Gas-sensing simulation of single-walled carbon nanotubes applied to detect gas decomposition products of SF6 in PD

Chemical products detection and analysis has been demonstrated as a powerful diagnosis method for SF₆ gas-insulated switchgear (GIS). In this paper, Materials Studio software was used to simulate single-walled carbon nanotube (SWNT) detecting gas decomposition products of SF₆ in partial discharge (PD). The simulation results show SWNT was the most sensitive to SO₂F₂ among the gas decomposition products of SF₆. SO₂F₂ molecules adsorbed on SWNT not only obviously changed electronic structures of SWNT, increasing the density of states (DOS) near Fermi level, but also greatly reduced the energy gap of SWNT, enhancing its electrical conductivity. However, SWNT is insensitive to HF, H₂S and CF₄ molecules because its properties were hardly changed when HF, H₂S and CF₄ molecules were adsorbed on SWNT. Although SO₂ and SOF₂ molecules adsorbed on SWNT have changed the properties of SWNT to some extent, SO₂ and SOF₂ cannot be respectively detected by SWNT due to the cross-sensitivity between them.