Kinetics of Hydrogen Desorption From Ni—In Composites, Synthesized by Electrochemical Method

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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Preparation and Hydrogen Storage Kinetics of Nanocrystalline and Amorphous Mg20Ni8M2 (M=Cu, Co) Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.586.50 ◽

2012 ◽

Vol 586 ◽

pp. 50-57

Author(s):

Yang Huan Zhang ◽

Tai Yang ◽

Hong Wei Shang ◽

Guo Fang Zhang ◽

Xia Li ◽

...

Keyword(s):

Hydrogen Storage ◽

Melt Spinning ◽

Nanocrystalline Structure ◽

Hydrogen Desorption ◽

Amorphous Structure ◽

Saturation Ratio ◽

Cu Alloy ◽

Nanocrystalline And Amorphous ◽

Kinetics Of ◽

Co Alloys

In order to obtain a nanocrystalline and amorphous structure, the Mg20Ni8M2 (M=Cu, Co) hydrogen storage alloys were fabricated by the melt spinning technology. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of the melt spinning on the hydriding and dehydriding kinetics of the alloys were investigated. The results indicate that the as-spun (M=Cu) alloys hold an entire nanocrystalline structure even if the limited spinning rate is applied, while the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure as the spinning rate grows to 30 m/s, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning remarkably improves the gaseous hydriding and dehydriding kinetics of the alloys. As the spinning rate grows from 0 (As-cast was defined as the spinning rate of 0 m/s) to 30 m/s, the hydrogen absorption saturation ratio ( ) is enhanced from 56.72% to 92.74% for the (M=Cu) alloy and from 80.43% to 94.38% for the (M=Co) alloy. The hydrogen desorption ratio ( ) is raised from14.89% to 40.37% for the (M=Cu) alloy and from 24.52% to 51.67% for the (M=Co) alloy.

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Kinetics of CxNy formation on electrode surface using the electrochemical method

Science of Sintering ◽

10.2298/sos0802147c ◽

2008 ◽

Vol 40 (2) ◽

pp. 147-154

Author(s):

A. Chekhovskii ◽

T. Tomila ◽

A. Ragulya ◽

I. Timofeeva ◽

A. Ivanchuk ◽

...

Keyword(s):

Electron Microscopy ◽

Ir Spectroscopy ◽

Electrode Material ◽

Electrode Surface ◽

Electrochemical Method ◽

Deposition Process ◽

Absorption Bands ◽

X Ray ◽

Kinetics Of ◽

Electrolysis Products

Powded CxNy coatings were deposited from acetonitrile on Ni, Si, and C surfaces at a voltage 500-2000 V by the electrochemical method. Electrolysis products were analyzed by IR spectroscopy, X-ray phase analysis and electron microscopy. According to FTIR data, at frequencies 1370 and 1530 cm-1, absorption bands characteristic for stretching C-N and C=N oscillations are observed. The obtained results indicate that the deposition process occurs in a different manner in each specific case, i.e., the kinetics of the electrode depends on the electrode material (Ni, Si, and C).

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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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A new, general electrochemical method of determining enzyme kinetics. Kinetics of the enzymic hydrolysis of thiocholine lodide esters

Analytical Biochemistry ◽

10.1016/0003-2697(63)90118-0 ◽

1963 ◽

Vol 5 (3) ◽

pp. 208-216 ◽

Cited By ~ 14

Author(s):

George G. Guilbault ◽

David N. Kramer ◽

Paul L. Cannon

Keyword(s):

Enzyme Kinetics ◽

Electrochemical Method ◽

Enzymic Hydrolysis ◽

Kinetics Of ◽

Hydrolysis 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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