INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2022
·Vol. 23
·期 13
·7477
·
IF 6.208
Dun Wu,Jiaming Zhao,Junfeng Cheng,Chunlin Liu,Qiang Wang
The reliable and cost-effective production of high-performance film electrodes for hydrogen evolution reactions remains a challenge for the laser surface modification community. In this study, prior to a thermal imidization reaction, a small number of Fe3O4nanoparticles were vortexed into a poly(amic acid) (PAA) prepolymer, and the achieved flat composite film was then ablated by a 1064 nm fiber laser. After laser irradiation, the hierarchical architectures of carbon nanosheets decorated with Fe3O4nanoparticles were generated. Although pure polyimide (PI) film and laser carbonized PI film, as well as bare Fe3O4, showcase poor intrinsic catalytic activity toward alkaline hydrogen evolution reactions, our laser-derived Fe3O4/carbon nanosheet hybrid film demonstrated enhanced electrocatalytic activity and stability in 1 M KOH electrolyte; the overpotential(η10) reached 247 mV when the current density was 10 mA cm−2with a slight current decay in the chronoamperometric examination of 12 h. Finally, we proposed that the substitution of N to O in Fe−O sites of trans spinel structured magnetite would be able to modulate the free energy of hydrogen adsorption (ΔGH*) and accelerate water dissociation.Keywords:laser ablation;photothermal agent;hydrogen evolution reaction
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
Metals
·
2022
·Vol. 12
·期 9
·1419
·
IF 2.695
Jie Wang,Hongtao Yang,Long Cheng,Pin Gao,Yanchun Li,Dongming Song
To improve the combustion stability and ignition performance of thermite, B/NC/CuO micro particles were prepared from boron (B), nano copper oxide (CuO), and nitrocellulose (NC) as an energetic binder through the electrospray technique. The burning rate dependency on boron content, ambient temperature, and pressure was estimated by compressing B/NC/CuO micro particles into columns. Scanning electron microscopy results show that the sizes of these particles mostly lie in the range of 3–4 μm. The particles are ignitable and burn consistently with minor variations in the conditions: B content (8.3–17%), ambient temperature (−50–55 °C), and ambient pressure (0.02–0.1 MPa). The optimum formula was observed for micro particles with 11 wt% B content. Compared with the ball milling sample, the standard deviation of the burning rate of the electrosprayed sample was reduced by 32%. Combustion is barely affected by ambient pressure. Between −50 °C to 55 °C, the burning rate of B/NC/CuO increases by 14.16% from an initial rate of 13.35 mm⋅s−1. In addition, the laser ignition energy required for B/NC/CuO microparticles was also reduced from 70 to 45 mJ.Keywords:boron;thermite;burning rate;combustion performance
研究领域:
材料科学
·
燃烧学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Biao He,Zhiwei Han,Jingyan Wang,Yaning Li,Jian Li,Saichao Song,Chen Li,Wei Liu,Chengyang Wu
Fluorine-based aluminum thermite have excellent ignition and combustion properties. Nonetheless, its combustion kinetics and energy release are hindered by slow mass diffusion and incomplete reactions. Therefore, this study successfully prepared an Al@PTFE composite with a core-shell structure, utilizing mechanical activation and sintering techniques, to enhance combustion properties and energy release rate. SEM, XRD, FTIR and XPS characterization results demonstrate the unique core-shell structure of the samples and the homogeneous distribution of elements on the surface. In comparison to the physical mixture, the Al@PTFE composite exhibits significantly higher values for P max (2.19 times), P max /Δt (11.30 times), and flame propagation velocity (4.5 times). Furthermore, the combustion duration required to reach the maximum flame height was reduced by 131.75 ms. The adsorption, decomposition and reaction processes of PTFE on the surface of aluminum particles were demonstrated based on RMD simulations. The promotion mechanism of PTFE on combustion in aluminum particles was elucidated.
