First-principles study of the adsorption and sensing properties of transition metal-modified CrSe2 for CH4, H2S, and CO

The excessive accumulation of gas in coal mines can easily lead to gas explosions, which can pose a threat to the safety of miners. Therefore, real-time monitoring of gas concentration in coal mines was particularly important. In this work, the adsorption mechanism and sensing performance of gases (CH4, H2S, CO) on transition metal (TM) Os, Re, Ta, and W modified CrSe2 monolayer was investigated byfirst-principles calculations method. These calculated results show that the modified TM-CrSe2 can be stabilised at room temperature, and the adsorption capacity of TM-modified CrSe2 on target gas was significantly enhanced. The CrSe2 bandgap after loading TM (Os, Re, Ta, and W) changes from 0.7751 eV to 0.5477 eV, 0.0059 eV, 0.2730 eV and 0.0416 eV, respectively. The adsorption results show that the adsorption of CH4 on the substrate was physical adsorption, while the adsorption of H2S and CO was chemical adsorption. The recovery time analysis concluded that TM-CrSe2 can function as a room-temperature CH4 gas sensor. In this work, the adsorption mechanism of CH4, CO, and H2S on TM-CrSe2 monolayer film was explained, which offers theoretical guidance for the selection of mine gas sensors.