Enhanced Hydrogen Storage Properties of LiAlH₄ by Excellent Catalytic Activity of XTiO₃@<i>h</i>‐BN (X = Co, Ni)

Abstract

Abstract The high desorption temperature and slow kinetics still restrict the applications of LiAlH 4 in hydrogen storage. To solve the above problems, NiTiO 3 @ h ‐BN and CoTiO 3 @ h ‐BN prepared for the first time are introduced into LiAlH 4 by ball milling. LiAlH 4 doped with 7 wt% NiTiO 3 @ h ‐BN, selected as an optimal doping sample, starts to release hydrogen at 68.1 °C, and the total amount of hydrogen released is 7.11 wt% below 300 °C. The activation energies ( E a ) of the two‐step hydrogen release reactions are 55.93 and 59.25 kJ∙mol −1 , which are 45.8% and 69.0% lower than those of as‐received LiAlH 4 , respectively. Under 30 bar hydrogen pressure and 300 °C constant temperature, LiAlH 4 doped with 7 wt% NiTiO 3 @ h ‐BN after dehydrogenation can absorb ≈1.05 wt% hydrogen. Based on density functional theory calculations, AlNi 3 and NiTi, in situ formed nanoparticles during ball milling, can decrease the desorption energy barrier of AlH bonding in LiAlH 4 and accelerate the breakdown of AlH bonding due to the interfacial charge transfer and the dehybridization. Furthermore, NiTi can enhance the adsorption and splitting of H 2 , promoting the activation of H 2 molecules during the rehydrogenation process.