研究领域:
材料科学
·
燃烧化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 5
·4115-4123
·
IF 2.993
Zhou Xiang,Zhu Ying,Ke Xiang,Zhang Kaili
In this study, we use simultaneous differential scanning calorimetry and thermogravimetric analysis to analyze the solid-state reaction characteristics of Al/Fe 2 O 3 nanothermites before n -Al melts. Different experimental setups for thermal analysis are compared, and the heat-release characteristics are studied on Al/Fe 2 O 3 nanothermites in the form of powder and pellet, respectively. It is found that protection provided by mere argon flow is far from enough for thermal analysis of Al/Fe 2 O 3 nanothermites. The experimental setup must be free of oxygen; otherwise, the determined exothermic peak is mostly the oxidation of n -Al by the residue oxygen molecules in the furnace body, due to the high reactivity and moderate accessibility of free oxygen molecules. Under proper experimental setup, it is found that besides the redox reaction between n -Al and n -Fe 2 O 3 , intermetallic reaction also occurs to form Fe 4 Al 13 . Moreover, the intermetallic reaction is more noticeable for nanothermite pellet than for nanothermite powder, and the eutectic reaction of Fe 4 Al 13 and n -Al leads to melting peaks below 655 °C. The results indicate that instrument configuration and sample status affect the testing results to a large extent, and one should be prudent to derive reaction characteristics of nanothermites.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Colloid and Interface Science Communications
·
2020
·
IF 2.831
Jiaxing Song,Tao Guo,Miao Yao,Jialin Chen,Wen Ding,Xiaonan Zhang,Fengli Bei,Junyi Huang
Graphene oxide (GO) with outstanding mechanical properties and high temperature stability is attractive to many researchers. As a flame retardant, GO also has been widely used in fire resistance applications of polymers. Herein, to explore ignition resistance effect of GO on nanothermite, GO/Al/MnO 2 nanocomposites were prepared. Due to the large specific surface area, GO can completely cover the surface of nanothermite components. Thermal results showed that exothermic thermite reaction occurred in the range of 500 °C to 600 °C while with GO addition, thermite reaction did not happen at all. Originally, combustion phenomenon of Al/MnO 2 nanothermite was intense with bright flame, but GO/Al/MnO 2 nanocomposites cannot be ignited even if the current on heating wires was higher. The physical barrier of GO hinders the direct contact between fuel and oxidizer which prevents the occurrence of self-propagating thermite reaction. This work provides guiding significance to the design of nanothermite flame retardant.
研究领域:
材料科学
·
燃烧化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2020
·
IF 3.871
Lei Xiao,Lujia Zhao,Xiang Ke,Tengyue Zhang,Gazi Hao,Yubing Hu,Guangpu Zhang,Hu Guo,Wei Jiang
Nanothermites have a promising study in micro propellant due to its faster reaction rate, higher energy-release efficiency, and significantly enhanced combustion performance. However, most thermites prepared by physical mixing are easy to separate during the propellant preparation process, significantly impeding the embodiment of the advantages of thermite. In this study, Al/CuO/PVDF microspheres incorporating high explosive RDX have been successfully assembled by electrospray technology. The thermal and combustion performance of the composite microspheres have significantly improved. They have shorter delay time, burning time, and higher pressure, pressurization rate than the physical mixtures, which are attributed to their uniform structure and the interaction of the components. And based on combustion tests, the combustion performance of microspheres is mainly affected by the content of RDX. These results indicate that the electrospray technology and adding RDX into microspheres are effective methods to prepare nanothermites with enhanced reactivity.
