Adsorption behavior of heptafluorobutyronitrile decomposition components on the Cu(1 1 1) surface

Abstract

The interaction mechanism of heptafluorobutyronitrile (C4F7N) decomposition components with Cu(1 1 1) surface under the external electric fields is investigated by DFT and MD. The results show that nitrile gases as well as COF2 molecules have smaller orbital energy gaps compared to perfluorinated gases, making it easy for the C4F7N decomposition component to lose electrons during the interaction with the Cu(1 1 1) surface. The interaction energy of CF3CN and C2F5CN in nitrile gas with Cu(1 1 1) surface is weakened under external electric fields, while the two CN groups of C2N2 make it almost unaffected compared to CF3CN and C2F5CN. The MD study shows that some gas molecules accumulate on the Cu(1 1 1) surface when negative electric field is applied, while no gas molecules are found to accumulate on the Cu(1 1 1) surface when positive electric field is applied. Furthermore, as the temperature increases, the accumulation of gas molecules occurs in both positive and negative electric fields, among which nitrile gas molecules are predominate, which is not conducive to the compatibility of the gas-solid interface. The conclusions can provide theoretical guidance for the operation and maintenance of insulation equipment.