Thermal desorption of hydrogen from magnesium hydride (MgH2): An in situ microscopy study by environmental SEM and TEM

As-received magnesium hydride (MgH2), and MgH2 doped with lithium borohydride (LiBH4) and titanium (III) chloride (TiCl3) catalyst were heated – in situ – in an environmental scanning electron microscope (ESEM) and a transmission electron microscope (TEM). Morphological and structural changes during heating and hydrogen desorption were recorded in real time. The studies show that native MgH2 undergoes dramatic and destructive structural changes upon heating, whereas the doped/catalyzed MgH2 mixture showed a benign outgassing with little structural change. Videos of the morphological changes during heating can be viewed online at the McGrady group website: http://www.unb.ca/fredericton/science/chem/smcgrady/group/shanebeattie/InsituESEMandTEM-MgH2.html.