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1.
Sci Bull (Beijing) ; 2024 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-38944633

RESUMEN

The conventional Hall effect is linearly proportional to the field component or magnetization component perpendicular to a film. Despite the increasing theoretical proposals on the Hall effect to the in-plane field or magnetization in various special systems induced by the Berry curvature, such an unconventional Hall effect has only been experimentally reported in Weyl semimetals and in a heterodimensional superlattice. Here, we report an unambiguous experimental observation of the antisymmetric planar Hall effect (APHE) with respect to the in-plane magnetic field in centrosymmetric rutile RuO2 and IrO2 single-crystal films. The measured Hall resistivity is found to be linearly proportional to the component of the applied in-plane magnetic field along a particular crystal axis and to be independent of the current direction or temperature. Both the experimental observations and theoretical calculations confirm that the APHE in rutile oxide films is induced by the Lorentz force. Our findings can be generalized to ferromagnetic materials for the discovery of anomalous Hall effects and quantum anomalous Hall effects induced by in-plane magnetization. In addition to significantly expanding knowledge of the Hall effect, this work opens the door to explore new members in the Hall effect family.

2.
Natl Sci Rev ; 11(7): nwae175, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38883296

RESUMEN

Anisotropy is a significant and prevalent characteristic of materials, conferring orientation-dependent properties, meaning that the creation of original symmetry enables key functionality that is not found in nature. Even with the advancements in atomic machining, synthesis of separated symmetry in different directions within a single structure remains an extraordinary challenge. Here, we successfully fabricate NiS ultrafine nanorods with separated symmetry along two directions. The atomic structure of the nanorod exhibits rotational symmetry in the radial direction, while its axial direction is characterized by divergent translational symmetry, surpassing the conventional crystalline structures known to date. It does not fit the traditional description of the space group and the point group in three dimensions, so we define it as a new structure in which translational symmetry and rotational symmetry are separated. Further corroborating the atomic symmetric separation in the electronic structure, we observed the combination of stripe and vortex magnetic domains in a single nanorod with different directions, in accordance with the atomic structure. The manipulation of nanostructure at the atomic level introduces a novel approach to regulate new properties finely, leading to the proposal of new nanotechnology mechanisms.

3.
Nanomicro Lett ; 16(1): 213, 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38861114

RESUMEN

The exploration of novel multivariate heterostructures has emerged as a pivotal strategy for developing high-performance electromagnetic wave (EMW) absorption materials. However, the loss mechanism in traditional heterostructures is relatively simple, guided by empirical observations, and is not monotonous. In this work, we presented a novel semiconductor-semiconductor-metal heterostructure system, Mo-MXene/Mo-metal sulfides (metal = Sn, Fe, Mn, Co, Ni, Zn, and Cu), including semiconductor junctions and Mott-Schottky junctions. By skillfully combining these distinct functional components (Mo-MXene, MoS2, metal sulfides), we can engineer a multiple heterogeneous interface with superior absorption capabilities, broad effective absorption bandwidths, and ultrathin matching thickness. The successful establishment of semiconductor-semiconductor-metal heterostructures gives rise to a built-in electric field that intensifies electron transfer, as confirmed by density functional theory, which collaborates with multiple dielectric polarization mechanisms to substantially amplify EMW absorption. We detailed a successful synthesis of a series of Mo-MXene/Mo-metal sulfides featuring both semiconductor-semiconductor and semiconductor-metal interfaces. The achievements were most pronounced in Mo-MXene/Mo-Sn sulfide, which achieved remarkable reflection loss values of - 70.6 dB at a matching thickness of only 1.885 mm. Radar cross-section calculations indicate that these MXene/Mo-metal sulfides have tremendous potential in practical military stealth technology. This work marks a departure from conventional component design limitations and presents a novel pathway for the creation of advanced MXene-based composites with potent EMW absorption capabilities.

