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1.
《International Journal of Hydrogen Energy》2019,44(55):29150-29158
The effect of LiCe(BH4)3Cl on the hydrogen storage properties of Mg(NH2)22LiH system was studied systematically, which has a high Li ion conductivity. The hydrogen desorption temperatures for LiMgNH system shift to lower temperatures by 0.05LiCe(BH4)3Cl doping with the onset temperature of dehydrogenation decreasing by 40 °C and the peak temperature decreasing by 30 °C. The Mg(NH2)22LiH–0.03LiCe(BH4)3Cl composite exhibits an improved comprehensive hydrogen storage properties, which can reversibly store about 5.0 wt% hydrogen at 160 °C, and released hydrogen as much as 8.6 times faster than that of the Mg(NH2)22LiH composite at 160 °C. The results indicated that the LiCe(BH4)3Cl-containing sample exhibited much better cycling properties than that of Mg(NH2)22LiH sample. XRD and FTIR results show that the structure of LiCe(BH4)3Cl does not change before and after hydrogen absorption/desorption, indicating it plays the catalytic effect. The hydrogen desorption activation energy of Mg(NH2)22LiH doped with 0.03LiCe(BH4)3Cl was reduced by 37.5%. The rate-controlling step of desorption shifted from the diffusion to the chemical reaction by the addition of LiCe(BH4)3Cl, indicating that the diffusion rates of small ions like H+, Li+ and Mg2+ in LiMgNH system are significantly enhanced, which could be well explained by the improved ionic conductivity of LiCe(BH4)3Cl doped sample. 相似文献
2.
《International Journal of Hydrogen Energy》2019,44(44):24292-24300
Mg(BH4)2 occupies a large hydrogen storage capacity of 14.7 wt%, and has been widely recognized to be one of the potential candidates for hydrogen storage. In this work, 2D MXene Ti3C2 was introduced into Mg(BH4)2 by a facile ball-milling method in order to improve its dehydrogenation properties. After milling with Ti3C2, Mg(BH4)2–Ti3C2 composites exhibit a novel “layered cake” structure. Mg(BH4)2 with greatly reduced particle sizes are found to disperse uniformly on Ti3C2 layered structure. The initial dehydrogenation temperature of Mg(BH4)2 has been decreased to 124.6 °C with Ti3C2 additive and the hydrogen liberation process can be fully accomplished below 400 °C. Besides, more than 10.8 wt% H2 is able to be liberated from Mg(BH4)2–40Ti3C2 composite at 330 °C within 15 min, while pristine Mg(BH4)2 merely releases 5.3 wt% hydrogen. Moreover, the improved dehydrogenation kinetics can be retained during the subsequent second and third cycles. Detailed investigations reveal that not only Ti3C2 keeps Mg(BH4)2 particles from aggregation during de/rehydrogenation, but also the metallic Ti formed in-situ serves as the active sites to catalyze the decomposition of Mg(BH4)2 by destabilizing the B–H covalent bonds. This synergistic effect of size reduction and catalysis actually contributes to the greatly advanced hydrogen storage characteristics of Mg(BH4)2. 相似文献
3.
《International Journal of Hydrogen Energy》2020,45(3):2127-2134
Lithium amidoborane (LiNH2BH3) is known as one of the most prospective hydrogen storage materials. In this paper, the differences between two allotropes (α-LiNH2BH3 and β-LiNH2BH3) of LiNH2BH3 in the dehydrogenation properties was reported for the first time. A series of mixtures of α-LiNH2BH3/β-LiNH2BH3 with different mass ratios were prepared by ball milling for different time and the contents of two phases in samples were determined with Rietveld's method. The thermal decomposition behaviors of samples were investigated by DSC. It shows that the initial dehydrogenation temperature of samples decreases with the content of α-LiNH2BH3 phase increasing. The initial dehydrogenation temperature of α-LiNH2BH3 is about 61 °C, which is approximately 15 °C lower than that of β-LiNH2BH3. Dehydrogenation kinetic analysis shows that α-LiNH2BH3 has the lower activation energy (157 kJ mol−1) and higher rate (k = 1.422 × 101 min−1) than that of β-LiNH2BH3 (272 kJ mol−1 and 1.023 × 10−1 min−1, respectively). It is suggested that α-LiNH2BH3 is more supportive for hydrogen desorption. It gives a critical clue on exploring the dehydrogenation mechanism of lithium amidoborane. Moreover, the significant decrease of desorption temperature will shine a light on on-board hydrogen storage systems. 相似文献
4.
