Density functional theory study of hydrogen sulfide adsorption onto transition metal-doped bilayer graphene using external electric fields

Abstract

The adsorption of hydrogen sulfide molecules onto bilayer graphene (BG) doped with transition metals (TM), such as V, Cr, Mn, Fe, Co, and Ni, was studied using external electric fields and density functional theory calculations. The adsorption of H 2 S onto TM-doped BG was significantly improved compared with adsorption onto pristine BG. An external electric field can promote the adsorption of H 2 S onto BG, and the stability of this adsorption increases with the intensity of the electric field. Typically, this stability is independent of the direction of the electric field (upward or downward). However, H 2 S is sensitive to the direction of the electric field, and a downward (negative value) electric field is more favorable for H 2 S adsorption onto TM-doped BG. The desorption of H 2 S molecules from TM-doped BG was achieved using an upward (positive value) electric field, and the maximum desorption effect occurred at an electric field intensity of approximately 0.2 V/Å. The adsorption of gas molecules was also observed to modify the electronic structures of the TM/BG systems. All the TM/BG-H 2 S systems demonstrated semiconductive characteristics with different band gaps, except for the V/BG-H 2 S system. Overall, the results of this study showed that TM-doped BG has potential applications to methods for the adsorption, storage, and detection of H 2 S gas. • The TM/BG systems can significantly improve the adsorption stability of H 2 S compared with pristine bilayer graphene. • The external electric field promotes the adsorption of H 2 S onto bilayer graphene. • The adsorption of H 2 S is sensitive to the direction of the electric field. • The desorption of H 2 S gas molecules from TM-doped bilayer graphene can be achieved using an upward electric field. • The adsorption of gas molecules modifies the electronic structures of the TM/BG systems.