4.
Adv Mater ; : e2403322, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38690808

RESUMEN

2D layered metallic graphite composites are promising electromagnetic wave absorption materials (EWAMs) for their combined properties of abundant interlayer free spaces, rich metallic polarized sites, and high conductivity, but the controllable synthesis remains rather challenging. Herein, a dual-step redox engineering strategy is developed by employing cobalt boron imidazolate framework (Co-BIF) to construct 2D CoNi-alloy embedded B, N-doped carbon layers (2D-CNC) as a promising EWAM. In the first step, a chemical etching oxidation process on Co-BIF is used to obtain an optimized 2D-CoNi-layered double hydroxide (2D-CoNi-LDH) intermediate and in the second, high-temperature calcination reduction is implemented to modify graphitization of the degree of the 2D-CNC. The obtained sample delivers superior reflection loss (RLmin) of -60.1 dB and wide effective absorption bandwidth (EAB) of 6.24 GHz. The synergy mechanisms of interfacial/dipole polarization and magnetic coupling are in-depth evidenced by the hologram and Lorentz electron microscopy, revealing its significant contribution on multireflection and impedance matching. Further theoretical evaluation by COMSOL simulation in different fields based on the dynamic loss process toward the test ring reveals the in situ EW attenuation process. This work presents a strategy to develop multifunctional light-weight infrared stealthy aerogel with superior pressure-resistant, anti-corrosion, and heat-insulating properties for future applications.

5.
Small ; : e2401618, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38712450

RESUMEN

Heterointerface engineering is presently considered a valuable strategy for enhancing the microwave absorption (MA) properties of materials via compositional modification and structural design. In this study, a sulfur-doped multi-interfacial composite (Fe7S8/NiS@C) coated with NiFe-layered double hydroxides (LDHs) is successfully prepared using a hydrothermal method and post-high-temperature vulcanization. When assembled into twisted surfaces, the NiFe-LDH nanosheets exhibit porous morphologies, improving impedance matching, and microwave scattering. Sulfur doping in composites generates heterointerfaces, numerous sulfur vacancies, and lattice defects, which facilitate the polarization process to enhance MA. Owing to the controllable heterointerface design, the unique porous structure induced multiple heterointerfaces, numerous vacancies, and defects, endowing the Fe7S8/NiS@C composite with an enhanced MA capability. In particular, the minimum reflection loss (RLmin) value reached -58.1 dB at 15.8 GHz at a thickness of 2.1 mm, and a broad effective absorption bandwidth (EAB) value of 7.3 GHz is achieved at 2.5 mm. Therefore, the Fe7S8/NiS@C composite exhibits remarkable potential as a high-efficiency MA material owing to the synergistic effects of the polarization processes, multiple scatterings, porous structures, and impedance matching.

6.
Small ; : e2401878, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38742982

RESUMEN

Atomic doping is widely employed to fine-tune crystal structures, energy band structures, and the corresponding electrical properties. However, due to the difficulty in precisely regulating doping sites and concentrations, establishing a relationship between electricity properties and doping becomes a huge challenge. In this work, a modulation strategy on A-site cation dopant into spinel-phase metal sulfide Co9S8 lattice via Fe and Ni elements is developed to improve the microwave absorption (MA) properties. At the atomic scale, accurately controlling doped sites can introduce local lattice distortions and strain concentration. Tunned electron energy redistribution of the doped Co9S8 strengthens electron interactions, ultimately enhancing the high-frequency dielectric polarization (ɛ' from 10.5 to 12.5 at 12 GHz). For the Fe-doped Co9S8, the effective absorption bandwidth (EAB) at 1.7 mm increases by 5%, and the minimum reflection loss (RLmin) improves by 26% (EAB = 5.8 GHz, RLmin = -46 dB). The methodology of atomic-scale fixed-point doping presents a promising avenue for customizing the dielectric properties of nanomaterials, imparting invaluable insights for the design of cutting-edge high-performance microwave absorption materials.

