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.

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