摘要
Novel graphene-supported FeOOH nanodots(FeOOH NDs@G)were successfully prepared by a facile hydrothermal method and doped into MgH_(2)through mechanical ball-milling.MgH_(2)with 10wt%FeOOH NDs@G began to release hydrogen at 229.8℃,which is106.8℃ lower than that of pure MgH_(2).The MgH_(2)-10wt%FeOOH NDs@G composite could reversibly absorb 6.0wt%hydrogen at 200℃ under a 3.2 MPa hydrogen pressure within 60 min.With the addition of FeOOH NDs@G,the dehydrogenation and hydrogenation activation energy of MgH_(2)was decreased to 125.03 and 58.20 kJ·mol^(-1)(156.05 and 82.80 kJ·mol^(-1)for pure MgH_(2)),respectively.Furthermore,the hydrogen capacity of the FeOOH NDs@G composite retained 98.5%of the initial capacity after 20 cycles,showing good cyclic stability.The catalytic action of FeOOH NDs@G towards MgH_(2)could be attributed to the synergistic effect between graphene nanosheets and in-situ formed Fe,which prevented the aggregation of Mg/MgH2 particles and accelerated the hydrogen diffusion during cycling,thus enabling the Mg H_(2)-10wt%FeOOH NDs@G composite to exhibit excellent hydrogen storage performance.