7.
Small ; : e2311312, 2024 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-38566552

RESUMEN

The exploitation of multicomponent composites (MCCs) has become the main pathway for obtaining advanced microwave absorption materials (MAMs). Herein, a metal valence state modulation strategy is proposed to tune the electromagnetic (EM) parameters and improve microwave absorption performances. Core@shell hollow carbon microspheres@MoSe2 and hollow carbon microspheres@MoSe2/MoOx MCCs with various mixed-valence states content are well-designed and produced by a simple hydrothermal reaction or/and heat treatment process. The results reveal that the thermal treatment of hollow carbon microspheres@MoSe2 in Ar and Ar/H2 leads to the in situ formation of MoOx and multivalence state, respectively, and the enhanced content of Mo4+ in the designed MCCs greatly boosts their impedance matching characteristics, polarization, and conduction loss capacities, which lead to their evidently improved EM wave absorption properties. Amongst, the as-prepared hollow carbon microspheres@MoSe2/MoOx MCCs achieve an effective absorption bandwidth of 5.80 GHz under a matching thickness of 1.97 mm and minimum reflection loss of -21.49 dB. Therefore, this work offers a simple and universal method to fabricate core@shell hollow carbon microspheres@MoSe2/MoOx MCCs, and a novel and feasible metal valence state modulation strategy is proposed to develop high-efficiency MAMs.

8.
Nat Commun ; 15(1): 3278, 2024 Apr 16.
Artículo en Inglés | MEDLINE | ID: mdl-38627376

RESUMEN

Distinct skyrmion phases at room temperature hosted by one material offer additional degree of freedom for the design of topology-based compact and energetically-efficient spintronic devices. The field has been extended to low-dimensional magnets with the discovery of magnetism in two-dimensional van der Waals magnets. However, creating multiple skyrmion phases in 2D magnets, especially above room temperature, remains a major challenge. Here, we report the experimental observation of mixed-type skyrmions, exhibiting both Bloch and hybrid characteristics, in a room-temperature ferromagnet Fe3GaTe2. Analysis of the magnetic intensities under varied imaging conditions coupled with complementary simulations reveal that spontaneous Bloch skyrmions exist as the magnetic ground state with the coexistence of hybrid stripes domain, on account of the interplay between the dipolar interaction and the Dzyaloshinskii-Moriya interaction. Moreover, hybrid skyrmions are created and their coexisting phases with Bloch skyrmions exhibit considerably high thermostability, enduring up to 328 K. The findings open perspectives for 2D spintronic devices incorporating distinct skyrmion phases at room temperature.

9.
Adv Mater ; 36(24): e2313411, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38469974

RESUMEN

Precise manipulation of van der Waals forces within 2D atomic layers allows for exact control over electron-phonon coupling, leading to the exceptional quantum properties. However, applying this technique to diverse structures such as 3D materials is challenging. Therefore, investigating new hierarchical structures and different interlayer forces is crucial for overcoming these limitations and discovering novel physical properties. In this work, a multishelled ferromagnetic material with controllable shell numbers is developed. By strategically regulating the magnetic interactions between these shells, the magnetic properties of each shell are fine-tuned. This approach reveals distinctive magnetic characteristics including regulated magnetic domain configurations and enhanced effective fields. The nanoscale magnetic interactions between the shells are observed and analyzed, which shed light on the modified magnetic properties of each shell, enhancing the understanding and control of ferromagnetic materials. The distinctive magnetic interaction significantly boosts electromagnetic absorption at low-frequency frequencies used by fifth-generation wireless devices, outperforming ferromagnetic materials without multilayer structures by several folds. The application of magnetic interactions in materials science reveals thrilling prospects for technological and electronic innovation.

10.
Langmuir ; 40(11): 5731-5737, 2024 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-38452376

RESUMEN

Carbon layers-coated porous Co3O4/NiO (denoted as PCNO@C) chains are synthesized by the facile solvothermal method and subsequently annealing treatment under an Ar atmosphere, which are assembled from numerous Co3O4/NiO nanosheets. Benefiting from the unique porous chain structure, the volume change of the electrode is greatly relieved during the long-term cycling processes, and then an excellent cycling stability is obtained (the reversible specific capacity of the 1000th cycle can reach 637.3 mA h g-1 at 5000 mA g-1). Besides, a continuous conductive network is constructed by the coated carbon layers and long chains, the movement rate of electrons is effectively accelerated, and the high rate capability is obtained (the high reversible specific capacity of 480.6 mA h g-1 is retained at 10,000 mA g-1). This work contributes a new idea to construct porous chain structure anode materials.

