CHEMICAL PHYSICS LETTERS
·
2018
·
IF 1.686
Huaiwei Zhang,Jianbo Qi,Zhenguo Ji
Synergic effects of rare earth-magnesium based hydrides (LaH 3 -MgH 2 ) on thermal dehydrogenation of potassium borohydride (KBH 4 ) are discussed in the paper. Comparing to above 675 K for the LaH 3 -MgH 2 or KBH 4 , the dehydrogenation temperature can be decreased to 346 K for the composites (LaH 3 -MgH 2 -KBH 4 ). The apparent activation energy of desorption process for the mixture is also greatly reduced. On the other hand, the products in the temperature programmed desorption process are also illustrated.
研究领域:
材料化学
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无机化学
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能源材料
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储氢材料
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固态化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2018
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IF 3.779
Jiaguang Zheng,Xuezhang Xiao,Yan He,Man Chen,Meijia Liu,Shouquan Li,Lixin Chen
The Mg(BH 4 ) 2 -AlH 3 - x LiH ( x = 0, 0.5, 1) novel ternary composites have been synthesized through mechanical ball milling, their favorable dehydrogenation properties and mechanism have been experimentally investigated. It can be found that during ball milling, a slight amount of Mg(BH 4 ) 2 would react with LiH and transform into LiBH 4 , while most Mg(BH 4 ) 2 remained stable after ball milling. Two major dehydrogenation steps can be detected in the Mg(BH 4 ) 2 -AlH 3 - x LiH composite, which belong to the decomposition of AlH 3 and Mg(BH 4 ) 2 , respectively. Remarkably, the onset hydrogen desorption temperature of Mg(BH 4 ) 2 -AlH 3 - x LiH composite can be reduced to 125.9 °C, with a total hydrogen desorption capacity of 10.3 wt%. It is worth emphasizing that the reversible dehydrogenation capacity is obviously improved to 3.8 wt%, compared to the Mg(BH 4 ) 2 -AlH 3 composite. This reversible capacity can be held for 3 cycles without obvious degeneration. Microstructural analysis on de/rehydrogenated composite has identified the regeneration of [BH 4 ] - in Mg(BH 4 ) 2 -AlH 3 -0.5LiH composite and revealed the role of LiH in the cycling hydrogen desorption and absorption processes. The formation of LiBH 4 and MgH 2 resulted from the rehydrogenation between MgAlB 4 and LiH could be helpful for the stability of reversible hydrogen storage performance.
研究领域:
材料科学
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能源存储
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2015
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IF 3.313
Liuting Zhang,Jiaguang Zheng,Lixin Chen,Xuezhang Xiao,Teng Qin,Yiqun Jiang,Shouquan Li,Hongwei Ge,Qidong Wang
Mg(BH 4 ) 2 is considered as one of the most promising light metal complex hydrides because of its high volumetric and gravimetric hydrogen capacities and world-wide abundance. However, its higher major desorption temperatures (above 300 °C) and poor reaction kinetics have to be improved for the practical application. Herein, Mg(BH 4 ) 2 was successfully synthesized via wet-chemical technique and a significant enhancement in dehydrogenation performance of Mg(BH 4 ) 2 is achieved by the synergetic effect of fluorographite (FGi) and LiBH 4 . Under the effect of FGi, the hydrogen desorption of 6 Mg(BH 4 ) 2 -4FGi composite could be completed below 170 °C in seconds. However, the hydrogen released from 6 Mg(BH 4 ) 2 -4FGi suffers from impurities of B 2 H 6 and HF. More importantly, it is demonstrated that almost all the B 2 H 6 and HF impurities can be suppressed by synergetic modifying Mg(BH 4 ) 2 with FGi and LiBH 4 . The 3 Mg(BH 4 ) 2 –3LiBH 4 -4FGi composite exhibits a capacity over 8.0 wt% H 2 and starts to release hydrogen at 125.7 °C, which is 143.8 °C and 254.3 °C lower than that of pure Mg(BH 4 ) 2 and LiBH 4 , respectively. These significant improvements could be attributed to both the novel morphology that numerous nano-scale borohydride spots formed on the surface of FGi, and the formations of stable fluorides (MgF 2 and LiF) from the interaction between borohydrides and FGi.
