Reversible and high-capacity hydrogen storage on two-dimensional monolayer C2N-h2D expected by first-principles calculations

Abstract

The main objective of many researches is to find an excellent reversible material for hydrogen storage applications under ambient conditions. The hydrogen adsorption on pure C2N-h2D shows an attractive result using density functional theory (DFT) calculations implemented with the van der Waals corrections, and ab-initio molecular dynamics (AIMD). A high adsorption energy up to - 0.3150 eV, the adsorption occurs through physisorption and no chemical bond is formed between the molecule and the C2N surface irrespective of the site of interaction, the migration process of H2 molecule on the substrate was so easy due to the low activation energy which was found around 7.08 meV. The study shows large gravimetric capacity as well as volumetric capacity around 11.62 wt% and 117.20 g/l. Compared to the critical point of hydrogen (33.25 K), the desorption temperature (TD) was found to be around 229.23 K, which is considerably higher. The adsorption of 30H2 molecules on C2N-h2D and the stability of the system was verified through AIMD simulations. Therefore, our material proved to be a promising candidate for hydrogen storage applications at room temperature.