Insights into the interaction between C4F7N decomposition products and Cu (1 1 1), Ag (1 1 1) surface

C4F7N is under wide consideration as an environment-friendly gas insulating medium to replace the strong greenhouse gas SF6 using in medium-voltage and high-voltage gas insulated equipment. At present, there are few reports on the compatibility between C4F7N characteristic decomposition products and materials used in the equipment. Investigations about the material compatibility between new gas and materials used in equipment are required to decide about a long term behavior. In this paper, we studied the interaction between characteristic decomposition products of C4F7N and copper, silver based on the density functional theory. The adsorption energy, charge transfer and density of states of C2F5CN, CF3CN, COF2, CF4 gas molecules adsorbed on Cu (1 1 1) and Ag (1 1 1) surfaces were obtained. It was found that the interaction between C2F5CN, CF3CN and Cu (1 1 1) is stronger than that of COF2 and CF4. But there is no chemical bond formation process occurs between gas molecules and Cu (1 1 1) surface. And the interaction between characteristic decomposition products of C4F7N with Ag (1 1 1) is weaker than that of Cu (1 1 1). Relevant results not only reveal the interaction between C4F7N decomposition products and copper, silver, but also provide guidance for the engineering application and long term behavior assessment of C4F7N gas mixture.