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•The proper impedance enables the material to efficiently allow the EM waves into its interior.•Aggregation state of PANI can influence the conductivity, dielectric and its wave ...absorption.•MS@PANI achieves ultra-low density and effective absorption of whole X-band EM waves.
In the field of electromagnetic (EM) wave absorption, intrinsic conductive polymers with conjugated long-chain structures, such as polyaniline (PANI) and polypyrrole (PPy), have gained widespread use due to their remarkable electrical conductivity and loss ability. However, current research in this area is limited to macroscopic descriptions of the absorption properties of these materials and the contribution of various components to the absorption effect. There has been insufficient exploration of the impact mechanisms of polymer aggregation states on the material's absorption performance and mechanism. To address this, a series of flexible PANI sponge absorbers with different molecular weights and aggregation states were prepared. By carefully controlling the crystallinity and other aggregation characteristics of PANI through the adjustment of its preparation conditions, we were able to influence its electrical conductivity and electromagnetic parameters, thereby achieving control over the material's absorption properties. The resulting PANI sponge absorbers exhibited an effective absorption bandwidth (EAB) that covered the entire X-band at a thickness of 3.2 mm. This study comprehensively explores the absorption mechanisms of conductive polymer absorbers, starting from the microstructure of PANI, and providing a more complete theoretical support for the research and promotion of polymer absorbers.
Photocatalytic treatment of antibiotics in aqueous ecosystems has become a promising method. However, the low efficiency photogenerated charge separation and slow kinetics of the catalyst severely ...limit its deployment for industrial applications. Here, the three-dimensional bismuth tungstate (Bi
2
WO
6
)/bismuth oxyiodide (BiOI) loaded on biochar (BC/BWI) composite catalyst was designed for the efficient removal of tetracycline (adsorption capacity: 227.09 mg g
−1
, removal rate: 99.8%).
Via
construction of Z-scheme heterojunctions at the interface of Bi
2
WO
6
and BiOI, the built-in electric field promotes the directional separation of photogenerated carriers to achieve efficient separation and utilization of photogenerated charges. Meanwhile, the introduction of electron-rich biochar (BC) effectively enhances the adsorption performance, photogenerated electron migration capacity and mass transfer process of the material. The introduction of BC and the building of Z-scheme heterojunctions effectively achieve the spatially synergistic separation of photogenerated charges. The &z.rad;O
2
−
dominates the photocatalytic process, according to the mechanistic studies. The degradation intermediate product testing revealed that tetracycline is efficiently degraded through two main pathways. This work provides ideas for the design of catalysts for the efficient removal of antibiotics from water bodies.
In the synthesized BC/BWI catalyst, the introduction of biochar and construction of Z-type heterojunctions accelerated the photogenerated carrier separation to reach an efficient removal of tetracycline.
All-solid-state sodium batteries (AS3B) emerged as a strong contender in the global electrochemical energy storage market as a replacement for current lithium-ion batteries (LIB) owing to their high ...abundance, low cost, high safety, high energy density, and long calendar life. Inorganic electrolytes (IEs) are highly preferred over the conventional liquid and solid polymer electrolytes for sodium-ion batteries (SIBs) due to their high ionic conductivity (∼10-2-10-4 S cm-1), wide potential window (∼5 V), and overall better battery performances. This review discusses the bird's eye view of the recent progress in inorganic electrolytes such as Na-β"-alumina, NASICON, sulfides, antipervoskites, borohydride-type electrolytes, etc. for AS3Bs. Current state-of-the-art inorganic electrolytes in correlation with their ionic conduction mechanism present challenges and interfacial characteristics that have been critically reviewed in this review. The current challenges associated with the present battery configuration are overlooked, and also the chemical and electrochemical stabilities are emphasized. The substantial solution based on ongoing electrolyte development and promising modification strategies are also suggested.All-solid-state sodium batteries (AS3B) emerged as a strong contender in the global electrochemical energy storage market as a replacement for current lithium-ion batteries (LIB) owing to their high abundance, low cost, high safety, high energy density, and long calendar life. Inorganic electrolytes (IEs) are highly preferred over the conventional liquid and solid polymer electrolytes for sodium-ion batteries (SIBs) due to their high ionic conductivity (∼10-2-10-4 S cm-1), wide potential window (∼5 V), and overall better battery performances. This review discusses the bird's eye view of the recent progress in inorganic electrolytes such as Na-β"-alumina, NASICON, sulfides, antipervoskites, borohydride-type electrolytes, etc. for AS3Bs. Current state-of-the-art inorganic electrolytes in correlation with their ionic conduction mechanism present challenges and interfacial characteristics that have been critically reviewed in this review. The current challenges associated with the present battery configuration are overlooked, and also the chemical and electrochemical stabilities are emphasized. The substantial solution based on ongoing electrolyte development and promising modification strategies are also suggested.
