The hydrogen storage on heptacoordinate carbon motif CTi72+

•The covalent interaction nature in CTi72+ cluster was revealed.•The CTi72+ cluster can bind 20 H2 at most, resulting into gravimetric density of 19%.•The interaction energies meet the requirement for ambient condition applications.

The highly stable CTi72+ cluster recently theoretical predicted (J. Phys. Chem. Lett. 2012, 3, 2264) were investigated as a candidate for hydrogen storage material within DFT framework. The covalent interactions stemming from strong orbital overlaps between C-2p and Ti-3d (4s) was revealed by QTAIM and DOS analyses. The CTi72+ cluster can bind 20 H2 molecules at most, which can result into the gravimetric density of 19%. The interaction energies between H2 molecules and CTi72+ cluster are in the range of 0.24–0.31 eV at B3LYP level of theory, and these energies are about 0.1 eV larger when long range interaction was considered with wB97xD and CAM-B3LYP functionals. The binding energies for the present systems meet the thermodynamic requirement for reversible hydrogen reaction.

Graphical abstractThe CTi72+ cluster can attach up to 20 H2 molecules, which can result into gravimetric density of 19%. The interaction energies for the present systems meet the thermodynamic requirement for reversible hydrogen reaction.Figure optionsDownload full-size imageDownload as PowerPoint slide