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.

The Role of Cr in H Desorption Kinetics in Rapidly Solidified Al

2014 ◽  
Vol 783-786 ◽  
pp. 264-269 ◽  
Author(s):  
Iya I. Tashlykova-Bushkevich ◽  
Keitaro Horikawa ◽  
Goroh Itoh
Keyword(s):  
High Temperature ◽  
Thermal Desorption ◽  
High Purity ◽  
Thermal Desorption Spectroscopy ◽  
Secondary Phase ◽  
Hydrogen Desorption ◽  
Oxide Surface ◽  
Desorption Kinetics ◽  
Hydrogen Trapping ◽  
Rapidly Solidified

Hydrogen desorption kinetics for rapidly solidified high purity Al and Al-Cr alloy foils containing 1.0, 1.5 and 3.0 at % Cr were investigated by means of thermal desorption analysis (TDA) at a heating rate of 3.3°C/min. For the first time, it was found that oxide inclusions of Al2O3 are dominant high-temperature hydrogen traps compared with pores and secondary phase precipitates resulted in rapid solidification of Al and its alloys. The correspondent high-temperature evolution rate peak was identified to be positioned at 600°C for high purity Al and shifted to 630°C for Al-Cr alloys. Amount of hydrogen trapped by dislocations increases in the alloys depending on Cr content. Microstructural hydrogen trapping behaviour in low-and intermediate temperature regions observed here was in coincidence with previous data obtained for RS materials using thermal desorption spectroscopy (TDS). The present results on hydrogen thermal desorption evolution indicate that the effect of oxide surface layers becomes remarkable in TDA measurements and show advantages in combinations of both desorption analysis methods to investigate hydrogen desorption kinetics in materials.

Non-isothermal and isothermal hydrogen desorption kinetics of zirconium hydride

2015 ◽  
Vol 467 ◽  
pp. 349-356 ◽  
Author(s):  
Mingwang Ma ◽  
Wei Xiang ◽  
Binghua Tang ◽  
Li Liang ◽  
Lei Wang ◽  
...  
Keyword(s):  
Hydrogen Desorption ◽  
Zirconium Hydride ◽  
Desorption Kinetics ◽  
Kinetics Of

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.

scholarly journals Effect of Al, Fe Addition on Thermodynamic Stability and Hydrogen Desorption KInetics from MgH2 Phase OF Mechanical Alloy

2015 ◽  
Vol 16 (3) ◽  
pp. 576-585 ◽  
Author(s):  
О.G. Еrshova ◽  
A.Yu. Koval ◽  
Yu.М. Solonin ◽  
V.D. Dobrovolsky
Keyword(s):  
Mechanical Alloy ◽  
Mechanochemical Synthesis ◽  
Thermodynamic Stability ◽  
Thermal Desorption Spectroscopy ◽  
Hydrogen Desorption ◽  
Hydrogen Atmosphere ◽  
Desorption Kinetics ◽  
Reactive Milling ◽  
Kinetics Of ◽  
Complex Doping

With the aim of lowering the temperature, improve the kinetics of the decomposition of stoichiometric hydride MgH2 was investigated the possibility of its complex doping Al, Fe using mechanochemical synthesis (RMS). The MA1 sample was derived by reactive milling  Mg + 10 wt% Al + 10 wt. % Fe powder mixture in the hydrogen atmosphere at pressure of 1.2 MPa in a reactor for 10 h. The formation (in conditions of mechanochemical synthesis) of hydride of solid solution of Al and Fe in magnesium Mg(Al,Fe)H2 was experimentally checked. Found that adding to magnesium Al & Fe leads to lower of thermodynamic stability and, consequently, to lower the temperature of the beginning of desorption of hydrogen to 250 0C at 0,1MPa H2 (compared to MgH2 without Al and Fe). After the first cycles of hydrogenation-dehydrogenation from gas phase MA, established by isobaric thermal desorption spectroscopy, the effect of lowering the temperature of the beginning desorbtion 315 0C (for non-alloy phase MgH2) to 250 0C was observed. Adding to magnesium aluminum with Fe significantly improves the kinetics of desorption of hydrogen from the hydride phase MgH2 mechanical alloy produced by RMS.

Kinetics of subsurface hydrogen adsorbed on niobium: Thermal desorption studies

2002 ◽  
Vol 17 (10) ◽  
pp. 2698-2704 ◽  
Author(s):  
A. L. Cabrera ◽  
J. Espinosa-Gangas ◽  
Johan Jonsson-Akerman ◽  
Ivan K. Schuller
Keyword(s):  
Heat Treatment ◽  
Carbon Monoxide ◽  
Thermal Desorption ◽  
Hydrogen Adsorption ◽  
Thermal Desorption Spectroscopy ◽  
Hydrogen Desorption ◽  
X Ray Diffraction ◽  
Surface Sites ◽  
Adsorption Desorption ◽  
Kinetics Of

The adsorption/absorption of hydrogen and the adsorption of carbon monoxide by niobium foils, at room temperature, was studied using thermal desorption spectroscopy. Two hydrogen desorption peaks were observed with a maximum at 404 and 471 K. The first hydrogen desorption peak is regarded as hydrogen desorbing from surface sites while the second peak, which represents desorption from surface sites stronger bound to the surface, also has a component—due to its tailing to higher temperatures—of hydrogen diffusing from subsurface sites. Carbon monoxide adsorption was used to determine the number of surface sites, since it does not penetrate below the surface. Two carbon monoxide desorption peaks are observed in these experiments: at 425 and 608 K. The first peak is regarded as the adsorption of molecular carbon monoxide, and the second, as carbon monoxide dissociated on the niobium surface. The crystallographic orientation of the foils was determined by x-ray diffraction and showed a preferential (110) orientation of the untreated foil due to the effect of cold rolling. This preferential orientation decreased after hydrogen/heat treatment, appearing strong also in the (200) and (211) orientations. This change in texture of the foils is mainly due to the effect of heat treatment and not to hydrogen adsorption/desorption cycling. The kinetics of hydrogen and CO desorption is compared with that of Pd and Pd alloys.

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.

Oxidation behaviour of zirconium hydride and its influence on the thermal desorption kinetics

2018 ◽  
Vol 134 ◽  
pp. 199-210 ◽  
Author(s):  
Mingwang Ma ◽  
Lei Wang ◽  
Yuan Wang ◽  
Wei Xiang ◽  
Binghua Tang ◽  
...  
Keyword(s):  
Thermal Desorption ◽  
Oxidation Behaviour ◽  
Zirconium Hydride ◽  
Desorption 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
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