Exploring the synergistic effects of components and structures has emerged as a pivotal strategy for advancing high-performance electromagnetic wave (EMW) absorbing materials. In this work, we present an approach that integrates magnetic-dielectric components and porous structures by incorporating unidirectionally frozen-drying aramid nanofiber aerogels with ZIF-67 and subsequently preparing Co/Co3O4@carbon nanotubes/carbon nanofibers aerogels through heat treatment and catalyst chemical vapor deposition. By combining different functional components, a multiple heterostructure with excellent absorption capacity, wide effective absorption bandwidth (EAB), and thin thickness can be achieved. The inclusion of the magnetic-dielectric component significantly enhances the impedance matching, generating multiple loss mechanisms. Additionally, the threedimensional porous structure of the aerogel facilitates multiple reflections and scattering of the incident EMWs, thereby enhancing the microwave absorption. Specifically, the obtained samples exhibit outstanding EMW performance, with a minimum reflection loss of -73.50 dB at a thickness of merely 2.08 mm and an EAB of 5.90 GHz. Furthermore, simulations evaluating radar cross-section values, electric field strengths, and energy loss density are conducted to assess the stealth capabilities under radar detection. This study culminates in the preparation of an aerogel characterized by excellent wave-absorbing properties and effective thermal insulation, offering vast potential for practical applications.

The novel fabrication of multiple components and unique heterostructure can inject infinite vitality into the electromagnetic wave (EMW) attenuation field. Herein, through the self-assembly of polyimide complexes and catalytic chemical vapor deposition, porous carbon microflowers were synthesized accompanied by carbon nanotubes (CNTs). By regulating the metal ions, the composition and structure of the as-obtained hybrids are modified correspondingly, and thus the adjustable thermal management and EMW absorption capabilities are obtained. In detail, the rich pores and huge specific surface area endow the hierarchical structures with distinguished thermal insulation ability (lambda<0.07). The carbon framework and CNTs are beneficial for consuming EMWs via conductive loss and defect polarization loss while reducing the filling ratio and thickness. The doped heteroatoms and abundant heterointerfaces generate ample dipole polarization and interface polarization losses (supported by DFT calculation). The metal nanoparticles uniformly embedded in the carbon framework offer optimized impedance matching, proper defect polarization, and suitable magnetic loss. Accordingly, the synergy of magnetic-dielectric balance and flower-like superstructure enables FNCFN2 and NNCFN2 to accomplish remarkable microwave absorbing capacity with thin thickness (14 wt.%). Therefore, respectable specific reflection loss and specific effective absorption bandwidth are acquired (215.39 dB mm(-1) and 22.10 GHz mm(-1), 257.23 dB mm(-1) and 22.12 GHz mm(-1) respectively), superior to those of certain renowned carbon-based absorbers. The simulation results of electric field intensity distributions, power loss density, and radar cross section reduction (maximum value of 36.02 dBm(2)) also verify the prominent radar stealth capability. Moreover, the customizable approach can be applied to other metals to obtain fulfilling behaviors. Henceforth, this work provides profound insights into the relationship between structure and performance, and proposes an efficient path for mass-producing multifunctional and high-performance EMW absorbers with excellent thermal properties. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Carbon-based electromagnetic wave (EMW) absorbing materials attached with metal sulfides famous for good dielectric properties are favored by researchers, which can form heterogeneous interfaces and thus provide supplementary loss mechanisms to make up for the deficiencies of a single material in energy attenuation. Here, Co9S8/Co@coral-like carbon nanofibers (CNFs)/porous carbon hybrids are successfully fabricated by hydrothermal and chemical vapor deposition. The samples have exceptional EMW absorbing properties, with a minimum reflection loss of −57.48 dB at a thickness of 2.94 mm and an effective absorption bandwidth of up to 6.10 GHz at only 2.20 mm. The interlocking structure formed by Co@coral-like CNFs, interfacial polarization generated by heterostructure of Co9S8, abundant defects and large specific surface area resulted from porous properties are important factors in attaining magnetic-dielectric balance and excellent absorption performance. Different matrixes are selected instead of paraffin to investigate the effect of matrix materials on EMW absorbing capacity. Besides, the EMW attenuation potential for practical applications is also demonstrated by radar cross-section simulations, electric field intensity distribution and power loss density. This work provides a novel strategy for designing outstanding EMW absorbers with unique microstructures using facile and low-cost synthetic routes.

