We report here a method of synthesizing MgH2-Fe3S4 composite with a series of remarkable hydrogen storage properties. For instance, compared to pure MgH2, three times higher hydrogen absorption weight (3.41 wt.% vs 0.98%) and two times faster hydrogen desorption rate (4.01 wt.% vs 2.32 wt.%) are seen in MgH2-Fe3S4 composite. Furthermore, the dehydrogenation temperature of MgH2 is also found to be reduced by 90 K with the addition of Fe3S4. By studying the reactions between MgH2 and Fe3S4 during the hydrogenation/dehydrogenation process, we found the formation of new phases (Fe and MgS) as well as their coordination play a remarkable effect on improving the hydrogen storage properties of MgH2. (C) 2015 Elsevier Ltd. All rights reserved.