JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2024
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IF 11.2
Guorong Zhang,Jiaxi Liu,Sheng Wei,Fen Xu,Lixian Sun,Yongpeng Xia,Hehui Wang,Jinfan Wu,Yuan Gao,Qiwei Shao,Yiting Bu,Yanxun Guan,Lumin Liao,Taigen Liang,Lina Qin
Herein, a novel TiO 2 /CN heterojunction material has been prepared by one-step bubble template-assisted calcination to enhance the hydrogen storage capability of LiAlH 4 . The TEM, XPS and UPS analysis confirm that a heterostructure is formed between TiO 2 and g-C 3 N 4 successfully. The experimental findings indicate that the TiO 2 /CN significantly enhances the dehydrogenation performance of LiAlH 4 . For instance, the LiAlH 4 -7 wt% TiO 2 /CN starts to dehydrogenize at 76 °C (94 °C less than pure LiAlH 4 ) and releases 6.5 wt% H 2 at 200 °C. Meanwhile, LiAlH 4 -7 wt% TiO 2 /CN releases 4.9 wt% H 2 at 120 °C within 50 min. The mechanism analysis illustrates that AlTi 3 N is formed in situ during ball-milling. And density functional theory (DFT) calculation results reveal that the AlTi 3 N can weaken the Al-H bonds in LiAlH 4 through interfacial charge transfer. Furthermore, the TiO 2 /CN heterostructure creates an internal electric field that generates an electron-rich layer. As a result, the negative electron layer at one end of the TiO 2 /CN heterojunction has an increased affinity for H, which enhances the dehydrogenation reaction of LiAlH 4 . Clearly, both the TiO 2 /CN heterostructure and AlTi 3 N contribute to the improvement of the dehydrogenation properties of LiAlH 4 .
研究领域:
材料科学
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能源化学
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产品关联
DOI
高影响因子
KEY ENGINEERING MATERIALS
·
2017
·
IF 0
Dong Han Li,Ming Yi Liao
Preparation of telechelic hydroxyl low molecular weight fluoropolymers by reduction reaction was presented. The telechelic carboxyl low molecular weight fluoropolymers were chosen as raw materials which were prepared by oxidative degradation method. The molecular weights of telechelic carboxyl low molecular weight fluoropolymers were about 3700. Then, using lithium aluminum hydride reacted with carboxyl groups to prepare the telechelic hydroxyl low molecular weight fluoropolymers. The effects of reaction temperatures, reaction times, contents of solvent and lithium aluminum hydride were investigated in detail. The structures, Mn and dynamic viscosity of low molecular weight fluoropolymers were analyzed by FTIR, 1H-NMR, GPC and viscometer respectively. Finally telechelic hydroxyl low molecular weight fluoropolymers were prepared. The conversion rate of that reduction reaction was about 95%. The product was a viscous fluid with a dynamic viscosity of 48Pa·s at 50°C.
研究领域:
材料化学
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高分子化学
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产品关联
DOI
Materials Today Nano
·
2019
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IF 0
Y. Xia,H. Zhang,Y. Sun,L. Sun,F. Xu,S. Sun,G. Zhang,P. Huang,Y. Du,J. Wang,S.P. Verevkin,A.A. Pimerzin
Lowering the thermodynamic and kinetic barriers for dehydrogenation of high-capacity hydrides has been a key challenge for the realization of practical hydrogen energy. One of the most efficient strategies is doping hydrides with catalysis while nanosizing the composites. Although numerous catalytic additives have been investigated, more efficient dopants are still under exploration, and the underling mechanism of catalysis is highly desirable. In this study, a two-dimensional (2D) layered metal carbide , Ti 3 C 2 , was doped to improve the dehydrogenation performance of LiAlH 4 . The results show that, by doping 5 wt% of Ti 3 C 2 , the initial desorption temperature of LiAlH 4 decreased significantly from 180.1 to 58.6 with 6.5 wt% of hydrogen release. Approximately 5.5 wt% of hydrogen was liberated from the LiAlH 4 +5 wt% Ti 3 C 2 sample at 200 °C within 35 min. Combining density functional theory calculations, we reveal that contact of 2D Ti 3 C 2 significantly decreases the desorption energy barrier of Al–H bonding in LiAlH 4 and accelerates the breakdown of Al–H bonding through the interfacial charge transfer and the dehybridization of the Al–H cluster.
