scholarly journals Facilitated Synthesis of Mg2Ni Based Composites with Attractive Hydrogen Sorption Properties

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1936
Author(s):  
Eli Grigorova ◽  
Petar Tzvetkov ◽  
Stanislava Todorova ◽  
Pavel Markov ◽  
Tony Spassov
Keyword(s):  
Particle Size ◽  
Gas Phase ◽  
Storage Capacity ◽  
Hydrogen Atmosphere ◽  
Hydrogen Gas ◽  
Hydrogen Storage Capacity ◽  
Primary Metal ◽  
High Hydrogen ◽  
Good Contact ◽  
Kinetics Of

Composites based on Mg2Ni with 5% activated carbon from apricot stones (ACAP) have been prepared by ball milling and subsequent annealing in hydrogen atmosphere. The purpose of the primary metal (Mg, Ni, and V) milling was to reduce the particle size and achieve a good contact between them, without forming intermetallic compounds. During hydriding/dehydriding at 300 °C the amount of the Mg2Ni phase progressively increased, and after 10 cycles about 50% Mg2(Ni,V) was achieved. The hydrogenation produced mainly Mg2NiH4, but small amounts of MgH2 and VHx were also detected in the powder mixture. Relatively high hydrogen storage capacity and fast hydriding/dehydriding kinetics of the Mg2.1Ni0.7V0.3—5 wt.% ACAP composite were determined both from hydrogen gas phase and electrochemically.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Mechanochemical synthesis of a Mg-Li-Al-H complex hydride

2009 ◽  
Vol 24 (9) ◽  
pp. 2880-2885 ◽  
Author(s):  
Jing Zhang ◽  
Wei Yan ◽  
Chenguang Bai ◽  
Fusheng Pan
Keyword(s):  
Solid Solution ◽  
Hydrogen Storage ◽  
Storage Capacity ◽  
Raw Materials ◽  
Initial Step ◽  
Hydrogen Atmosphere ◽  
Al Alloy ◽  
Hydrogen Storage Capacity ◽  
Scanning Calorimetry ◽  
Complex Hydride

Mg-Li-Al alloy was prepared by ingot casting and then underwent subsequent reactive ball milling. A Mg-Li-Al-H complex hydride was obtained under a 0.4 MPa hydrogen atmosphere at room temperature, and as high as 10.7 wt% hydrogen storage capacity was achieved, with the peak desorption temperature of the initial step at approximately 65 °C. The evolution of the reaction during milling, as well as the effect of Li/Al ratio in the raw materials on the desorption properties of the hydrides formed, were studied by x-ray diffraction and simultaneous thermogravimetry and differential scanning calorimetry techniques. The results showed that mechanical milling increases the solubility of Li in Mg, leading to the transformation of bcc β(Li) solid solution to hcp α(Mg) solid solution, the latter continues to incorporate Li and Al, which stimulates the formation of Mg-Li-Al-H hydride. A lower Li/Al ratio resulted in faster hydrogen desorption rate and a greater amount of hydrogen released at a low temperature range, but sacrificing total hydrogen storage capacity.

scholarly journals Improvement in Hydriding and Dehydriding Features of Mg–TaF5–VCl3 Alloy by Adding Ni and x wt% MgH2 (x = 1, 5, and 10) Together with TaF5 and VCl3

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1194
Author(s):  
Young-Jun Kwak ◽  
Myoung-Youp Song
Keyword(s):  
Particle Size ◽  
Hydrogen Storage ◽  
Mechanical Milling ◽  
Storage Capacity ◽  
Reaction Rates ◽  
Cycling Performance ◽  
Hydrogen Storage Capacity ◽  
Effective Hydrogen

