Effect of defect types in monolayer MoS 2 on SO 2 adsorption

As a two-dimensional semiconductor material, molybdenum disulfide (MoS 2 ) is extensively applied to sulfur dioxide (SO 2 ) gas sensor. However, point defects will inevitably be produced in the preparation of MoS 2 , which significantly affect the adsorption properties of MoS 2 . Thus, understanding the properties of different point defects is essential for the successful application of MoS 2 . In this work, four types of point defects (V S -MoS 2 , V S2 -MoS 2 , V MoS3 -MoS 2 and V MoS6 -MoS 2 ) of monolayers MoS 2 were proposed, and the adsorption characteristics of SO 2 on four typical defective MoS 2 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 -MoS 2 defect has excellent adsorption properties for SO 2 due to its largest adsorption energy, charge transfer and electrical response. The obtained results will contribute to the understanding of the effects on the MoS 2 monolayers with different defects for SO 2 sensing application.