PROPELLANTS EXPLOSIVES PYROTECHNICS
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2025
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IF 2
Bo Hao,Zhitao Dong,Yuxiang Cui,Geng Chen,Yuangen Lu
This study aims to enhance the combustion reproducibility and stability of tungsten-based delay compositions, focusing on a basic formula with the composition W/BaCrO 4 /KClO 4 (38%/52%/10%). Relevant experiments were conducted to analyze the combustion characteristics by adding calcium fluoride (CaF 2 ) to the composition. Seven tungsten-based delay compositions with varying calcium fluoride concentrations were prepared to examine the effects of this additive on combustion characteristics. In the experiment, the combustion rate was first tested, and the formula exhibiting the best combustion reproducibility and stability was selected. The microstructure of the optimal formulation sample was observed using scanning electron microscopy with energy dispersive spectroscopy, and the combustion product composition was analyzed with an x-ray diffractometer; Thermal analysis was performed on all formulations to investigate their thermal behavior. The experimental results indicated that a calcium fluoride content of 16% yielded the optimal combustion reproducibility and stability. Different formulations offered a wider adjustable range for combustion speed. This study provides both theoretical and experimental insights for regulating the delay time range of delay compositions.
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2025
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IF 9.7
Yuxuan Zhang,Junzhe Zhang,Hongming Zhao,Danfeng Zhang,Mei Wang,Peng Li,Liyong Wang,Yan-Bing He,Huiqi Wang
Quantum dots have been extensively utilized in diverse components of lithium-ion batteries (LIBs) due to their distinctive electronic structures, extremely high specific surface area, and remarkable interfacial regulation ability. In this work, a facile liquid-phase exfoliation method was employed to break down bulk boron into quantum-sized dots using a probe high-power ultrasonic crusher. The obtained boron quantum dots (BQDs) were confined within highly dispersed Ti 3 C 2 MXene, thereby forming BQDs/Ti 3 C 2 stacked composite anode materials for lithium-ion batteries. Based on the quantum confinement effect, BQDs exhibit superior electrochemical activity compared to bulk boron, providing abundant active sites for ion insertion and extraction. The well-dispersed BQDs in the Ti 3 C 2 MXene form a continuous network, facilitating efficient charge and ion diffusion and transport throughout the entire structure. Electron deficiency induced by BQDs occurs in the interlayers of Ti 3 C 2 MXene, thus the local electronic defect is introduced into the originally perfect periodic atomic arrangement and electronic potential field. This would cause ripples in the entire electronic system, leading to a redistribution of electrons. This not only enhances the charge transfer kinetics but also modulates the lithium-ion diffusion pathways through local electric field intensification. The as-prepared BQDs/Ti 3 C 2 stacked composite thus delivers an extremely high initial discharge capacity of 2514.5 mAh g −1 at 0.05 A g −1 , a large reversible capacity of 835.3 mAh g −1 at 0.1 A g −1 , and outstanding long-term cycle stability, with 958.0 mAh g −1 retained after 300 cycles. Notably, it also demonstrates exceptional long-term cycling performance at 2.0 A g −1 , with the capacity increasing from 459.5 mAh g −1 after 163 cycles to 1251.7 mAh g −1 after 759 cycles. The exploration of BQDs embedded in Ti 3 C 2 MXene is anticipated to inspire in-depth investigations into advanced BQD-powered MXene anode materials for LIBs.
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DOI
PubMed
高影响因子
CARBON
·
2025
·
IF 11.6
Zhaojin Li,Zezhao Li,Chenze Di,Di Zhang,Qiujun Wang,Huilan Sun,Qujiang Sun,Fei Yuan,Ranran Li,Bo Wang
Oxygen (O) and Boron (B) heteroatom doping has emerged as a promising strategy to enhance the capacitive performance of activated carbon (AC) for supercapacitors. However, the synergistic mechanism between these heteroatoms remains ambiguous due to intertwined morphological and compositional changes during conventional doping processes. This study employs a stepwise doping methodology to independently control O and B concentrations while preserving the structural integrity of AC. Through sequential high-temperature B doping and low-temperature oxidation, dual-doped AC (AC-O-B) retains comparable specific surface area and pore structure to pristine AC. Electrochemical evaluations reveal that O-B double doping has no significant effect on the double-layer capacitance, but it greatly improves the pseudocapacitance. Mechanistic analysis demonstrates that O doping introduces abundant C-O groups and facilitating the formation of BC 2 O structures via B integration. The presence of C-O groups and BC 2 O structure not only enhance surface wettability but also optimize charge transfer kinetics and redox-active site density. This work provides critical insights into heteroatom co-doping strategies for designing high-performance carbon-based supercapacitors.
