Ultrasonic irradiation as a tool to modify the H-desorption from hydrides: MgH2 suspended in decane

Effects of ultrasonic irradiation on magnesium hydride (MgH2) suspended in decane were investigated with the purpose of improving its hydrogen desorption process. Firstly, we have found that the presence of MgH2 improves the sonolysis of decane enhancing the amount of hydrogen evolved during the sonication process. The sonicated-MgH2 maintains its microstructural properties practically unaltered but a drastic reduction of the particle size of MgH2 (down to ∼20 μm) as well as a high pressure MgH2 phase are observed. However, no substantial modifications of H-kinetic properties of hydride occur as is determined by thermal desorption measurements. This could be attributed to decomposition of decane during sonication which leads to the formation of carbon compounds that hinder the thermal decomposition of MgH2.