DFT study on adsorption properties of TM(Ni, Co)Nx -doped graphene for high-temperature sensing of SF6 decomposed gases

Gas sensing is the key to online monitoring SF6 decomposition gases in gas-insulated switchgear (GIS) fault diagnosis. However, the gas sensors for high-temperature sensing of SF6 decomposed gases are still lacking. In this paper, the adsorption performance of TM(Co, Ni)Nx-doped graphene as gas-sensing materials for the SF6 decomposed gases of SO2, SOF2, and SO2F2 were studied by DFT calculations, especially for the case at high temperatures. The adsorption energy (Eads), adsorption distance (D), transferred charge (Qt), and molecular dynamics simulations were performed to study the gas adsorption ability of TMN2-doped graphene. The electronic structures were clarified by analysis of the density of states (DOS), the partial density of states (PDOS), electron density difference, and molecular orbitals. The molecular dynamics simulations at 873 K indicated the high thermodynamic stability of TM(Co, Ni)Nx-doped graphene, which promised their superior gas sensing performance to detect SF6 decomposed gases at high temperatures.