《International Journal of Hydrogen Energy》2020,45(33):16654-16662
Magnesium borohydride (Mg(BH4)2) is an attractive materials for solid-state hydrogen storage due to its high hydrogen content (14.9 wt%). In the present work, the dehydrogenation performance of Mg(BH4)2 by adding different amounts (10, 20, 40, 60 wt%) of two-dimensional layered Ti3C2 MXene is studied. The Mg(BH4)2-40 wt% Ti3C2 composite releases 7.5 wt% hydrogen at 260 °C, whereas the pristine Mg(BH4)2 only releases 2.9 wt% hydrogen under identical conditions, and the onset desorption temperature decreases from 210 °C to a relative lower temperature of 82 °C. The special layered structure of Ti3C2 MXene and fluorine plays an important role in dehydrogenation process especially at temperatures below 200 °C. The main dehydrogenation reaction is divided into two steps, and activation energy of the Mg(BH4)2-40 wt% Ti3C2 composite is 151.3 kJ mol−1 and 178.0 kJ mol−1, respectively, which is much lower than that of pure Mg(BH4)2. 相似文献
5.
Jiaguang Zheng Xuezhang Xiao Liuting Zhang Yan He Shouquan Li Hongwei Ge Lixin Chen 《International Journal of Hydrogen Energy》2017,42(12):8050-8056
Mg(BH4)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 AlH3 was introduced into complex borohydride Mg(BH4)2 to synthesize a new Mg(BH4)2AlH3 composite by ball milling method. It is found that the active Al1 formed from the self-decomposition of AlH3 can effectively improve the dehydrogenation properties of Mg(BH4)2, the Mg(BH4)2AlH3 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 Mg2Al3 and B at 350 °C, resulting in the improved hydrogen desorption properties of Mg(BH4)2AlH3 composite. The Mg2Al3 and B products would be further transformed into MgAlB4 and Al at 500 °C. Moreover, the Mg2Al3 and B dehydrogenated products show better reversible hydrogen storage property than that of the MgAlB4 and Al products. This research shows a way to alter hydrogen de/hydrogenation route and reversibility of Mg(BH4)2 complex hydride by compositing with AlH3 and controlling the dehydrogenation temperature. 相似文献
6.
《International Journal of Hydrogen Energy》2019,44(14):7414-7421
Mg(BH4)2⋅(NH3)2 (NH3BH3) is an important H-enriched hydrogen storage material capable of releasing high-purity hydrogen. This work investigated the elastic and electronic properties of Mg(BH4)2⋅(NH3)2 (NH3BH3) using first-principle calculations for the elastic constants, bulk modulus, Young's modulus, B/G. Results show this compound is mechanically stable and classified as a brittle material. Three-dimensional curves indicate significant anisotropy exists in the (010) and (100) planes for bulk modulus and the (001) plane for Young's modulus. The (001) plane elastic anisotropy is larger than those of the (010) and (0‾1 0) planes. An electronic properties analysis indicates this compound is a semiconductor with a 1.151 eV band gap. There exist the strong B-H, Mg-N interactions from the analysis of density of state, which are further confirmed by Bader's quantum theory of atoms in molecules (QTAIM). 相似文献
7.
《International Journal of Hydrogen Energy》2020,45(3):2044-2053
The solvent-free amorphous Mg(BH4)2 composite was in-situ synthesized by ball milling LiBH4 and MgCl2. It is found that the onset dehydrogenation temperature of the as-synthesized composite is 126.9 °C, which is roughly 156 °C lower than that of pristine Mg(BH4)2. The activation energy of the amorphous Mg(BH4)2 and pristine Mg(BH4)2 for the first dehydrogenation step was calculated as 120.01 kJ/mol and 487.99 kJ/mol, respectively. Hence the kinetics improvement is certified by the lower Ea value of the dehydrogenation process. When adding NbF5 into the composite, the catalyzed composite exhibits better hydrogen storage properties compared to pristine and amorphous Mg(BH4)2. The catalyzed composite starts to release hydrogen at proximately 120 °C with a total capacity of 10.04 wt%. The reversibility of the catalyzed composite is also improved. The capacity of the catalyzed composite at the second cycle is 5.5 wt%. For the third and fourth cycles the catalyzed composite can still liberate 4 wt% H2. Besides, the onset hydrogen desorption temperature during four cycles are extremely lower than those of pristine and amorphous Mg(BH4)2. The peaks of the intermediate MgB12H12 is detected by FTIR as the regenerated hydrogenation product in the catalyzed composite. It can be speculated from the detailed analysis that there are mainly three reasons for the improved properties. Firstly, the additive NbF5 is favorable to enhance the hydrogen storage properties by modifying the dehydrogenation path and producing MgF2 and NbB2 as new products. Secondly, the in-situ formation of amorphous Mg(BH4)2 is likely to improve the dehydrogenation properties of the samples due to its different reactivity comparing to crystal ones. Finally, LiCl can serve as buffer in the composite and thus improve the dehydrogenation properties. 相似文献
8.
