Catalytic effect of monoclinic WO₃, hexagonal WO₃ and H_0.23WO₃ on the hydrogen sorption properties of Mg

Florent Tonus (1) , Valeria Fuster (2) , Guillermina Urretavizcaya (2) , Facundo J. Castro (2) , Jean-Louis Bobet (1)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Centro Atómico Bariloche [Argentine]

The H sorption properties of mixtures Mg + WO₃ (having various structures) and Mg + H_0.23WO₃ are reported. First, the higher conversion of Mg into MgH₂ during reactive mechanical grinding (under 1.1 MPa of H₂) for higher WO₃ content is due to the improvement of the milling efficiency. Then, it is shown that the hydrogen absorption properties are almost independent of the crystal structure of the catalyst and that only the particles' size and the specific surface play a major role. Finally, for the desorption process, it appears that the chemical composition and structure of the catalyst, together with the particle size and specific surface have an effect.

Mots clés: Hydrogen storage; Magnesium hydride; Kinetics; Mechanical alloying

Domaines: Matériaux

Florent Tonus, Valeria Fuster, Guillermina Urretavizcaya, Facundo J. Castro, Jean-Louis Bobet. Catalytic effect of monoclinic WO₃, hexagonal WO₃ and H_0.23WO₃ on the hydrogen sorption properties of Mg. International Journal of Hydrogen Energy, 2009, 34 (8), pp.3404-3409. ⟨10.1016/j.ijhydene.2009.02.030⟩. ⟨hal-00382198⟩