Abstract
Owing to the existence of periodic channels in phosphorene, this 2D material can be a good candidate for room temperature reversible hydrogen storage. The density functional theory calculations (DFT), including van der Waals interactions (vdW-DF2) coupled with the cooper exchange functional (C09), has been applied to study the potential of phosphorene as a new 2D material for hydrogen storage. Our results show that the adsorption energy (-292 to -277 meV) of H-2 on phosphorene is appropriate for storage. The analysis of diffusion pathways between different physisorbed states on phosphorene shows that a single hydrogen molecule diffuses very easily along the open channel (less than 1 meV along the zigzag direction), as compared to 14 meV for diffusion across the channels (along the armchair direction). The potential energy surfaces for the dissociative chemisorption of H-2 was computed on highly symmetric sites of phosphorene and the highest activation barrier was found to be 2.77 eV. The very large dissociation energy coupled with a strong physisorption of H-2 on phosphorene and facile diffusion, makes this 2D material a promising candidate for H-2 storage at room temperature. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.