Hostname: page-component-76fb5796d-wq484 Total loading time: 0 Render date: 2024-04-25T07:48:22.534Z Has data issue: false hasContentIssue false
  • English
  • Français

Hydrogen Sorption in Magnesium Nanoparticles: Size- and Surface-related Phenomena

Published online by Cambridge University Press:  31 January 2011

Luca Pasquini ,
Elsa Callini ,
Emanuela Piscopiello ,
Amelia Montone ,
Torben René Jensen ,
Marco Vittori Antisari  and
Ennio Bonetti
Luca Pasquini
Affiliation:
luca.pasquini@unibo.it, University of Bologna, Physics, Bologna, Italy
Elsa Callini
Affiliation:
elsa.callini@unibo.it, University of Bologna, Physics, Bologna, Italy
Emanuela Piscopiello
Affiliation:
emanuela.piscopiello@enea.it, ENEA, Brindisi, Italy
Amelia Montone
Affiliation:
amelia.montone@enea.it, ENEA, Rome, Italy
Torben René Jensen
Affiliation:
trj@chem.au.dk, Univeristy of Aarhus, Dept. of Chemistry and iNANO, Aarhus, Denmark
Marco Vittori Antisari
Affiliation:
marco.vittori@enea.it, ENEA, Rome, Italy
Ennio Bonetti
Affiliation:
ennio.bonetti@unibo.it, University of Bologna, Physics, Bologna, Italy
Get access

Abstract

The aim of this work is the investigation of the metal-hydride transformation in magnesium (Mg) nanoparticles both as a function of particle size and in response to surface functionalization by clusters of transition metals (TM): Pd, Ni, Ti.

Mg nanoparticles were synthesized by the inert-gas condensation technique, which yields single crystals with six-fold symmetry whose average size can be controlled by tuning the inert gas pressure. After the synthesis the nanoparticles were passivated by slow exposure to oxygen, obtaining a core-shell morphology where a metallic core is coated by a MgO shell of about 5 nm thickness.

The material structure was investigated by Transmission Electron Microscopy (TEM), also in High Resolution (HRTEM) mode, and by X-Ray Diffraction (XRD). The sorption kinetics were analysed by a volumetric Sievert apparatus, which also allowed for a determination of the activation energies.

Small nanoparticles (≈35 nm) display interesting kinetics with gravimetric capacity of 4.5 wt.% at saturation, limited by the oxide fraction. Hydride formation proceeds by one-dimensional growth controlled by diffusion through the hydride, while the reverse transformation to metal involves interface-controlled three-dimensional growth of nuclei formed at constant rate.

On the contrary, large nanoparticles (≈450 nm) exhibit very low reactivity due to reduced probability of hydrogen dissociation/recombination and nucleation at the particle surface. For this reason, large nanoparticles were surface-decorated by TM through in situ evaporation in the inert-gas condensation chamber. This procedure results in clusters of 3-4 nm located over a portion of the MgO shell, as shown by XRD and HRTEM on Pd-decorated sample. This treatment results in dramatically improved hydrogen sorption behavior. In fact, previously inert nanoparticles now exhibit of up to 5.6 wt.%.

Real-time diffraction studies using Synchrotron Radiation were carried out during hydrogen desorption on the Pd-decorated nanoparticles. We clearly show that a Mg-Pd intermetallic phase is formed after the first heating treatment and takes active part in the transformation.

Keywords

Hnanostructurekinetics
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1216: Symposium W – Hydrogen Storage Materials , 2009 , 1216-W05-04
Copyright
Copyright © Materials Research Society 2010

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Durgun, E. Ciraci, S. Yildirim, T. Phys. Rev. B77 085405 (2008).Google Scholar
2 Zhao, Y. Kim, Y.H. Dillon, A.C. Heben, M.J. Zhang, S.B. Phys. Rev. Lett. 94, 155504 (2005).Google Scholar
3 Yoon, M. Yang, S. Hicke, C. Wang, E. Geohegan, D. Zhang, Z. Phys. Rev. Lett. 100 206806 (2008).Google Scholar
4 Rosi, N.L. Eckert, J. Eddaoudi, M. Vodak, D.T. Kim, J. O'Keeffe, M., Yaghi, O.M. Science 300 1127 (2003).Google Scholar
5 Gremaud, R. Baldi, A. Gonzalez-Silveira, M., Dam, B. Griessen, R. Phys. Rev. B77 144204 (2008).Google Scholar
6 Barkhordarian, G. Klassen, T. Bormann, R. J. Phys. Chem. B110 11020 (2006).Google Scholar
7 Wagemans, R.W.P. van Lenthe, J.H., de Jongh, P.E., van Dillen, A.J., Jongh, K.P. de, J. Am. Chem. Soc. 127 16675 (2005).Google Scholar
8 Gross, A.F. Ahn, C.C. Atta, S. L. Van, Liu, P. Vajo, J.J. Nanotechnology 20 204005 (2009).Google Scholar
9 Nielsen, T.K. Manickam, K. Hirscher, M. Besenbacher, F. Jensen, T.R. ACS NANO, in the press, DOI: 10.1021/nn901072w.Google Scholar
10 Pasquini, L. Callini, E. Piscopiello, E. Montone, A. Antisari, M. Vittori, Bonetti, E. Appl. Phys. Lett. 94 221905 (2009).Google Scholar
11 Callini, E. Pasquini, L. Piscopiello, E. Montone, A. Antisari, M. Vittori, Bonetti, E. Appl. Phys. Lett. 94 041918 (2009).Google Scholar
12 Huot, J. Yonkeu, A. Dufour, J. J. Alloys Comp. 475 168 (2009).Google Scholar
13 Montone, A. Grbovic, J. Antisari, M. Vittori, Bassetti, A. Bonetti, E. Fiorini, A.L. Pasquini, L. Mirenghi, L. Rotolo, P. Int. J. Hydrog. Energy 32 2926 (2007).Google Scholar