Ir-decorated MoS2 monolayer as a promising candidate to detect dissolved gas in transformer oil: A DFT study

Abstract

The gas-sensing properties of Ir-decorated MoS2 monolayer to three typical dissolved gases in transformer oil, including methane (CH4), ethane (C2H4) and acetylene (C2H2), were studied by the density functional theory (DFT) method. The physical structure and adsorption parameters of Ir-decorated MoS2 based sensing materials were systematically studied. The calculated results indicate that Ir modification significantly improves the conductivity of MoS2.Based on the analysis of the density of states (DOS) and charge density difference (CDD), the electronic properties and adsorption strength of Ir-decorated MoS2 monolayer improve significantly after adsorbing C2H4 and C2H2 gases, while the Ir-decorated MoS2 material is less sensitive to CH4 gas owing to the weakly changes of DOS and energy gap. In addition, we used the frontier molecular orbital analysis to in-depth investigate the electronic clouds distribution of proposed structures and the effect of gas adsorption on material conductivity. The sensitivity order and recovery time of Ir-decorated MoS2 were also predicted. All these results give the theoretical possibility of applying Ir-decorated MoS2 as a gas sensor for dissolved gases detection.