Hydrogen capability of bimetallic boron cycles: A DFT and ab initio MD study

Abstract

Bimetallic boron cycle, B6C2TM2 (TM = scandium, titanium), was recently predicted to have high stability and aromaticity. The hydrogen capabilities of these clusters were studied in the present work. Our computational results indicate that the gravimetric hydrogen uptake capacity of B6C2Sc2 and B6C2Ti2 and clusters are 11.7% and 11.4%, respectively. The adsorption energies of H2 molecules on B6C2Sc2 and B6C2Ti2 clusters are predicted with different calculational schemes to meet the criteria of reversible hydrogen storage. The interaction of H2 with B6C2Ti2 cluster is a little stronger than that with B6C2Sc2. Ab initio molecular dynamics simulations indicate that H2 molecules can be efficiently released from the metal sites of B6C2TM2 clusters at room temperature. The bulk-like B6C2Sc2 and B6C2Ti2 tetramer can also efficiently adsorb H2 molecules.