Au (n = 1–4) cluster doped MoSe2 nanosheet as a promising gas-sensing material for C2H4 gas in oil-immersed transformer

In the long running of oil-immersed transformers, it is inevitable for the oil and insulating paper in transformers to decompose, which can lead to degradation of their insulation performance. Moreover, without timely detection to deal with the equipment failure, electric discharge occurs in transformers, which will affect the stability and security of the whole power system. In this paper, MoSe2 modified by Au and its cluster are proposed to adsorb both single and double C2H4 gas molecules, one of the typical decomposition products of the oil and paper in transformers. Based on DFT, adsorption systems were built and analyzed by analyzing adsorption parameters, DOS, and molecular orbit. The adsorption ability to single C2H4 molecule is in order as: Au3 > Au2 > Au > Au4, and Au4 > Au3 > Au2 > Au to double C2H4 molecules. Moreover, After C2H4 adsorption, the conductivity of Au and Au4 doped systems enhances, while that of Au2 and Au3 systems reduces for both single and double C2H4 adsorption systems. According to the results, Au3-MoSe2 can be a promising material as C2H4 adsorbent and gas sensor applied in detecting and diagnosing the discharge fault in oil-immersed transformers.