Gas Sensitive Analysis of Composite MoS2(001) Surface to Air Discharge Products: A DFT Study

Air discharge characteristic gas detection is considered as one of the most reliable methods in fault diagnosis of air switchgear. Based on the first-principles of density functional theory, the adsorption and sensing properties of transition metal (Cr) modified MoS2(001) monolayer on three air discharge characteristic gases (CO, NO, and NO2) are analyzed. First, the Cr-doped MoS2(001) monolayer model is obtained by modeling and analyzing different doping sites, and the subsequent density functional theory (DFT) calculation is done. Based on this model, many kinds of adsorption structures were constructed and optimized. The parameters of adsorption structure, adsorption energy, and adsorption distance were obtained. Furthermore, the differential charge density (DCD), state density, response performance, and adsorption performance of the system were analyzed. The results show that Cr-MoS2(001) monolayer has good adsorption performance to three gases. CO gas molecules can be rapidly desorbed from Cr-MoS2(001) monolayer surface at room temperature. Cr-MoS2(001) monolayer has the potential as a low-power gas sensor material for detecting CO characteristic gases and a solid adsorbent material for cleaning NO and NO2 gases. This work provides theoretical guidance for the development of MoS2-based sensors for detecting characteristic gases in air discharge.