Alkali and alkaline-earth atom-decorated B38 fullerenes and their potential for hydrogen storage

•The hydrogen storage capacity reaches up to 6.47 wt.%.•Alkali and alkaline-earth metal atoms (Li, Na, K, Mg, Ca) decorated B38 fullerene.•The adsorption of H2 is intermediate between physisorbed and chemisorbed state.

The structural and electronic properties of alkali and alkaline-earth metal (Li, Na, K, Mg, and Ca) atom-decorated B38 fullerene, as well as their potential for hydrogen storage, are studied using all-electron density functional theory. The metal atoms favor face-capping on top of the center of hexagonal holes of fullerene. Large binding energy prevents alkali and alkaline-earth atoms from clustering on the surface of B38. Large amounts of positive charges are found on Na, K, and Ca atoms. We find that calcium-coated B38 is the best candidate for hydrogen storage, with moderate adsorption energy of H2. One Ca atom can adsorb up to five H2 molecules, resulting in 20 H2 molecules that can be stored in Ca4–B38 with an average binding energy intermediate of 0.075 and 0.240 eV/H2. The hydrogen storage capacity reaches up to 6.47 wt.%. Charge-induced dipole interaction is responsible for the high hydrogen storage capacity of Ca4–B38.

Graphical abstractThe structural and electronic properties of alkali and alkaline-earth metal atoms decorated B38 fullerene as well as their potential for hydrogen storage are theoretical studied. Ca coated B38 can adsorb 20 H2 molecules with binding energy of 0.075–0.240 eV/H2 and hydrogen storage capacity of 6.47 wt.%.Figure optionsDownload full-size imageDownload as PowerPoint slide