Effect of deformation on dehydrogenation mechanisms of crumpled graphene: molecular dynamics simulation

Abstract

In this work, the effect of hydrostatic compression on dehydrogenation of crumpled graphene is investigated using molecular dynamics simulation. Crumpled graphene is a carbon structure composed of a large number of graphene flakes interacted by van der Waals forces. These ultralight materials have unique mechanical properties and can be used in various applications, for example, in hydrogen technologies. One of the important issues in the study of carbon structures is the search for the new materials for hydrogen storage and transportation. In the present work, it is shown that pores of crumpled graphene can be used as the caves for the storage of hydrogen atoms and molecules, and hydrostatic compression is an effective way of keeping hydrogen inside the caves. Based on the analysis of changes in the capacity of hydrogen absorption, it is found that the application of deformation leads to a significant improvement in the sorption characteristics of crumpled graphene. At the same time, hydrostatic compression of crumpled graphene leads to an increase in volumetric hydrogen capacity. It has been established that, with an increase in the degree of compression, the number of hydrogen atoms leaving the pores of crumpled graphene decreases after exposure at 300 K. It is expected that the subsequent heating of the structure will lead to the release of hydrogen due to the opening of graphene flakes and an increase in thermal fluctuation oscillations of atoms, which is important for the dehydrogenation process.