Cu_γ (γ = 1-3)-Modified MoS₂ Monolayer as a Gas Sensor for Detecting C₄F₇N and Its Decomposition Components

Perfluorinated isobutyronitrile (C₄F₇N) is favored in electrical engineering because it is an environmentally friendly gas-insulating medium with a low greenhouse effect. Unfortunately, under the influence of electricity and over-heating, its decomposition results in the deterioration of its insulating properties, which potentially leads to partial discharge or even gas breakdown. In this paper, the adsorption behavior of C₄F₇N gas and its toxic decomposition product, acetonitrile (C₂N₂), on MoS₂ surfaces doped with small copper clusters was investigated by calculating the adsorption energy and density of states, etc. The effects of multiple initial adsorption positions as well as externally applied electric fields were also taken into account. The results depict that the maximum adsorption energy of C₄F₇N on the Cu_γ (γ = 1-3)-MoS₂ surface gradually decreases with the increase in γ. The Cu₃-modified MoS₂ is most suitable for use as a resistive-based gas-sensitive sensor substrate. This paper provides the theoretical foundation for the maintenance of future power equipment with environmentally friendly insulating gas.