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

•Enhanced gas sensing performance: the study demonstrates that the SnO2-graphene sensor exhibits improved gas sensing properties compared to a pure SnO2 sensor. This suggests that the incorporation of graphene into the SnO2 sensor enhances its sensitivity and detection capabilities for SF6 decomposition products.•Improved selectivity towards SF6 decomposition products: The SnO2-graphene sensor shows enhanced selectivity towards SF6 decomposition products. This means that it can effectively distinguish and detect specific gases or compounds associated with SF6 decomposition, making it a promising sensor for monitoring SF6 gas in various applications.•Lower operating temperature requirement: The research findings indicate that the SnO2-graphene sensor requires a lower operating temperature for gas sensing. This is significant as it reduces the energy consumption and potential safety risks associated with high-temperature operation, making the sensor more practical and efficient for real-world applications. 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. [Display omitted]