction for the creation of sophisticated electromagnetic functional materials.

6.
Nanomicro Lett ; 16(1): 16, 2023 Nov 17.
Artículo en Inglés | MEDLINE | ID: mdl-37975962

RESUMEN

Carbon-based aerogels derived from biomass chitosan are encountering a flourishing moment in electromagnetic protection on account of lightweight, controllable fabrication and versatility. Nevertheless, developing a facile construction method of component design with carbon-based aerogels for high-efficiency electromagnetic wave absorption (EWA) materials with a broad effective absorption bandwidth (EAB) and strong absorption yet hits some snags. Herein, the nitrogen-doped magnetic-dielectric-carbon aerogel was obtained via ice template method followed by carbonization treatment, homogeneous and abundant nickel (Ni) and manganese oxide (MnO) particles in situ grew on the carbon aerogels. Thanks to the optimization of impedance matching of dielectric/magnetic components to carbon aerogels, the nitrogen-doped magnetic-dielectric-carbon aerogel (Ni/MnO-CA) suggests a praiseworthy EWA performance, with an ultra-wide EAB of 7.36 GHz and a minimum reflection loss (RLmin) of - 64.09 dB, while achieving a specific reflection loss of - 253.32 dB mm-1. Furthermore, the aerogel reveals excellent radar stealth, infrared stealth, and thermal management capabilities. Hence, the high-performance, easy fabricated and multifunctional nickel/manganese oxide/carbon aerogels have broad application aspects for electromagnetic protection, electronic devices and aerospace.

7.
Nanomicro Lett ; 15(1): 240, 2023 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-37917275

RESUMEN

There is an urgent demand for flexible, lightweight, mechanically robust, excellent electromagnetic interference (EMI) shielding materials. Two-dimensional (2D) transition metal carbides/nitrides (MXenes) have been potential candidates for the construction of excellent EMI shielding materials due to their great electrical electroconductibility, favorable mechanical nature such as flexibility, large aspect ratios, and simple processability in aqueous media. The applicability of MXenes for EMI shielding has been intensively explored; thus, reviewing the relevant research is beneficial for advancing the design of high-performance MXene-based EMI shields. Herein, recent progress in MXene-based macrostructure development is reviewed, including the associated EMI shielding mechanisms. In particular, various structural design strategies for MXene-based EMI shielding materials are highlighted and explored. In the end, the difficulties and views for the future growth of MXene-based EMI shields are proposed. This review aims to drive the growth of high-performance MXene-based EMI shielding macrostructures on basis of rational structural design and the future high-efficiency utilization of MXene.

8.
ACS Nano ; 17(23): 23761-23771, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-37982387

RESUMEN

Carbon dioxide (CO2) hydrogenation to methane (CH4) is regarded as a promising approach for CO2 utilization, whereas achieving desirable conversion efficiency under mild conditions remains a significant challenge. Herein, we have identified ultrasmall Ru nanoparticles (∼2.5 nm) anchored on MnCo2O4 nanosheets as prospective photothermal catalysts for CO2 methanation at ambient pressure with light irradiation. Our findings revealed that MnCo2O4 nanosheets exhibit dual functionality as photothermal substrates for localized temperature enhancement and photocatalysts for electron donation. As such, the optimized Ru/MnCo2O4-2 gave a high CH4 production rate of 66.3 mmol gcat-1 h-1 (corresponding to 5.1 mol gRu-1 h-1) with 96% CH4 selectivity at 230 °C under ambient pressure and light irradiation (420-780 nm, 1.25 W cm-2), outperforming most reported plasmonic metal-based catalysts. The mechanisms behind the intriguing photothermal catalytic performance improvement were substantiated through a comprehensive investigation involving experimental characterizations, numerical simulations and density functional theory (DFT) calculations, which unveiled the synergistic effects of enhanced charge separation efficiency, improved reaction kinetics, facilitated reactant adsorption/activation and accelerated intermediate conversion under light irradiation over Ru/MnCo2O4. A comparison study showed that, with identical external input energy during the reaction, Ru/MnCo2O4-2 had a much higher catalytic efficiency compared to Ru/TiO2 and Ru/Al2O3. This study underscores the pivotal role played by photothermal supports and is believed to engender a heightened interest in plasmonic metal nanoparticles anchored on photothermal substrates for CO2 methanation under mild conditions.

