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Fabrication and hydrogen sorption behaviour of nanoparticulate MgH_2 incorporated in a porous carbon host

Gross, Adam F. and Ahn, Channing C. and Van Atta, Sky L. and Liu, Ping and Vajo, John J. (2009) Fabrication and hydrogen sorption behaviour of nanoparticulate MgH_2 incorporated in a porous carbon host. Nanotechnology, 20 (20). p. 204005. ISSN 0957-4484. https://resolver.caltech.edu/CaltechAUTHORS:20090812-105527043

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Abstract

Nanoparticles of MgH_2 incorporated in a mesoporous carbon aerogel demonstrated accelerated hydrogen exchange kinetics but no thermodynamic change in the equilibrium hydrogen pressure. Aerogels contained pores from <2 to ~30 nm in diameter with a peak at 13 nm in the pore size distribution. Nanoscale MgH_2 was fabricated by depositing wetting layers of nickel or copper on the aerogel surface, melting Mg into the aerogel, and hydrogenating the Mg to MgH_2. Aerogels with metal wetting layers incorporated 9–16 wt% MgH_2, while a metal free aerogel incorporated only 3.6 wt% MgH_2. The improved hydrogen sorption kinetics are due to both the aerogel limiting the maximum MgH_2 particle diameter and a catalytic effect from the Ni and Cu wetting layers. At 250 °C, MgH_2 filled Ni decorated and Cu decorated carbon aerogels released H_2 at 25 wt% h^−1 and 5.5 wt% h^−1, respectively, while a MgH_2 filled aerogel without catalyst desorbed only 2.2 wt% h^−1 (all wt% h^−1 values are with respect to MgH_2 mass). At the same temperature, MgH_2 ball milled with synthetic graphite desorbed only 0.12 wt% h^−1, which demonstrated the advantage of incorporating nanoparticles in a porous host.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/0957-4484/20/20/204005DOIArticle
http://www.iop.org/EJ/abstract/0957-4484/20/20/204005/PublisherArticle
Additional Information:© 2009 IOP Publishing. Received 29 September 2008, in final form 27 October 2008. Published 23 April 2009. We thank the US Department of Energy (DOE contract DEFC36- 05GO15067) for support of this work. One of us (CCA) would like to acknowledge DoE through contract DE-FC36- 05GO15065. TEM work benefited from use of the Caltech KNI and Mat Sci TEM facilities supported by the MRSEC Programme of the National Science Foundation under Award Number DMR-0520565.
Group:Kavli Nanoscience Institute
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-FC36-05GO15067
Department of Energy (DOE)DE-FC36-05GO15065
NSFDMR-0520565
Issue or Number:20
Record Number:CaltechAUTHORS:20090812-105527043
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20090812-105527043
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:14986
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:12 Aug 2009 18:19
Last Modified:03 Oct 2019 00:54

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