Thermal Decomposition Mechanism of Environmental-Friendly Insulating Gas C5F10O on Cu (1 1 1) Surface

Since the environmental-friendly insulating gas C5F10O not only has good environmental compatibility, but also has excellent insulating properties, it has the potential to replace SF6 in equipment such as medium and low voltage switchgear. When a partial over-thermal fault occurs on metal material surface inside the gas-insulated equipment, the C5F10O can be decomposed by overheating, and the presence of the gas–solid interface has a certain influence on C5F10O decomposition process. To this end, this article uses the Density Functional Theory to study on C5F10O over-thermal decomposition mechanism on metal materials surface in the equipment. The results show that when it does not involve Cu atoms in the reaction, the energy barrier of C5F10O decomposed into C2F4O and C3F6 is reduced by about 14.7 kcal/mol compared with that in free space; when C5F10O decomposition involves Cu atoms in the reaction and chemical adsorption occurs, the reaction energy barrier is further reduced by about 7.4 kcal/mol. In addition, the participation of Cu surface reduces the reaction energy barrier of 2 C2F4O → CF2O + C3F6O and C2F4O → CF4 + CO by 8.4 kcal/mol and 26.6 kcal/mol respectively, and increases the reaction energy barrier of C3F6 + CF2O → C3F8 + CO by 23.4 kcal/mol. It is believed that copper material has the effect of promoting the C5F10O decomposition to some degree. The research conclusions in this article can provide theoretical guidance for selections of internal metal materials or surface coating for the design of environmentally friendly gas-insulated switchgear in the future.