The high-capacity hydrogen storage abilities of the Ti atoms coated Si@Al12 clusters

The storage of hydrogen molecules by Ti atoms coated Si@Al12 clusters is investigated using the density functional method. Ti atoms are bonding strongly to the surface of Si@Al12 and are not clustered. Ti–Si@Al12 and Ti2–Si@Al12 can adsorb 6 and 12 H2 molecules with the adsorption energy per H2 of 0.53 and 0.44 eV respectively. The hydrogen gravimetric density of Ti2–Si@Al12·12H2 is 6.6 wt%, exceeding the 5.5 wt% at 2015 specified by US Department of Energy. Therefore, the stable Si@Al12 can be applied as one candidate for hydrogen storage materials at near-ambient conditions.