Hydrogen adsorption property of Na-decorated boron monolayer: A first principles investigation

Abstract

We use the first principles methods based on density functional theory to study the hydrogen storage capacity of Na-decorated two dimensional (2D) boron monolayer (BM). The result shows the favorable position for Na to adsorb is on the top of hexagon of BM with the highest binding energy of −2.087 eV. Moreover, the single-sided Na-decorated BM can store up to seven H2 molecules with average adsorption energy of −0.145 eV/H2. For double-sided Na-decorated BM, the 28 H2 molecules are captured around 4Na/BM complex with average adsorption energy of −0.152 eV/H2 and the hydrogen storage capacity of 8.28 wt.%. In addition, first principles molecular dynamics simulations indicate H2 molecules are quickly released from 28H2/4Na/BM structure at room temperature and the metal clusters are avoided at the same time. Finally, the linear periodic [(Na7H2)2BM]n polymer is considered as a promising hydrogen storage candidate for industrial applications.