scholarly journals Atoms and Nanoparticles of Transition Metals as Catalysts for Hydrogen Desorption from Magnesium Hydride

2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
N. Bazzanella ◽  
R. Checchetto ◽  
A. Miotello
Keyword(s):  
Composite Materials ◽  
Transition Metal ◽  
Transition Metals ◽  
Hydrogen Desorption ◽  
Magnesium Hydride ◽  
Desorption Kinetics ◽  
Fast Diffusion ◽  
Desorption Process ◽  
Metal Additives ◽  
Kinetics Of

The hydrogen desorption kinetics of composite materials made of magnesium hydride with transition metal additives (TM: Nb, Fe, and Zr) was studied by several experimental techniques showing that (i) a few TM at.% concentrations catalyse the H2desorption process, (ii) the H2desorption kinetics results stabilized after a few H2sorption cycles when TM atoms aggregate by forming nanoclusters; (iii) the catalytic process occurs also at TM concentration as low as 0.06 at.% when TM atoms clustering is negligible, and (iv) mixed Fe and Zr additives produce faster H2desorption kinetics than single additive. The improved H2desorption kinetics of the composite materials can be explained by assuming that the interfaces between the MgH2matrix and the TM nanoclusters act as heterogeneous sites for the nucleation of the Mg phase in the MgH2matrix and promote the formation of fast diffusion channels for H migrating atoms.

Effect of transition-metal additives on hydrogen desorption kinetics of MgH2

2013 ◽  
Vol 102 (3) ◽  
pp. 033902 ◽  
Author(s):  
Anindya Roy ◽  
Anderson Janotti ◽  
Chris G. Van de Walle
Keyword(s):  
Transition Metal ◽  
Hydrogen Desorption ◽  
Desorption Kinetics ◽  
Metal Additives ◽  
Kinetics Of

Effects of Ti-based catalysts on hydrogen desorption kinetics of nanostructured magnesium hydride

2014 ◽  
Vol 39 (36) ◽  
pp. 21007-21014 ◽  
Author(s):  
M. Daryani ◽  
A. Simchi ◽  
M. Sadati ◽  
H. Mdaah Hosseini ◽  
H. Targholizadeh ◽  
...  
Keyword(s):  
Hydrogen Desorption ◽  
Magnesium Hydride ◽  
Desorption Kinetics ◽  
Kinetics Of

The Kinetics of Hydrogen Desorption From Zirconium Hydride

2013 ◽  
Author(s):  
Mingwang Ma ◽  
Ruiyun Wan ◽  
Yuan Wang ◽  
Yanlin Cheng ◽  
Li Liang ◽  
...  
Keyword(s):  
Thermal Desorption ◽  
Thermal Desorption Spectroscopy ◽  
Hydrogen Desorption ◽  
Pressure Effects ◽  
Zirconium Hydride ◽  
Desorption Kinetics ◽  
Desorption Process ◽  
Exponential Factor ◽  
Predict Weight Loss ◽  
Kinetics Of

Thermal desorption spectroscopy (TDS) was used to study the thermal desorption kinetics of zirconium hydride films, which were deposited on molybdenum substrates and thermally charged with gas phase hydrogen. The observed desorption peaks were attributed to phase transforming steps. The activation energy and pre-exponential factor for desorption kinetics was estimated as 116 kJ/mol and 8762 s−1 according to Kissinger relation, respectively. A simulation of TDS spectra was made, which showed that the desorption process followed a first order kinetics. The kinetic parameters were then utilized to predict weight loss behavior at a temperature profile. Pressure effects that can potentially reduce the desorption rate were discussed.

scholarly journals Improvement of Hydrogen Desorption Characteristics of MgH2 With Core-shell Ni@C Composites

Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3113 ◽  
Author(s):  
Cuihua An ◽  
Qibo Deng
Keyword(s):  
Low Cost ◽  
Hydrogen Desorption ◽  
Core Shell ◽  
Desorption Kinetics ◽  
Hydrogen Storage Materials ◽  
High Hydrogen ◽  
Dehydrogenation Kinetics ◽  
Materials Research ◽  
High Theoretical Capacity ◽  
Kinetics Of

