  Graphene-based materials (GBMs) constitute a large family of materials which
has attracted great interest for potential applications. In this work, we apply
first-principles calculations based on density functional theory (DFT) and
fully atomistic reactive molecular dynamics (MD) simulations to study the
structural and electronic effects of hydrogenation in Me-graphene, a non-zero
bandgap GBM composed of both $sp^2$ and $sp^3$-hybridized carbon. Our DFT
results show a substantial tuning of the electronic properties of Me-graphene
by hydrogenation, with the bandgap varying from $0.64$ eV to $2.81$ eV in the
GGA-PBE approach, passing through metallic ground-states and a narrower bandgap
state depending on the hydrogen coverage. The analyses of structural properties
and binding energies have shown that hydrogenated Me-graphene presents strong
and stable \ce{C-H} bonds, and all of the carbon atoms are in $sp^3$
hybridization resulting in a boat-like favorable conformation for
fully-hydrogenated Me-graphene. Our MD simulations have indicated that the
hydrogenation of Me-graphene is temperature-dependent, and the covalent
adsorption tends to grow by islands. Those simulations also show that the most
favorable site, predicted by our DFT calculations, acts as trigger adsorption
for the extensive hydrogenation.
