Comparative analysis of hydrogen uptake and release kinetics in MgH2/C composites synthesized using varied surface areas graphite powders

The synthesis process vastly conditions the temperature behaviour decomposition reactions of magnesium hydride. In our experiments, the MgH 2 /C composites were prepared by the high-energy reactive co-milling (HERBM) technique of the elemental magnesium with graphite powders in a hydrogen gas atmosp...

Full description

Saved in:
Bibliographic Details
Published in:Applied physics. A, Materials science & processing Materials science & processing, 2024-05, Vol.130 (5), Article 283
Main Authors: Lakhnik, Andrey, Kirian, Inna, Rud, Alexander
Format: Article
Language:English
Subjects:
Activation energy
Characterization and Evaluation of Materials
Composite materials
Condensed Matter Physics
Decomposition reactions
Desorption
Graphite
Hydrides
Hydrogen
Kinetics
Machines
Magnesium
Manufacturing
Nanotechnology
Optical and Electronic Materials
Physics
Physics and Astronomy
Processes
Sorption
Surface area
Surfaces and Interfaces
Thin Films
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The synthesis process vastly conditions the temperature behaviour decomposition reactions of magnesium hydride. In our experiments, the MgH 2 /C composites were prepared by the high-energy reactive co-milling (HERBM) technique of the elemental magnesium with graphite powders in a hydrogen gas atmosphere. The graphite powders with different initial specific surface areas were admixed before HERBM to magnesium as active dopants. The forming/decomposition kinetics of magnesium hydride, activation energy, and sorption/desorption mechanisms in MgH 2 /C composites were explored by the Johnson–Mehl–Avrami–Kolmogorov method. A correlation has been found between the activation energy of sorption/desorption processes and the specific area of graphite powder. The lowest hydrogen desorption activation energy (78 kJ/mol) is for the composite MgH 2 /C fabricated using graphite powder with 8.1 m 2 /g of surface area. In contrast, the lowest hydrogen sorption activation energy (65 kJ/mol) is for the MgH 2 /C composite, fabricated by co-milling magnesium and graphite powder with 329 m 2 /g surface area. It was shown the several concurrent processes rather than a single well-defined one is responsible for the hydrogen uptake/release reactions for a graphite-less sample and graphite-added ones.
ISSN:0947-8396
1432-0630
DOI:10.1007/s00339-024-07421-x