Theoretical and experimental study on gas sensing properties of SnO2-graphene sensor for SF6 decomposition products

Based on theoretical calculation and experimental detection, SnO2-modified graphene (SnO2-graphene) was proposed as a gas-sensing material for the SF6 characteristic decomposition products (SO2, H2S, SOF2, SO2F2) in SF6-insulated equipment. Based on density functional theory calculations, the most stable modifying structure of single and double SnO2 on the surface of graphene is optimized. The adsorption structure, adsorption energy, and charge transfer of four gas molecules on the surface of SnO2-graphene are calculated and analyzed. Then the total density of states (DOS) and partial density of states (PDOS) of the system before and after gas adsorption were compared and analyzed to explore the interaction mechanism between different gases and SnO2-graphene. In experimental study, graphene was prepared by the modified Hummers oxidation-reduction method in the laboratory. four concentration gradients of SnO2 modified on the surface of graphene, and then specific gas sensing experiments were carried out with 10, 25, 50, 100 ppm of the SF6 characteristic decomposition products. The gap between simulation and experiment is compared and analyzed, which lays a theoretical and experimental foundation for the development of new specific sensors.