## 1 Introduction  
Ensuring the safety and stability of gas-insulated switchbgear (GIS) operation is the focus of the power system [1]. In GIS, SF\({}_{6}\) has become the most popular insulating gas due to its superior insulation performance and arc extinguishing performance [2; 3; 4; 5; 6]. However, with the development of society, the use of SF\({}_{6}\) increasingly violates the requirements of production and environmental friendliness [7; 8; 9]. For example, SF\({}_{6}\) has high liquefaction temperature, and under a nonuniform electric field, its dielectric strength will drop sharply [10; 11]. As a kind of gas that causes the greenhouse effect, it is harmful to the environment [12]. Therefore, in the future, the use of SF\({}_{6}\) shows a limited trend. How to reduce the use of SF\({}_{6}\) in the power system is an urgent problem to be solved [13; 14]. SF\({}_{6}\)-gas mixtures instead of pure SF\({}_{6}\) can improve technical and economic performance [15; 16; 17; 18]. SF\({}_{6}\)-N\({}_{2}\) gas mixture is a great alternative, which can reduce the use of SF\({}_{6}\) while ensuring insulation performance. It was found that the mixture containing 30% SF\({}_{6}\) can be applied to GIS bus [19]. Partial discharge (PD) can cause insulation degradation and endanger the life of GIS [20]. Under PD, the SF\({}_{6}\)-N\({}_{2}\) mixture decomposes mainly as SOF\({}_{2}\), SO\({}_{2}\)F\({}_{2}\), SOF\({}_{4}\), CF\({}_{4}\), CO\({}_{2}\), NO, NO\({}_{2}\) and NF\({}_{3}\)[21]. PD failure can be judged by detecting characteristic gases of NO\({}_{2}\), SO\({}_{2}\)F\({}_{2}\), SOF\({}_{2}\) and SOF\({}_{4}\). SOF\({}_{2}\) and SO\({}_{2}\)F\({}_{2}\) are the most common, and the sensitivity of detecting the two gases by gas chromatography can reach 1 ppmv [22].  
Undoped InN is an n-type wide band gap semiconductor, a graphene-like material with excellent performance, which makes up for the defect of the zero band gap of graphene and becomes a research hotspot. According to the X-ray diffractometer (XRD) analysis, [PERSON] et al. [23] reported the influence of substrate temperature (Ts) on the growth of InNthin films on indium tin oxide (ITO) substrates, and clarified that gradually increasing the temperature above 200 \({}^{\circ}\)C is beneficial to the growth of InN (101) plane. Due to the graphene-like properties of InN, a new-type modified InN gas sensor can be developed to detect the SF\({}_{6}\)-N\({}_{2}\) decomposition components. Studies showed the effect of transition metal (Cr, Fe, Ni, Mn and Co) doping on InN [24; 25; 26]. Metal oxide doping can be used to improve the gas sensing properties of materials in previous studies. [PERSON] showed that the selectivity and sensitivity of SnO\({}_{2}\) and In\({}_{2}\)O\({}_{3}\) thin films to gases can be improved by structural engineering [27]. [PERSON] et al. revealed that ZnO and CuO doped graphene has good adsorption and sensing properties for SO\({}_{2}\), SOF\({}_{2}\), and SO\({}_{2}\)F\({}_{2}\)[28]. [PERSON] et al. showed that Ag\({}_{2}\)O-doped MoSe is a potential SF\({}_{6}\) decomposition products sensor [29]. However, there is little study on the gas sensitivity studies of Ag\({}_{2}\)O-modified InN monolayers to the of SF\({}_{6}\)-N\({}_{2}\) decomposition components.  
In this work, pristine and Ag\({}_{2}\)O doped InN monolayers are analyzed using density functional theory (DFT), focusing on the spin unrestricted electronic structure behavior. The adsorption capacity and sensing behavior of NO\({}_{2}\), SOF\({}_{4}\), SOF\({}_{2}\), and SO\({}_{2}\)F\({}_{2}\) gas molecule on the adsorbent surface are the key research targets. Therefore, this paper simulated the adsorption process of gas molecules on the InN monolayer surface, and systematically calculated the adsorption energy, band structure, density of states (DOS), partial density of states (PDOS), and charge transfer, and thus provided a theoretical basis for the experimental development of new-type gas sensor.