Carbon aerogels have revolutionized the design of advanced electromagnetic wave absorbers by offering low density, multi-functionality, and versatility. However, traditional carbon aerogels face limitation due to their high electrical conductivity and reliance on single loss mechanism, which hinders their widespread applications. To overcome these challenges, a series of multilayered hierarchical CoNi/bamboo-like carbon nanotubes (BCNTs)/carbon nanofiber (CNFs) aerogels are prepared using directional freeze-drying, hydrothermal methods, and catalytic chemical vapor deposition. The effects of layer spacing and thermal growth on the microwave absorption properties of the hybrids are investigated by varying the content of aramid nanofibers and growth temperature. The synergistic effect of dielectric and magnetic loss optimizes the electromagnetic parameters and impedance matching of the samples, which obtains an optimal minimum reflection loss of-80.30 dB at only 2.07 mm. Furthermore, the composite aerogel demonstrates an ultra-wide effective absorption bandwidth of 6.60 GHz at 2.28 mm. The practical application capabilities of the samples are evaluated through theoretical analysis. Besides, the as-prepared aerogels exhibit excellent thermal insulation properties and the ability to adsorb light oils. This study presents an attractive strategy for fabricating CoNi/BCNTs-modified carbon aerogel absorbers, which hold great promise for applications in electromagnetic protection and thermal management devices.

The article presents a new method for constructing self-supporting surfaces using arch beams that are designed to convert their thrust into supporting force, thereby eliminating shear stress and bending moments. Our method allows for the placement of the arch beams on the boundary or within a surface and partitions the surface into multiple self-supporting parts. The use of arch beams enhances stability and durability, adds aesthetic appeal, and allows for greater flexibility in the design process. We develop an iterative algorithm for designing self-supporting surfaces with arch beams that enables the user to control the shape of the beams and surface through intuitive parameters and specify the desired location of the arch beams. We verify the physical stability of the structure using finite element analysis. Experimental results show that our method can produce visually pleasing self-supporting surfaces that satisfy the equilibrium equation with high accuracy.

Multifunctional carbon aerogels have garnered significant attention due to their promising applications in thermal insulation and electromagnetic wave (EMW) absorption. In this study, MIL-88C/CuCo2S4 composite powders were self-assembled and anchored onto the aerogel framework, followed by the deposition of carbon nanotubes (CNTs) via catalytic chemical vapor deposition, yielding MIL-88C/CuCo2S4-derived bamboo-like CNTs/carbon nanofiber aerogels (FCC@CC series). By modulating component loading ratios, the formation of a three-dimensional conduction network, the presence of heterogeneous interfaces, enhanced magnetic loss, and engineered defects synergistically optimized dielectric and magnetic loss. This adjustment improved the impedance matching of the composite carbon aerogel, resulting in exceptional EMW absorption performance. The FCC@CC2 sample achieved a minimum reflection loss of-71.15 dB and an effective absorption bandwidth of 6.10 GHz. CST simulations further demonstrated the practical applicability, showing a maximum radar cross-section reduction of 34.92 dBm2. Power loss density and electric field distribution analyses corroborated the superior electromagnetic attenuation capabilities of the FCC@CC. This work establishes a methodology for developing lightweight multifunctional aerogels with pressure resistance, thermal insulation, and infrared stealth properties, providing a novel strategy for the fabrication of microwave absorbers for use under complex conditions.

