Adsorption and Sensing of NO2, SO2, and NH3 on a Janus MoSeTe Monolayer Decorated with Transition Metals (Fe, Co, and Ni): A First-Principles Study

This paper reports the adsorption of toxic gases (NO2, SO2, and NH3) on a MoSeTe structure based on first principles. It was found that the gas (NO2, SO2, and NH3) adsorption on a pure MoSeTe monolayer was weak; however, the adsorption performance of these gas molecules on transition-metal-atom-supported MoSeTe monolayers (TM–MoSeTe) was better than that on pure MoSeTe monolayers. In addition, there was more charge transfer between gas molecules and TM–MoSeTe. By comparing the adsorption energy and charge transfer values, the trend of adsorption energy and charge transfer in the adsorption of NO2 and SO2 was determined to be Fe–MoSeTe > Co–MoSeTe > Ni–MoSeTe. For the adsorption of NH3, the effect trend was as follows: Co–MoSeTe > Ni–MoSeTe > Fe–MoSeTe. Finally, by comparing their response times, the better gas sensor was selected. The Ni–MoSeTe system is suitable for NO2 gas sensors, and the Fe–MoSeTe and Co–MoSeTe systems are suitable for SO2 gas sensors. The Fe–MoSeTe, Co–MoSeTe, and Ni–MoSeTe systems are all suitable for NH3 gas sensors. Janus transition-metal dichalcogenides have the potential to be used as gas-sensing and scavenging materials.