Enhanced Hydrogen Storage Properties of Magnesium Nanotrees with Nanoleaves

2009 ◽  
Vol 1216 ◽  
Author(s):  
Mehmet Cansizoglu ◽  
Tansel Karabacak
Keyword(s):  
Thin Film ◽  
Solid State ◽  
Hydrogen Storage ◽  
Hydrogen Absorption ◽  
Quartz Crystal ◽  
Gas Absorption ◽  
Desorption Kinetics ◽  
Absorption Kinetics ◽  
Solid State Materials ◽  
20 Nm

AbstractHydrogen storage in advanced solid state materials has been an intense area of research due to many drawbacks in conventional high pressure or cryogenic liquid hydrogen storage methods. A practical hydrogen storing material is required to have high storage capacity and fast dehydrogenation kinetics. Among many solid state materials for hydrogen storage, magnesium hydride (MgH2) combines a hydrogen capacity of 7.6 wt % with the benefit of the low cost of production and abundance. The main difficulties for implementing MgH2 are slow absorption/desorption kinetics and high reactivity towards air and oxygen, which are also common issues in most lightweight metal hydrides. Previously, improvements in hydrogen storage and release properties have been reported by using nanostructured magnesium that can be obtained through various fabrication methods including ball-milling, mechanical alloying, and vapor transport. In this study, we investigate the hydrogen absorption and desorption properties of magnesium “nanotrees” fabricated by glancing angle deposition (GLAD) technique, and also conventional Mg thin films deposited at normal incidence. Mg nanotrees are about 15 μm long, 10 μm wide, and incorporate “nanoleaves” of about 20 nm in thickness and 1,2 μm in lateral width. A quartz crystal microbalance (QCM) gas absorption/desorption measurement system has been used for our hydrogen storage studies. Nanostructured and thin film Mg have been deposited directly on the surface of the gold coated unpolished quartz crystal samples. QCM hydrogen storage experiments have been performed at temperatures ranging between 100-300 °C, and at H2 pressures of 10 and 30 bars. Our QCM measurements revealed that Mg nanotrees can absorb hydrogen at lower temperatures and also at a faster rate compared to Mg thin film. In addition, Mg nanotrees can reach hydrogen storage values of about 4.80 wt% at 100 °C, and up to about 6.71 wt% (which is close to the theoretical maximum storage value of Mg) at temperatures lower than 150 °C. The significant enhancement in hydrogen absorption properties of our Mg nanotrees is believed to originate from novel physical properties of their nanoleaves. These nanoleaves are very thin (∼20 nm) and both surfaces are exposed to hydrogen enhancing the diffusion rate of hydrogen together with a decreased diffusion length. Based on X-ray diffraction measurements, individual nanoleaves have non-close-packed crystal planes that can further enhance the hydrogen absorption kinetics. In addition, our nanostructured Mg have been observed to quite resistant to surface oxidation, which is believed to due to the single crystal property of the Mg nanoleaves, which further improves the absorption kinetics of hydrogen.

scholarly journals Preparation of Mg2FeH6Nanoparticles for Hydrogen Storage Properties

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
N. A. Niaz ◽  
I. Ahmad ◽  
N. R. Khalid ◽  
E. Ahmed ◽  
S. M. Abbas ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Absorption ◽  
Hydrogen Pressure ◽  
Absorption Rate ◽  
Desorption Kinetics ◽  
Prepared Compound ◽  
Hydrogen Storage Properties ◽  
Storage Properties ◽  
Effective Hydrogen ◽  
Type Apparatus

Magnesium (Mg) and iron (Fe) nanoparticles are prepared by thermal decomposition of bipyridyl complexes of metals. These prepared Mg-Fe (2 : 1) nanoparticles are hydrogenated under 4 MPa hydrogen pressure and 673 K for 48 hours to achieve Mg2FeH6. Their structural analysis was assessed by applying manifold techniques. The hydrogen storage properties of prepared compound were measured by Sieverts type apparatus. The desorption kinetics were measured by high pressure thermal desorption spectrometer (HP-TDS). More than 5 wt% hydrogen released was obtained by the Mg2FeH6within 5 min, and during rehydrogenation very effective hydrogen absorption rate was observed by the compound.

Solid-State Materials for Hydrogen Storage

2018 ◽  
pp. 443-467 ◽  
Author(s):  
Rolando Pedicini ◽  
Irene Gatto ◽  
Enza Passalacqua
Keyword(s):  
Solid State ◽  
Hydrogen Storage ◽  
Solid State Materials

An Investigation on the Gaseous and Electrochemical Hydrogen Storage Kinetics of As-Spun Nanocrystalline Mg20Ni10-xCOx (x=0-4) Alloys

2011 ◽  
Vol 393-395 ◽  
pp. 587-592
Author(s):  
Bao Wei Li ◽  
Hui Ping Ren ◽  
Zhong Hui Hou ◽  
Xiao Gang Liu ◽  
Le Le Chen ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Absorption ◽  
Melt Spinning ◽  
Nanocrystalline Structure ◽  
Hydrogen Desorption ◽  
Amorphous Structure ◽  
Desorption Kinetics ◽  
Hydrogen Storage Kinetics ◽  
Electrochemical Hydrogen Storage ◽  
Kinetics Of

