First-principles calculations of adsorption sensitivity of Au-doped MoS2 gas sensor to main characteristic gases in oil

Detecting oil-dissolved gases in transformer is crucial for internal discharge fault diagnosis. Methane (CH4), acetylene (C2H2), ethylene (C2H4), ethane (C2H6) are some of the important fault characteristic gases in oil-immersed transformer discharge faults. The concentration and production rate can effectively reflect the insulation performance of oil-paper power transformer. In order to realize the effective detection of gases in the oil, the Au atom-doped MoS2 (Au-MoS2) monolayer was proposed. To study adsorption properties of different gases, the density functional theory (DFT) was used to study applicability of Au-MoS2 two-dimensional (2D) nanomaterials for gas sensor. Meanwhile, the adsorption properties, sensitivity and electronic behavior were calculated. The results show that the doped systems have a better sensing performance for C2H2, C2H4 and C2H6. And Au-MoS2 monolayer has a unique response to C2H2 with appropriate adsorption energy (- 1.056 eV) and charge transfer (0.252 e), which are far more than CH4 (- 0.065 eV, 0.037 e). Based on the above data, Au-MoS2 monolayer has selectivity for different oil-dissolved gases.