  Graphene functionalization by hydrogen and fluorine has been proposed as a
route to modulate its reactivity and electronic properties. However, until now,
proposed systems present degradation and limited hydrogen adsorption capacity.
In this study, combining first-principles calculations based on density
functional theory (DFT) and reactive molecular dynamics, we analyze the tuning
of hydrogen adsorption and electronic properties in fluorinated and
hydrogenated monolayer graphenes. Our results indicate that fluorine adsorption
promotes stronger carbon$-$hydrogen bonds. By changing the concentration of
fluorine and hydrogen, charge density transfer and electronic properties such
as the band gap and spin-splitting can be tailored, increasing their potential
applicability for electronic and spintronic devices. Despite fluorine not
affecting the total H incorporation, the $\textit{ab initio}$ molecular
dynamics results suggest that 3% fluorinated graphene increases hydrogen
anchoring, indicating the hydrogenated and fluorinated graphenes potential for
hydrogen storage and related applications.