In order to improve the gaseous and electrochemical hydrogen storage kinetics of the Mg2Ni-type alloys, Ni in the alloy was partially substituted by element Co. Melt-spinning technology was used for the preparation of the Mg20Ni10-xCox (x=0, 1, 2, 3, 4) hydrogen storage alloys. The structures of the as-cast and spun alloys are characterized by XRD, SEM and TEM. The gaseous hydrogen absorption and desorption kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The electrochemical hydrogen storage kinetics of the as-spun alloys is tested by an automatic galvanostatic system. The results show that the as-spun Co-free alloy holds a typical nanocrystalline structure, whereas the as-spun alloys substituted by Co display a nanocrystalline and amorphous structure, confirming that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. Both the melt spinning and the substitution of Co for Ni evidently ameliorate the hydriding and dehydriding kinetics and the HRD of the alloys. With an increase in the spinning rate from 0 (As-cast was defined as spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio ( ) of the Co4 alloy grows from 77.1 to 93.5 wt.%, the hydrogen desorption ratio ( ) from 54.5% to 70.2%, the HRD from 60.3% to 76.0%, respectively.

scholarly journals A Comprehensive Review on Hydrogen Absorption Behaviour of Metal Alloys Prepared through Mechanical Alloying

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 562 ◽  
Author(s):  
Thabang Ronny Somo ◽  
Thabiso Carol Maponya ◽  
Moegamat Wafeeq Davids ◽  
Mpitloane Joseph Hato ◽  
Mykhaylo Volodymyrovich Lototskyy ◽  
...  
Keyword(s):  
Surface Modification ◽  
Hydrogen Storage ◽  
Mechanical Alloying ◽  
Spark Plasma Sintering ◽  
Hydrogen Absorption ◽  
Melt Spinning ◽  
Desorption Kinetics ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Hydriding Kinetics

Hydride-forming alloys are currently considered reliable and suitable hydrogen storage materials because of their relatively high volumetric densities, and reversible H2 absorption/desorption kinetics, with high storage capacity. Nonetheless, their practical use is obstructed by several factors, including deterioration and slow hydrogen absorption/desorption kinetics resulting from the surface chemical action of gas impurities. Lately, common strategies, such as spark plasma sintering, mechanical alloying, melt spinning, surface modification and alloying with other elements have been exploited, in order to overcome kinetic barriers. Through these techniques, improvements in hydriding kinetics has been achieved, however, it is still far from that required in practical application. In this review, we provide a critical overview on the effect of mechanical alloying of various metal hydrides (MHs), ranging from binary hydrides (CaH2, MgH2, etc) to ternary hydrides (examples being Ti-Mn-N and Ca-La-Mg-based systems), that are used in solid-state hydrogen storage, while we also deliver comparative study on how the aforementioned alloy preparation techniques affect H2 absorption/desorption kinetics of different MHs. Comparisons have been made on the resultant material phases attained by mechanical alloying with those of melt spinning and spark plasma sintering techniques. The reaction mechanism, surface modification techniques and hydrogen storage properties of these various MHs were discussed in detail. We also discussed the remaining challenges and proposed some suggestions to the emerging research of MHs. Based on the findings obtained in this review, the combination of two or more compatible techniques, e.g., synthesis of metal alloy materials through mechanical alloying followed by surface modification (metal deposition, metal-metal co-deposition or fluorination), may provide better hydriding kinetics.

Mechanism of Improved Hydrogen Absorption Kinetics in Cast Mg-Ni Alloys

2009 ◽  
Vol 618-619 ◽  
pp. 391-394 ◽  
Author(s):  
Kazuhiro Nogita ◽  
Sean Ockert ◽  
Andrew Duguid ◽  
Jordan Pierce ◽  
Matthew Greaves
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Absorption ◽  
Atomic Scale ◽  
Desorption Kinetics ◽  
Eutectic Alloys ◽  
Atmospheric Conditions ◽  
Hydrogen Storage Properties ◽  
Ni Alloys ◽  
Slow Kinetics ◽  
Storage Properties

The potential for Mg and Mg-Ni alloys to be used as hydrogen storage alloys has been known for some time. Although the maximum storage capacity in these alloys is high (7.6wt%H2 for Mg and 3.4wt%H2 for Mg2Ni), they have, until recently, been disregarded for practical applications due to their slow kinetics and high reaction temperatures. This paper discusses the recent discovery that the non-faceted/faceted hypo-eutectic Mg-Mg2Ni system can, similar to Al-Si eutectic alloys, be modified by trace additions and that this results in improved hydrogen storage properties. The hydrogen storage properties depend on the composition, including trace levels of modifying elements, and processing conditions. In alloys of optimal composition it has been shown that the reversible storage of 6.5-7wt% H2 is possible at a rate of reaction that is far better than that previously documented. In addition, the alloy can be satisfactorily processed in air, as opposed to controlled atmospheric conditions. This paper discusses the mechanism of improved hydrogen absorption/desorption kinetics when eutectic Mg-Ni hypo-eutectic alloys are modified. This discussion is based on atomic scale analysis using electron microscopy and examination with synchrotron radiation.

