Simulation and experiment on thermocatalytic conversions of SF 6 by TiO 2 /SiC

Sulphur hexafluoride (SF6) is in urgent need of efficient degradation methods due to its widespread use in high-voltage electrical equipment and strict emission regulations. This study proposes a novel TiO2 /SiC catalyst synthesised via the sol–gel method for thermocatalytic SF6 conversion. Experimental evaluations revealed that TiO2/SiC achieves complete decomposition of 4% SF6 in a mixed gas (initial pressure: 0.14 MPa, temperature: 700°C) within 9 h, exhibiting a catalytic efficiency 3.73 times higher than pure TiO2. Key degradation products, including SOF4, SO2F2, SOF2, SO2, CF4, and CO2, were identified via GC-MS, with SO2 and SO2F2 as dominant sulphur-containing species. Density Functional Theory (DFT) simulations elucidated the catalytic mechanism: TiO2 facilitates charge transfer between Ti/O atoms and SF6, reducing the activation energy of the initial defluorination step. This energy reduction destabilises S–F bonds, accelerating SF6 breakdown into low-fluorine intermediates, which further oxidise to stable products. The SiC support enhances thermal stability by preventing TiO2 aggregation. TiO2/SiC combines superior efficiency, stability, and simpler synthesis, offering a practical solution for industrial SF6 waste treatment. This work bridges experimental and computational insights, advancing the design of high-performance catalysts for greenhouse gas mitigation.A novel and efficient catalyst, TiO2/SiC was successfully synthetised for the thermocatalytic conversion of SF6 waste gas by the sol–gel method. In addition, the catalytic defluorination mechanism was investigated via the density functional theory and transition state theory.