Magnesium hydride (MgH2) has become popular to study in hydrogen storage materials research due to its high theoretical capacity and low cost. However, the high hydrogen desorption temperature and enthalpy as well as the depressed kinetics, have severely blocked its actual utilizations. Hence, our work introduced Ni@C materials with a core-shell structure to synthesize MgH2-x wt.% Ni@C composites for improving the hydrogen desorption characteristics. The influences of the Ni@C addition on the hydrogen desorption performances and micro-structure of MgH2 have been well investigated. The addition of Ni@C can effectively improve the dehydrogenation kinetics. It is interesting found that: i) the hydrogen desorption kinetics of MgH2 were enhanced with the increased Ni@C additive amount; and ii) the dehydrogenation amount decreased with a rather larger Ni@C additive amount. The additive amount of 4 wt.% Ni@C has been chosen in this study for a balance of kinetics and amount. The MgH2-4 wt.% Ni@C composites release 5.9 wt.% of hydrogen in 5 min and 6.6 wt.% of hydrogen in 20 min. It reflects that the enhanced hydrogen desorption is much faster than the pure MgH2 materials (0.3 wt.% hydrogen in 20 min). More significantly, the activation energy (EA) of the MgH2-4 wt.% Ni@C composites is 112 kJ mol−1, implying excellent dehydrogenation kinetics.

Investigation of surface and near-surface effects on hydrogen desorption kinetics of MgH2

2014 ◽  
Vol 39 (2) ◽  
pp. 862-867 ◽  
Author(s):  
Sandra Kurko ◽  
Igor Milanović ◽  
Jasmina Grbović Novaković ◽  
Nenad Ivanović ◽  
Nikola Novaković
Keyword(s):  
Surface Effects ◽  
Hydrogen Desorption ◽  
Desorption Kinetics ◽  
Near Surface ◽  
Kinetics Of

scholarly journals Hydrogen desorption kinetics of MgH2 synthesized from modified waste magnesium

2014 ◽  
Vol 32 (3) ◽  
pp. 385-390
Author(s):  
Aysel Kantürk Figen ◽  
Bilge Coşkuner ◽  
Sabriye Pişkin
Keyword(s):  
Hydrogen Desorption ◽  
Nitrogen Atmosphere ◽  
Desorption Kinetics ◽  
X Ray Diffraction ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Xrf Scanning ◽  
Isothermal Kinetic ◽  
Kinetics Of

AbstractIn the present study, hydrogen desorption properties of magnesium hydride (MgH2) synthesized from modified waste magnesium chips (WMC) were investigated. MgH2 was synthesized by hydrogenation of modified waste magnesium at 320 °C for 90 min under a pressure of 6 × 106 Pa. The modified waste magnesium was prepared by mixing waste magnesium with tetrahydrofuran (THF) and NaCl additions, applying mechanical milling. Next, it was investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) techniques in order to characterize its structural properties. Hydrogen desorption properties were determined by differential scanning calorimetry (DSC) under nitrogen atmosphere at different heating rates (5, 10, and 15 °C/min). Doyle and Kissenger non-isothermal kinetic models were applied to calculate energy (Ea) values, which were found equal to 254.68 kJ/mol and 255.88 kJ/mol, respectively.

Hydriding and Dehydriding Characteristics of As-Spun Nanocrystalline and Amorphous Mg20Ni10-xMnx (x = 0-4) Alloys

2011 ◽  
Vol 347-353 ◽  
pp. 3420-3424
Author(s):  
Yang Huan Zhang ◽  
Xiao Gang Liu ◽  
Le Le Chen ◽  
Hui Ping Ren ◽  
Guo Fang Zhang ◽  
...  
Keyword(s):  
Amorphous Phase ◽  
Hydrogen Absorption ◽  
Melt Spinning ◽  
Hydrogen Desorption ◽  
Absorption Capacity ◽  
Desorption Kinetics ◽  
Nanocrystalline And Amorphous ◽  
Cast Alloys ◽  
Mn Content ◽  
Kinetics Of

The nanocrystalline and amorphous Mg2Ni-type Mg20Ni10-xMnx (x = 0, 1, 2, 3, 4) alloys were synthesized by melt-spinning technique. The structures of the as-cast and spun alloys were characterized by XRD, SEM and HRTEM. The hydrogen absorption and desorption kinetics of the alloys were measured. The results show that the substitution of Mn for Ni, instead of changing the major phase Mg2Ni, leads to the formation of Mg and MnNi phases. No amorphous phase is detected in the as-spun Mn-free alloy, but the as-spun alloys substituted by Mn display the presence of an amorphous phase, suggesting that the substitution of Mn for Ni enhances the glass forming ability of the Mg2Ni-type alloy. The hydrogen absorption capacity of the as-cast alloys first increases and then decreases with the variation of the amount of Mn substitution. The hydrogen desorption capacity of the alloys markedly increases with growing Mn content.

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