Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy
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 nan...
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| Format: | Article |
| Language: | English |
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MDPI AG
2016-12-01
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| Series: | Energies |
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| Online Access: | http://www.mdpi.com/1996-1073/9/12/1073 |
| _version_ | 1818007191711383552 |
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| author | Chaoqi Shen Kondo-Francois Aguey-Zinsou |
| author_facet | Chaoqi Shen Kondo-Francois Aguey-Zinsou |
| author_sort | Chaoqi Shen |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-14T05:12:27Z |
| format | Article |
| id | doaj.art-458fe0ccf8094f459f04dee90ded5209 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-04-14T05:12:27Z |
| publishDate | 2016-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-458fe0ccf8094f459f04dee90ded52092022-12-22T02:10:29ZengMDPI AGEnergies1996-10732016-12-01912107310.3390/en9121073en9121073Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation EnergyChaoqi Shen0Kondo-Francois Aguey-Zinsou1Merlin Group, School of Chemical Engineering, The University of New South Wales, Sydney 2052, NSW, AustraliaMerlin Group, School of Chemical Engineering, The University of New South Wales, Sydney 2052, NSW, AustraliaThe 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.http://www.mdpi.com/1996-1073/9/12/1073hydrogen storagemagnesiumparticle sizenanosizeactivation energy |
| spellingShingle | Chaoqi Shen Kondo-Francois Aguey-Zinsou Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy Energies hydrogen storage magnesium particle size nanosize activation energy |
| title | Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy |
| title_full | Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy |
| title_fullStr | Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy |
| title_full_unstemmed | Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy |
| title_short | Electrodeposited Magnesium Nanoparticles Linking Particle Size to Activation Energy |
| title_sort | electrodeposited magnesium nanoparticles linking particle size to activation energy |
| topic | hydrogen storage magnesium particle size nanosize activation energy |
| url | http://www.mdpi.com/1996-1073/9/12/1073 |
| work_keys_str_mv | AT chaoqishen electrodepositedmagnesiumnanoparticleslinkingparticlesizetoactivationenergy AT kondofrancoisagueyzinsou electrodepositedmagnesiumnanoparticleslinkingparticlesizetoactivationenergy |