研究领域:
材料科学
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能源化学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2023
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IF 4.6
Darvaish Khan,Jianxin Zou,Saz Muhammad,Niaz Ali Khan,Shah Saud,Subrata Panda
In this study, a MgH 2 –Ru composite is prepared by mechanical ball milling of MgH 2 and Ru powders. The microstructural analysis revealed the uniform distribution of Ru nanoparticles in the MgH 2 matrix and the formation of intermetallic compounds (i.e. Mg 6.2 Ru and Mg 1.5 Ru) after dehydrogenation of the composite. The substantial improvements in the de/hydrogenation properties of MgH 2 are due to the adjustable catalytic role of Ru under low temperature and pressure conditions. MgH 2 –Ru composite started to release hydrogen at an onset temperature of 300 °C, much lower than the mechanically milled pure MgH 2 (350 °C). Hydrogen absorption of the MgH 2 –Ru composite is relatively fast at 350 °C and stored 6.1 wt% in 5 min. At the same temperature, the hydrogenated MgH 2 –Ru composite released all stored hydrogen in less than 5 min. Compared with the catalyst-free MgH 2 , the hydrogenation and dehydrogenation activation energies of the MgH 2 –Ru composite are reduced to 65.12 ± 2.4 kJ/mol H 2 , and 97.46 ± 4.15 kJ/mol H 2 , respectively. In addition, it further demonstrated how the reversible transformation of Mg–Ru intermetallic phases induces the thermodynamic destabilization of the MgH 2 system. The presence of Ru not only facilitated the breaking of the Mg–H bond but also provided very good catalytic interfaces for enhanced de/hydrogenation properties of MgH 2 .
研究领域:
材料科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Man Chen,Yiqi Wang,Xuezhang Xiao,Yunhao Lu,Meng Zhang,Jiaguang Zheng,Lixin Chen
Magnesium hydride (MgH 2 ) has attracted extensive attention over the past decades due to its highly reversible hydrogen storage density (7.6 wt%). But intrinsic high activation energy barriers for de/rehydrogenation of MgH 2 /Mg restrict its potential application as an on-board hydrogen carrier. Herein, ZrH 2 nanocatalyst homogeneously distributed on the surfaces of MgH 2 exhibits pronounced low temperature de/rehydrogenation kinetics, resulting from the vast lattice distortions between ZrH 2 and MgH 2 /Mg phases. The ZrH 2 doped MgH 2 composite (MgH 2 -ZrH 2 ) starts to release H 2 at 203 °C, 102 °C lower than that of undoped MgH 2 . Most importantly, MgH 2 -ZrH 2 quickly absorbs 5.90 wt% H 2 at the temperature as low as 65 °C. Further deep investigations found that H atoms preferentially accumulates around ZrH 2 , since the lower hydrogen dissociation energy on the surfaces of ZrH 2 (1.421 eV) than that of pure Mg (2.301 eV). Then, the large lattice disordered zone between ZrH 2 and Mg phases enables H atoms diffuse easily into the lattice of Mg nearby, thus triggering the formation of MgH 2 . These findings are critically important to understand the mechanism of other metal hydride catalysts, as well as offer an opportunity for the practical on-board fuel cell applications in the future.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2016
·
IF 3.205
Jiaguang Zheng,Xuezhang Xiao,Liuting Zhang,Yan He,Shouquan Li,Hongwei Ge,Lixin Chen
Mg(BH 4 ) 2 has been considered as one of the promising light metal complex hydrides due to its high hydrogen capacity and low cost. But its higher thermal stability (dehydrogenation at above 300 °C) needs to be improved for the practical application. In this study, the aluminum hydride AlH 3 was introduced into complex borohydride Mg(BH 4 ) 2 to synthesize a new Mg(BH 4 ) 2 AlH 3 composite by ball milling method. It is found that the active Al ∗ formed from the self-decomposition of AlH 3 can effectively improve the dehydrogenation properties of Mg(BH 4 ) 2 , the Mg(BH 4 ) 2 AlH 3 composite starts to release hydrogen at 130.8 °C with a total hydrogen capacity of 11.9 wt.%. The dehydrogenated products of the composite is composed of Mg 2 Al 3 and B at 350 °C, resulting in the improved hydrogen desorption properties of Mg(BH 4 ) 2 AlH 3 composite. The Mg 2 Al 3 and B products would be further transformed into MgAlB 4 and Al at 500 °C. Moreover, the Mg 2 Al 3 and B dehydrogenated products show better reversible hydrogen storage property than that of the MgAlB 4 and Al products. This research shows a way to alter hydrogen de/hydrogenation route and reversibility of Mg(BH 4 ) 2 complex hydride by compositing with AlH 3 and controlling the dehydrogenation temperature.
