Synthesis of MgH2 and Mg2FeH6 by Reactive Milling of Mg-Based Mixtures Containing Fluorine and Iron

2008 ◽  
Vol 570 ◽  
pp. 39-44 ◽  
Author(s):  
Antoine Vaichere ◽  
Daniel Rodrigo Leiva ◽  
Tomaz Toshimi Ishikawa ◽  
Walter José Botta Filho

A good method to store hydrogen is in it atomic form in crystalline structure of metals at low pressure. Thanks to magnesium’s high hydrogen storage capacity, its low weight and its high natural abundance, it is an attractive material to develop hydrogen solid state storage. The production of Mg-based nanocomposites can enhance the kinetics of H-sorption of magnesium and the temperature of release of hydrogen. Transition metals as iron, which have important catalytic activity in hydrogen reactions with Mg, and the surface protective compound MgF2, are interesting additions for magnesium mixtures for hydrogen storage. In this work, Mg-based nanocomposites containing Fe and MgF2 were produced by reactive milling under hydrogen using the addition of FeF3, or directly MgF2 and Fe. The efficiency of centrifugal and planetary mill in MgH2 synthesis was compared. The phase evolution during different milling times (from 1 to 96 h) using the planetary was investigated. The different H-desorption behavior of selected milled mixtures was studied and associated with the different present phases in each case.

RSC Advances ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 408-428 ◽  
Author(s):  
Jianfeng Zhang ◽  
Zhinian Li ◽  
Yuanfang Wu ◽  
Xiumei Guo ◽  
Jianhua Ye ◽  
...  

Magnesium hydride and its compounds have a high hydrogen storage capacity and are inexpensive, and thus have been considered as one of the most promising hydrogen storage materials for on-board applications.


2005 ◽  
Vol 884 ◽  
Author(s):  
Nahid Mohajeri ◽  
Ali T-Raissi

AbstractAt the Florida Solar Energy Center (FSEC), a research program is underway for developing a high-density hydrogen storage system based on amine-borane (AB) complexes. Due to their high hydrogen capacity, these hydrides have been employed, in the past, as disposable hydrogen sources for fuel cell applications. However, to meet the requirements for hydrogen storage onboard vehicles, it is essential that cost effective and energy efficient methods for the regeneration (i.e. hydrogenation) of the spent (dehydrogenated) AB complexes can be found that utilize only hydrogen and/or electricity (i.e. the only plausible hydrogen economy energy carriers).We are studying two ammoniaborane (NH3BH3)-based systems with high hydrogen storage capacity. The first system employs a borazine-cyclotriborazane cycle. Borazine is a product of NH3BH3 thermolysis. Cyclotriborazane is the inorganic analog of cyclohexane. The second system employs polymeric AB complexes such as poly-(aminoborane) and polyborazylene. Poly-(aminoborane), an inorganic analog of polyethylene, is also a product of amoniaborane thermolysis whilepolyborazylene is the product of borazine thermolysis.For the two systems above, we are developing regeneration (i.e. reduction of borazine, poly-(aminoborane) and polyborazylene) schemes based on: 1) catalytic hydrogenation and 2) indirect (multi-step) synthesis techniques.


2021 ◽  
Vol 59 (10) ◽  
pp. 721-729
Author(s):  
Myoung Youp Song ◽  
Seong Ho Lee ◽  
Young Jun Kwak

VCl3 (vanadium (III) chloride) was selected as an additive to Mg to increase the hydrogenation and dehydrogenation rates and the hydrogen storage capacity of Mg. Instead of MgH2, Mg was used as a starting material since Mg is cheaper than MgH2. Samples with a composition of 95 wt% Mg + 5 wt% VCl3 (named Mg-5VCl3) were prepared by milling in hydrogen atmosphere (reactive milling). In the first cycle (n=1), Mg-5VCl3 absorbed 5.38 wt% H for 5 min and 5.95 wt% H for 60 min at 573 K in 12 bar hydrogen. The activation of Mg-5VCl3 was completed after three hydrogenation-dehydrogenation cycles. During milling in hydrogen, β-MgH2 and γ-MgH2 were produced. The formed β-MgH2 and γ-MgH2 are considered to have made the effects of reactive milling stronger as β-MgH2 and γ-MgH2 themselves were being pulverized. The introduced defects and the interfaces between the Mg and the phases formed during the reactive milling and during hydrogenation-dehydrogenation cycling are believed to serve as heterogeneous active nucleation sites for MgH2 and Mg-H solid solution. The phases generated during hydrogenation-dehydrognation cycling are also believed to prevent the particles from coalescing during hydrogenation-dehydrognation cycling.


