Metal Oxide (Ag₂O, ZnO)-Doped MoSe₂ Monolayer as a Highly Sensitive Gas Sensor for Greenhouse Gases (CO₂, CH₄, N₂O, SF₆) Detection

With the increasing severity of greenhouse gas emissions, studying the detection and adsorption of greenhouse gases (GHGs) is indispensable. Therefore, aiming at four typical GHGs (CO2, CH4, N2O, and SF6), this study uses density functional theory (DFT) to calculate the gas-sensitive properties of metal oxide (Ag2O, ZnO)-doped MoSe2 (MO-MoSe2) nanomaterials to these gases. By analyzing the properties of adsorption energy, density of states, band structure, work function, and recovery time, we found that metal oxide (Ag2O, ZnO) doping can markedly enhance the adsorption capacity of MoSe2 monolayer on greenhouse gases, and the two doping materials have the application prospect as highly sensitive greenhouse gas sensors. Both Ag2O-MoSe2 and ZnO-MoSe2 have chemical adsorption on CO2 and N2O with adsorption energies ranging from −0.8 to −0.9 eV, and strong physical adsorption on CH4 and SF6 with adsorption energies between −0.7 and −0.8 eV. The large adsorption energy indicates that the two doping materials can be used as adsorbents for these gases. In addition, Ag2O-MoSe2 and ZnO-MoSe2 have excellent desorption capacity for these four gases at room temperature, such as recovery times of 3.40, 25.54, etc., making them the potential to be used as recyclable gas sensor materials. This research can provide theoretical guidance for the preparation of greenhouse gas sensors, which is conducive to the recovery and emission reduction of greenhouse gases.