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

Since the environmental-friendly insulating gas C 5 F 10 O not only has good environmental compatibility, but also has excellent insulating properties, it has the potential to replace SF 6 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 C 5 F 10 O can be decomposed by overheating, and the presence of the gas–solid interface has a certain influence on C 5 F 10 O decomposition process. To this end, this article uses the Density Functional Theory to study on C 5 F 10 O 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 C 5 F 10 O decomposed into C 2 F 4 O and C 3 F 6 is reduced by about 14.7 kcal/mol compared with that in free space; when C 5 F 10 O 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 C 2 F 4 O → CF 2 O + C 3 F 6 O and C 2 F 4 O → CF 4 + CO by 8.4 kcal/mol and 26.6 kcal/mol respectively, and increases the reaction energy barrier of C 3 F 6 + CF 2 O → C 3 F 8 + CO by 23.4 kcal/mol. It is believed that copper material has the effect of promoting the C 5 F 10 O 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.