Effect of activated carbons derived from apricot stones or polyolefin wax on hydrogen sorption properties of MgH2

The hydriding and dehydriding properties of 95 wt.% MgH2 - 5 wt. % C composites, synthesized by ball milling under argon with two different carbon additives (activated carbon derived from apricot stones - AS and from polyolefin wax POW), were studied. Both samples showed no significant difference in the hydrogen absorption kinetics and reached absorption capacity of 5.8 wt.% for 95 wt.% MgH2b - 5 wt. % AS and 5.4 wt. % for 95 wt.% MgH2 - 5 wt. % POW at 573K and 1MPa after 60 min of hydriding. Faster desorption rate at 623 K and 0.15 MPa was demonstrated by the composite containing activated carbon derived from apricot stones. Morphology and phase composition of the composites were investigated by TEM and XRD.