Dehydrogenation of a crumpled graphene flake: molecular dynamics

Using molecular dynamics simulation, the dehydrogenation process of a crumpled graphene flake during annealing at 77, 100, 150, 200, 250, and 300 K for 200 ps is considered. It is found, that annealing at T = 77 K during the first 50 ps does not affect the gravimetric density. Further, exposure at this temperature results in a sharp decrease in the gravimetric density to 7.6 wt.%. It is found that the higher the temperature, the faster the dehydrogenation process of the carbon structure. At annealing temperatures above 150 K, the gravimetric density of crumpled graphene is set to a constant value, and an increase in the annealing time does not lead to a change of gravimetric density. This is because some of the hydrogen atoms remaining in the structure are deposited on the edge carbon atoms, forming a strong covalent bond that cannot be broken at such temperature.