APPLIED CATALYSIS A-GENERAL
·
2024
·
IF 4.7
Cong Wang,Gang Li,Zheng Huang,Anfeng Peng
Alkyl-aluminum, which is sensitive to air, has been a major obstacle to the development of ethylene oligomerization. Herein, LiAlH 4 is used as an effective alkyl-aluminum substitute. The performance of LiAlH 4 itself in the reaction is investigated, proving that it possesses moderate activity. Further addition of Versailles/Santa Barbara-1 (VSB-1) catalysts with different morphologies can effectively improve the reaction, in which VSB-1/LiAlH 4 presents the activity of 32.1 g ‧ g LiAlH4 −1 ·h −1 (154.1 g ‧ g VSB-1 −1 ‧h −1 ) and the selectivity of 1-butene, 1-hexene and 1-octene in all products could reach 51.4 %, 18.9 % and 7.9 %, respectively. The co-catalytic system is stable and the VSB-1 catalyst therein can be effectively reused at least three times under the suitable treatment conditions. In addition, the product analysis of the co-catalyzed system reveals that the addition of VSB-1 catalyst tended to produce 1-butene, 1-hexene and 1-octene at 20 bar. Based on above result, a possible reaction mechanism is proposed.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Chunmin Zhang,Chunli Wang,Qingyun Shi,Xiaoli Wang,Shaolei Zhao,Long Liang,Qingshuang Wang,Limin Wang,Yong Cheng
The high hydrogen release temperature and thermodynamic stability of the coordination hydride LiAlH 4 render it unsuitable for direct application. This work intends to improve the hydrogen release properties via compositing LiAlH 4 and AlH 3 with similar initial hydrogen release temperatures and introduce efficient additive Ni/CeO 2 composite. The thermal stability of the composite system LiAlH 4 -AlH 3 is enormously reduced compared to that of LiAlH 4 . In addition, the preferential release of hydrogen from LiAlH 4 in the composite system provides additional heat for the subsequent release of hydrogen from AlH 3 , accelerating the hydrogen release process. As a result, LiAlH 4 -AlH 3 -Ni/CeO 2 composite performs enhanced hydrogen release performance with a hydrogen release capacity of 8.27 wt% hydrogen within 300 ℃ and a dehydrogenation onset temperature as low as 72.9 ℃. The enthalpy change of the first step hydrogen release reaction decreases from −11.99 kJ mol −1 (LiAlH 4 ) to −2.02 kJ mol −1 (LiAlH 4 -AlH 3 ). Theoretical calculations indicate that both atomic dehybridisation and electron redistribution expedite the breaking of the Al-H bond and the consequent release of hydrogen.
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
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Jing Lin,Zhanyi Cao,Lianshan Sun,Fei Liang,Limin Wang
Ti 1.4 V 0.6 Ni + x LiAlH 4 ( x = 0.5, 1, 1.5, 2, 2.5, wt.%) composites were prepared by ball-milling, and the effects of LiAlH 4 content on structure and electrochemical properties of the composites were investigated systematically. The addition of LiAlH 4 to the Ti 1.4 V 0.6 Ni alloy significantly affected the morphology and size of the composite particles . The electrochemical cycling stability and rate dischargeability of the composite electrodes benefitted from adding some LiAlH 4 ( x = 1), which however deteriorated when the LiAlH 4 content increased further. The positive effect of LiAlH 4 on the electrochemical performance of the studied alloy was caused by suppression of the dissolution of active components of the Ti 1.4 V 0.6 Ni hydrogen storage alloy.
