Influence of VO <inf>2</inf> nanostructured ceramics on hydrogen desorption properties from magnesium hydride

Abstract

The hydrogen desorption properties and kinetics of MgH 2-VO 2 composite prepared by mechanical milling of MgH 2 and VO 2 have been investigated. Structural characterization of produced nanocomposite was done by X-ray powder diffraction (XRD), particle size analysis and scanning electron microscopy (SEM). The structure and morphology of the composite have been correlated with hydrogen desorption properties investigated by differential thermal analysis (DTA). It has been shown that short mechanical milling of nanostructured VO 2 and MgH 2 leads to decrease of hydrogen desorption temperature of MgH 2 by 80 K. The mechanism of desorption has been changed from phase boundary reaction, spherical symmetry for untreated MgH 2 to phase boundary reaction, cylindrical symmetry for the composite material. The activation energy for desorption has been reduced by adding VO 2 ceramics as a catalyst. © 2012 Elsevier Ltd and Techna Group S.r.l.