Adsorption and Gas Sensing Properties of h‐BN/WS2 Heterojunction for Toxic Gases: A DFT Study

Abstract

ABSTRACTTungsten disulfide (WS2) and hexagonal boron nitride (h‐BN) monolayer, and h‐BN/WS2 heterojunction with low lattice mismatch is constructed using density functional theory (DFT). The band structures, density of states (DOS), charge density differences (CDD), work function (WF), adsorption energy and adsorption distance of h‐BN/WS2 heterojunction for six gases molecules (CO, CO2, NO, NO2, SO2, and H2S) are systematically discussed. Gas adsorption on one‐side and both‐sides of the heterojunction is considered. The results indicate that the band gap of the heterojunction is lower than that of h‐BN and WS2, indicating that the construction of heterojunction is beneficial for conductivity. For six gases, the adsorption energy of one‐sided adsorption is significantly greater than that of both‐sided adsorption, except for CO2 and NO. The adsorption of NO and NO2 introduces the magnetism into the system. Interestingly, the h‐BN/WS2 heterojunction demonstrates excellent selectivity for NO gas under one‐sided and both‐sided adsorption. The corresponding adsorption mechanism is explored.