The present study provides a facile one-pot pyrolysis strategy to prepare serial nitrogen-doped (N-doped) metal/carbon composites derived from six types of metal ethylenediaminetetraacetic acid (EDTA-M, M = Co, Cu, Mn, Fe, Mg, and Ca). N-doped Co/C composite integrated carbonaceous with magnetic components to attain dielectric-magnetic double loss mechanisms. The minimum reflection loss and effective absorption bandwidth reached -57.6 dB at 1.75 mm and 4.64 GHz at 1.52 mm, respectively. The electromagnetic simulation further confirms that the dissipation ability increases with the improvement of carbonization temperature. Results show that altering the metal species of precursors can significantly improve the electrochemical performance of the composites using the identical strategy. N-doped Cu/C composite performed a maximum specific capacitance of 2383.3 F g-1 at 0.5 A g-1-1, and maintained 86.3% cycling stability at 20 A g-1 after 5000 cycles. The energy density of a symmetrical two-electrode configuration achieved 350.13 Wh kg-1 at a power density of 4000.04 W kg-1. Density functional theory calculations indicate that nitrogen dopants cause faster ion transport and stronger adsorption capacity. Moreover, the bifunctionality of other composites types are also systematically characterized. Serial nitrogen-doped (N-doped) metal/carbon composites can perform adjustable performance by simply changing precursor type. N-doped Co/C composites are used for electromagnetic wave absorption. Electromagnetic simulations confirm the effects of pyrolysis temperature on dissipation ability and the variation of interface polarization with frequency. N-doped Cu/C composites deliver good electrochemical performance with the assistance of density functional theory calculations. image

The catalytic process of Li 2 S formation is considered a key pathway to enhance the kinetics of lithium-sulfur batteries. Due to the system‘s complexity, the catalytic behavior is uncertain, posing significant challenges for predicting activity. Herein, we report a novel cascaded dual-cavity nanoreactor (NiCo−B) by controlling reaction kinetics, providing an opportunity for achieving hierarchical catalytic behavior. Through experimental and theoretical analysis, the multilevel structure can effectively suppress polysulfides dissolution and accelerate sulfur conversion. Furthermore, we differentiate the adsorption (B−S) and catalytic effect (Co−S) in NiCo−B, avoiding catalyst deactivation caused by excessive adsorption. As a result, the as-prepared battery displays high reversible capacity, even with sulfur loading of 13.2 mg cm −2 (E/S=4 μl mg −1 ), the areal capacity can reach 18.7 mAh cm −2 .

Carbon fiber (CF) has emerged as a promising candidate for microwave absorbers to resolve the escalating electromagnetic wave (EMW) pollution issue, not just serving as a structural reinforcement. However, the drawbacks, such as high conductivity, limit its ability to strongly absorb EMWs over a wide bandwidth. To address these challenges, graphite wrapped FeNi3/Co with carbon nanotubes (CNTs) anchored on MgO@CF heterostructures were synthesized by introducing MgO nanofilms on a CF surface and subsequent chemical vapor deposition catalyzed by two-phase catalysts. The synthesis of MgO suppresses the etching of CF during the experimental processes, effectively maintaining the inherent structure of CF, which is conducive to constructing rich conductive networks and developing excellent mechanical properties. By modulating the catalyst concentration, deposited CNTs with appropriate defects increase the conduction loss and stimulate defect polarization loss. The abundant interfaces formed by multiple components lead to fulfilling interface polarization, while the doping of O heteroatoms causes dipole polarization. In addition, the introduction of FeNi3/Co generates effective magnetic loss and optimizes electromagnetic parameters to form more matching impedance conditions. At a low filler loading of 23 wt%, the stable sample obtains a remarkable minimum reflection loss of up to - 72.08 dB at merely 1.38 mm with an effective absorption bandwidth reaching 4.88 GHz at only 1.44 mm, which is superior to that of numerous distinguished carbon-based composites in regard to being "thin, light, wide and strong". CST simulation reveals that the maximum radar cross section reduction acquires 26.88 dBm(2), ascertaining the radar stealth capability of the distinctive heterostructure. Moreover, great mechanical and electromagnetic interference shielding performance is demonstrated by epoxy composites. Henceforth, this study proposes profound insights into the intricate relationship between the structure and EMW absorbing mechanism, and elucidates an attractive strategy for mass-producing modified CF-based hybrids for versatile applications.

