Abstract
In this work, Ti deposited C-20, Si-20, and KSi20 as hydrogen storage materials have been studied utilizing the DFT (B3LYP and M06-2X)/6-311 g (d,p). The encapsulated K atom in the Si-20 cluster provides the fullerene regular shape to the KSi20 cluster. The Ti atom tends to bind with two adjacent C or Si atoms. The Ti@Si-20 can absorb up to five hydrogen molecules while Ti@C-20 and Ti@KSi20 can adsorb more than five hydrogen molecules. The calculated enthalpy difference emphasizes the physisorption of hydrogen on the investigated clusters for a number of hydrogen molecules greater than one. For a wide range number of hydrogen molecules (n = 1-6) for the nH(2)/Ti@KSi20, the adsorption energy per hydrogen molecule ((E) over bar (ads)) values satisfy the United States Department of Energy (DOE) target for hydrogen storage materials while for nH(2)/Ti@C-20 and nH(2)/Ti@Si-20 the target is satisfied for n = 3-6 and n = 4-5, respectively. This means that the small-stabilized KSi20 fullerene may be a candidate material for hydrogen storage applications. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.