研究领域:
材料科学
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能源化学
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理论计算
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产品关联
DOI
Inorganics
·
2025
·Vol. 13
·期 3
·74
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IF 3
Yan Chu,Shiwei Fang,Yingjue Chen,Xiaoqi Zhang,Jie Zheng,Zhenglong Li,Wubin Du,Wengang Cui,Jian Miao,Yaxiong Yang,Yongfeng Liu,Mingxia Gao,Hongge Pan
LiAlH4, characterized by high hydrogen capacity and metastable properties, is regarded as a promising hydrogen source under mild conditions. However, its reversible regeneration from dehydrogenated production is hindered thermodynamically and kinetically. Herein, we demonstrate an active Li–Al–Ti nanocrystalline alloy prepared by melt spinning and cryomilling to enable directly synthesizing nano-LiAlH4. Due to the non-equilibrium preparation methods, the grain/particle size of the alloy was reduced, stress defects were introduced, and the dispersion of the Ti catalyst was promoted. The refined Li–Al–Ti nanocrystalline alloy with abundant defects and uniform catalytic sites demonstrated a high reactivity of the particle surface, thereby enhancing hydrogen absorption and desorption kinetics. Nano-LiAlH4was directly obtained by ball milling a 5% Ti containing Li–Al–Ti nanocrystalline alloy with a grain size of 17.4 nm and Al3Ti catalytic phase distributed under 20 bar hydrogen pressure for 16 h. The obtained LiAlH4exhibited room temperature dehydrogenation performance and good reversibility. This finding provides a potential strategy for the non-solvent synthesis and direct hydrogenation of metastable LiAlH4hydrogen storage materials.
研究领域:
材料科学
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氢能技术
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产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2020
·Vol. 7
·期 5
·1257-1272
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IF 5.958
Yongpeng Xia,Sheng Wei,Qiang Huang,Jianquan Li,Xinghua Cen,Huanzhi Zhang,Hailiang Chu,Lixian Sun,Fen Xu,Pengru Huang
Lithium alanate (LiAlH4), as a prototypical high-capacity complex hydride, has attracted intense interest as a promising hydrogen storage material. However, the drawbacks of high dehydrogenation temperatures and slow kinetics in the dehydrogenation process limit its practical applications. Herein, we have successfully synthesized NiCo2O4 nanorods anchored on rGO through a low-temperature solution method coupled with annealing treatment, and efficient effects derived from the NiCo2O4@rGO composite towards the dehydrogenation of LiAlH4 are demonstrated. The ball-milled LiAlH4 + 7 wt% NiCo2O4@rGO sample starts to decompose at 62.7 °C and releases a total of 6.28 wt% hydrogen, which is 118 °C lower than that of as-received LiAlH4, and 42.8 °C lower than that of ball-milled LiAlH4. The isothermal dehydrogenation kinetics show that the LiAlH4 + 7 wt% NiCo2O4@rGO sample could release approximately 4.0 wt% hydrogen within 20 min at 150 °C, whereas less than 0.04 wt% hydrogen release was detected for LiAlH4 under identical conditions within 100 min. Kinetic measurements reveal 21.9% and 37.1% reduction in the apparent activation energy of the two-step dehydrogenation of undoped LiAlH4, respectively, in the presence of a 7 wt% NiCo2O4@rGO additive. It is reasonable to conclude that the large surface area and mesoporous structures provided by NiCo2O4@rGO nanocomposites play a synergistic role in remarkably improving the dehydrogenation properties of LiAlH4.