Enormous endeavors have been made to cope with microwave pollution and energy crisis. Here, porous nitrogen-doped C/TiO2 composites with absorption/shielding/supercapacitor functions were derived from MXene/polyaniline. It was discovered that KOH acted as porogen and had an etching–bridging–reaction effect during the activation process. As a microwave absorber, the composite/paraffin with a filler loading of 16 wt% reaches a minimum reflection loss of −52.8 dB and an effective absorption bandwidth of 4.72 GHz. Moreover, microwave absorption can be maintained within 45 days in air. Compared with untreated MXene, the absorber shows long-term functional stability in an oxygen-containing environment. As for electromagnetic interference shielding, the composite/paraffin at a filler loading of 50 wt% achieves 30.5 dB from 8.0 to 12.4 GHz. Additionally, the heterostructure delivers a desirable specific capacitance of 1,096.3 F g−1 at 0.5 A g−1. The trifunctional characteristics enrich the application trials of MXene derivatives and satisfy the strong need for versatile materials.

To investigate the failure characteristics of jointed rock masses in cold regions after freeze–thaw (F-T) cycles, uniaxial compressive tests are conducted on rock-like specimens (a type of cement mortar) with prefabricated arc-shape flaws subjected to 0, 25, 50 and 100F-T cycles to determine their mechanical properties. Test results reveal that F-T cycles greatly affect the uniaxial compressive strengths (UCS) of the specimens, and the relationship between the peak strength and the number of freeze–thaw cycles is exponentially fitted. Notably, the initial 50 cycles have a more pronounced effect on UCS reduction compared to the subsequent 50 cycles, indicating that early F-T cycles are more detrimental to UCS. To further investigate the failure mechanism of the specimens, two-dimensional particle flow code (PFC2D) is utilized to simulate the F-T cycle process of the specimens. The mechanical properties and failure mechanism of specimens can be obtained after F-T cycles under uniaxial compression through numerical simulations. The findings indicate that F-T cycles can obviously deteriorate the ductility of the specimens, and to some extent, they also affect crack propagation during specimen failures. Through crack classification statistics and stress contour analysis of the simulated specimens, it reveals that different prefabricated flaw morphologies lead to distinct stress distributions, subsequently affecting crack propagation and specimen failure. It is also worth mentioning that the large curvature and inclination angle of the flaws may generate additional tensile and shear stress zones at the top of the flaw vault, which in turn may contribute to the development of crack propagation. The relevant experimental and numerical results are useful for investigating mechanical properties and failure mechanisms of rock masses in cold regions subjected to F-T cycles.

Sediment transport serves as a link for material exchange between land and sea. Using sediment traps, we can observe the capture and transport processes of sediments. Based on the sediment particle size distribution characteristics in Jiaozhou Bay, this paper analyzes the influence of a newly designed 3D sediment trap on the water–sand two-phase flow process inside and outside a trap device during its operation. Meanwhile, under a certain concentration condition, a numerical formula model is researched and proposed to evaluate the impact of the device’s structure, the environmental flow speed, and the particle size on particle capture efficiency. This model is based on the CFD-DPM coupling in Fluent 2021R1 software, and the particle filtration process is solved using a combination of porous media and UDF functions. Finally, by analyzing the distribution of sediment movement in the fluid domain, two concepts, namely the percentage of particles entering the tube and the effective capture rate, are proposed. Suggestions for optimizing the structure of the trap are put forward to achieve optimal capture effects.

Ultra-flexible and stretchable organic photodetectors (s-OPDs) sensitive in the near-infrared (NIR) region hold great potential for wearable health monitoring with excellent physiological signal and skin conformability. However, the development of OPDs that combines NIR sensitivity, low power consumption, low cost, simple fabrication structure, and good mechanical properties is still challenging and has not been well explored. In this work, we report a self-powered s-OPD with a simple fabrication structure used for organic solar cells and a detectivity of more than 1 × 1012 Jones (corrected by noise current) in the NIR region at 10% tensile strain and short response time (2.46 μs), representing state-of-the-art performances. Reducing energetic disorders other than discrete traps in photoactive layers is more crucial to further reduce the dark current at zero bias. The dark current of the OPDs exhibits higher mechanical stability than photocurrent due to the slower degradation of the parallel resistance than the series resistance under tensile strain. The higher stability of dark current enables the s-OPDs as a stretchable organic photoplethysmogram heart rate sensor, showing excellent detectivity under 30% strain or 800 stretching–release cycles at 10% strain, indicating the great potential for application in wearable optoelectronics.