《International Journal of Hydrogen Energy》2019,44(8):4253-4262
Magnesium borohydride, Mg(BH4)2, is an interesting material for hydrogen storage due to its high hydrogen content (14.9 wt.% of H2). Unfortunately, a temperature of at least 350 °C is needed for releasing its hydrogen and the rehydrogenation process is only feasible under harsh conditions (950 bar H2 and 300 °C). In order to improve the performances of this compound, we analyze in this study the concomitant effects of nano-confinement into mesoporous carbons and addition of NiPt catalysts. This study uses different characterization tools to determine the effects of both nano-confinement and catalysts onto the pathway of decomposition. Usually, bulk Mg(BH4)2 decomposes in several steps passing through intermediate species for which activation energies are high. In this study, we show that the confinement and catalyst addition on Mg(BH4)2 result in a single step of hydrogen release and an activation energy below that of the bulk material with a value of 178 ± 14 kJ mol−1 as determined by the Kissinger's method. Interestingly, the hydrogen release is fully completed, i.e. 8H atoms per Mg(BH4)2 formula unit are released, in less than 2 h at 350 °C. 相似文献
9.
《International Journal of Hydrogen Energy》2019,44(39):21979-21987
Titanium fluoride (TiF3) is doped into the reactive hydride composite of 2NaAlH4 + Ca(BH4)2 by ball milling to enhance the hydrogen storage properties of the composite system. NaAlH4 and Ca(BH4)2 phases were fully transformed to Ca(AlH4)2 and NaBH4 phases after the ball-milling process (6 h). Four major stages were discovered in the undoped and TiF3-doped system, which is corresponding to; (i) Ca(AlH4)2, (ii) CaAlH5, (iii) CaH2 and (iv) NaBH4, respectively. The addition of TiF3 to the studied composite resulted in both reduced decomposition temperature and enhanced sorption kinetics compared with the undoped composite. The onset desorption temperature was reduced from 125 °C to 60 °C for the first stage in the TiF3-doped composite, compared with the undoped composite. From differential scanning calorimetry analysis, the decomposition temperature for all stages has shifted to a lower temperature after doping with TiF3. The activation energy has greatly reduced by 63.6 and 21.9 kJ/mol for CaAlH5 and NaBH4 stages, respectively, as compared with the undoped 2NaAlH4 + Ca(BH4)2 composite. During the dehydrogenation process, the formation of new active species of Al3Ti together with CaF2 played a vital role in accelerating the reactions in 5 wt% TiF3 doped to the studied composite system. 相似文献
10.
《International Journal of Hydrogen Energy》2019,44(52):28227-28234
Study on the catalytic roles of MgFe2O4 on the dehydrogenation performance of LiAlH4 was carried out for the first time. Notable improvement on the dehydrogenation of LiAlH4–MgFe2O4 compound was observed. The initial decomposition temperatures for the catalyzed LiAlH4 were decreased to 95 °C and 145 °C for the first and second stage reactions, which were 48 °C and 28 °C lower than the milled LiAlH4. As for the desorption kinetics performance, the MgFe2O4 doped-LiAlH4 sample was able to desorb faster with a value of 3.5 wt% of hydrogen in 30 min (90 °C) while the undoped LiAlH4 was only able to desorb 0.1 wt% of hydrogen. The activation energy determined from the Kissinger analysis for the first two desorption reactions were 73 kJ/mol and 97 kJ/mol; which were 31 and 17 kJ/mol lower as compared to the milled LiAlH4. The X-ray diffraction result suggested that the MgFe2O4 had promoted significant improvements by reducing the LiAlH4 decomposition temperature and faster desorption kinetics through the formation of active species of Fe, LiFeO2 and MgO that were formed during the heating process. 相似文献
11.
