Investigating the Gas-sensitive Response of Graphene doped by Different TiO2 Concentrations towards SF6 Decomposition Products

SF6 gas will decompose four characteristic decomposition products (H2S, SO2, SO2F2 and SOF2) when an insu-lation failure occurs early in SF6 gas-insulated equipment. By building gas-sensitive sensors into insulation de-vices it is possible to detect the characteristic gases of insulation faults. In this paper, we use Graphene which is available with good gas sensitivity, as a substrate and then improve the gas response of Graphene by doping with TiO2 clusters. The adsorption mechanism of (TiO2)n-Graphene (n = 1-4) on four characteristic decomposition gases is firstly analyzed based on first principles, and then verifies experimentally. (TiO2)n-Graphene (n = 1-4) shows the largest change in Eg after adsorption of SO2 gas with 61.70%, 1.07%, 23.19% and 64.04%, respec-tively. The SEM characterization shows that Graphene has an obvious lamellar structure, and TiO2 nanoparticles are mainly distributed on the outer wall of Graphene, which has a large curvature and strong surface activity. The gas-sensitive response values of the (TiO2)n-Graphene (n = 1-4) sensor for different gases at the same gas concentration are ranked as SO2 > H2S > SO2F2 > SOF2. The results show that TiO2 cluster-doped Graphene is a potential gas-sensitive sensing material that can be a new material for online monitoring of faulty gas content in SF6 gas-insulated equipment.