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Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy
- Source :
- Energies, Vol 9, Iss 12, p 1073 (2016), Energies; Volume 9; Issue 12; Pages: 1073
- Publication Year :
- 2016
- Publisher :
- MDPI AG, 2016.
-
Abstract
- 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.
- Subjects :
- Control and Optimization
Hydrogen
Energy Engineering and Power Technology
Nanoparticle
chemistry.chemical_element
nanosize
Nanotechnology
02 engineering and technology
Activation energy
magnesium
010402 general chemistry
01 natural sciences
lcsh:Technology
Catalysis
hydrogen storage
Hydrogen storage
Electrical and Electronic Engineering
Engineering (miscellaneous)
Renewable Energy, Sustainability and the Environment
Chemistry
Magnesium
lcsh:T
particle size
021001 nanoscience & nanotechnology
0104 chemical sciences
activation energy
Nickel
Chemical engineering
Particle size
0210 nano-technology
Energy (miscellaneous)
Subjects
Details
- Language :
- English
- ISSN :
- 19961073
- Volume :
- 9
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- Energies
- Accession number :
- edsair.doi.dedup.....69266af1496c9bc5ce2a6316a22038cc