Interaction of hydrogen molecules with perfect, defective and scandium doped polycyclic aromatic hydrocarbon structures

In the present work the interaction of hydrogen molecules with perfect, defective and scandium doped polycyclic aromatic hydrocarbon (PAH) has been evaluated. At first the potential barrier for the penetration of hydrogen molecules through PAH structures has been investigated and then the adsorption of hydrogen molecules over PAH structures has been studied. To model the graphene surface for barrier calculations, it is shown that coronene can successfully estimate the graphene monolayer. The barrier height is calculated for perfect and two different defective PAH structures including Stone–Wales (SW) and 585. It is found that PAH even with small defects is impermeable to hydrogen molecules. In the adsorption section, it is revealed that adsorption of hydrogen molecules over defective PAH structures is as weak as perfect graphene (less than 0.1 eV). To enhance the hydrogen storage capacity, scandium (Sc) has been used as the dopant and it is shown that Sc binds more strongly to 585 defective structure with higher number of hydrogen molecules in comparison with SW structure.