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

The structural and electronic properties of alkali and alkaline-earth metal (Li, Na, K, Mg, and Ca) atom-decorated B 38 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 B 38 . Large amounts of positive charges are found on Na, K, and Ca atoms. We find that calcium-coated B 38 is the best candidate for hydrogen storage, with moderate adsorption energy of H 2 . One Ca atom can adsorb up to five H 2 molecules, resulting in 20 H 2 molecules that can be stored in Ca 4 –B 38 with an average binding energy intermediate of 0.075 and 0.240 eV/H 2 . The hydrogen storage capacity reaches up to 6.47 wt.%. Charge-induced dipole interaction is responsible for the high hydrogen storage capacity of Ca 4 –B 38 . [ABSTRACT FROM AUTHOR]