Catalitic effect of Co on hydrogen desorption form nanostucturated magnesium hydride

To study the influence of 3d transition metal addition on desorption kinetics of MgH2 ball milling of MgH2-Co blends was performed under Ar. Microstructural and morphological characterization, performed by XRD and SEM, show a huge correlation with thermal stability and hydrogen desorption properties investigated by DSC. A complex desorption behavior is correlated with the dispersion of the metal additive particles on hydride matrix. The activation energy for H2 desorption from MgH2-Co composite was calculated from both non-isothermal and isothermal methods to be 130 kJ/mol which means that mutually diffusion and nucleation and growth of new phase control the dehydration process.

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Hydrogen desorption from nanostructured magnesium hydride composites

Hemijska industrija ◽

10.2298/hemind0702071b ◽

2007 ◽

Vol 61 (2) ◽

pp. 71-74

Author(s):

Tanja Brdaric ◽

Ljiljana Stamenkovic ◽

Nikola Novakovic ◽

Jasmina Grbovic-Novakovic

Keyword(s):

Hydrogen Desorption ◽

Morphological Characterization ◽

Magnesium Hydride ◽

Sem Analysis ◽

Main Role ◽

Desorption Peak ◽

Additive Particles ◽

Metal Addition ◽

Thermal Stability Of ◽

Metal Additive

The influence of 3d transition metal addition (Fe, Co and Ni) on the desorption properties of magnesium hydride were studied. The ball milling of MgH2-3d metal blends was performed under Ar. Microstructural and morphological characterization were performed by XRD and SEM analysis, while the hydrogen desorption properties were investigated by DSC. The results show a strong correlation between the morphology and thermal stability of the composites. The complex desorption behavior (the existence of more than one desorption peak) was correlated with the dispersion of the metal additive particles that appear to play the main role in the desorption. The desorption temperature can be reduced by more than 100 degrees if Fe is added as additive. The activation energy for H2 desorption from the MgH2-Fe composite is 120 kJ/mol, implying that diffusion controls the dehydration process.

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

Molecules ◽

10.3390/molecules23123113 ◽

2018 ◽

Vol 23 (12) ◽

pp. 3113 ◽

Cited By ~ 3

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.

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

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2013.10.107 ◽

2014 ◽

Vol 39 (2) ◽

pp. 862-867 ◽

Cited By ~ 15

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

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Hydrogen desorption kinetics of MgH2 synthesized from modified waste magnesium

Materials Science-Poland ◽

10.2478/s13536-014-0218-9 ◽

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.347-353.3420 ◽

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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