研究领域:
材料科学
·
金属功能材料
·
能源存储
·
电化学
·
氢能技术
✓ 已验证
DOI
高影响因子
Nanoscale
·
2019
·Vol. 11
·期 13
·5998-6003
·
IF 6.97
Dongjun Shen,Yijuan Long,Jie Wang,Yuanyuan Yu,Jiangli Pi,Lili Yang,Huzhi Zheng
A reduction pathway was developed to tune the fluorescence quantum yield (QY) and emission wavelength of carbon dots (CDs). Reducing the original CDs (QY ca. 1.55%, maximum emission ca. 520 nm) with NaBH4 increased QY to 7.25% and blue-shifted the maximum emission to 450 nm. Treating the original CDs with LiAlH4 increased QY to ca. 7.44% and blue-shifted the maximum emission to 345 nm. The distinct fluorescence characteristics of the original CDs, NaBH4-treated CDs, and LiAlH4-treated CDs were conferred by their differing surface groups. Moreover, the original CDs, NaBH4-treated CDs, and LiAlH4-treated CDs responded differently to a specific oxidizer of hydroxyl groups. The increase in the fluorescence QY and blue-shift of the emission wavelength were explained. This study provides a foundation for the preparation and tuning of CDs with excellent fluorescence performance, as well as for the development CD-based fluorescent probes.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2023
·
IF 6.4
Na Yang,Huchen Yao,Fanqi Bu,Mengyue Gu,Xuewen Zhao,Lei Huang,Chonghan Zhao,Yonghong Cheng,Jinying Zhang
Hydrolysis of LiAlH4 is a promising path to supply hydrogen at low temperatures due to its high hydrogen storage capacity, where an anti-icing aqueous solution is necessary. However, no hydrolysis kinetics of LiAlH4 with an anti-icing aqueous solution has been reported due to its complexity. Herein, an optimized anti-icing aqueous solution with 27.1 wt% KOH and 30.0% ethylene glycol has been found to obtain full and controllable hydrolysis kinetics of LiAlH4 at −40 to 0 °C. The effects of compactness, mass, and temperature on the hydrolysis of LiAlH4 have been investigated. The LiAlH4 tablet with compactness of 92.7% was demonstrated to obtain a wide constant reaction region (>95%) and be suitable for the hydrolysis reactions. The hydrogen release rates at constant reaction regions were found to follow a linear relationship with the 0.42 power of the mass of a compacted LiAlH4 tablet. A strong temperature-dependent hydrolysis was observed, where the activation energy was deduced from experimental data to be 6.83 ± 0.34 kJ·mol–1. The hydrolysis products of LiAlH4 with the adopted anti-icing aqueous solution after washing with deionized water were found to be the same as those directly with water, indicating no consumption of KOH and ethylene glycol in the reactions. The hydrolysis reaction of LiAlH4 with the adopted solution at −40 to 0 °C has been demonstrated to follow the shrinking core model controlled by liquid film diffusion.
研究领域:
无机化学
·
能源材料
·
催化化学
·
氢能源存储
·
反应动力学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Cong Wang,Gang Li,Zheng Huang,Anfeng Peng
The cumbersome air isolation process is one of the main constraints in the development of linear α-olefins prepared by ethylene oligomerization. An effective way to solve this problem is to eliminate the use of an alkyl-aluminum cocatalyst. Herein, two forms of Versailles/Santa Barbara-5 (VSB-5) (VSB-5-H3PO4 and VSB-5-NaH2PO2) are prepared and used as heterogeneous catalysts in ethylene oligomerization in the presence of LiAlH4 as a cocatalyst. Compared to other Ni-MOFs and Ni silica–aluminate catalysts, VSB-5s maintain a wider distribution of Linear α-olefin (LAO) products at relatively high activity. In the reuse test of the catalyst, the Al species from LiAlH4 cover the surface of the catalyst and decrease its activity, which could be removed by acid treatment. In situ IR studies show that active centers for ethylene oligomerization may form in VSB-5 assisted by LiAlH4. In addition, a Cossee–Arlman-type mechanism is proposed.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Inorganics
·
2025
·Vol. 13
·期 3
·74
·
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
·
氢能技术
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2020
·Vol. 45
·期 52
·28123-28133
·
IF 4.939
Hao Cheng,Jiaguang Zheng,Xuezhang Xiao,Zhe Liu,Xiujuan Ren,Xuancheng Wang,Shouquan Li,Lixin Chen
LiAlH 4 modified by different weight ratios of fluorographite (FGi) can be synthesized through mechanical ball-milling and their dehydrogenation behaviors were investigated. LiAlH 4 particles distributed on the FGi surface with greatly decreased sizes are achieved, comparing with ball-milled pristine LiAlH 4 . Greatly reduced dehydrogenation temperatures are discovered in LiAlH 4 -FGi composites. Among these composites, LiAlH 4 -40FGi composite exhibits an ultra-fast hydrogen release at very low temperature as 61.2 °C, and 5.7 wt% hydrogen is liberated in seconds. Besides, the released hydrogen is of high purity according to MS test. Furthermore, XRD analysis on the dehydrogenated products proves that FGi changes the dehydrogenation reaction pathway of LiAlH 4 , through which the dehydrogenation reaction enthalpy change is remarkably reduced, leading to greatly improved hydrogen desorption properties. Such investigations have discovered the potential of solid-state way of producing hydrogen under ambient temperatures.
