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

Abstract

AbstractThe high desorption temperature and slow kinetics still restrict the applications of LiAlH4 in hydrogen storage. To solve the above problems, NiTiO3@h‐BN and CoTiO3@h‐BN prepared for the first time are introduced into LiAlH4 by ball milling. LiAlH4 doped with 7 wt% NiTiO3@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 (Ea) 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 LiAlH4, respectively. Under 30 bar hydrogen pressure and 300 °C constant temperature, LiAlH4 doped with 7 wt% NiTiO3@h‐BN after dehydrogenation can absorb ≈1.05 wt% hydrogen. Based on density functional theory calculations, AlNi3 and NiTi, in situ formed nanoparticles during ball milling, can decrease the desorption energy barrier of AlH bonding in LiAlH4 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 H2, promoting the activation of H2 molecules during the rehydrogenation process.