Armazenamento e liberação de H2 em materiais bidimensionais

Abstract

Two-dimensional (2D) carbon-based materials have been extensively investigated in recent years, due to their excellent mechanical, thermal and electronic properties. Among the discoveries that have emerged from these investigations, we would like to highlight here the possibility of controlling several properties in these materials using mechanical strain. In our work, we used the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) program to analyze whether deformation could be used to release adsorbed gases in 2D materials. To determine if this was possible, we first examined whether the strain altered the interaction between the adsorbed gas and four structures: graphene, α-graphyne, β-graphyne, and γ-graphyne. Towards this end, we inserted a H2 molecule at a height z from the surface of each material, and changed its position to determine the interaction energy throughout the surface. Analysis of the results revealed that the strain reduced the attractive interaction between H2 and all of the investigated 2D materials. To confirm that the amount of adsorbed gas would decrease in the presence of deformation, we performed Monte Carlo simulations in the grand canonical ensemble, using structures with and without deformation. Our results confirmed that the strain reduced the amount of adsorbed gas on the surface of all of the investigated materials. Thus, we conclude that deformation can be applied to any of the studied materials to partially release the adsorbed gas. Comparing the studied materials, we observed that γgraphyne showed the best performance at low pressures, and that α-graphyne showed the best performance at pressures near one atmosphere.