The surface and encapsulated storage of H2 on Ga12N12

Ga12N12 is a fullerene cage and particularly stable. The surface adsorption and encapsulated storage of H2 on the Ga12N12 are thoroughly explored by applying a genetic algorithm combined with DFT calculations. The results reveal that one H2 can form physical adsorption on the surface sites of Ga12N12 with ideal adsorption intensities (−0.227∼-0.303 eV) and the mode of H2 adsorption on a Ga atom is the most energy favored. Interestingly, the Ga12N12 can adsorb a maximum of 38H2 molecules with mass density of 7.01 wt%. The electronic structure analysis indicates that the charge transferring between H2 and Ga12N12 is observed. Meanwhile, H2 is also effectively polarized, and thus the electrostatic interaction is improved. When H2 is adsorbed on the Ga atom, weak covalent interactions are also induced. The encapsulation of H2 in the Ga12N12 is an endothermic process and six H2 molecules can be encapsulated in the Ga12N12 with the moderate encapsulation and releasing energy barrier of 3.286∼4.508 eV and 0.390∼3.008 eV, respectively. Our results suggest that Ga12N12 is regarded as a potential hydrogen storage material.