Tuning hydrogen adsorption and electronic properties from graphene to fluorographone

Abstract

Graphene functionalization by hydrogen and fluorine has been proposed as a route to modulate its reactivity and electronic properties. However, until now, proposed systems have presented degradation and limited hydrogen adsorption capacity. In this paper, combining first-principles calculations based on density-functional theory and reactive molecular dynamics, we analyze the tuning of hydrogen adsorption and electronic properties in fluorinated and hydrogenated monolayer graphene. 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 ab initio molecular dynamics results suggest that 3% fluorinated graphene increases hydrogen anchoring, indicating the hydrogenated and fluorinated graphene potential for hydrogen storage and related applications.