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Deleterious volumetric expansion and poor electrical conductivity seriously hinder the application of Si-based anode materials in lithium-ion batteries (LIBs). Herein, boron-doped ...three-dimensional (3D) porous carbon framework/carbon shell encapsulated silicon (B-3DCF/Si@C) hybrid composites are successfully prepared by two coating and thermal treatment processes. The presence of 3D porous carbon skeleton and carbon shell effectively improves the mechanical properties of the B-3DCF/Si@C electrode during the cycling process, ensures the stability of the electrical contacts of the silicon particles and stabilizes the solid electrolyte interface (SEI) layer, thus enhancing the electronic conductivity and ion migration efficiency of the anode. The developed B-3DCF/Si@C anode has a high reversible capacity, excellent cycling stability and outstanding rate performance. A reversible capacity of 1288.5 mAh/g is maintained after 600 cycles at a current density of 400 mA g−1. The improved electrochemical performance is demonstrated in a full cell using a LiFePO4-based cathode. This study presents a novel approach that not only mitigates the large volume expansion effects in LIB anode materials, but also provides a reference model for the preparation of porous composites with various functionalities.
Compared with traditional injection foaming, co-injection foaming serves as a method to prepare products with high-quality surfaces and enhanced mechanical properties, demonstrating excellent ...technical advantages and economic benefits. The effects of high-density polyethylene (HDPE) content, foaming agent content, melting temperature of core material, and nano-organic montmorillonite (OMMT) content on the cell structure, mechanical properties, and crystallization behavior of isotactic polypropylene (iPP)/HDPE composite foam prepared by co-injection foaming were systematically studied. At a foaming agent content of 2 wt.%, HDPE content of 30 wt.%, OMMT content of 3 wt.%, and the melting temperature of core material of 190 °C, the composite foam exhibited a cell size measuring 85 μm, a cell density of 2.5 × 105 cells/cm3, a tensile strength of 25.8 MPa, and an impact strength of 12.5 kJ/m2. The addition of HDPE reduced the crystallinity of iPP matrix, while enhancing the solubility of carbon dioxide within the matrix. The non-miscible interface between HDPE and iPP helped reduce the energy barrier for cell nucleation. Furthermore, the introduction of OMMT as a nucleating agent in iPP/HDPE composite material dramatically decreased the energy barrier for cell nucleation. These synergistic effects result in foam with the smaller cell size and the higher cell density, exhibiting excellent comprehensive mechanical properties. This work provides a feasible method for preparing composite foam with excellent comprehensive performance.
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•The addition of HDPE reduced the crystallinity of iPP matrix, while enhancing the solubility of CO2 within the matrix.•The non-miscible interface between HDPE and iPP helped reduce the energy barrier of cell nucleation.•The introduction of OMMT in iPP/HDPE composite material dramatically reduced the energy barrier of cell nucleation.
The high density, high cost, and environmental pollution hinder the application of iron-based electromagnetic wave-absorbing materials. Although bio-carbon is a green and lightweight dielectric ...wave-absorbing material, the wave-absorbing performance of bio-carbon is still limited. This work successfully combined magnetite Fe3O4 with porous carbon derived from spinach stem using hydrothermal and calcination methods. This process optimizes the matching of the dielectric constant and magnetoconductivity of the as prepared composite material, resulting in a significant improvement in electromagnetic microwave absorption capacity. XRD, SEM, TEM, XPS, VSM and EMW absorption network analyzer are used to detect and characterize the samples. The composite material shows a excellent minimum reflection loss value of −48.81 dB and an efficacious absorption bandwidth of 4.73 GHz at the optimal raw material ratio. The tests also show the porous structure of the sample with the coercivity and saturation magnetization of 29.36 Oe and 10.75 emu/g, respectively. The test results indicate that the excellent electromagnetic wave absorption is due to the synergistic effect of multiple reflection, Debye relaxation, and interfacial polarization. This Fe3O4-bio-carbon composite is cheap and simple to prepare, and it also has excellent wave absorption performance. Therefore, it shows great application potential in civilian and military electromagnetic wave absorption fields.
