Remarkable hydrogen storage on Sc2B42+ cluster: A computational study

The structural features, stability and hydrogen storage capacity of Sc2B42+ have been explored using density functional theory method. The former two low-lying isomers Sc2B42+01 and Sc2B42+02 can adsorb 14 and 12 hydrogen molecules respectively with respective H2 gravimetric uptake capacity of 17.49 and 15.37 wt %. Moreover, the Sc2B42+01 and Sc2B42+02 clusters are confirmed to be favorable for reversible adsorption and desorption of H2 molecules under ambient conditions, because the average adsorption energies of Sc2B42+01 (nH2) and Sc2B42+02(nH2) are in the range of −0.42 to −0.27eV/H2. The kinetic stability of H2 adsorbed on Sc2B42+01 and Sc2B42+02 clusters are researched by gap between highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). The gap values of Sc2B42+01 and Sc2B42+01 (14H2) are 2.47 and 2.88 eV, which manifests the Sc2B42+01 will be more stable after 14H2 adsorbed. Most importantly, the results of hydrogen adsorption energies with Gibbs free energy correction point that 14H2 on Sc2B42+01 and 12H2 on Sc2B42+02 are energetically favorable below 163.92 K and 174.86 K, respectively.