Hydrogen recirculation systems (HRSs) are vital components of proton exchange membrane fuel cells (PEMFCs), and it is necessary to investigate different HRS schemes to meet the needs of high-power PEMFCs. PEMFCs are developing in the direction of low cost, high power, wide working conditions, low noise, compact structure, etc. Currently, it is difficult for hydrogen recirculation pumps (HRPs) to meet the flow requirements of high-power PEMFCs. HRPs inevitably have high parasitic energy consumption, loud noise output, high cost, easy leakage, and high failure rates. Therefore, it is necessary to study different HRS schemes to develop a better solution for high-power PEMFCs. In this study, the functional prototype of a piping and instrumentation diagram (P&ID) based on three HRSs of HRPs was designed, and a functional prototype was built. Working according to the analysis and comparison of PEMFC performance test data, we find that the net power trend of PEMFC systems using three different HRS technology schemes is consistent. The ejector scheme and the combination scheme do not reduce the performance of PEMFCs and have advantages in different power ranges, such as 24 A, 48 A, and other small current points. The PEFMC system net power order is as follows: ejector scheme > HRP scheme > combination scheme. At about 120 A, the net power outputs of the three HRS schemes in the PEMFC system coincide. From around 180 A onwards, the PEMFC system power of the combined HRS scheme gradually dominates. At 320 A, the PEFMC system net power order is as follows: combined HRS scheme > HRP scheme > ejector scheme.

Photo-thermal catalytic (PTC) degradation as an ideal candidate for wastewater treatment is yet suffering from the unsatisfied recyclability due to the thermal effect-exacerbated serious photocorrosion of semiconductorbased catalysts. Based on polymeric graphite carbon nitride (g-C3N4) hybridized with antioxidative hexagonal boron nitride (h-BN) and grafted with stable Au nanoparticles (NPs), we provide thermostable g-C3N4/h-BN/Au nano-catalysts for high-efficient degradation of organic dyes at solar-activated heating condition. The fantastic PTC activity with optimal degradation rate up to - 0.30 min-1 is far better than most mainstream hybrid catalysts. The unprecedented thermal recyclability is convincingly verified by consecutive 10 repeated tests within 500 min measurements under solar-driven heating condition (-60 degrees C), wherein the negligible drop of degradation efficiency is only - 0.2% lower than pristine one. The ingenious self-floating PTC membranes can be conveniently established by immobilizing the resultant nano-catalysts into bio-carbon porous frames and viscous bacterial nano-celluloses, facilitating practical wastewater decontamination in real-world scenarios.

Based on hydrogen peroxide (H2O2)-modified bacterial nanocelluloses (BNCs(M)), we report in-situ overgrowth of highly dense plasmonic Au nanoparticles (NPs) on these filamentous three-dimensional (3D) supports by an ingenious "green" photochemical strategy. The measured relative atomic ratio of Au element in the resultant BNCs(M)@Au NPs is similar to 13 times higher than that formed on pristine BNCs. The BNCs(M)@Au NPs exhibit a higher surface-enhanced Raman scattering spectroscopy (SERS) activity than the reference BNCs@Au NPs. The flexible SERS biosensors enable the label-free detection limit of glucose molecules to be achieved as low as 10(-10) M, surpassing many reports in previous works and then facilitating the ultrasensitive evaluation of glucose metallic diseases.

The upgrading of ethanol to produce n-butanol and other >C-4 alcohols is a promising reaction. However, the development of efficient catalysts for this reaction has been slow. In this study, we prepared a series of Pd@UiO66-X catalysts using ligands functionalized with electron-donating groups (-NH2 and -CH3) and electronaccepting groups (-H and -NO2). These functional groups play two roles in mediating the microenvironment of the Pd metal. Firstly, they regulate the electronic properties of the Pd metal, and secondly, they alter the hydrophilicity/hydrophobicity surrounding the Pd metal. The intrinsic electronic properties of the Pd metal significantly influence ethanol conversion, while the hydrophilicity/hydrophobicity surrounding the Pd metal is an extrinsic factor. As a result, the Pd@UiO-66-CH(3 )catalyst with a hydrophobic microenvironment around the electron-rich Pd metal exhibits the highest ethanol conversion and n-butanol yield among all the Pd@UiO-66-X catalysts. It also achieves an impressive >C-4 alcohols yield of up to 47.7 %, which is the highest reported to date.

