Formation mechanism of CF3I discharge components and effect of oxygen on decomposition

CF3I, a typical electronegative gas with stable performance and less greenhouse effect, has been a topic of interest in recent years. However, some gaps in the study of its decomposition process, the microscopic formation mechanism of the main decomposition products, and the influence of oxygen on the decomposition characteristics of CF3I remain. In this study, based on the density functional theory and transition state theory, the formation process of the decomposition product of CF3I was investigated, and the reaction heat and activation energy were calculated. Moreover, the influence of oxygen on the decomposed components was explored. Finally, the insulation performance of the CF3I/O-2 mixture was tested by a breakdown experiment and the composition of the mixtures after discharge was validated through infrared spectroscopy. Simulation and experiment results indicated that the main products of CF3I are CF4, C2F6, C2F4, C2F5I, C3F6, C3F8, and I-2. The decomposition rate of CF3I is accelerated, and COF2 is produced in the presence of oxygen. The existence of oxygen can accelerate the decomposition of CF3I and the content of oxygen cannot exceed 7% to ensure the insulation performance of CF3I and should be lower than 20% to ensure safety.