DFT analysis of the sensitivity of graphene/MoS2 heterostructures toward H2CO

Indoor toxic gases detection is very important for human health, and the use of novel two-dimensional materials to detect or adsorb toxic gases is significant. With these prospects in mind, the potential application of graphene/MoS2 two-dimensional heterostructure as a gas sensor was explored. This study investigated the sucking stability and electronic and magnetic properties of H2CO adsorbed on perfect, vacancy-defected, transition metal (TM)-doped graphene/MoS2 heterostructures through density functional theory analysis. Perfect graphene/MoS2 (GMoS2) exhibited small adsorption energy and low charge transfer, and the TM-doped Mo-vacancy-defected heterostructures exhibited physical adsorption toward H2CO molecules with a shorter desorption time. However, the interaction between H2CO and the substrate changed to chemisorption when TMs (Sc, V, Cr, Mn) were doped with S-vacancy-defected graphene/MoS2. Meanwhile, the density of states of the S-defected heterostructure indicated the hybridization of the d orbitals of the dopants and the p orbital of the H2CO molecule that considerably enhanced the adsorption energy. Furthermore, the asymmetric electron spin distribution of dopants and Mo atoms induced a strong magnetic moment. In summary, this study established an effective approach for H2CO gas detection based on heterostructure.