Adsorption and gas-sensing properties of SnO2 doped MoS2 monolayer

Abstract

• Construction of correct and effective SnO 2 -MoS 2 monolayer model. • The changes and effects of electronic properties of each adsorption system. • The application of SnO 2 -MoS 2 monolayer in the field of gas sensing. • New ways for the exploration of other gas sensing materials. Selective monitoring and capture of some gases (CH 4 , C 2 H 2 , NO 2 , H 2 S, SO 2 , SO 2 F 2 , CO, H 2 , CO 2 ) 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 SnO 2 -MoS 2 monolayer and the above gases. The electronic structure parameters and adsorption parameters such as binding energy ( E b ), adsorption energy ( E ads ), transfer charge (Δ Q ), total density of states (TDOS), energy band structure, the change rate of band gap energy (Δ E g ), sensitivity ( S ), and recovery time ( τ ) were used to obtain the optimal adsorption configuration and microscopic gas sensing mechanism. The results show that the SnO 2 -MoS 2 monolayer has strong adsorption on CH 4 , C 2 H 2 , and NO 2 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 CH 4 > NO 2 > C 2 H 2 > H 2 S > SO 2 > SO 2 F 2 > CO > H 2 > CO 2 . This letter provides a theoretical basis for the application of SnO 2 -MoS 2 monolayer in the field of gas sensing and provides new ideas and ways for the exploration of other gas sensing materials.