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高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2024
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IF 4.3
Yonghui Yu,Jie Wei,Xianghui Yan,Yuhong Chen,Biao Zhang,Yujin Wang,Feng Ye,Limeng Liu
TaB 2 –SiC composites with 0–20 wt% SiC contents were prepared by reaction hot pressing using Ta, B and SiC powders as starting materials. Densification, constituent phases, microstructure and mechanical properties, namely Vickers hardness, fracture toughness and flexure strength, were evaluated by means of inspection of sintering shrinkage, density measurement, XRD, SEM, TEM, HRTEM, EDS, SAED, indentation and three-point bending tests. Phase formation, including dominant (TaB 2 , SiC) and minor (TaC, glassy SiO 2 ) phases, was checked by thermodynamic assessment relevant with Ta 2 O 5 and B 2 O 3 impurities introduced into the reaction system by the starting powders. The results showed that mixtures of Ta, B and SiC powders would initiate self-propagating combustion synthesis (SPCS) at about 900 °C; a transient hold at 800 °C for 1 h could suppress this reaction. Volatilization of B 2 O 3 impurity in association with local high temperature due to SPCS helped reduce the TaC and glassy SiO 2 minor phase formation. TaB 2 –SiC composites could reach 99 % relative densities with 3 wt% SiC addition and above. Compositions with <7.5 wt% SiC additions showed uniform dispersion of SiC particles at multi-TaB 2 grain junctions while compositions with higher SiC content revealed SiC segregation. Bending strength of 503 MPa and fracture toughness of 6.69 MPa⋅m 1/2 could be reached with 7.5–20 wt% SiC addition.
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高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2025
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IF 4.3
Xue Liu,Jianguo Deng,Yingchun Lu,Xin Li,Fuhan Mai,Lanxiang Ji,Xiaofeng Bai
This study focused on radiation shielding materials for nuclear applications, employing a vacuum-assisted impregnation method to optimise the microstructure and establish a synergistic shielding mechanism combining scattering and absorption. Specifically, melamine sponge (MS) is first modified using KH550 to form –NH 2 active sites on its pore surfaces. Subsequently, it is immersed in a composite solution to construct “reflective capsules”. Finally, gradient encapsulation is performed using polyborosiloxane and polyurethane. The results show that compared with pure MS, the tensile strength of this material doubles, the elongation increases by 179 %, and its shielding capabilities against 59.6 keV γ-rays and 0.025 keV thermal neutrons increase by 1442 % and 1593 % respectively, reaching 27.14 % and 43.35 %. Additionally, it has a photothermal peak temperature of 78.5 °C and stable thermal response. Furthermore, relying on the three-dimensional elastic network of the MS and the conductive pathway of MXene, the material achieves a piezoresistive coefficient of 5.27 kPa −1 , demonstrating potential for application as a pressure-sensitive sensor. Through microstructure design and functional integration, this work makes the material suitable for complex scenarios such as nuclear facility maintenance and emergency rescue.
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2025
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IF 6.3
Yuanyuan Wu,Yuhui Sun,Bozhen Li,jihui Lang,Guangbo Che,Xingjing Zhang,Chunbo Liu
Water splitting requires the development of efficient and economical materials that catalyze hydrogen evolution reaction (HER) in diverse and complex environments. At present, HER in multi-environment mainly relies on noble metal catalysts, because the tolerance of non-noble metals is greatly limited under acidic conditions. In this study, we report the synthesis of sulfur (S)-anion-doped rhenium diboride (ReB 2 ) nanosheets using a molten salt-assisted method. This novel approach facilitates the uniform incorporation of S anions into the ReB 2 lattice. This leads to enhanced electrocatalytic activity. The resulting S-doped ReB 2 nanosheets exhibit superior performance with remarkable activity and stability across a wide pH range in HER. Specifically, overpotential of 144 mV, 158 mV, and 139 mV (1.0 M KOH) are required in 1.0 M PBS, 0.5 M H 2 SO 4 , and 1.0 M KOH, respectively, to achieve a current density of 10 mA/cm 2 . with long-term durability over 50 h in all three media. Due to their unique porous structure, the nanosheets exhibit a large electrochemical active area, exposing more active sites, promoting the diffusion of electrolyte and the generation and release of gas bubbles on the catalyst surface, and they can be used as efficient bifunctional electrocatalysts for overall water splitting. In addition, the introduction of anion S effectively regulates the electronic structure of Re, thereby enhancing the catalytic reaction kinetics and intrinsic catalytic performance.
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高影响因子
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