研究领域:
材料科学
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能源化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2024
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IF 6.5
Xilun Zhang,Hongliang Liang,Fei Chang
Catalytic hydrogenation of alkynes to alkenes is pivotal in both petrochemical and fine chemical industries. Its implementation relies on the use of transition metals, especially those precious Pd-based catalysts. In this work, we utilize a melt infiltration method to prepare magnesium oxide-supported potassium hydride (KH/MgO), which is illustrated as a transition-metal-free catalyst for selective hydrogenation of alkynes. H 2 -D 2 exchange experiment proves that dihydrogen activation and dissociation on KH/MgO is plausible at room temperature and ambient pressure. KH/MgO catalyzes hydrogenation of diphenylacetylene (DPA) already at 40 ℃, implying its high intrinsic activity at very mild conditions. Under an optimized condition of 80°C, 2 bar H 2 , and 40 h, 75 % conversion of DPA is achieved, affording 82 % selectivity to stilbenes. Mechanistic study suggests that surface hydride on KH/MgO plays an important role toward dihydrogen activation, and involved in the hydrogenation step to form stilbenes. This work shows the promise for using light metal hydrides consisting of earth-abundant elements as alternative hydrogenation catalysts.
研究领域:
化学
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2024
·Vol. 43
·期 9
·4387-4400
·
IF 9.6
Xia Ao,Zheng Jia-Guang,Zhang Qing-Bo,Shu Yu-Gang,Yan Cheng-Guo,Zhang Liu-Ting,Tao Zhan-Liang,Chen Li-Xin
The facile construction of nanoscale NbH x supported by Ti 3 C 2 (NbH x @Ti 3 C 2 ) was achieved using facile ball milling strategy to improve the hydrogen desorption kinetics and reversibility of magnesium borohydride (Mg(BH 4 ) 2 ). The doping of 30 wt% NbH x @Ti 3 C 2 catalyst reduced the onset dehydrogenation temperature of Mg(BH 4 ) 2 to 71.2 °C. Additionally, the Mg(BH 4 ) 2 + 30NbH x @Ti 3 C 2 composite achieved remarkable hydrogen release of over 9.2 wt% at a temperature as low as 230 °C, indicating unexpected dehydrogenation kinetics. Moreover, the reversibility of NbH x @Ti 3 C 2 doped Mg(BH 4 ) 2 was retained to more than 4.2 wt% after four cycles, which was increased by 68% compared to that of undoped Mg(BH 4 ) 2 . The strong catalysis of NbH x @Ti 3 C 2 catalyst could be attributed to the synergistic effect of NbH x and Ti 3 C 2 in hydrogen spillover and diffusion. NbH x acted as a “hydrogen pump” for effective hydrogen spillover, while Ti 3 C 2 created numerous diffusion channels for hydrogen dissolution and provided the active catalytic site to facilitate the re/dehydrogenation of Mg(BH 4 ) 2 . Graphical abstract
研究领域:
材料科学
·
能源储存
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Xiaolu Fan,Yao Zhang,Yunfeng Zhu,Cassandra Phillips,Xinli Guo,Jian Chen,Zengmei Wang,Liquan Li
