Synthesis and hydrogen storage properties of mechanically ball-milled SiC/MgH2 nanocomposites

The hydrogen storage characteristics of SiC/MgH2 nanocomposites which are prepared by mechanical ball milling of MgH2 and SiC with cyclohexane have been studied. MgH2 as a starting material exhibited a desorption peak of hydrogen at 705 K in thermal desorption spectrometry (TDS), while the ball-milled SiC/MgH2 nanocomposites showed much lower desorption temperatures near 437 K. The hydrogen storage properties of SiC/MgH2 were significantly improved as a result of nanocomposite formation. In addition, the nanocomposites were characterized by X-ray diffraction (XRD), thermogravimetry (TG), differential scanning calorimeter (DSC) and pressure–composition isotherm (PCT) measurements. For the SiC/MgH2 nanocomposites, the reversibility of hydrogen absorption/desorption was observed, but heating above 573 K led to the irreversible breakdown of nanocomposites into MgH2 and SiC.