11.
Nat Commun ; 15(1): 1295, 2024 Feb 12.
Artículo en Inglés | MEDLINE | ID: mdl-38346953

RESUMEN

Two-dimensional (2D) superlattices, formed by stacking sublattices of 2D materials, have emerged as a powerful platform for tailoring and enhancing material properties beyond their intrinsic characteristics. However, conventional synthesis methods are limited to pristine 2D material sublattices, posing a significant practical challenge when it comes to stacking chemically modified sublattices. Here we report a chemical synthesis method that overcomes this challenge by creating a unique 2D graphene superlattice, stacking graphene sublattices with monodisperse, nanometer-sized, square-shaped pores and strategically doped elements at the pore edges. The resulting graphene superlattice exhibits remarkable correlations between quantum phases at both the electron and phonon levels, leading to diverse functionalities, such as electromagnetic shielding, energy harvesting, optoelectronics, and thermoelectrics. Overall, our findings not only provide chemical design principles for synthesizing and understanding functional 2D superlattices but also expand their enhanced functionality and extensive application potential compared to their pristine counterparts.

12.
Nanomicro Lett ; 16(1): 66, 2024 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-38175333

RESUMEN

Polarization and conductance losses are the fundamental dielectric attenuation mechanisms for graphene-based absorbers, but it is not fully understood in revealing the loss mechanism of affect graphene itself. For the first time, the reduced graphene oxide (RGO) based absorbers are developed with regulatory absorption properties and the absorption mechanism of RGO is mainly originated from the carrier injection behavior of trace metal Fe nanosheets on graphene. Accordingly, the minimum reflection loss (RLmin) of Fe/RGO-2 composite reaches - 53.38 dB (2.45 mm), and the effective absorption bandwidth achieves 7.52 GHz (2.62 mm) with lower filling loading of 2 wt%. Using off-axis electron hologram testing combined with simulation calculation and carrier transport property experiments, we demonstrate here the carrier injection behavior from Fe to graphene at the interface and the induced charge accumulation and rearrangement, resulting in the increased interfacial and dipole polarization and the conductance loss. This work has confirmed that regulating the dielectric property of graphene itself by adding trace metals can not only ensure good impedance matching, but also fully exploit the dielectric loss ability of graphene at low filler content, which opens up an efficient way for designing lightweight absorbers and may be extended to other types materials.

13.
Adv Mater ; 36(18): e2311831, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38253422

RESUMEN

Controlling the multi-state switching is significantly essential for the extensive utilization of 2D ferromagnet in magnetic racetrack memories, topological devices, and neuromorphic computing devices. The development of all-electric functional nanodevices with multi-state switching and a rapid reset remains challenging. Herein, to imitate the potentiation and depression process of biological synapses, a full-current strategy is unprecedently established by the controllable resistance-state switching originating from the spin configuration rearrangement by domain wall number modulation in Fe3GeTe2. In particular, a strong correlation is uncovered in the reduction of domain wall number with the corresponding resistance decreasing by in-situ Lorentz transmission electron microscopy. Interestingly, the magnetic state is reversed instantly to the multi-domain wall state under a single pulse current with a higher amplitude, attributed to the rapid thermal demagnetization by simulation. Based on the neuromorphic computing system with full-current-driven artificial Fe3GeTe2 synapses with multi-state switching, a high accuracy of ≈91% is achieved in the handwriting image recognition pattern. The results identify 2D ferromagnet as an intriguing candidate for future advanced neuromorphic spintronics.

14.
Small ; 20(2): e2305625, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37658509

RESUMEN

Highly symmetrical and streamlined nanostructures possessing unique electron scattering, electron-phonon coupling, and electron confinement characteristics have attracted a lot of attention. However, the controllable synthesis of such a nanostructure with regulated shapes and sizes remains a huge challenge. In this work, a peanut-like MnO@C structure, assembled by two core-shell nanosphere is developed via a facile hydrogen ion concentration regulation strategy. Off-axis electron holography technique, charge reconstruction, and COMSOL Multiphysics simulation jointly reveal the unique electronic distribution and confirm its higher dielectric sensitive ability, which can be used as microwave absorption to deal with currently electromagnetic pollution. The results reveal that the peanut-like core-shell MnO@C exhibits great wideband properties with effective absorption bandwidth of 6.6 GHz, covering 10.8-17.2 GHz band. Inspired by this structure-induced sensitively dielectric behavior, promoting the development of symmetrical and streamlined nanostructure would be attractive for many other promising applications in the future, such as piezoelectric material and supercapacitor and electromagnetic shielding.

