Adsorption and gas-sensing properties of SnO2 doped MoS2 monolayer

Selective monitoring and capture of some gases (CH4, C2H2, NO2, H2S, SO2, SO2F2, CO, H-2, CO2) are helpful to discover and warn the problems such as dangerous accidents and gas pollution caused by too low or too high specific gas content. In this letter, the first-principles density functional theory (DFT) was used to calculate and analyze the geometric structure parameters of the adsorption systems composed of SnO2-MoS2 monolayer and the above gases. The electronic structure parameters and adsorption parameters such as binding energy (E-b), adsorption energy (E-ads), transfer charge (delta Q), total density of states (TDOS), energy band structure, the change rate of band gap energy (delta E-g), sensitivity (S), and recovery time (tau) were used to obtain the optimal adsorption configuration and microscopic gas sensing mechanism. The results show that the SnO2-MoS2 monolayer has strong adsorption on CH4, C2H2, and NO2 gas molecules, mainly chemical adsorption. Gas-sensitive response to other gases is relatively insensitive, mainly for weak physical adsorption. The adsorption strength of each adsorption system was CH4 > NO2 > C2H2 > H2S > SO2 > SO2F2 > CO > H-2 > CO2. This letter provides a theoretical basis for the application of SnO2-MoS2 monolayer in the field of gas sensing and provides new ideas and ways for the exploration of other gas sensing materials.