研究领域:
材料科学
·
燃烧与爆炸领域
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Pan Liu,Xiangyu Li,Long Cheng,Xuqiang Zhu,Yanchun Li,Dongming Song
A new type of nanothermite composed of n-Al (metal fuel) and FeF 3 (oxidizer) was investigated in this paper. The thermal behavior and combustion properties of the n-Al/FeF 3 nanothermite were compared with that of n-Al/Fe 2 O 3 nanothermite by TG/DSC-MS, XRD, SEM and high-speed camera. The results showed that the decomposition of FeF 3 begins at 300 °C and releases free F ions. The F ions react with Al 2 O 3 shell covered on the surface of aluminum. The start and exothermic peak temperatures of the major reaction of n-Al/FeF 3 are at 415 °C and 520 °C respectively, which are 95 °C and 34 °C lower than those of n-Al/Fe 2 O 3 . Furthermore, the FeF 3 will be reduced to Fe completely at 700 °C. However, the Fe 2 O 3 could only be converted to Fe 3 O 4 . It demonstrates that the reaction of n-Al/FeF 3 is completely, but only a part of n-Al/Fe 2 O 3 reacts at 700 °C. The n-Al/FeF 3 has larger, brighter flame and shorter burning time than n-Al/Fe 2 O 3 in open air.
研究领域:
材料科学
·
燃烧化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Research Express
·
2021
·Vol. 8
·期 3
·035507
·
IF 1.62
Shi Li,Tao Guo,Miao Yao,Wen Ding,Jialin Chen,Jiaxing Song,Sheng Zhang,Rui Zhu
To study the effect of the addition of potassium perchlorate (KClO4) on the performance of nano thermites, Al/Bi2O3 nano thermites with different mass fraction (wt%) of KClO4 was made by ultrasonic dispersion method. Then, all samples were tested by SEM, DSC and rapid excitation ignition. DSC results showed Al/Bi2O3/10 wt%KClO4 had the highest heat release. Compared with Al/Bi2O3, the heat release increased by 28.32%. The results of activation energy calculations showed Al/Bi2O3/30 wt%KClO4 had the lowest activation energy (Ea). Its activation energy was reduced by 30%, mere about 149.17 KJ mol−1. Finally, it can be seen from the combustion situation that the addition of KClO4 reduced the intensity of burning. This work found a way to increase the heat release or reduce the activation energy of nano thermites by controlling the amount of KClO4 added.
研究领域:
材料科学
·
燃烧学
·
化学工程
✓ 已验证
DOI
高影响因子
PROPELLANTS EXPLOSIVES PYROTECHNICS
·
2024
·Vol. 49
·期 5
·e202300285
·
IF 1.7
Mi Li,Zhongxuan Han,Lin Jiang,Guozhong Xu
Nano-thermite has become a subject of significant interest in the composite energetic materials field due to its high energy release rate. To cater to diverse engineering needs, thermite formulations are often customized to fulfill specific criteria. This study investigates the potential of metal nickel (Ni) as an additive to modify nano-thermite formulations, selected for its optimal calorific values and chemical reactivity. The base materials, nano-aluminum (Al) and iron oxide (Fe 2 O 3 ), are blended with varying mass ratios of Ni (1 %, 3 %, 5 %, 7 %, 9 %) using the wet ball milling method. Pre-reaction and post-reaction morphological and compositional alterations in the resultant thermite samples are scrutinized through SEM and XRD characterization tests. Moreover, DSC analysis and combustion experiments were conducted to examine the pyrolysis and combustion behaviors of the evaluated samples. The results reveal a reduced exothermic peak on the DSC curves with the introduction of Ni, making the liquid-solid ( L - S ) phase reaction more challenging compared to the Al/Fe 2 O 3 thermite. Intriguingly, Ni addition progressively decreases the combustion temperature of thermites as the Ni's mass ratio increases, with a peak efficiency at 7 % in the perforation tests on stainless-steel plates. This research further reveals that the thermite reaction mechanism is a combined consequence of the “pre-ignition-fusion” and “fusion-diffusion” mechanisms. These insights can provide valuable guidance for designing thermite formulations for potential applications in storage, management, and pyrotechnic cutting areas.