研究领域:
材料科学
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能源存储与转换
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产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
·
IF 5.162
Weisheng Yang,Liang Jiao,Xiu Wang,Weibing Wu,Hailan Lian,Hongqi Dai
Most phenolic resins are synthesized with non-renewable petroleum-based phenol and formaldehyde, which have adverse effects on the environment and human health. To achieve green and sustainable production of phenolic resins, it is important to replace non-renewable toxic phenol and formaldehyde. Herein, a new strategy was proposed to completely replace phenol and formaldehyde, using lignin-derived monomers to synthesize renewable phenolic resins. Lithium aluminum hydride was utilized to reduce lignin-derived monomers, including vanillin , methyl vanillate, and syringaldehyde, to generate the corresponding vanillyl and syringic alcohol. With oxalic acid as the catalyst, vanillyl and syringic alcohol could be polymerized to phenolic resins without using formaldehyde. The structure of the phenolic resins based on lignin-derived monomers was analyzed by Fourier transform infrared spectroscopy and 13 C and 31 P nuclear magnetic resonance spectroscopy. Differential scanning calorimetry and thermogravimetric analysis were performed to characterize the thermal properties of the phenolic resins. The phenolic resins based on lignin-derived monomers exhibited excellent adhesion strength (6.14 MPa), glass transition temperature (T g ) (107–115 °C), and thermal stability , and its performance was similar to that of the commercial Novolak phenolic resin. This study presents a promising green and sustainable approach to synthesize renewable phenolic resins based on lignin-derived monomers without using formaldehyde.
研究领域:
材料科学
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绿色化学
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产品关联
DOI
PubMed
高影响因子
Polymers
·
2023
·Vol. 15
·期 11
·2574
·
IF 5
Donghan Li,Chen Yang,Ping Li,Lu Yu,Shufa Zhao,Long Li,Hailan Kang,Feng Yang,Qinghong Fang
Functional liquid fluoroelastomers are in high demand in new energy fields. And these materials have potential applications in high-performance sealing materials and as electrode materials. In this study, a novel high-performance hydroxyl-terminated liquid fluoroelastomer (t-HTLF) with a high fluorine content, temperature resistance, and curing efficiency was synthesised from a terpolymer of vinylidene fluoride (VDF), tetrafluoroethylene (TFE), and hexafluoropylene (HFP). A carboxyl-terminated liquid fluoroelastomer (t-CTLF) with controllable molar mass and end-group content was first prepared from a poly(VDF-ter-TFE-ter-HFP) terpolymer using a unique oxidative degradation method. Subsequently, an efficient “one-step” reduction of the carboxyl groups (COOH) in t-CTLF into hydroxyl groups (OH) was achieved via the functional-group conversion method using lithium aluminium hydride (LiAlH4) as the reductant. Thus, t-HTLF with a controllable molar mass and end-group content and highly active end groups was synthesised. Owing to the efficient curing reaction between OH and isocyanate groups (NCO), the cured t-HTLF exhibits good surface properties, thermal properties, and chemical stability. The thermal decomposition temperature (Td) of the cured t-HTLF reaches 334 °C, and it exhibits hydrophobicity. The oxidative degradation, reduction, and curing reaction mechanisms were also determined. The effects of solvent dosage, reaction temperature, reaction time, and ratio of the reductant to the COOH content on the carboxyl conversion were also systematically investigated. An efficient reduction system comprising LiAlH4can not only achieve an efficient conversion of the COOH groups in t-CTLF to OH groups but also the in situ hydrogenation and addition reactions of residual double bonds (C=C) groups in the chain, such that the thermal stability and terminal activity of the product are improved while maintaining a high fluorine content.Keywords:liquid fluoroelastomer;LiAlH4;reduction;hydroxyl
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）