2021 ◽  
Vol 59 (10) ◽  
pp. 709-717
Author(s):  
Myoung Youp Song ◽  
Seong Ho Lee ◽  
Young Jun Kwak

VCl3 (vanadium (III) chloride) was selected as an additive to Mg to increase the hydrogenation and dehydrogenation rates and the hydrogen storage capacity of Mg. Instead of MgH2, Mg was used as a starting material since Mg is cheaper than MgH2. Samples with a composition of 95 wt% Mg + 5 wt% VCl3 (named Mg-5VCl3) were prepared by milling in hydrogen atmosphere (reactive milling). In the first cycle (n=1), Mg-5VCl3 absorbed 5.38 wt% H for 5 min and 5.95 wt% H for 60 min at 573 K in 12 bar hydrogen. The activation of Mg-5VCl3 was completed after three hydrogenation-dehydrogenation cycles. During milling in hydrogen, β-MgH2 and γ-MgH2 were produced. The formed β-MgH2 and γ-MgH2 are considered to have made the effects of reactive milling stronger as β-MgH2 and γ-MgH2 themselves were being pulverized. The introduced defects and the interfaces between the Mg and the phases formed during the reactive milling and during hydrogenation-dehydrogenation cycling are believed to serve as heterogeneous active nucleation sites for MgH2 and Mg-H solid solution. The phases generated during hydrogenation-dehydrognation cycling are also believed to prevent the particles from coalescing during hydrogenation-dehydrognation cycling.


2015 ◽  
Vol 252 (9) ◽  
pp. 2072-2078 ◽  
Author(s):  
Feng Li ◽  
Changwen Zhang ◽  
Wei-Xiao Ji ◽  
Mingwen Zhao

2013 ◽  
Vol 681 ◽  
pp. 31-37
Author(s):  
Qi Wan ◽  
Ping Li ◽  
Teng Wang ◽  
Xuan Hui Qu

Two kinds of novel materials, Mg-1.6mol%Ni-0.4mol%NiO-2mol%MF (MF=NbF5, CrF3), along with Mg-1.6mol%Ni-0.4mol%NiO for comparison, were examined for their potential use in hydrogen storage applications, having been fabricated via cryomilling. The effects of NbF5 and CrF3 on hydrogen storage performance were investigated. A microstructure analysis showed that, aside from the main phase Mg, Ni and NiO phases, NbO, MgF2 and Mg2Ni were present in all samples after ball milling, MgH2 and NbH2 were observed in all samples after absorption. The CrF3-containing composite exhibited a good PCT results and a low onset desorption temperature under 0.1 MPa. The NbF5-containing composite exhibited a low absorption temperature of 323 K, a high hydrogen storage capacity of 4.03wt% at 373 K under the hydrogen pressure of 4.0 MPa, and it absorbed 90% of its full hydrogen capacity in 2700 sec and 100% in 5100 sec, it desorbed more than 1.8wt% in 3600 sec under vacuum environment. The CrF3-doped sample exhibited a low onset desorption temperature of 543 K under 0.1 MPa, and a low hysteresis coefficient of 0.25 at 573 K, and lower than 0.2 when temperature was 623 K. NbO and NbH2 played an important role in improving the absorption and desorption performance.


MRS Advances ◽  
2020 ◽  
Vol 5 (20) ◽  
pp. 1059-1069
Author(s):  
Ntumba Lobo ◽  
Alicja Klimkowicz ◽  
Akito Takasaki

AbstractMagnesium hydride (MgH2) is a prospective material for the storage of hydrogen in solid materials. It can also be envisaged for thermal energy storage applications since it has the potential to reversibly absorb hydrogen in large quantities, theoretically up to 7.6% by weight. Also, MgH2 is inexpensive, abundant, and environmentally friendly, but it operates at relatively high temperatures, and the kinetics of the hydrogenation process is slow. Mechanical milling and the addition of catalyst can alter the activation energy and the kinetic properties of the MgH2 phase. It is known that the addition of titanium hydride (TiH2) lowers the enthalpy and enhances the absorption of hydrogen from MgH2, titanium oxide (TiO2) enhances the desorption of hydrogen and niobium oxide (Nb2O5) enhances the absorption of hydrogen. In this work, the influences of the catalysts, as mentioned above on the properties of MgH2, were studied. The samples were analyzed in terms of crystal and microstructure as well as hydrogen storage properties using a pressure-composition isotherm (PCT)measurement. It has been found that the simultaneous addition of the three catalysts enhances the properties of MgH2, lowers the activation energy and operating temperature, increases the rate of intake and release of hydrogen, and provides the largest gravimetric hydrogen storage capacity.


2016 ◽  
Vol 52 (50) ◽  
pp. 7826-7829 ◽  
Author(s):  
Ayesha Naeem ◽  
Valeska P. Ting ◽  
Ulrich Hintermair ◽  
Mi Tian ◽  
Richard Telford ◽  
...  

New zirconium based metal–organic framework (UBMOF-31) synthesised using mixed-linker strategy showing permanent porosity, excellent hydrogen uptake, and high selectivity for adsorption of CO2 over N2.


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