Mixed alkali alanates Li x Na 3-x AlH 6 have been successfully synthesized by means of grinding mixtures of Li 3 AlH 6 and Na 3 AlH 6 in specific molar ratios. Non-stoichiometric Li x Na 3-x AlH 6 compounds with single perovskite-type structures (space group Fm-3m) can be formed only within the composition range of x = 0.9–1.3. Li 1.3 Na 1.7 AlH 6 exhibits superior hydrogen storage properties over other Li x Na 3-x AlH 6 compounds. Its onset dehydrogenation temperature (∼423 K) was lowered by more than 40 K from other samples in temperature programmed dehydrogenation (TPD) curves. Also, the dehydrogenation capacity of Li 1.3 Na 1.7 AlH 6 (3.45 wt.%) is the highest among the compounds. The dehydrogenation enthalpy values of Li x Na 3-x AlH 6 decreased as x increased from 0.9 to 1.3 according to the results by isothermal pressure-composition (PCI) curves and van't Hoff plots. It shows that the dehydrogenation Li 1.3 Na 1.7 AlH 6 (49.7 kJ mol H 2 −1 ) was greatly destabilized from that of LiNa 2 AlH 6 (68.1 kJ mol H 2 −1 ). Furthermore, the apparent activation energy of dehydrogenation for Li 1.3 Na 1.7 AlH 6 (138.1 kJ mol −1 ) was remarkably lowered from that of LiNa 2 AlH 6 . This illustrates that Li 1.3 Na 1.7 AlH 6 exhibits enhanced dehydrogenation kinetics from that of LiNa 2 AlH 6 .
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Darvaish Khan,Jianxin Zou,Mingguang Pan,Zhewen Ma,Wen Zhu,Tianping Huang,Xiaoqin Zeng,Wenjiang Ding
In this study, MgH 2 and Co powders were mechanically milled in the molar ratio 2:1 and compressed to hard-packed cylindrical pellets. The microstructure, phase changes, and hydrogen storage properties of the mechanically milled 2MgH 2 Co powder and the 2MgH 2 Co compressed pellet were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and synchronous thermal (DSC/TG) analyses. Dehydrogenation of the 2MgH 2 Co compressed pellet is mainly due to the decomposition of Mg 2 CoH 5 while it is the dehydriding of MgH 2 for the milled 2MgH 2 Co powder. Pressure composition absorption isotherms of the 2MgH 2 Co powder and 2MgH 2 Co compressed pellet show two and three plateaus, respectively, corresponding to the formation of Mg 6 Co 2 H 11 and Mg 2 CoH 5 hydride phases . For the compressed 2MgH 2 Co pellet, enthalpies of formation/decomposition were measured to be −58.11±7.69 kJ/mol H 2 /55.70±3.34 kJ/mol H 2 for Mg 2 CoH 5 and -81.89±10.39 kJ/mol H 2 /74.47±5.27 kJ/mol H 2 for Mg 6 Co 2 H 11 . In contrast, hydrogenation/dehydrogenation enthalpies of Mg 2 CoH 5 and Mg 6 Co 2 H 11 mechanically milled 2MgH 2 Co powder were −73.98±10.1 kJ/mol H 2 /71.67±1.38 kJ/mol H 2 and -96.86±8.73 kJ/mol H 2 /89.95±10.81 kJ/mol H 2 , respectively. Fast hydrogenation was observed in the dehydrided 2MgH 2 Co compressed pellet with about 2.75 wt% absorbed in less than 1 min at 300 °C and a maximum hydrogen storage capacity of 4.43 wt% (2.32 wt% for the 2MgH 2 Co powder) was achieved. The hydrogen absorption activation energy of the 2MgH 2 Co compressed pellet (64.34 kJ-mol −1 H 2 ) is lower than the mechanically milled 2MgH 2 Co powder (73.74 kJ-mol −1 H 2 ). The results show that mechanical milling followed by high-pressure compression is an efficient method for the synthesis of Mg-based complex hydrides with superior hydrogen sorption properties .