9.
iScience ; 26(7): 107132, 2023 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-37456858

RESUMEN

To address the electromagnetic wave (EMW) pollution issues caused by the development of electronics and wireless communication technology, it is urgent to develop efficient EMW-absorbing materials. With controllable composition, diverse structure, high porosity, and large specific surface area, metal-organic framework (MOF) derivatives have sparked the infinite passion and creativity of researchers in the electromagnetic field. Against the challenges of poor inherent impedance matching and insufficient attenuation capability of pure MOF derivative, designing and developing MOF derivative-based composites by compounding MOF with other materials, such as graphene, CNTs, MXene, and so on, has been an effective strategy for constructing high-efficiency EMW absorbing materials. This review systematically expounds the research progress of MOF derivative-based composite strategies, and discusses the challenges and opportunities faced by MOF derivatives in the field of EMW absorption. This work can provide some good ideas for researchers to design and prepare high-efficiency MOF-based EMW absorbing materials in applications of next-generation electronics and aerospace.

10.
ACS Nano ; 17(13): 12510-12518, 2023 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-37350557

RESUMEN

Metal-organic frameworks (MOFs) manifest enormous potential in promoting electromagnetic wave (EMW) absorption thanks to the tailored components, topological structure, and high porosity. Herein, rodlike conductive MOFs (cMOFs) composed of adjustable metal ions of Zn, Cu, Co, or Ni and ligands of hexahydroxytriphenylene (HHTP) are prepared to attain tunable dielectric properties for a tailored EMW absorption. Specifically, the influences of the cMOFs' composition, charge transport characteristic, topological crystalline structure, and anisotropy microstructure on dielectric and EMW absorption performance are ascertained, advancing the understanding of EMW attenuation mechanisms of MOFs. The boosted conductive and polarization losses derived from the conjugation effects and terminal groups, as well as shape anisotropy, lead to a prominent EMW absorption of the cMOFs. The Cu-HHTP confers a minimum reflection loss (RLmin) of -63.55 dB at the thickness of 2.9 mm and a maximum effective absorption bandwidth of 5.2 GHz. Moreover, Zn-HHTP showcases the absorption superiority in the S-band (2-4 GHz) with an RLmin of -62.8 dB at a thickness of 1.9 mm. This work not only hoists the mechanistic understanding of the structure-function relationships for the cMOFs but also offers guidelines for preparing functional MOF materials.

11.
Materials (Basel) ; 16(9)2023 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-37176459

RESUMEN

Zinc hydroxyfluoride (ZnOHF) is a newly found resistive semiconductor used as a gas-sensing material with excellent selectivity to NO2 because of its unique energy band structure. In this paper, Al3+ doping and UV radiation were used to further improve the gas-sensing performance of ZnOHF. The optimized 0.5 at.% Al-ZnOHF sample exhibits improved sensitivity to 10 ppm NO2 at a lower temperature (100 °C) under UV assistance, as well as a short response/recovery time (35 s/96 s). The gas-sensing mechanism demonstrates that Al3+ doping increases electron concentration and promotes electron transfer of the nanorods by reducing the bandgap of ZnOHF, and the photogenerated electrons and holes with high activity under UV irradiation provide new reaction routes in the gas adsorption and desorption process, effectively promoting the gas-sensing process. The synergistic effect of Al3+ and UV radiation contribute to the enhanced performance of Al-ZnOHF.

