Hydrogen storage property of alkali and alkaline-earth metal atoms decorated C-24 fullerene: A DFT study

The hydrogen storage behavior of alkali and alkaline-earth metal (AM = Li, Na, K, Mg, Ca) atoms decorated C-24 fullerene was investigated by using density functional theory (DFT) study. Our results indicate that the AM atoms prefer to adsorb atop the center of tetragon of C-24 fullerene with the largest binding energy than other possible adsorption sites. Moreover, the hydrogen storage gravimetric density of 24H(2)/6Li/C-24, 24H(2)/6Na/C-24 and 36H(2)/6Ca/C-24 configurations reaches up to 12.7 wt%, 10.1 wt% and 12 wt%, higher than the year 2020 target from the US department of energy (DOE). Also, the average adsorption energies of H-2 molecules of the 24H(2)/6Li/C-24, 24H(2)/6Na/C-24 and 36H(2)/6Ca/C-24 configurations are -0.198 eV/H-2, -0.164 eV/H-2 and -0.138 eV/H-2, locate the desirable range under the physical adsorption at near ambient conditions. These findings will have important implications on designing new hydrogen storage materials in the future. (C) 2018 Elsevier B.V. All rights reserved.