Effect of S vacancy or non-metallic atom (C, N and F) doping on the adsorption behaviors of molecules (H2S, BF4) on monolayer MoS2

Abstract

Abstract Adsorption of molecules ( H 2 S , BF 4 ) on defective monolayer MoS 2 (X- MoS 2 , X is S vacancy or non-metallic atom such as C, N, or F) is investigated by first-principle calculations based on the density function theory. The stable adsorption geometry and electronic structures of two kinds of molecules reaching the surface of monolayer X- MoS 2 are discussed in detail. The results show that the adsorption of H 2 S and BF 4 are enhanced for the substitution of S atom in monolayer MoS 2 by X. H 2 S is chemisorbed on the C- MoS 2 surface because of the more excellent adsorbing behavior, otherwise physisorbed by that of ( S V , N or F)- MoS 2 . The beneficial results of adsorption on C- MoS 2 suggest that C atom can be appropriate dopants filled into MoS 2 sheets for detecting H 2 S molecule. For the case of adsorbing BF 4 , the adsorption behavior differs a lot as the BF 4 molecule exhibits a tendency toward ionic bonding with the substrate, hybridizing (N or F)- MoS 2 . Especially for BF 4 adsorbed on ( S V ,C)- MoS 2 , a F atom broken away from BF 4 molecule repairs the vacancy or combines with C atom in the surface to form C–F bond. The remaining BF 3 molecule is physisorbed on the surface of ( S V ,C)- MoS 2 . What is more, organic superhalogens, BF 4 , shows the strong oxidizability for the distinguished large adsorption energy and more charge transfer when adsorbed on the monolayer which may provide a way to regulate the materials properties.