12.
Small ; 19(40): e2302686, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37208798

RESUMEN

Developing carbon encapsulated magnetic composites with rational design of microstructure for achieving high-performance electromagnetic wave (EMW) absorption in a facile, sustainable, and energy-efficiency approach is highly demanded yet remains challenging. Here, a type of N-doped carbon nanotube (CNT) encapsulated CoNi alloy nanocomposites with diverse heterostructures are synthesized via the facile, sustainable autocatalytic pyrolysis of porous CoNi-layered double hydroxide/melamine. Specifically, the formation mechanism of the encapsulated structure and the effects of heterogenous microstructure and composition on the EMW absorption performance are ascertained. With the presence of melamine, CoNi alloy emerges its autocatalysis effect to generate N-doped CNTs, leading to unique heterostructure and high oxidation stability. The abundant heterogeneous interfaces induce strong interfacial polarization to EMWs and optimize impedance matching characteristic. Combined with the inherent high conductive and magnetic loss capabilities, the nanocomposites accomplish a high-efficiency EMW absorption performance even at a low filling ratio. The minimum reflection loss of -84.0 dB at the thickness of 3.2 mm and a maximum effective bandwidth of 4.3 GHz are obtained, comparable to the best EMW absorbers. Integrated with the facile, controllable, and sustainable preparation approach of the heterogenous nanocomposites, the work shows a great promise of the nanocarbon encapsulation protocol for achieving lightweight, high-performance EMW absorption materials.

13.
Adv Sci (Weinh) ; 10(19): e2301073, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37092564

RESUMEN

Achieving scalable synthesis of nanoscale transition-metal carbides (TMCs), regarded as substitutes for platinum-group noble metals, remains an ongoing challenge. Herein, a 100-g scale synthesis of single-phased cobalt carbide (Co2 C) through carburization of Co-based Prussian Blue Analog (Co-PBA) is reported in CO2 /H2 atmosphere under mild conditions (230 °C, ambient pressure). Textural property investigations indicate a successful preparation of orthorhombic-phased Co2 C nanomaterials with Pt-group-like electronic properties. As a demonstration, Co2 C achieves landmark photo-assisted thermal catalytic CO2 conversion rates with photo-switched product selectivity, which far exceeds the representative Pt-group-metal-based catalysts. This impressive result is attributed to the excellent activation of reactants, colorific light absorption, and photo-to-thermal conversion capacities. In addition to CO2 hydrogenation, the versatile Co2 C materials show huge prospects in antibacterial therapy, interfacial water evaporation, electrochemical hydrogen evolution reaction, and battery technologies. This study paves the way toward unlocking the potential of multi-functional Co2 C nanomaterials.

14.
Adv Sci (Weinh) ; 10(15): e2300122, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-36932051

RESUMEN

Photo-thermal catalytic CO2 hydrogenation is currently extensively studied as one of the most promising approaches for the conversion of CO2 into value-added chemicals under mild conditions; however, achieving desirable conversion efficiency and target product selectivity remains challenging. Herein, the fabrication of Ir-CoO/Al2 O3 catalysts derived from Ir/CoAl LDH composites is reported for photo-thermal CO2 methanation, which consist of Ir-CoO ensembles as active centers that are evenly anchored on amorphous Al2 O3 nanosheets. A CH4 production rate of 128.9 mmol gcat⁻ 1 h⁻1  is achieved at 250 °C under ambient pressure and visible light irradiation, outperforming most reported metal-based catalysts. Mechanism studies based on density functional theory (DFT) calculations and numerical simulations reveal that the CoO nanoparticles function as photocatalysts to donate electrons for Ir nanoparticles and meanwhile act as "nanoheaters" to effectively elevate the local temperature around Ir active sites, thus promoting the adsorption, activation, and conversion of reactant molecules. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) demonstrates that illumination also efficiently boosts the conversion of formate intermediates. The mechanism of dual functions of photothermal semiconductors as photocatalysts for electron donation and as nano-heaters for local temperature enhancement provides new insight in the exploration for efficient photo-thermal catalysts.