✓ 已验证
DOI
高影响因子
Energy Storage Materials
·
2021
·
IF 17.789
Pengfei Wang,Yan Meng,Yujue Wang,Lu Chen,Zhaokun Zhang,Wei Pu,Jianming Li,Chi Yang,Dan Xiao
LiCoO 2 with a cut-off voltage of 4.6 V (versus Li/Li + ) could increase by about 28% of energy density compared with the commercial 4.45 V LiCoO 2 cathode. However, severe issues such as oxygen evolution and dramatic phase transition strangle the practical application of 4.6 V LiCoO 2 . We herein develop a one-step wet chemical coating method at room temperature to stabilize the interface of LiCoO 2 under high voltage. Through the treatment of LiCoO 2 particles by LiAlH 4 solution, the oxygen framework of the surface was reconstructed forming a composite coating layer which is featured a morphology with an inside-out transition structure from order to disorder. Benifited from the Al-containing composite layer, an excellent cycling performance has been obtained on the treated commerical samples, delivering a capacity retention of 70.4% even after 1000 cycles. The key to the improvement of electrochemical performance is to restrain the loss of lattice oxygen which is further elucidated by the results from differential electrochemical mass spectroscopy (DEMS). The interface evolution in different depths was carefully investigated delineating the relationship between the fluorated interface and the enhanced performance. Since the introduction of aluminum hydroxide , it facilitates the capture of F − bringing the interface layer from oxide to more stable fluoride during the cycling. Combining with the first principles calculation results, the aluminum coating surface suppresses the evolution of surfacial oxygen confirmed by oxygen release energy, and the optimized models infer that the fluorinated layer can obviously stabilize the interface structure of LiCoO 2 . This study provides a direct coating method which confers a notable improvement on cycling stability of LiCoO 2 under high voltage and enables the implementation of high energy storage applications .
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2014
·Vol. 39
·期 22
·11642-11650
·
IF 2.93
Si Zhou,Jianxin Zou,Xiaoqin Zeng,Wenjiang Ding
The catalytic effects of rare earth fluoride REF 3 (RE = Y, La, Ce) additives on the dehydrogenation properties of LiAlH 4 were carefully investigated in the present work. The results showed that the dehydrogenation behaviors of LiAlH 4 were significantly altered by the addition of 5 mol% REF 3 through ball milling . The destabilization ability of these catalysts on LiAlH 4 has the order: CeF 3 >LaF 3 >YF 3 . For instance, the temperature programmed desorption (TPD) analyses showed that the onset dehydrogenation temperature of CeF 3 doped LiAlH 4 was sharply reduced by 90 °C compared to that of pristine LiAlH 4 . Based on differential scanning calorimetry (DSC) analyses, the dehydriding activation energies of the CeF 3 doped LiAlH 4 sample were 40.9 kJ/mol H 2 and 77.2 kJ/mol H 2 for the first and second dehydrogenation stages, respectively, which decreased about 40.0 kJ/mol H 2 and 60.3 kJ/mol H 2 compared with those of pure LiAlH 4 . In addition, the sample doped with CeF 3 showed the fastest dehydrogenation rate among the REF 3 doped LiAlH 4 samples at both 125 °C and 150 °C during the isothermal desorption. The phase changes in REF 3 doped LiAlH 4 samples during ball milling and dehydrogenation were examined using X-ray diffraction and the mechanisms related to the catalytic effects of REF 3 were proposed.
研究领域:
材料科学
·
氢气储存
·
固态化学
·
能源材料
✓ 已验证
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2011
·
IF 2.141
Qiang Chen,Dun-qiang Tan,Rui Liu,Wen-xian Li
Electrodepositing Al coatings on W 90 Cu 10 foils in AlCl 3 + LiAlH 4 Tetrahydrofuran–benzene electrolyte was reported in this work. Effects of variations in molar ratios of AlCl 3 /LiAlH 4 , current density and plating time on surface morphology and crystal orientations were studied, and the optimal values of three parameters were preliminarily gained. Results showed that Al coatings displayed dense and cone-shaped micro-crystallites, and the particle size of coatings increased obviously with increasing current density or decreasing the proportion of AlCl 3 . It was indicated that all of the electrodeposits exhibited a strong preferred (111), (220) crystal orientation, and the (220) crystal orientation became strong along with electroplating time and current density, but weak with the proportion of AlCl 3 in baths. On the contrary, the changes of the (111) orientation exhibited an opposite trend.
研究领域:
材料科学
·
电化学
·
表面工程
✓ 已验证
DOI
高影响因子
Materials Today Nano
·
2019
·
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
·
能源化学
·
理论计算
✓ 已验证
产品关联
DOI
危险品化学品经营许可证（带存储）