Study On Adsorption Characteristics Of C₅F₁₀O Gas Discharge Decomposition Components On Cu（110） Surface

SF₆has good insulation and arc extinguishing characteristics,and is widely used in GIS/GIL and other equipment.However,the massive use of SF₆has exacerbated the impact of the greenhouse effect,for which people began to take measures to limit the use of SF₆.In recent years,C₅F₁₀O insulating gas has attracted widespread attention from domestic and foreign researchers due to its good insulation and environmental protection characteristics.However,for the new insulating gas,the research on its discharge decomposition and gas-solid compatibility is still in its infancy,and there are still few related studies.Therefore,this paper analyzes the decomposition mechanism and adsorption characteristics of C₅F₁₀O discharge at the micro level based on density functional theory（DFT）.The specific work is as follows:（1）Based on density functional theory,the C₅F₁₀O gas discharge decomposition path and product synthesis path were analyzed.The reaction energies of the related reaction paths were calculated,and the effects of temperature and pressure on the discharge decomposition characteristics of C₅F₁₀O gas were considered.With the addition of micro-water and micro-oxygen conditions,the variation of C₅F₁₀O gas decomposition products was analyzed,the ionization parameters of C₅F₁₀O gas decomposition products were calculated,and the difference of gas insulation properties before and after C₅F₁₀O discharge decomposition was analyzed.（2）Based on the Langmuir monolayer adsorption theory,a surface model of C₅F₁₀O and Cu（110）was established.The adsorption characteristics of C₅F₁₀O on Cu（110）surface were analyzed by calculating the adsorption energy,transfer charge,charge layout and density of states produced by the adsorption of C₅F₁₀O on Cu（110）surface.The adsorption model of SF₆on the Cu（110）surface was established under the same conditions,and the gas-solid compatibility between the two insulating media and metallic copper was compared and analyzed.（3）Combined with the discharge decomposition characteristics and adsorption characteristics of C₅F₁₀O,the adsorption model of C₅F₁₀O main discharge decomposition products CF₄,C₂F₆and C₄F₁₀on the Cu（110）surface was established.By calculating the adsorption energy,transfer charge and density of states generated by the adsorption of C₅F₁₀O decomposition products on the Cu（110）surface,the gas-solid compatibility between C₅F₁₀O discharge decomposition products and copper was analyzed.The research results show that C₅F₁₀O cannot be spontaneously decomposed by discharge at room temperature.C₅F₁₀O starts to decompose along the path of C₅F₁₀O→CF₃·+CF₃CFCOCF₃·→CF₃·+CF₃CFCO·→CO·+CF₃CF·→CF₃·+CF·in the temperature range of 600-800K.The spontaneous degree of decomposition reaction increases with increasing temperature and weakening with increasing pressure.The decomposition products of C₅F₁₀O include CF₄,C₂F₆,C₃F₆,C₃F₈,C₄F₁₀,C₆F₁₄,etc and the types of decomposition products will further increase under the conditions of low water and low oxygen.The ionization energy of the decomposition products of C₅F₁₀O is larger,and the electron affinity is smaller.After the decomposition of C₅F₁₀O,the gas products are more difficult to ionize,but the overall insulation ability is reduced.The adsorption energy and transfer charge of C₅F₁₀O at the top position of Cu（110）surface are relatively large,and the adsorption property is chemical adsorption.However,the main discharge decomposition products of C₅F₁₀O,are not easily adsorbed on the Cu（110）surface,and their adsorption properties are physical adsorption.Compared with the adsorption characteristics of SF₆on the Cu（110）surface,the adsorption capacity of C₅F₁₀O and its decomposition products on the surface of metallic copper is significantly weaker than that of SF₆.