Highly Sensitive Gas Sensor for Detection of Air Decomposition Pollutant (CO, NO_x): Popular Metal Oxide (ZnO, TiO₂)-Doped MoS₂ Surface

When partial discharges occur in air-insulated equipment, the air decomposes to produce a variety of contamination products, resulting in a reduction in the insulation performance of the insulated equipment. By monitoring the concentration of typical decomposition products (CO, NO, and NO 2 ) within the insulated equipment, potential insulation faults can be diagnosed. MoS 2 has shown promising applications as a gas-sensitive semiconductor material, and doping metal oxides can improve the gas-sensitive properties of the material. Therefore, in this work, MoS 2 has been doped using the popular metal oxides (ZnO, TiO 2 ) of the day, and its gas-sensitive properties to the typical decomposition products of air have been analyzed and compared using density functional theory (DFT) calculations. The stability of the doped system was investigated using molecular dynamics methods. The related adsorption mechanism was analyzed by adsorption configuration, energy band structure, density of states (DOS) analysis, total electron density (TED) analysis, and differential charge density (DCD) analysis. Finally, the practical application of related sensing performance is evaluated. The results show that the doping of metal oxide nanoparticles greatly improves the conductivity, gas sensitivity, and adsorption selectivity of MoS 2 monolayer to air decomposition products. The sensing response of ZnO–MoS 2 for CO at room temperature (25 °C) reaches 161.86 with a good recovery time (0.046 s). TiO 2 –MoS 2 sensing response to NO 2 reaches 3.5 × 10 6 at 25 °C with a good recovery time (0.108 s). This study theoretically solves the industrial challenge of recycling sensing materials and provides theoretical value for the application of resistive chemical sensors in air-insulated equipment.