Preparation and Hydrogen Storage Properties of Mg-20 wt.% Mg2Ni0.8Cr0.2 Composite with TiO2 Nanoparticles

2007 ◽  
Vol 121-123 ◽  
pp. 1293-1296
Author(s):  
X.L. Wang ◽  
Jiang Ping Tu ◽  
X.B. Zhang ◽  
C.P. Chen
Keyword(s):  
Hydrogen Storage ◽  
Tio2 Nanoparticles ◽  
Ball Milling ◽  
Driving Force ◽  
Hydrogen Absorption ◽  
Desorption Kinetics ◽  
Combined Effects ◽  
Hydrogen Storage Properties ◽  
Storage Properties

Mg and Mg-Ni-based hydrides were mechanically milled with TiO2 nanoparticles to prepare Mg-20 wt.% Mg2Ni0.8Cr0.2-1.5 wt.% TiO2 composite. XRD results showed that the hydrides decomposed partly during ball milling. Under the combined effects of the catalyst of TiO2 nanoparticles, Mg2Ni0.8Cr0.2 alloy and Ni particles precipitated, and the mechanical driving force, the composite showed rapid hydrogen absorption/desorption kinetics. The absorption temperatures of the composite were greatly decreased and the rates of hydriding were increased. The composite can absorb 4.6 wt.% H at 373 K within 3 min and desorb 4.33 wt.% H at 573 K within 20 min.

scholarly journals Water Content of Polyelectrolyte Multilayer Films Measured by Quartz Crystal Microbalance and Deuterium Oxide Exchange

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 771
Author(s):  
Joshua Kittle ◽  
Jacob Levin ◽  
Nestor Levin
Keyword(s):  
Thin Film ◽  
Water Content ◽  
Quartz Crystal Microbalance ◽  
Quartz Crystal ◽  
Deuterium Oxide ◽  
Layer By Layer ◽  
Good Precision ◽  
Poly Styrene Sulfonate ◽  
20 Nm ◽  
Instrumental Methods

Water content of natural and synthetic, thin, polymer films is of considerable interest to a variety of fields because it governs properties such as ion conductivity, rigidity, porosity, and mechanical strength. Measuring thin film water content typically requires either complicated and expensive instrumentation or use of multiple instrumental techniques. However, because a quartz crystal microbalance (QCM) is sensitive to changes in mass and viscosity, deuterated solvent exchange has emerged as a simple, single-instrument, in situ method to quantify thin film water content. Relatively few studies, though, have employed this technique to measure water content of polyelectrolyte multilayers formed by layer-by-layer (LbL) assembly. In this work, poly (allyl amine) (PAH) and poly (styrene sulfonate) (PSS) films of up to nine layers were formed and the water content for each layer was measured via QCM with deuterium oxide exchange. The well-characterized nature of PAH/PSS films facilitated comparisons of the technique used in this work to other instrumental methods. Water content results showed good agreement with the literature and good precision for hydrated films thicker than 20 nm. Collectively, this work highlights the utility, repeatability, and limitations of this deuterated exchange technique in measuring the solvent content of thin films.

Phase Structure and Hydrogen Storage Characterization of the As-Cast Mg-10Ni-2Mm Alloy

2010 ◽  
Vol 650 ◽  
pp. 150-156 ◽  
Author(s):  
N. Xing ◽  
P.C. Bai ◽  
Ying Wu ◽  
Z.C. Lu ◽  
W. Han ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Hydrogen Absorption ◽  
Absorption Capacity ◽  
Desorption Kinetics ◽  
Isothermal Temperature ◽  
Hydrogen Storage Properties ◽  
Metallic Particles ◽  
Kinetics Of ◽  
Storage Properties

The microstructural revolution of non-hydrogenated and hydrogenated Mg-based Mg-10Ni-2Mm alloy was studied. PCT and H-absorption/desorption kinetics were performed to evaluate the hydrogen storage properties. Storage capacities of 4.75, 5.03 and 5.27wt.%H for the alloy were obtained at 300, 325 and 350°C, respectively. The phases in the hydrogenated samples are mainly MgH2 and Mg2NiH4. Two absorption/desorption plateau existed in the PCT curves at each isothermal temperature. The values of ΔH and ΔS of the Mg2NiH4-formation was respectively -61.5 kJ/mol H2 and -118.6 J/mol H2 K which is lower compared with literature values. The kinetics of the H-absorption/desorption reactions for the alloy was improved by increasing the temperature. The alloy at 350°C showed the best kinetics performance of the H-absorption/desorption among the three temperatures. It is suggested that metallic particles and Mm may be mainly responsible for the improvement of the H-absorption/desorption kinetics, and Ni for the enhancement of hydrogen absorption capacity of the alloys.

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