Porous MgH2/C composite with fast hydrogen storage kinetics

A porous MgH2/C composite can be synthesized through decomposition of an organo-magnesium precursor under hydrogen pressure. XRD patterns of the porous MgH2/C composite exhibit a pure MgH2 phase with a tetragonal structure. The morphology of the resulted samples is significantly dependent on the synthesis temperature and hydrogen pressure. The samples exhibit a rod-like structure and composed of nano-crystallites of MgH2 with a size of less than 5 nm. TPD spectra of a sample synthesized at 220 °C for 4 h show a remarkable decrease of the onset hydrogen release temperature. Further, this sample also exhibits fast hydrogen adsorption kinetics adsorbing 6 wt % of hydrogen in 3 min at 250 °C. The same amount of hydrogen is adsorbed in 11 min at 200 °C and 40 min at 150 °C, respectively. N2 physisorption measurements of this sample indicate meso-porosity with a BET surface area of 40.9 m2 g−1 and an average pore diameter of 20 nm.