15.
Small ; 20(3): e2208135, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37587762

RESUMEN

High-efficiency electromagnetic (EM) wave (EMW)-absorbing materials have attracted extensive scientific and technical interest. Although identifying the dominant EM loss mechanism in dielectric-loss materials is indispensable, it is challenging due to a complex synergism between dipole/interfacial polarization and conduction loss. Modulation of defects and microstructures can be a possible approach to determine the dominant EM loss mechanism and realize high-efficiency absorption. Herein, 2D reduced graphene oxide (rGO) flakes are integrated into a 3D hollow bowl-like structure, which increases defect sites (i.e., oxygen vacancy and lattice defect) and reduces the stacked thickness of rGO. Despite their lower stacked thicknesses, the hollow rGO bowls with more defects exhibit lower conductivities but higher permittivities. Accompanied by the transformation from 2D flakes to 3D hollow bowls, the dominant EM loss mechanism of rGO transforms from conduction loss to defect-induced polarization. Furthermore, the defect engineering and structural design endow rGO with well-matched impedance and strong EMW-absorbing capacity. A minimum reflection loss of -41.6 dB (1.3 mm) and an effective absorption bandwidth of 4.8 GHz (1.5 mm) is achieved at a filler loading of 5 wt%. This study will provide meaningful insights into the development of materials with superior EMW-absorbing performances via defect engineering and structural design.

16.
J Colloid Interface Sci ; 657: 716-727, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38071820

RESUMEN

The ultrathin multi-nanolayered structure with ultrathin monolayer thickness (<10 nm) and certain interlayer spacing can significantly shorten Li+ paths and alleviate the volume effect for Li+-storage materials. However, unlike layered materials such as MXene and MoS2, shear ReO3-type niobates have difficulty forming ultrathin multi-nanolayered structures due to their crystal structures, which still remains a challenge. Herein, by a polyvinylpyrrolidone (PVP)-assisted solvothermal method, we first synthesize ultrathin multi-nanolayered Cu2Nb34O87-x with oxygen vacancies composed of ultrathin nanolayers (2-10 nm in thickness) and interlayer spacing (1-5 nm). Oxygen vacancies can radically enhance the inherent electronic/ionic conductivity and Li+ diffusion coefficient of this material. The PVP-induced formation mechanism of this material is expounded in detail. The well-preserved ultrathin multi-nanolayered structure and excellent multi-electron electrochemical reversibility (Nb5+ â†” Nb4+ â†”N b3+ and Cu2+ â†” Cu+) of this material during cycling are fully verified. Based on an ultrathin multi-nanolayered structure and oxygen vacancies, this material as the anode of lithium-ion batteries is highly competitive among reported shear ReO3-type Cu-Nb-O anodes, displaying a high reversible capacity (315.3 mAh g-1 after 300 cycles at 1 C), durable cycling stability (85.7 % capacity retention after 1000 cycles at 10 C), and outstanding rate performance. Moreover, the application of this material to lithium-ion capacitors generates a large energy density (97.9 Wh kg-1 at 87.5 W kg-1) and a high power density (17,500 W kg-1 at 12.6 Wh kg-1), thus further indicating its fast faradaic pseudocapacitive behavior for practical applications. The results of this work indicate a breakthrough in synthesizing ultrathin multi-nanolayered shear ReO3-type niobates.

17.
Small ; 20(16): e2308581, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38039500

RESUMEN

Structure engineering of magnetic-dielectric multi-components is emerging as an effective approach for presuming high-performance electromagnetic (EM) absorption, but still faces bottlenecks due to the ambiguous regulation mechanism of surface morphology. Here, a novel wrinkled surface structure is tailored on the ZnFe2O4 microsphere via a spray-pyrolysis induced Kirkendall diffusion effect, the conductivity of the sample is affected, and a better impedance matching is adjusted by modulating the concentration of metal nitrate precursors. Driven by a vapor phase polymerization, conductive polypyrrole (PPy) shell are in situ decorated on the ZnFe2O4 microsphere surfaces, ingeniously constructing a core-shell ZnFe2O4@PPy composites. Moreover, a systematic investigation reveals that this unique wrinkled surface structure is highly dependent on the metal salt concentration. Optimized wrinkle ZnFe2O4@PPy composite exhibits a minimum reflection loss (RLmin) reached -41.0 dB and the effective absorption bandwidth (EAB) can cover as wide as 4.1 GHz. The enhanced interfacial polarization originated from high-density ZnFe2O4-PPy heterostructure, and the conduction loss of PPy contributes to the boosted dielectric loss capability. This study gives a significant guidance for preparing high-performance EM composites by tailoring the surface wrinkle structure.

