Theoretical assessment of discharge effects on the decomposition tendency of C6F12O over metallic surfaces

Abstract

C₆F₁₂O is proposed to be one potential eco-friendly insulation gas to replace SF₆. However, the assessment of its decomposition properties and the compatibility with metal electrodes in discharge faults is still challenging, which greatly hinders the development of its insulation and arc-extinction applications. Herein, a theoretical method is proposed to reasonably address the discharge effects on C₆F₁₂O decomposition over typical Cu and Al electrodes at atomic scale. The results show that both the external electric field and the excess electrons could affect the activation of C₆F₁₂O by changing the electron acceptance of C₆F₁₂O and the orbital hybridisation during the surface bonding. On metal surfaces, the C-F single bond in adsorbed C₆F₁₂O is the weakest position to decompose, and its cleavage could be promoted by the discharge effects. After the C-F breaking, the C-C cleavage remains unfavourable on Cu (111), but it is significantly promoted on Al (111), indicating a higher corrosion risk on the Al surface via continuous C₆F₁₂O decompositions. The proposed method as a valid supplement to the experiment reveals the discharge effects and the decomposition tendency of C₆F₁₂O on metal electrodes in discharge faults, which broadens the means for insulation gas evaluation.