Reversible hydrogen storage with Na-modified Irida-Graphene: A density functional theory study

Abstract

Two-Dimensional carbon-based materials as a potential hydrogen storage medium have attracted great attention. In this study, various key aspects such as structure, electronic properties, stability, and hydrogen storage performance of Na-modified Irida-Graphene (IG) were thoroughly investigated using density functional theory (DFT) calculation methods. The calculation results show that the binding energy of Na atoms with the substrate is 1.51 eV, far exceeding the cohesive energy. The AIMD results reflect the good thermal stability of the model. One Na atom can adsorb up to 5H2 molecules. The IG loaded with eight Na atoms on both sides can adsorb 32H2 molecules, achieving a hydrogen storage capacity of 7.82 wt%, far exceeding the US DOE target of 5.5 wt%. The calculated Van ’t Hoff equation indicates a desorption temperature of 248 K for the model. Moreover, reversible hydrogen storage can be achieved at medium to low pressures, with desorption temperatures ranging from 285 K to 417 K. These results suggest that Na-Modified IG models are candidate materials for reversible hydrogen storage under near-ambient conditions.