Perovskiet-like BaZrO3 nanocatalyst with rich oxygen vacancies on boosting hydrogen storage property of MgH2

Magnesium hydride (MgH 2 ) as a promising solid hydrogen syorage material has been extensively researched. but the higher separating temperature and sluggish kinetics hinder its large-scale practical application. To solve this problem, a BaZrO 3 nanocatalyst with abundant oxygen vancies is manuscripted, exerts significant improvement to the hydrogen storage performance of MgH 2 . Impressively, the onset dehydrogenation temperature of MgH 2 -10 wt% BaZrO 3 -O v composite is reduced markedly from 390 °C(for pure MgH 2 ) to 260 °C. Additionally, the composite can discharge 4.22 wt% H 2 with 10 min at 275 °C and a total dehydrogenation amouut of 5.88 wt% is achieved at 300 °C. For hydrogen absorption, the composite can rapidly recharge hydrogen at a low temperature of 150 °C and approximately 5.08 wt% H 2 can be absorbed at 275 °C within 10 min. The dehydrogenation activation energy of BaZrO 3 -O v -added MgH 2 is as low as 92.61 kJ mol −1 compared to pure MgH 2 (164.78 kJ mol −1 ). Meantime, the composite presents unexceptionable reversible kinetic performance with a retention rate of 97.35 % after 10 cycles. The excellent catalytic effects can be attributed to the in-situ generation of ZrO 2 -O v , BaO-O v and ZrH 2 from BaZrO 3 -O v during the first de-/rehydrogenation cycle, which function as nanosized active sites on MgH 2 matrix to accelerate electron transfer and provide abundant hydrogen diffusion channels. Density functional theory calculations results verify that the Mg–H length and dehydrogenation energy barrier are ameliorated through BaZrO 3 -O v . This work provides a unique perspective on modification MgH 2 by perovskiet-like BaZrO 3 -O v nanocatalyst.