DFT insights on the adsorption and sensing performance of TMO-MoSSe for oil dissolved gases

Abstract

The safe operation of oil-immersed transformers is crucial to the overall stability of the power system, making the prevention of partial discharges vitally important. This study proposes the use of MoSSe doped with TMOs (CuO, Ag2O, TiO2) to detect dissolved gases (CO, C2H2, CH4) in transformer oil. The adsorption of target gases on pristine and modified substrates is systematically studied using density functional theory (DFT). Given the unique sandwich structure of MoSSe, this paper explores the stability of the S-plane and Se-plane doping, ultimately selecting the S-plane for doping. Compared with the initial band gap of the substrate (1.598 eV), doping with CuO, Ag2O, and TiO2 reduces the band gap of MoSSe to 1.535, 0.677, and 0.752 eV, respectively. In terms of sensing performance, the improvement provided by the oxide particles on the substrate is confirmed by analyzing the geometric structure, density of states (DOS), differential charge density (DCD), and work function (WF) of the adsorption system. By comparing the adsorption parameters of the target gas adsorbed on both the doped and initial substrates, it is found that the metal oxides enhance the adsorption of the target gas on MoSSe. CH4 exhibits weak physical adsorption on the three modified substrates, with the order of adsorption capacity being: C2H2 > CO > CH4. The results of this study provide a theoretical basis for future applications in transformer condition monitoring and gas sensing.