Effect of Nickel Doping on Adsorption of SF6 Decomposition Products over MoS2 Surface

To ensure the operating stability of SF6-insulated equipment, an Ni-MoS2 monolayer has been used as an adsorbent to remove the characteristic decomposition products of SF6, viz. SOF2 and SO2F2 gases, from SF6-insulated equipment. All of the calculations are carried out in the density functional theory (DFT) framework. Several adsorption configurations are built and optimized to determine the most stable adsorption structure. In addition, the adsorption geometry, adsorption energy, density of states (DOS), charge transfer, transition states, and electron density difference are calculated to analyze the adsorption properties. The results show that the Ni-MoS2 monolayer exhibits excellent adsorption properties towards both target gases. SOF2 adsorbs on the Ni-MoS2 monolayer by nondissociative chemisorption, while SO2F2 adsorption occurs via dissociative chemisorption. Due to the strong chemical activity of Ni, it significantly increases the electrical conductivity and enhances the adsorption properties of MoS2. The Ni-MoS2 monolayer shows excellent sensitivity to SOF2 and SO2F2, reflected in decreases of the electrical conductivity after adsorption of SOF2 and SO2F2. The Ni-MoS2 monolayer could thus be a promising material for removal of these characteristic SF6 decomposition products under partial discharge conditions. The results of these calculations provide a new approach to ensure the operational stability of SF6-insulated gas-insulated switchgear (GIS) equipment.