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LAPSE:2019.0383
Published Article
LAPSE:2019.0383
Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy
February 27, 2019
The kinetics of hydrogen absorption/desorption can be improved by decreasing particle size down to a few nanometres. However, the associated evolution of activation energy remains unclear. In an attempt to clarify such an evolution with respect to particle size, we electrochemically deposited Mg nanoparticles on a catalytic nickel and noncatalytic titanium substrate. At a short deposition time of 1 h, magnesium particles with a size of 68 ± 11 nm could be formed on the nickel substrate, whereas longer deposition times led to much larger particles of 421 ± 70 nm. Evaluation of the hydrogen desorption properties of the deposited magnesium nanoparticles confirmed the effectiveness of the nickel substrate in facilitating the recombination of hydrogen, but also a significant decrease in activation energy from 56.1 to 37.8 kJ·mol−1 H₂ as particle size decreased from 421 ± 70 to 68 ± 11 nm. Hence, the activation energy was found to be intrinsically linked to magnesium particle size. Such a reduction in activation energy was associated with the decrease of path lengths for hydrogen diffusion at the desorbing MgH₂/Mg interface. Further reduction in particle size to a few nanometres to remove any barrier for hydrogen diffusion would then leave the single nucleation and growth of the magnesium phase as the only remaining rate-limiting step, assuming that the magnesium surface can effectively catalyse the dissociation/recombination of hydrogen.
Keywords
activation energy, hydrogen storage, magnesium, nanosize, particle size
Suggested Citation
Shen C, Aguey-Zinsou KF. Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy. (2019). LAPSE:2019.0383
Author Affiliations
Shen C: Merlin Group, School of Chemical Engineering, The University of New South Wales, Sydney 2052, NSW, Australia
Aguey-Zinsou KF: Merlin Group, School of Chemical Engineering, The University of New South Wales, Sydney 2052, NSW, Australia [ORCID]
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Journal Name
Energies
Volume
9
Issue
12
Article Number
E1073
Year
2016
Publication Date
2016-12-16
Published Version
ISSN
1996-1073
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Original Submission
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PII: en9121073, Publication Type: Journal Article
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LAPSE:2019.0383
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doi:10.3390/en9121073
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Feb 27, 2019
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CC BY 4.0
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Feb 27, 2019
 
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Original Submitter
Calvin Tsay
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