Exploring carbon materials is promising for innovative electromagnetic wave (EMW) absorption materials, nevertheless challenged by balancing efficient EMW absorption and continuous large-scale fabrication. In this work, CNTs/CNFs@CF with inimitable 3D network hierarchical structures are fabricated as EMW absorbers via the chemical vapor deposition method. Through detailed characterization of its morphology, structure, composition, and magnetic properties, the material obtained optimal electromagnetism parameters and showed exceptional EMW absorption performance. Herein, the minimum reflection loss (RLmin) was -66.00 dB at 1.00 mm and the maximum effective absorption bandwidth of 4.48 GHz was obtained at 1.29 mm. In addition, good mechanical properties with a single-filament tensile strength of 4.99 GPa were achieved, thereby expanding the range of applications. Undoubtedly, CNTs/CNFs@CF realizes the synergy of multiple synergistic loss mechanisms and impedance matching for EMW absorption. In summary, this implies a good prospect for the continuous large-scale preparation of ultrathin and efficient EMW absorbers.

Refining the electromagnetic wave absorption characteristics of traditional metal-organic framework (MOF)-derived carbon composites remains a challenge because of their discontinuous conductive path. To overcome this limitation, in this work, MOF-derived hierarchical Cu9S5/C nanocomposite fibers are fabricated by electrospinning and subsequent carbonization-sulfurization process. Morphological analyses show that MOF-derived octahedral Cu9S5/C particles are evenly monodispersed inside carbonaceous fibers. This configuration creates a unique hierarchical structure, ranging from Cu(9)S(5 )particle embedding, MOF-derived skeleton, to a three-dimensional network. The optimized composite fibers (Cu9S5/C-40) exhibit extraordinary electromagnetic wave absorption performance at a low mass fraction (20 wt%): the minimum reflection loss value reaches - 69.6 dB, and the maximum effective absorption bandwidth achieves 5.81 GHz with an extremely thin thickness of only 1.83 mm. Systematic investigations demonstrate that constructing the three-dimensional conductive network to connect MOF derivatives is crucial for activating performance enhancement. The unique nano-micro hierarchical structure synergized with elaborate-configured components endows the materials with optimal impedance matching and amplifies the loss capacity of each part. This work provides a reliable example and theoretical guidance for fabricating new-generation high-efficiency MOF-derived fibrous electromagnetic wave absorbers.

Morphological engineering is crucial for conceiving high-efficiency electromagnetic wave (EMW) absorption materials. However, for carbon fiber-based composites, the management of micromorphology is significantly astricted by complex fabrication. It remains highly challenging to clarify the micromorphological influences on the EMW loss mechanism of carbon fiber-based absorption materials. In this work, micromorphology-optimized Cu/C nanocomposite fibers are prepared by virtue of a metal-organic framework (MOF) template-assisted strategy. Through skillfully grafting the morphology-regulation capacity of MOFs onto composite fibers, the Oswald maturation and particle distribution issues of Cu nanoparticles are settled, and the efficient electron transport pathways are established by the bead-like structure of the fiber matrix. Compared to prepared conventional Cu/C nanocomposite fibers, the MOF template-assisted strategy stimulates a remarkable leap in EMW absorption performance. The minimum reflection loss value of Cu/C-40 can reach -64.5 dB, 15.96 times lower than that of a conventional sample (Cu/C-2). The maximum effective absorption bandwidth extends to 6.08 GHz, contrasting the ineffective performance of Cu/C-2. Systematic research demonstrates that the enabled graphite-catalytic function of Cu nanoparticles collaborated with an optimized conductive network structure plays a pivotal role in creating field-induced leakage currents, facilitating conductive loss, the primary contributor to EMW dissipation. This work establishes a correlation mechanism between micromorphology and EMW loss, presenting a compelling example of customizable carbon fiber-based absorbers.