Ionization-degree induced hydrogen storage by boron substituted fullerene C₁₉Bⁿ⁺ (n = 0-3)

In this paper, the density functional theory method is used to study the structures and energies of the non-dissociative adsorption state, chemical adsorption state, and of the transition state transformation from the non-dissociative adsorption state to chemical adsorption state, for the system of hydrogen molecules on the surface of boron substituted fullerene C₁₉Bⁿ⁺ (n = 0-3). The potential energy surface (PES) of the conversion reaction between the two adsorption states is obtained. Studies have shown that by adjusting the ionization charge of the system, the population of the charged sites can be adjusted. As the number of charged sites on the hydrogen-absorbing active sites of the C₁₉Bⁿ⁺ ionized by boron-substituted fullerenes increases, the hydrogen molecules are polarized. The degree of adsorption of hydrogen molecules on the surface of the material is gradually increasing, while changing the charge population also has an effect of several Kcal/mol on the height of the transition barrier between the two states of hydrogen molecules adsorbed on the surface. We hope that our research can provide a reference for the further development of fullerene hydrogen storage. (authors)