Understanding the mechanism of hydrogen storage on pristine B2CO monolayer: A DFT study

Abstract

The search of a cost-effective material with high gravimetric capacity and efficient reversibility to store hydrogen is a crucial subject these days. In this work, we systematically investigated the underlying mechanism to store hydrogen on pristine B2CO monolayer by employing density functional theory (DFT). The results demonstrate that the average adsorption energy for H2 molecules on the B2CO monolayer is calculated to be −0.614 eV, with individual adsorption energies ranging from - 0.066 eV to −1.712 eV for successive adsorptions. The electrostatic nature of H2 interactions with the B2CO monolayer is confirmed via density of states (DOS) and electron localization function (ELF) analyses. The PDOS analysis shows that hydrogen adsorption on the B2CO monolayer introduces low-energy states (−4 to −6 eV) without significantly altering the band gap. The material's gravimetric and volumetric hydrogen storage capacities are found to be 5.94 wt% and 103 g/L, respectively. The dehydrogenation temperature evaluated to be 785 K to predict reversibility of material. The desorption temperature calculated via the van ‘t Hoff model has shown that B2CO monolayer could operate as reversible hydrogen storage media under practical conditions. The Periodic energy decomposition (PEDA) analysis outcomes proved that H2 molecules interactions with material are attractive in nature. The simulation plots for the nudged elastic band (NEB) indicate that there is a remarkably low energy barrier observed during the adsorption of hydrogen into the material along the specified paths. The findings of this study suggest that the B2CO monolayer is potential candidate with effective, reversible, and substantial H2 storage capacity under realistic conditions.

keywords: B2CO monolayer, Hydrogen storage, Physisorption, Stability