Theoretical study of hydrogen storage reactions on nickel-decorated heterofullerene C58

Abstract

In the present study, hydrogen storage reactions on Ni − C58BN and Ni − C58X2(X = B, N) heterofullerene are investigated by using the density functional theory (DFT) calculations. The Ni atom prefers to bind at the bridge site between a six-membered ring of C58BN and between a fivemembered and six-membered ring for Ni − C58X2(X = B, N), and can bind up to six hydrogen molecules with adsorption energies in the range of (−1.06, −0.31 eV) for Ni − C58BN and (−1.07, −0.33 eV) for Ni − C58B2, while (−0.86, −0.2 eV) for Ni − C58N2 per hydrogen molecule. With no metal clustering, the system gravimetric capacities are expected to be as large as 12.75, 12.77 and 12.74 wt% for 6H2 − NiC58BN, 6H2 − NiC58B2 and 6H2 − NiC58N2, respectively. While the desorption activation barriers of the complexes nH2 − NiC58BN and nH2 − NiC58B2 with n = 1 − 3 is outside the Department of Energy domain (−0.2 to −0.6 eV), and with n = 4–6 are inside this domain. For nH2Ni − C58N2with n = 1 − 2 is outside the DOE domain, and with n = 3–6 are inside this domain. The hydrogen storage of the irreversible 3H2 + NiC58BN, 3H2 + NiC58B2, and 2H2 + NiC58N2 and reversible 4H2 + NiC58BN, 4H2 + NiC58B2 and 3H2 + NiC58N2 interactions are characterised in terms of density of states, pairwise and non-pairwise additivity, infrared, Raman (R), electrophilicity and molecular electrostatic potentials.