Stable two-dimensional Na decorated BeN 4 : a potential candidate for hydrogen storage

To overcome the prevalent challenge of reversible hydrogen storage, surface activation by metal atom decoration holds a great promise, thus, boosting the hydrogen storage capacity. In this work, sodium (Na) decorated beryllonitrene (BeN 4 ) monolayer has been identified as a hydrogen storage material using first-principles calculations. Our results reveal that Na decorated BeN 4 has ability to adsorb upto 12 H 2 molecules, leading to high gravimetric density of 4.26 wt.%. The adsorption energy per H 2 (adsorbate) is moderate, i.e., between 0.13 and 0.298 eV, good enough for hydrogen storage in practical applications. AIMD simulations disclose that adsorbate experiences no kinetic hindrance in desorption. Moreover, the desorption temperature of H 2 molecule on NaBeN 4 monolayer (substrate) varies from 162.5 to 382 K, confirming the reversibility of substrate and thus ensuring its potential for hydrogen storage medium. The short recovery time predicts that the substrate responds rapidly in the presence of H 2 molecules, which guarantees the fast kinetics of adsorbate. Our calculations predict Na-decorated BeN 4 monolayer as an excellent candidate for reversible and high-capacity hydrogen storage material.