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
·
无机化学
·
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
·
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
·
能源存储
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2015
·
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
·
能源化学
✓ 已验证
DOI
高影响因子
Journal of Chemistry
·
2020
·
IF 1.79
Zhaozhuo Yu,Weibo Wu,Hu Li,Song Yang
Hydrogenation of bio-based furfural (FUR) to furfuryl alcohol (FFA) is tremendously expanding the application of biomass in many industries such as resins, biofuels, and pharmaceuticals. However, mass manufacture of FFA from FUR is restrained by strict requirements of reaction conditions and expensive catalysts. In this work, an economical and benign catalytic system, containing an easily prepared and reusable catalyst 5 wt.% KF/ZrO2 and a low-cost hydrogen source polymethylhydrosiloxane (PMHS), was developed to be efficient for the hydrogenation of FUR to high-value FFA under mild conditions. The catalyst reactivity was found to be remarkably influenced by the support acid-base properties and KF loading doge. In the presence of 5 wt.% KF/ZrO2, a high FFA yield of 97% and FUR conversion of 99% could be obtained at 25°C in just 0.5 h, which was superior to those attained with other tested catalysts. The KF/ZrO2 catalyst could be recycled at least five times, with the FFA yield slightly decreasing from 97% to 71%. The spare decrease in FFA yield is possibly attributed to the catalyst pore blocking, as clarified by SEM, BET, XPS, and ICP-MS measurements of the fresh and reused catalysts.
研究领域:
化学工程
·
可再生资源利用
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zhuanghe Ren,Xin Zhang,Zhenguo Huang,Jianjiang Hu,Yangzhong Li,Shiyou Zheng,Mingxia Gao,Hongge Pan,Yongfeng Liu
Nanosized titanium compounds are particularly effective in catalyzing hydrogen cycling by NaAlH 4 . Titanium hydride (TiH 2 ), as a catalyst, is highly interesting since it contributes hydrogen in addition to active Ti. However, it has been challenging to fabricate nanosized TiH 2 due to the strong affinity of Ti with oxygen. Herein, TiH 2 nanoflakes with a lateral size of ~10 nm and thickness of ~1 nm are successfully synthesized through a novel facile one-pot solvothermal process. In an anhydrous THF solution, LiH reacts with TiCl 4 rapidly at 100 °C forming TiH 2 and LiCl. The newly formed TiH 2 nucleates and grows epitaxially on the graphene surface due to the well-matched lattice parameters, giving rise to the formation of TiH 2 nanoflakes. Both theoretical calculations and experiments reveal the generation of Cl· radicals and unsaturated C C bonds when TiCl 4 reacts with THF, which promotes the formation of TiH 2 . The nanoflake-like TiH 2 on graphene enables an outstanding hydrogen storage performance of NaAlH 4 , i.e., full dehydrogenation at 80 °C and hydrogenation at 30 °C and under 100 bar H 2 , with a practical hydrogen capacity of 4.9 wt%, which has been never reported before.
研究领域:
材料科学
·
纳米化学
·
能源化学
·
固态储氢
·
催化化学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2023
·
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
·
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
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Congwen Duan,Zhaohua Su,Yating Tian,Dong Fu,Yuling Zhang,Wei Lv,Jinghong Zhang,Lianxi Hu,Ying Wu
MgH 2 , as one of the most potential hydrogen storage materials, has received considerable attention. However, its development has been plagued by its slow hydriding kinetics. Mechanochemical milling is an effective and convenient method for producing MgH 2 @CNTs-Ni through a solid–gas reaction between Mg-CNTs-Ni and H 2 . However, the hydriding kinetics and the corresponding mechanism during the milling have not been mentioned. Thus, hydriding kinetics of Mg-CNTs-Ni was researched for the purpose of gaining insights into the reaction mechanism and obtaining the best milling parameters. Also, phase transition during the milling was analyzed using XRD and TEM . It is apparent that the Avrami-Erofeev (AE) model can well describe the mechanochemical process, which contains solid solution, phase transition and growth-controlled regime. Besides, kinetics of hydrogenation is limited by nucleation and growth of MgH 2 . By fitting with the Arrhenius equation, average apparent activation energy for the hydrogenation of Mg-CNTs-Ni is estimated to be 47.8 kJ mol −1 .
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
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
·
能源化学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 41
·19900-19908
·
IF 3.925
Hongwei Qiu,Xingbo Han,Shuyan Zang,Wei Liu,Guo Yang,Lijun Lv,Xiaofeng Wang,Jiaqi Duan,Shuangyu Wang
The MgH2–LiH composites with different composition ratios were prepared by different ball milling times, and the hydrogen generation performances of the composites were investigated and compared. X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy techniques were adopted to elucidate the performance improvement mechanisms. The results show that the hydrogen generation yield and kinetics can be improved with the increase of LiH content significantly. For the 7MgH2–3LiH and 1MgH2–1LiH, with the increase of the ball milling time, the hydrogen yield increases firstly, and then decreases, but the kinetics almost do not change. This may be caused by the change of particle size of the composites after ball milling. However, for the 9MgH2–1LiH, the hydrogen yield increases with ball milling time but the kinetics decrease gradually. This may be due to the gradual movement of LiH from the surface to the interior of MgH2 and to the covering of MgH2 after ball milling.
研究领域:
材料科学
·
无机化学
·
能源化学
·
纳米材料
·
储氢材料
✓ 已验证
DOI
高影响因子
Energy Storage Materials
·
2019
·
IF 0
Ke Wang,Xin Zhang,Zhuanghe Ren,Xuelian Zhang,Jianjiang Hu,Mingxia Gao,Hongge Pan,Yongfeng Liu
Magnesium hydride (MgH 2 ) is one of the most promising high-capacity hydrogen storage materials. However, limited progress has been made in storing hydrogen in Mg under ambient conditions. Here, we demonstrate for the first time that the dehydrogenated MgH 2 is fully hydrogenated below 100 °C with the presence of N-containing Nb 2 O 5 (N-Nb 2 O 5 ). MgH 2 composites doped with N-Nb 2 O 5 (10 wt%) releases hydrogen from 170 °C, which is lowered by 130 °C compared with pristine MgH 2 , while still having 6.3 wt% hydrogen capacity available. Most importantly, full hydrogenation can be achieved by the dehydrogenated N-Nb 2 O 5 -containing sample at temperature as low as 70 °C under 50 atm of hydrogen, which is superior to other known catalyst-doped MgH 2 systems. The in-situ formed NbN 0.9 O 0.1 plays the critical catalyst role due to the joint action of N and Nb as elucidated by density functional theory (DFT) calculations. This finding remarkably facilitates the future design and exploration of much higher-performance catalysts for room-temperature hydrogen storage in metal hydrides .
研究领域:
材料科学
·
化学工程
·
能源存储
✓ 已验证
产品关联
DOI
JOURNAL OF CATALYSIS
·
2024
·
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
·
催化科学
✓ 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）