Remarkable catalysis of spinel ferrite XFe2O4(X=Ni,Co,Mn,Cu,Zn)nanoparticles on the dehydrogenation properties of LiAlH_(4):An experimental and theoretical study

摘要

Safe,compact,lightweight and cost-effective hydrogen storage is one of the main challenges that need to be addressed to effectively deploy the hydrogen economy.LiAlH_(4),as a solid-state hydrogen storage material,presents several advantages such as high hydrogen storage capacity,low price and abundant sources.Unfortunately,neither thermodynamic nor kinetic properties of dehydrogenation for LiAlH_(4)can fulfill the requirements of practical application.Thus,a series of spinel ferrite nanoparticles such as XFe_(2)O_(4)(X=Ni,Co,Mn,Cu,Zn,Fe)were prepared by using the modified thermal decomposition method,and then doped into LiAlH_(4)by using ball milling.Our results show that LiAlH_(4)doped with 7 wt%NiFe_(2)O_(4)starts to release hydrogen at 69.1°C,and the total amount of hydrogen released is 7.29 wt%before 300°C.The activation energies of the two-step hydrogen release reactions of LiAlH_(4)doped with 7 wt%NiFe_(2)O_(4)are 42.32 kJ mol^(-1)and 71.42 k J mol,which are 59.0%and 63.6%lower than those of as-received LiAlH_(4),respectively.Combining the density functional theory(DFT)calculations,we reveal that both the presence of Ni FeOand in-situ formed AlNiin ball-milling decrease the desorption energy barrier of Al-H bonding in LiAlH_(4)and accelerate the breakdown of Al-H bonding through the interfacial charge transfer and the dehybridization of the Al-H cluster.Thus,the experimental and theoretical results open a new avenue toward designing high effective catalysts applied to LiAlH_(4)as a candidate for hydrogen storage.