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•A Fe3O4 and spinach stems-derived carbon composite was prepared.•The composites show excellent wave absorption properties.•The minimal RL value of −48.81 dB and bandwidth of 4.77 GHz were observed.
Present review emphatically introduces the synthesis, biocompatibility, and applications of silver nanoparticles (AgNPs), including their antibacterial, antimicrobial, and antifungal properties. A ...comprehensive discussion of various synthesis methods for AgNPs, with a particular focus on green chemistry mediated by plant extracts has been made. Recent research has revealed that the optical properties of AgNPs, including surface plasmon resonance (SPR), depend on the particle size, as well as the synthesis methods, preparation synthesis parameters, and used reducing agents. The significant emphasis on the use of synthesized AgNPs as antibacterial, antimicrobial, and antifungal agents in various applications has been reviewed. Furthermore, the application areas have been thoroughly examined, providing a detailed discussion of the underlying mechanisms, which aids in determining the optimal control parameters during the synthesis process of AgNPs. Furthermore, the challenges encountered while utilizing AgNPs and the corresponding advancements to overcome them have also been addressed. This review not only summarizes the achievements and current status of plant-mediated green synthesis of AgNPs but also explores the future prospects of these materials and technology in diverse areas, including bioactive applications.
To enhance the anticorrosive performance of coatings in harsh corrosive environments, a graphene/isophorone diisocyanate (IPDI) microcapsule is prepared by in-situ polymerization. The self-healing ...and anticorrosive performance of coatings based on these microcapsules are studied. The microcapsule with cross-linked shells prepared in this study solves the problems of excessive size and insufficient strength of traditional microcapsules. The addition of microcapsules improves the anticorrosive performance of coatings. The shape of the microcapsules is in the form of round balls, and the average particle size and thickness of the microcapsules are in the range of 17–23 μm and 0.5–3.4 μm, which are conducive to the preparation of the coatings. The average strength of microcapsules is 20.64 MPa and the wrap-around rate reaches 68%. The microcapsules have an initial evaporation temperature of 231.3 °C, the graphene organic cross-linking shell enhances the strength and improves the thermal stability of microcapsules. The electrochemical impedance spectroscopy (EIS) indicates that the |Z|f=0.01 Hz value of the coating with 10 wt% of microcapsule after 168 h of immersion is about 9.4 × 109 Ω cm2, nearly three orders of magnitude higher than that of the coating without microcapsule (6.9 × 106 Ω cm2). Monitoring the artificial scratches of coating using a scanning electron microscope (SEM) for 24 h reveals that the microcapsule repairs the cracks well. It is demonstrated that the incorporation of graphene/IPDI microcapsules improves the anti-corrosive performance of the coating.
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•Graphene organic crosslinked shell microcapsules were synthesized by in situ polymerization.•The wall thickness was controlled by graphene to achieve a uniform particle size distribution.•Organic crosslinked shells provided a certain degree of strength and enhanced thermal stability.•The addition of microcapsules to the coating showed a significant repair effect at 24 h of scratching.•After 720 h of salt spray, the microcapsule coating remained uncorroded.
This study investigates the oxidation behavior and microstructure characterization of C‐HRA‐5 (i.e., a new austenitic heat‐resistant steel) in the air at temperatures ranging from 650 to 750 °C over ...a 1000‐hour duration. The oxidation behavior and mechanism are analyzed using gravimetric evaluation, thermodynamic analysis, microscopic morphology, and microstructure characterization. The results indicate that the oxidation behavior follows a parabolic law at each temperature. With increasing temperature, the oxide film gradually grows and transforms from small lump particles to strips and needles, eventually covering the entire substrate surface over time. Moreover, long‐term oxidation exposure promotes the formation of various phases, including M23C6, σ, MX, Z, nanosized Cu‐rich, and Laves phases, within the metallic substrate. Considering potential applications in new‐generation power plants, this study provides a solid foundation to disclose the possible oxidation of C‐HRA‐5 austenitic heat‐resistant steel at high temperatures.
Isothermal oxidation of the austenitic heat‐resistant steel C‐HRA‐5 (a new austenitic heat‐resistant steel) conforms to the parabolic weight gains. This study provides a solid foundation to disclose the possible oxidation of C‐HRA‐5 austenitic heat‐resistant steel at high temperatures