Solid–State Hydrogen Storage Materials with Excellent Selective Hydrogen Adsorption in the Presence of Alkanes, Oxygen, and Carbon Dioxide by Atomic Layer Amorphous Al2O3 Encapsulation

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 .