The Topology Impact Hydrogen Storage Capacity Y-Decorated on Porous Graphene

Hydrogen storage capacity of yttrium (Y)-decorated on porous graphene (PG) was examined through density functional theory calculations. PGs were selected considering topological symmetries. Our calculations show that the most stable locations for adsorption of Y are located on the center of carbon rings and the polarization and the hybridization mechanisms both contribute to the Y atom adsorption on PGs. Analysis of charge density difference demonstrated that the presence of Y could play an efficient role for stronger adsorption of hydrogen molecules rather than increasing pore sizes. Compared to H2 adsorption on graphene, injecting topological defect such as hexagon porous and decoration with a transition metal atom such as Y can effectively create much more conductive states at Fermi energy. A maximum of four hydrogen molecules can be adsorbed on
Y-PGs system. The highest average adsorption energy is related to porous graphene with larger pore size with average absorption energies of 0.513 eV.