Abstract
Metal hydrides with high hydrogen density provide promising hydrogen storage paths for hydrogen transportation. However, the requirement of highly pure H(2) for re-hydrogenation limits its wide application. Here, amorphous Al(2)O(3) shells (10 nm) were deposited on the surface of highly active hydrogen storage material particles (MgH(2)-ZrTi) by atomic layer deposition to obtain MgH(2)-ZrTi@Al(2)O(3), which have been demonstrated to be air stable with selective adsorption of H(2) under a hydrogen atmosphere with different impurities (CH(4), O(2), N(2), and CO(2)). About 4.79 wt% H(2) was adsorbed by MgH(2)-ZrTi@10nmAl(2)O(3) at 75 °C under 10%CH(4) + 90%H(2) atmosphere within 3 h with no kinetic or density decay after 5 cycles (~ 100% capacity retention). Furthermore, about 4 wt% of H(2) was absorbed by MgH(2)-ZrTi@10nmAl(2)O(3) under 0.1%O(2) + 0.4%N(2) + 99.5%H(2) and 0.1%CO(2) + 0.4%N(2) + 99.5%H(2) atmospheres at 100 °C within 0.5 h, respectively, demonstrating the selective hydrogen absorption of MgH(2)-ZrTi@10nmAl(2)O(3) in both oxygen-containing and carbon dioxide-containing atmospheres hydrogen atmosphere. The absorption and desorption curves of MgH(2)-ZrTi@10nmAl(2)O(3) with and without absorption in pure hydrogen and then in 21%O(2) + 79%N(2) for 1 h were found to overlap, further confirming the successful shielding effect of Al(2)O(3) shells against O(2) and N(2). The MgH(2)-ZrTi@10nmAl(2)O(3) has been demonstrated to be air stable and have excellent selective hydrogen absorption performance under the atmosphere with CH(4), O(2), N(2), and CO(2).