研究领域:
材料科学
·
燃烧与爆炸学
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2025
·
IF 2.3
Chen Jialin,An Ming,Dai Mengnan,Li Shutao,Chen Yeqing,Song Rui,Song Jiaxing,Chen Longming,Zhong Xiting,Tian Quanwei
The properties of oxidants significantly affect the thermal and combustion properties of nanothermites, and alpha and beta-MnO 2 nanorods with similar morphological appearances were prepared using the hydrothermal method. Corresponding nanothermites were prepared employing the electrostatic spraying method and their thermal and combustion properties have been compared through TG-DSC and combustion tests. The aluminothermic reaction process was simulated by molecular dynamics, and the results showed that the β-MnO 2 /Al nanothermite first underwent β-MnO 2 thermal decomposition followed immediately by an aluminothermic reaction, whereas the α-MnO 2 /Al nanothermite underwent a direct aluminothermic reaction. In contrast, the α-MnO 2 /Al nanothermite could release more heat. According to thermal analysis, the activation energy of α-MnO 2 /Al nanothermite was 100.15 kJ mol − 1 higher than β-MnO 2 /Al nanothermite, indicating better stability. Combustion experiments showed that the combustion propagation rate of the α-MnO 2 /Al nanothermite was faster than the β-MnO 2 /Al nanothermite. The results have been verified and the reaction process has been exhibited using molecular dynamics to simulate the aluminothermic reaction process. The notable differences in the thermal and combustion properties of nanothermites containing MnO 2 with varying phases can be attributed to the distinct crystal structures of α-MnO 2 and β-MnO 2 . The alternating 1 × 1 and 2 × 2 tunnel structure of α-MnO 2 is more stable, whereas β-MnO 2 undergoes thermal decomposition before the aluminothermic reaction.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Wanjun Zhao,Hui Ren,Tao Yan,Yapeng Ou,Qingjie Jiao,Haiyang Wang,Dylan J. Kline,Michael R. Zachariah
This work explores the ignition mechanism of silicon (Si) based thermites, and it is supposed that the phase change of silica (SiO 2 ) coating on the Si core producing fractures may play a crucial role in the ignition of Si-based thermites. Several Si-based thermites were evaluated by the combustion test and calorimeter, and potassium perchlorate (KClO 4 ) is turned out to be a promising oxidizer given the high reactivity and considerable heat release. Titanium (Ti) nanoparticles with a lower onset oxidization temperature than Si were incorporated into Si/KClO 4 system via a facile sonicating method. The ignition temperature of Si/KClO 4 has reduced markedly by ~80–130 °C with significant increases of ~5-8x in pressurization rate and decreases by a factor of ~2–3 in burn time when adding 30–70% Ti by mole into the fuel. The combustion efficiency is improved dramatically from ~59% to ~73%. The enhanced combustion performance could be attributed to the lower ignition temperature of Ti/KClO 4 leading to the initiation reaction of the ternary composites, thus promoting energy release and the reactivity of the ternary system. This work not only investigates the ignition mechanism of Si-based thermites but also sets a stage for tuning the ignition and combustion of Si-based thermites via facile incorporation of Ti nanoparticles.
研究领域:
材料科学
·
能源化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
·
2018
·Vol. 29
·期 2
·404-411
·
IF 1.444
Song Jia-Xing,Fang Xiang,Guo Tao,Bei Feng-Li,Ding Wen,Zhang Xiao-Nan,Yao Miao,Yu Hong-Jun
In this work, thermal properties and kinetics of Al-nanoparticles/α-MnO2 nanorods thermite were reported. The α-MnO2 nanorods were synthesized using a hydrothermal method and were characterized by X-ray powder diffraction (XRD) and X-ray photoelectron spectra (XPS), then combined with Al nanoparticles based on the ultrasonic mixing method to prepare the nanostructure thermite. Besides, both pure components and mixture were characterized by field emission scanning electron microscopy (FE-SEM) to observe their morphologies and structures. Subsequently, the thermal properties of Al/α-MnO2 nanostructure thermite were studied on the basis of thermogravimetric-differential scanning calorimetry (TG-DSC). According to the TG-DSC tests, the calculation results of activation energy for kinetics of Al/α-MnO2 thermite were obtained using different isoconversional methods. It was found that Al/α-MnO2 nanostructure thermite has high heat release and low onset temperature, and the heat release of the nanostructure thermite was approximately 1146.6 J g -1.
研究领域:
材料科学
·
热化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）