Jianglan Qu Bo Sun Jie Zheng Rong Yang Yuntao Wang Xingguo Li 《Journal of power sources》2010,195(4):1190-1194
Pd–Mg–Pd thin films prepared by magnetron sputtering could absorb hydrogen entirely at room temperature and dehydrogenate completely and rapidly in ambient air. Our investigations of the structural, optical and electrical properties gave a detailed insight into the desorption mechanism. The overall activation energy and the hydrogen diffusion coefficient were deduced to be 48 kJ mol−1 and 8.0 × 10−15 cm2 s−1 based on optical and electrochemical measurements, respectively. The desorption process followed the nucleation and growth mechanism by modeling and simulating the resistance data. The small activation energy and remarkable diffusion kinetics highlighted the applicability as on-board hydrogen storage systems. 相似文献
12.
Xuancheng Wang Xuezhang Xiao Jiaguang Zheng Zhouming Hang Wenping Lin Zhendong Yao Meng Zhang Lixin Chen 《International Journal of Hydrogen Energy》2021,46(46):23737-23747
Magnesium borohydride, Mg(BH4)2, is ball-milled with Ti nano-particles. Such catalyzed Mg(BH4)2 releases more hydrogen than pristine Mg(BH4)2 does during isothermal dehydrogenation at 270, 280, and 290 °C. The catalyzed Mg(BH4)2 also exhibits better dehydrogenation kinetics than the pristine Mg(BH4)2. Based on kinetics model fitting, the activation energy (Ea) of the catalyzed Mg(BH4)2 is calculated to be lower than pristine Mg(BH4)2. During partial dehydrogenation, the catalyzed Mg(BH4)2 releases 4.23 wt % (wt%) H2 for the second dehydrogenation at 270 °C, comparing to 4.05, and 3.75 wt% H2 at 280, and 290 °C. The reversibility of 4.23 wt% capacity is also one of the highest for Mg(BH4)2 dehydrogenation under mild conditions such as 270 °C as reported. 4 cycles of Mg(BH4)2 dehydrogenation are conducted at 270 °C. The capacities degrade during 4 cycles and tend to be stable at about 3.0 wt% for the last two cycles. By analyzing the hydrogen de/absorption products of the catalyzed sample, Mg(BH4)2 is found to be regenerated after rehydrogenation according to Fourier Transform Infrared (FTIR) spectroscopy. Ti nano-particles can react with Mg(BH4)2 during ball-milling and de/rehydrogenation. The products include TiH1.924, TiB, and TiB2, which can improve the dehydrogenation properties of Mg(BH4)2 from a multiple aspect. 相似文献
13.
《International Journal of Hydrogen Energy》2022,47(62):26458-26467
LiAlH4 is an ideal hydrogen storage material with a theoretical hydrogen storage capacity of 10.6 wt%. In order to reduce the hydrogen release temperature and increase the hydrogen release amount of LiAlH4, multilayer graphene oxide and nickel (FGO-Ni) composite catalyst were prepared by physical ball milling and doped into LiAlH4. The effect of FGO-Ni composite catalyst on the dehydrogenation performance of LiAlH4 was studied by pressure-composition-temperature apparatus, scanning electron microscope (SEM) and X-ray diffractometer. The results show that, compared with pure LiAlH4, the hydrogen release time of LiAlH4 doped with 9 wt%FGO-3wt%Ni is obviously shortened about 90min at 150 °C and the hydrogen release amount of LiAlH4 doped with 9 wt%FGO-3wt%Ni also increased 1.8 wt%. Importantly, the dehydrogenation amount of LiAlH4 (9 wt%FGO)-3wt% could reach 4 wt% at 135 °C which was 4 times higher than that of the pure LiAlH4. At the same temperature, the hydrogen release of pure LiAlH4 was only 0.84 wt%. In contrast, doping FGO-Ni composite catalyst reduces the hydrogen release temperature of LiAlH4 and weakens the hydrogen release barrier. Forthermore, SEM results showed that doping FGO-Ni reduced the agglomeration between LiAlH4 particles and increased the specific surface area of the sample, which improving the hydrogen release properties of LiAlH4. 相似文献
14.
