Investigation of the H-2 dissociation and H migration on the 3d transition metal modified carbon nanomaterials is very important for better understanding the hydrogen storage mechanism. Herein, the adsorption processes including H-2 dissociation and H migration on ScC6H6 complex are studied systematically. The optimal adsorption pathway indicates that five H(2 )molecules are continuously adsorbed on ScC6H6 until six adjacent CH2 groups is reached. The corresponding hydrogen storage capacity is up to 7.50 wt %. The optimal adsorption pathway is ScC6H6 -> 1d -> 1a -> 2a -> 3b -> 3e -> 3c -> 3d -> 3a -> 4a -> 5b -> 5c -> 5a (ScC6H2(H-2)-2H), and the whole reaction is exothermic by 6.19 kcal/mol and 1.89 kcal/mol using B3LYP and CCSD(T) functional, respectively. It indicates that the adsorption of multiple H-2 molecules on the ScC6H6 complex is a synergistic process of physisorption and chemisorption. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.