15.
Sensors (Basel) ; 23(3)2023 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-36772203

RESUMEN

Methane (CH4), as the main component of natural gas and coal mine gas, is widely used in daily life and industrial processes and its leakage always causes undesirable misadventures. Thus, the rapid detection of low concentration methane is quite necessary. However, due to its robust chemical stability resulting from the strong tetrahedral-symmetry structure, the methane molecules are usually chemically inert to the sensing layers in detectors, making the rapid and efficient alert a big challenge. In this work, palladium nanoparticles (Pd NPs) embedded indium oxide porous hollow tubes (In2O3 PHTs) were successfully synthesized using Pd@MIL-68 (In) MOFs as precursors. All In2O3-based samples derived from Pd@MIL-68 (In) MOFs inherited the morphology of the precursors and exhibited the feature of hexagonal hollow tubes with porous architecture. The gas-sensing performances to 5000 ppm CH4 were evaluated and it was found that Pd@In2O3-2 gave the best response (Ra/Rg = 23.2) at 370 °C, which was 15.5 times higher than that of pristine-In2O3 sensors. In addition, the sensing materials also showed superior selectivity against interfering gases and a rather short response/recovery time of 7 s/5 s. The enhancement in sensing performances of Pd@In2O3-2 could be attributed to the large surface area, rich porosity, abundant oxygen vacancies and the catalytic function of Pd NPs.

16.
Heliyon ; 9(2): e13486, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36814628

RESUMEN

Pristine SnO2, Fe-doped SnO2 and Ni-doped SnO2 were synthesized using facile hydrothermal method. Analysis based on XRD, TEM and UV-Vis DRS measurements demonstrated the successful insertion of Fe and Ni dopants into SnO2 crystal. Formaldehyde-detection measurements revealed that transition metal-doped SnO2 exhibited improved formaldehyde-sensing properties compared with that of pristine SnO2. When the amount of incorporated dopant (Fe or Ni) was 4 at.%, the most effective enhancement on sensing performance of SnO2 was obtained. At 160 °C, the 4 at.% Fe-SnO2 and 4 at.% Ni-SnO2 exhibited higher response values of 7.52 and 4.37 with exposure to low-concentration formaldehyde, respectively, which were 2.4 and 1.4 times higher than that of pristine SnO2. The change of electronic structure and crystal structure as well as catalytic effect of transition metals are chiefly responsible for the enhanced sensing properties.

17.
J Colloid Interface Sci ; 629(Pt A): 884-894, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36150266

RESUMEN

Regulating electromagnetic parameters and thus improving impedance matching characteristics by multi-component design is regarded as a prospective approach to obtain highly efficient electromagnetic wave absorption materials. Whereas, it is still challenging to fabricate microwave absorbers with strong absorption capacity and durability in harsh conditions. Based on the above considerations, three-dimensional porous multi-functional manganese oxide/nickel/carbon microspheres had been designed and prepared through a combined approach of facile solvothermal reactions and subsequent carbonization processes. The textural characteristic examinations demonstrated that, numerous manganese oxide and Ni nanoparticles of 15-20 nm in diameter were well dispersed in the carbon-based microspheres of approximately 0.8-1 µm in size. Microwave absorption property evaluation indicated that the minimum reflection loss reached up to -53.6 dB at 9.5 GHz, and effective absorption bandwidth of 3.7 GHz was achieved at matching thickness of merely 2.0 mm. The electromagnetic wave attenuation mechanisms analysis displayed that excellent impedance matching and various dissipation pathways, including magnetic loss, interfacial and dipole polarization relaxation synergistically contributed to the high microwave absorption performances of the porous composites. Radar cross-sectional simulation and photothermal measurements verified that the materials were supposed to have promising foregrounds in complicated circumstances.