Xavier A. Ojeda Facundo J. Castro Santiago A. Pighin Horacio E. Troiani M. Sergio Moreno Guillermina Urretavizcaya 《International Journal of Hydrogen Energy》2021,46(5):4126-4136
A study to determine the optimal content of Nb(V) ethoxide required to efficiently catalyze the H2 sorption kinetics in the Mg/MgH2 system is reported. The materials were synthesized by hand mixing different amounts of additive (from 0.10 to 1 mol%) to pre-milled MgH2. Considering kinetics and capacity the best performance corresponds to a 0.25 mol% of Nb ethoxide concentration. With this material, a remarkable kinetic behavior with excellent reversibility is obtained: 5.3 wt% and 5.1 wt% of hydrogen are absorbed and desorbed respectively at 300 °C in 3 min. At 250 °C the material absorbs 5.2 wt% of hydrogen and releases 3.7 wt% in 10 min. Thermal desorption starts at 247 °C and peaks at 268 °C. The H2 sorption properties of all the materials remain unchanged after 10 cycles of absorption and desorption at 300 °C, and the best material reversibly takes in and releases 5.3 wt% of H2 during a 10 min combined cycle. The kinetic improvement of the hydrogen desorption and absorption properties is attributed to an enhancement of the kinetic processes that occur on the surface of the material, due to the excellent spreading of the liquid additive at nanometric level, as revealed by SEM/EDS and TEM/EELS. 相似文献
15.
Jianjun Jiang Jia WeiHaiyan Leng Qian LiKuo-Chih Chou 《International Journal of Hydrogen Energy》2013
The various Mg–B–Al–H systems composed of Mg(BH4)2 and different Al-sources (metallic Al, LiAlH4 and its decomposition products) have been investigated as potential hydrogen storage materials. The role of Al was studied on the dehydrogenation and the rehydrogenation of the systems. The results indicate that the different Al-sources exhibit a similar improving effect on the dehydrogenation properties of Mg(BH4)2. Taking the Mg(BH4)2 + LiAlH4 system as an example, at first LiAlH4 rapidly decomposes into LiH and Al, then Mg(BH4)2 decomposes into MgH2 and B, finally the MgH2 reacts with Al, LiH and B, which forms Mg3Al2 and MgAlB4. The system starts to desorb H2 at 140 °C and desorbs 3.6 wt.% H2 below 300 °C, while individual Mg(BH4)2 starts to desorb H2 at 250 °C and desorbs only 1.3 wt.% H2 below 300 °C. The isothermal desorption kinetics of the Mg–B–Al–H systems is about 40% faster than that of Mg(BH4)2 at the hydrogen desorption ratio of 90%. In addition, the Mg–B–Al–H systems show partial reversibility at moderate temperature and pressure. For Al-added system, the product of rehydrogenation is MgH2, while for LiAlH4-added system the product is composed of LiBH4 and MgH2. 相似文献
16.
《International Journal of Hydrogen Energy》2019,44(23):11961-11969
The hydrogen absorption and desorption properties of a MgH2 – 1 mol.% Nb(V) ethoxide mixture are reported. The material was prepared by hand mixing the additive with previously ball-milled MgH2. Nb ethoxide reacts with MgH2 during heating, releasing C2H6 and H2, and producing MgO and Nb or Nb hydride. Hydriding and dehydriding are greatly enhanced by the use of the alkoxide. At 250 °C the material with Nb takes up 1.8 wt% in 30 s compared with 0.1 wt% of pure Mg, and releases 4.2 wt% in 30 min, whereas MgH2 without Nb does not appreciably desorb hydrogen. The absorption and desorption activation energies are reduced from 153 kJ/mol H2 to 94 kJ/mol H2, and from 176 kJ/mol H2 to 75 kJ/mol H2, respectively. The hydrogen sorption properties remain stable after 10 cycles at 300 °C. The kinetic improvement is attributed to the fine distribution of amorphous/nanometric NbHx achieved by the dispersion of the liquid additive. 相似文献
17.
《International Journal of Hydrogen Energy》2014,39(35):20024-20030
Holmium borohydride, Ho(BH4)3, its composites with LiBH4, and a mixed–cation derivative, K[Ho(BH4)4], have been prepared via mechanochemical reaction between HoCl3, LiBH4 (and also KBH4 in case of K[Ho(BH4)4]). These compounds are isostructural to the related rare earth borohydrides, adopting α-Y(BH4)3, β-Y(BH4)3, and Na[Sc(BH4)4]-type structures, respectively. The relative amount of α-Ho(BH4)3 and β-Ho(BH4)3 can be controlled by the composition of reagents. While β-Ho(BH4)3 has not been obtained from stoichiometric mixtures of HoCl3 and LiBH4, the excess of LiBH4 favours it as the main product. Thermal decomposition of α-Ho(BH4)3, as well as K[Ho(BH4)4] commences above 170 °C, with the fastest rate within 250–260 °C, which is slightly lower than for the corresponding borohydrides of yttrium. LiBH4 is destabilised thermally in the composites with β-Ho(BH4)3, which leads to desorption of >40% total amount of H2 below 450 °C, while in case of pure LiBH4 only <20% total amount of H2 is released in these conditions. The catalytic mechanism is as yet unknown. 相似文献
18.
