Construction of transition metal-decorated boron doped twin-graphene for hydrogen storage: A theoretical prediction

• Maximum hydrogen gravimetric hydrogen is up to 4.95 wt%. • The effect of boron doping sites on hydrogen adsorption is studied. • Transition metal-decorated boron doped twin-graphene is novel H 2 storage material. • Increased boron doping leads to more stability with weaker adsorption strength. • Best structure can stably adsorb eight H 2 molecules at 298.15 K and 2.1 MPa. The exploitation of solid hydrogen storage materials is an essential part of the large-scale utilization of hydrogen energy. However, existing hydrogen storage materials cannot have both high hydrogen density and great stability at ambient temperature. Herein, we develop transition metal-decorated boron doped twin-graphene as a novel hydrogen storage material based on first-principles calculations. Ten different twin graphene adsorbents with Ti-decorated and doped with five boron atoms are examined. Metal decorating has a decisive influence on whether the twin graphene can be used for hydrogen storage. As the amount of boron atoms doping increases, the binding interaction between metal and substrate becomes more stable while the hydrogen adsorption strength weakens. The best structure can stably adsorb eight hydrogen molecules with a gravimetric density of 4.95 wt%. From thermodynamic calculations, the material is stable at reasonable conditions, e.g. 0.1 MPa, 238.5 K and 2.1 MPa, 298.15 K. Considering its outstanding hydrogen storage performance, we believe that Ti-decorated boron doped twin-graphene provides new inspirations to the discovery of carbon-based hydrogen storage materials.