In our previous work, TaF5 and VCl3 were added to Mg, leading to the preparation of samples with good hydriding and dehydriding properties. In this work, Ni was added together with TaF5 and VCl3 to increase the reaction rates with hydrogen and the hydrogen-storage capacity of Mg. The addition of Ni together with TaF5 and VCl3 improved the hydriding and dehydriding properties of the TaF5 and VCl3-added Mg. MgH2 was also added with Ni, TaF5, and VCl3 and Mg-x wt% MgH2-1.25 wt% Ni-1.25 wt% TaF5-1.25 wt% VCl3 (x = 0, 1, 5, and 10) were prepared by reactive mechanical milling. The addition of MgH2 decreased the particle size, lowered the temperature at which hydrogen begins to release rapidly, and increased the hydriding and dehydriding rates for the first 5 min. Adding 1 and 5 wt% MgH2 increased the quantity of hydrogen absorbed for 60 min, Ha (60 min), and the quantity of hydrogen released for 60 min, Hd (60 min). The addition of MgH2 improved the hydriding–dehydriding cycling performance. Among the samples, the sample with x = 5 had the highest hydriding and dehydriding rates for the first 5 min and the best cycling performance, with an effective hydrogen-storage capacity of 6.65 wt%.

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
Keyword(s):  
Hydrogen Storage ◽  
Phase Evolution ◽  
Good Method ◽  
Planetary Mill ◽  
Hydrogen Storage Capacity ◽  
High Hydrogen ◽  
Reactive Milling ◽  
Low Weight ◽  
Hydrogen Reactions ◽  
Kinetics Of

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.

scholarly journals Recent advances on the thermal destabilization of Mg-based hydrogen storage materials

RSC Advances ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 408-428 ◽  
Author(s):  
Jianfeng Zhang ◽  
Zhinian Li ◽  
Yuanfang Wu ◽  
Xiumei Guo ◽  
Jianhua Ye ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Storage Capacity ◽  
Magnesium Hydride ◽  
Hydrogen Storage Materials ◽  
Hydrogen Storage Capacity ◽  
High Hydrogen ◽  
Storage Materials ◽  
Recent Advances

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.

Reduction Behavior of W and Cu Oxides Powder Mixture

2008 ◽  
Vol 135 ◽  
pp. 143-149
Author(s):  
Seong Lee ◽  
Joon Woong Noh ◽  
Eun Pyo Kim ◽  
Moon Hee Hong
Keyword(s):  
Gas Phase ◽  
Powder Mixture ◽  
Hydrogen Atmosphere ◽  
Hydrogen Gas ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
Composite Powders ◽  
Reduction Behavior ◽  
Scanning Electron Microscopic ◽  
Increasing Temperature

The reduction behavior of WO3 and CuO powder mixture has been studied by using thermo-gravimetric(TG), X-ray diffraction, and scanning electron microscopic analyses. The powder mixture was manufactured by ball-milling. It was found that W coated W-Cu composite powders were formed when reducing the powder mixture under hydrogen atmosphere. The following reduction steps are suggested as a mechanism for the formation of W coated W-Cu composite powders: with increasing temperature, Cu is initially reduced from CuO and the reduction reactions of WO3 to WO2 via WO2.9 and WO2.72 are followed. The gas phase WO2(OH)2 is formed by the reaction of the WO2 and water vapor, and then WO2(OH)2 diffuses toward Cu surface and deposits on it as W by reducing reaction with environmental hydrogen gas. The formation mechanism of W coated W-Cu composite powders involving the gas phase transportation reaction has been confirmed by the model experiment conducted by using Cu plate and WO3 powder.

Regeneration of Ammonia-Borane Complex for Hydrogen Storage

2005 ◽  
Vol 884 ◽  
Author(s):  
Nahid Mohajeri ◽  
Ali T-Raissi
Keyword(s):  
Hydrogen Storage ◽  
Energy Efficient ◽  
Storage Capacity ◽  
Storage System ◽  
Cost Effective ◽  
Hydrogen Storage Capacity ◽  
High Hydrogen ◽  
The Past ◽  
Hydrogen Storage System ◽  
Energy Center

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.

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