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Xin Zhang,Yukai Lin,Lingchao Zhang,Zhenguo Huang,Limei Yang,Zhenglong Li,Yaxiong Yang,Mingxia Gao,Wenping Sun,Hongge Pan,Yongfeng Liu
Sodium alanate, NaAlH 4 , has great potential as a hydrogen carrier but suffers from sluggish kinetics and poor reversibility caused by high energy barriers. Transition metal-based catalysts are especially effective in reducing kinetic energy barriers for hydrogen cycling of NaAlH 4 . Herein, we demonstrate a facile fabrication of TiC nanoparticles with 2–4 nm in size supported on carbon (nano-TiC@C). The resultant product consists of approximately 49.2 wt% of TiC and 50.8 wt% of C, and exhibits high and stable catalytic activity for hydrogen storage process of NaAlH 4 . The 7 wt% nano-TiC@C-containing NaAlH 4 releases 5 wt% H 2 starting from 65 °C and reabsorbs all released hydrogen at 30 °C under 100 bar H 2 , outperforming NaAlH 4 modified by commercial TiC nanoparticles (∼50 nm in size). The enhancement is related to the ultrasmall size and high reactive activity of as-synthesized TiC nanoparticles. Moreover, the weak electronegativity of C prevents the formation of Na-based by-products, which are often observed in oxide and halide-containing systems. This finding sheds light on how to design and synthesize high-performance catalytic additives for light-metal hydride-based hydrogen storage materials.
研究领域:
材料科学
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氢能技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Zhenji Li,Zhao Zhang,Jun Guo,Hongwei Jia,Wei Zhao,Lijun Lei,Que Huang,Lang Han,Changcheng Liu,Li Guo
MgH₂ is recognized as a promising material for hydrogen production due to its high hydrogen density, abundant availability, and non-polluting hydrolysis by-products, making it a viable hydrogen source for fuel cells. This study, for the first time, investigates the hydrogen production performance of the MgH₂-MOx-NaH (M = Ti, Zr, Mo, Fe, V, Bi) system, which exhibits remarkable hydrolysis properties in aqueous solutions. A series of MgH₂-MOx-NaH composite powders were synthesized via mechanical ball milling. The results revealed that V₂O₅-NaH and Bi₂O₃-NaH significantly enhanced the hydrolysis performance of MgH₂ for hydrogen production. Specifically, Bi₂O₃-NaH and V₂O₅-NaH effectively refined MgH₂ particles and mitigated agglomeration during the milling process. Hydrolysis tests demonstrated that the conversion rate and the hydrogen generation rate (mHGR) of composites initially increased with ball milling time and then decreased. The maximum hydrolysis hydrogen production yield and conversion rate for MgH₂-Bi₂O₃-NaH and MgH₂-V₂O₅-NaH composites occurred at a ball milling duration of 10 hours, and reached up to 1354.1 mL g⁻¹ (88.5 %) and 1273.5 mL g⁻¹ (81.8 %), respectively, within 8 minutes. Kinetic tests of hydrolysis hydrogen production showed that the reaction rate and hydrogen conversion increased with elevated hydrolysis temperatures. The activation energies for the hydrolysis of MgH₂-MOx-NaH (M = Ti, Zr, Mo, Fe, V, Bi) were calculated from the hydrolysis-hydrogen production curves using the Arrhenius formula, yielding values of 41.32, 37.66, 36.40, 34.60, 30.80, and 27.17 kJ mol⁻¹, respectively. The lower activation energies for hydrolysis indicate improved reaction kinetics, suggesting that the incorporation of transition metal oxides and sodium hydride effectively enhances both the hydrolytic conversion and reaction rate of MgH₂.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）