Catalytic effect of nano-particle 3d-transition metals on hydrogen storage properties in magnesium hydride MgH2 prepared by mechanical milling

Hanada Nobuko

Ichikawa Takayuki

Fujii Hironobu

Journal of Physics and Chemistry of Solids

We examined the catalytic effect of nano-particle 3d-transition metals on hydrogen desorption (HD) properties of MgH2 prepared by mechanical ball milling method. All the MgH2 composites prepared by adding a small amount of nano-particle Fenano, Conano, Ninano and Cunano metals and by ball milling for 2h showed much better HD properties than the pure ball-milled MgH2 itself. Especially, the 2 mol% Ninano-doped MgH2 composite prepared by soft milling for a short milling time of 15 min under a slow milling revolution speed of 200 rpm shows the most superior hydrogen storage properties: A large amount of hydrogen (~6.5 wt.%) is desorbed in the temperature range from 150 to 250 ºC at a heating rate of 5 ºC /min under He gas flow with no partial pressure of hydrogen. The EDX micrographs corresponding to Mg and Ni elemental profiles indicated that nano-particle Ni metals as catalyst homogeneously dispersed on the surface of MgH2. In addition, it was confirmed that the product revealed good reversible hydriding/dehydriding cycles even at 150 ºC. The hydrogen desorption kinetics of catalyzed and non-catalyzed MgH2 could be understood by a modified first order reaction model, in which the surface condition was taken into account.

Hydrogen storage materials

Magnesium hydride

Mechanical milling

catalytic effect

nano-particle metal

Physics [ 420 ]

eng

Elsevier B.V.

Copyright (c) 2003 Elsevier B.V.

[ISSN] 0022-3697

[DOI] 10.1016/j.jpcs.2003.08.039

[NCID] AA00704949

[DOI] http://dx.doi.org/10.1016/j.jpcs.2003.08.039