18.
Adv Mater ; 35(1): e2207969, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36281792

RESUMEN

Ambient-pressure-dried (APD) preparation of transition metal carbide/nitrides (MXene) aerogels is highly desirable yet remains highly challenging. Here, ultrathin, high-strength-to-weight-ratio, renewable cellulose nanofibers (CNFs) are efficiently utilized to assist in the APD preparation of ultralight yet robust, highly conductive, large-area MXene-based aerogels via a facile, energy-efficient, eco-friendly, and scalable freezing-exchanging-drying approach. The strong interactions of large-aspect-ratio CNF and MXene as well as the biomimetic nacre-like microstructure induce high mechanical strength and stability to avoid the structure collapse of aerogels in the APD process. Abundant functional groups of CNFs facilitate the chemical crosslinking of MXene-based aerogels, significantly improving the hydrophobicity, water resistance, and even oxidation stability. The ultrathin, 1D nature of the CNF renders the minimal MXenes' interlayered gaps and numerous heterogeneous interfaces, yielding the excellent conductivity and electromagnetic interference (EMI) shielding performance of aerogels. The synergies of the MXene, CNF, and abundant pores efficiently improve the EMI shielding performance, photothermal conversion, and absorption of viscous crude oil. This work shows great promises of the APD, multifunctional MXene-based aerogels in electromagnetic protection or compatibility, thermal therapy, and oil-water separation applications.

19.
J Colloid Interface Sci ; 630(Pt B): 47-56, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36327738

RESUMEN

One-dimensional carbon-based materials have emerged as promising electromagnetic wave absorption agents due to their outstanding conductivity, high stability, low weight, and easy availability. Properly optimizing their electromagnetic parameters is expected to further enhance the electromagnetic wave attenuation capacity. In this work, efficient Cu9S5/C nanocomposite fibers are prepared by a combined approach of electrospinning and subsequent carbonization-sulfurization processes. The Cu9S5 nanoparticles with size of ca. 100-200 nm were homogeneously embedded in fibrous carbon matrix with diameter of 300 nm. For electromagnetic wave absorption, the optimized composited nanofibers (Cu9S5/C-3) exhibited an extremely superb reflection loss of -65.4 dB (9.5 GHz, 2.7 mm) at a lower mass fraction (20 wt%). And the effective absorption bandwidth could be up to 4.1 GHz (8.0-12.1 GHz) with a matching thickness of 2.9 mm, covering the whole X-band. Electromagnetic wave attenuation mechanism investigation revealed that the performance enhancement originated from the synergy of various loss pathways, including interfacial polarization, dipole polarization, and conductive loss. The unique hierarchical structure from particle embedding, one-dimensional fiber, to three-dimensional network further amplified the performance advantages of each component. This work is anticipated to provide a feasible strategy to synthesize sulfide/carbon binary composite fibers for efficient electromagnetic wave absorption.

20.
ACS Nano ; 16(11): 19293-19304, 2022 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-36260760

RESUMEN

Lightweight, thin, large-area, and ultraflexible chemical-cross-linked MXene/superaligned carbon nanotube composite films with a bicontinuous structure are manufactured. The films exhibit high mechanical strength, good electrical conductivity, hydrophobicity, and oxidation stability, as well as wearable multifunctionalities involving electromagnetic interference (EMI) shielding, electrothermal conversion, and photothermal antibacterial performance. An X-band EMI shielding effectiveness (SE) of 24 to 70 dB at the thickness of 8 to 28 µm and an SE of more than 60 dB in ultrabroadband frequency range of 8.2-40 GHz are accomplished. A surface specific SE of 122 368 dB·cm2·g-1 is achieved, significantly outperforming other typical shields reported. The good electro-/photothermal performance of the films leads to high-efficiency deicing and antibacterial performance. Combined with the efficient and scalable manufacturing approach, the multifunctional wearable bicontinuous films show great potential for applications in wearable devices, defense, antibacterials, and the Internet of Things.


Asunto(s)
Nanotubos de Carbono , Nanotubos de Carbono/química , Antibacterianos/farmacología
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