First-principles study on hydrogen storage in Al-, Ca-, Mn-doped MgNi clusters

Abstract

Using a density functional approach calculation, the structural and electronic properties of Mg8Ni5, Mg8Ni4Al, Mg8Ni4Ca and Mg8Ni4Mn clusters are investigated. The Al-, Ca-, Mn-doping in MgNi clusters lengthen [Formula: see text], also increase the Mulliken charge, and improve magnetic moment on most shell atoms, so that the doping is helpful for hydrogen storage. The reaction heats of hydrogenation, the enthalpies of formation, the desorption energies show that the Mg8Ni4Mn, Mg8Ni5, Mg8Ni4Al clusters have a good property of hydrogen storage materials with relatively higher reaction heat of hydrogenation, and that their hydrides have a smaller desorption energy. So the Mg8Ni4M (M = Ni, Al, Ca, Mn) clusters are some preferred candidates of H storage. These results indicate the advantage of small size and suitable metal-doped MgNi clusters on hydrogenation and dehydrogenation.

Alloying Ratio Versus Cluster Size for Reversible Hydrogen Storage in Ni Doped Small Mg Clusters: Dispersion Corrected DFT Study

“…They reported the formation of Al 4 M 2 (H 2 ) 2n and Be 3 M 2 (H 2 ) 2n complexes by Al 4 M 2 and Be 3 M 2 clusters on adsorption of multiple hydrogen molecules [7]. Among the light elements, Mg based materials have been studied extensively in the recent years to design H 2 storage medium because of the advantageous properties such as cost effectiveness, abundance and non-toxicity etc [12,13,14,15,16,17,18,19,20,21,22,23,24].In a recent review, Xie et al have discussed the first principles studies of particle size and dehydrogenation of M gH 2 and hydrogen adsorption properties of Mg surfaces, where it has been observed that Mg-H bond gets weakened with decreasing particle size [12]. Yartys et al have given a comprehensive report on the latest activities and historic overviews of Mg based hydrogen storage materials conferring the seriousness of improving their kinetics and thermodynamic properties [15].…”

Accentuating the Competency of $3d$ Transition Metal Doped $Mg_4$ Clusters towards Molecular Hydrogen Adsorption: A DFT Study

“…Therefore, the light elements such as Be, Na, Mg, Al, K and Li due to their reasonably less molecular masses are given importance to achieve high gravimetric density of H 2 for on-board applications [4,5,6,7,8].In a previous study on aromatic bimetallic clusters via density functional theory (DFT) calculation, K. Srinivasu and co-workers have reported high gravimetric density of hydrogen in hydrogenated Al 4 M 2 , Be 3 M 2 , M g 3 M 2 etc (M=Li, Na, K) clusters and proposed the formation of complexes Al 4 M 2 (H 2 ) 2n and Be 3 M 2 (H 2 ) 2n by Al 4 M 2 and Be 3 M 2 clusters through adsorption of multiple hydrogen molecules [7]. Recently Mg based materials have been widely studied to design H 2 storage medium because of their many advantageous properties such as cost effectiveness, abundance, non-toxicity and storage capacity [9,10,11,12,13,14,15,16,17,18,19]. Yartys et al, in 2019 have reported a very comprehensive review on Mg based hydrogen storage materials including the latest activities, historic overviews and also projecting outlines on future developments putting special importance on improving kinetics and thermodynamic properties [12].…”