《International Journal of Hydrogen Energy》2022,47(74):31903-31910
Lithium alanate (LiAlH4) is considered as a promising material for storing hydrogen (H2) in solid-state form for onboard applications due to its advantage of high gravimetric H2 capacity. LiAlH4 could release H2 ~7.9 wt.% when heated up to ~250 °C. Nevertheless, the high desorption temperature, sluggish desorption kinetics, and irreversibility hamper the application of LiAlH4 for solid-state H2 storage materials. Therefore, in this study, we have used aluminum titanate (Al2TiO5) as an additive to diminish the desorption temperature and enhance the desorption kinetics of LiAlH4. The addition of a small amount of Al2TiO5 (5 wt.%) into LiAlH4 significantly decreased the decomposition temperature and enhanced the desorption kinetics, in which Al2TiO5-doped LiAlH4 started to release H2 at ~90 °C and was able to desorb H2 as much as ~3.5 wt.% at 90 °C within 1 h. Without the catalyst, pure LiAlH4 starts to release H2 at ~145 °C and only desorbs H2 as low as 0.3 wt.% at 90 °C within 1 h. The activation energies for H2 release in the two-step desorption process of LiAlH4 were reduced after catalysis with Al2TiO5. The activation energies of as-milled LiAlH4 were 80 kJ/mol and 91 kJ/mol, respectively, as calculated by the Arrhenius plot. The activation energies were lowered to 68 kJ/mol and 79 kJ/mol after milling with Al2TiO5. The scanning electron microscopy images revealed that the LiAlH4 particles became smaller and less agglomerated when Al2TiO5 was added. It is believed that the in-situ formation of active species during the desorption process and reduction in particles size play a vital role in improving the dehydrogenation properties of the Al2TiO5-doped LiAlH4 system. 相似文献
19.
Ya-Ru Zhang Bao-Xia Dong Juan Zhao Yun-Lei Teng Zong-wei Li Lu Wang 《International Journal of Hydrogen Energy》2017,42(27):17149-17156
In this paper, the hydrogen storage properties of the LiNH2LiH system doped with K2TiF6 were investigated and discussed. Interestingly, the hydrogen storage properties are significantly enhanced by introducing K2TiF6 into the LiNH2LiH system. By doping 5 mol% K2TiF6 in the LiNH2LiH system, we obtain the hydrogen desorption peak temperature (233 °C) at a heating rate of 10 °C min?1, which is approximately 66 °C lower than that of the pristine LiNH2LiH system. Moreover, the system begins to desorb H2 at 75 °C, which is approximately 124 °C lower than in the pristine LiNH2LiH system. The isothermal desorption kinetics at 250 °C and 300 °C clearly reflects the dramatically improved kinetic properties. Additionally, the reversibility of the LiNH2LiH system can be drastically enhanced by adding K2TiF6. We propose that the dehydrogenation property of the K2TiF6-doped LiNH2LiH sample is improved by the synergetic effects of K, Ti and F. 相似文献
20.
Juner Chen Yao ZhangZhitao Xiong Guotao WuHailiang Chu Teng HePing Chen 《International Journal of Hydrogen Energy》2012
Co-based catalyst can significantly improve the dehydrogenation kinetics of the eutectic composite of LiBH4–Mg(BH4)2 (1/1 M ratio). The onset hydrogen desorption temperature of the composite is at about 155 °C, which is ca. 245, 110 or 27 °C lower than that of LiBH4, Mg(BH4)2 or pristine LiBH4–Mg(BH4)2, respectively. Upon holding the samples at 270 °C, the Co catalyzed composite can release hydrogen at a rate 1.6 times faster than that of the pristine one. Electron Paramagnetic Resonance (EPR) characterization evidenced that Co was in a reduced state of Co+ which may serve as the functional species in catalyzing the dehydrogenation of the composite. 相似文献