18.
ACS Nano ; 18(1): 560-570, 2024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-38109426

RESUMEN

Induced polarization response and integrated magnetic resonance show prosperous advantages in boosting electromagnetic wave absorption but still face huge challenges in revealing the intrinsic mechanism. In this work, we propose a self-confined strategy to construct hierarchical Fe-Co@TiO2 microrods with numerous incoherent heterointerfaces and gradient magnetic domains. The results demonstrate that the use of polyvinylpyrrolidone (PVP) coating is crucial for the subsequent deposition of Co-zeolitic imidazolate frameworks (ZIF-67), the distance of ordered arranged metal ions manipulates the size of magnetic domains, and the pyrolysis of PVP layers restricts the eutectic process of Fe-Co alloys to some extent. As a result, these introduced lattice defects, oxygen vacancies, and incoherent heterointerfaces inevitably generate a strong polarization response, and the regulated gradient magnetic domains realize integrated magnetic resonance, including macroscopic magnetic coupling, long-range magnetic diffraction, and nanoscale magnetic bridge connection, and both of the intrinsic mechanisms in dissipating electromagnetic energy are quantitatively clarified by Lorentz off-axis electron holography. Owing to the cooperative merits, the Fe-Co@TiO2 absorbents exhibit enhanced absorption intensity and strong absorption bandwidth. This study inspires us to develop a generalized strategy for manipulating the size of magnetic domains, and the integrated magnetic resonance theory provides a versatile methodology in clarifying magnetic loss mechanism.

19.
Nanomicro Lett ; 16(1): 42, 2023 Dec 04.
Artículo en Inglés | MEDLINE | ID: mdl-38047957

RESUMEN

Metal-organic gel (MOG) derived composites are promising multi-functional materials due to their alterable composition, identifiable chemical homogeneity, tunable shape, and porous structure. Herein, stable metal-organic hydrogels are prepared by regulating the complexation effect, solution polarity and curing speed. Meanwhile, collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination. Subsequently, two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect. FeCo/nitrogen-doped carbon (NC) aerogel demonstrates an ultra-strong microwave absorption of - 85 dB at an ultra-low loading of 5%. After reducing the time taken by atom shifting, a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained, which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles. Furthermore, both aerogels show excellent thermal insulation property, and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology. The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels, which will enable the development and application of novel and lightweight stealth coatings.

20.
Small ; : e2308192, 2023 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-38072794

RESUMEN

The single-atom sites (SAs) have achieved enhanced performance toward oxygen reduction reaction (ORR) with the effective utilization of the active sites. However, the excess adsorption of the intermediates and the limited stability hinders performance improvement. Metal clusters with promising stability and weak adsorption can be used as potential substitutions, but the lack of active sites is considered undesirable for catalytic reactions. Herein, a framework of Fe nanoclusters combined with SAs on One dimensional (1D) carbon nanotubes (Fe3 C-NCNTs 90 min CC-1 ) is synthesized to confirm the synergistic atom-cluster interaction. The composite exhibits strong polarization and electron redistribution between nanocluster and SAs. The electron redistribution will significantly boost the electron transport and the desorption of the intermediates, which is confirmed by off-axis holography and DFT calculation. The electrocatalytic performance is significantly enhanced as the half-wave potential of ORR increased 75 mV and the potential of OER increased 133 mV compared with the sample without nanoclusters. Furthermore, such a bifunctional catalyst endows homemade Zn-air batteries (ZABs) with high power density and long-term stability. This work paves a facile route to design bifunctional ORR/OER electrocatalysts consisting of 0D composite structures.

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