Density functional theory study on gas-sensing property of (SnO2)n (n = 1–3) modified MoTe2 towards chlorine, ammonia, and sulphur dioxide upon diesel-driven vehicle

Abstract

Chlorine (Cl2), ammonia (NH3), and sulphur dioxide (SO2) are three typical toxic gases of tank-vehicle transportation. it is necessary to conduct online detection of these gases to ensure transportation safety and exhaust emission monitoring. In this study, tin dioxide (SnO2)n (n = 1–3) modified molybdenum (IV) telluride (MoTe2) monolayer were selected to explore its adsorption characteristics towards Cl2, NH3, and SO2 gases. All calculations are based on density function theory, geometric structure, charge transfer, adsorption energy, the density of states, and molecular orbitals were taken into account to compare and analyze the adsorption performance of the gas-sensing material before and after surface modification. The results show that these three gases are physically adsorbed on the intrinsic material. The modified (SnO2)n (n = 1–3) are all stably bound to the MoTe2 surface. For both Cl2 and NH3, the adsorption energies are in order of SnO2-MoTe2 > (SnO2)2-MoTe2 > (SnO2)3-MoTe2. And the adsorption energies for SO2 can be ranked as (SnO2)3-MoTe2 > SnO2-MoTe2 > (SnO2)2-MoTe2. The significant changes in electrical conductivity indicate the modified MoTe2 system consistently showed excellent sensitivity to the three gases. Therefore, the (SnO2)n-modified MoTe2 system is expected to be a candidate gas-sensing material for Cl2, NH3, and SO2, opening up a new perspective on MoTe2 in the field of gas detection.