Reversible hydrogen storage in Ti decorated small boron clusters: Insights from molecular dynamics simulations

Abstract

We report the hydrogen adsorption capacity of Ti doped boron clusters (BnTi2, n = 6–10) using dispersion corrected density functional theory. The stability and the reactivity of the studied clusters were confirmed by their reactivity indices. It was shown that each titanium atom can accommodate up to 5H2 molecules with average adsorption energy falling in the range of 0.15–0.21 eV/H2 via Niu-Rao-Jena kind of interaction. An elongation in H–H bond length was found to be 0.76–0.80 Å with average Ti–H2 bond distance being 2.754 Å which confirmed molecular physisorption of H2. The molecular dynamics simulation demonstrated that, these clusters could adsorb all H2 molecules at low temperature (77K) while desorbing almost all the H2 molecules at 300K and 373K. The occupation number calculation revealed that these clusters could hold up to 10.20 wt % of H2 molecules at storage condition (100K-60bar).