Decoration of doped C60 fullerene with alkali metals: Prototype nanomaterial with enhanced binding energy toward hydrogen

The metal decorated fullerenes form a new class of important nanostructured materials with various potential applications. This work presents a comprehensive study to investigate the decoration of a series of alkali metals (Li, Na, and K) on pristine fullerene (C-60) as well as boron-doped (BC59) and aluminum-doped (AlC59) structures. In the framework of density functional theory (DFT), we analyze the effects of metal decoration on the structure, stability, reactivity and electronic properties of considered fullerenes. The obtained reactivity patterns for considered metallofullerenes are validated by explicit adsorption of H-2 molecule. The following outcomes can be derived from our calculations: (1) Alkali metal decoration enhances the reactivity of considered cages, however, it is more effective in the case of AlC59. (2) Whereas the boron or aluminum doping of C-60 does not alter the static dipole polarizability of the fullerene, metal decoration induces more pronounced effect on the cage polarizability. Moreover, the static dipole polarizability of pristine C-60 and AlC59 fullerenes are more sensitive to metal decoration (3) Atoms in molecules analysis show that the interactions between alkali metal atoms and pristine as well as doped-C-60 are noncovalent with electrostatic dominant character. (4) Consistent with the prediction of reactivity descriptors, the maximum binding strength for H-2 adsorption is related to the K/AlC59 system. However, we envisage that the outcomes of current study can stimulate further researches in this area, particularly in manipulating fullerene materials for designing promising hydrogen storage medium. (c) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.