Effect of defect types in monolayer MoS2 on SO2 adsorption

As a two-dimensional semiconductor material, molybdenum disulfide (MoS2) is extensively applied to sulfur dioxide (SO2) gas sensor. However, point defects will inevitably be produced in the preparation of MoS2, which significantly affect the adsorption properties of MoS2. Thus, understanding the properties of different point defects is essential for the successful application of MoS2. In this work, four types of point defects (V-S-MoS2, V-S2-MoS2, V-MoS3-MoS2 and V-MoS6-MoS2) of monolayers MoS2 were proposed, and the adsorption characteristics of SO2 on four typical defective MoS2 monolayers were investigated based on first principles. The adsorption models were established to calculate the electronic properties and adsorption parameters of the adsorption systems. The results show that V-MoS6-MoS2 defect has excellent adsorption properties for SO2 due to its largest adsorption energy, charge transfer and electrical response. The obtained results will contribute to the understanding of the effects on the MoS2 monolayers with different defects for SO2 sensing application.