First-principles study of the gas-sensing properties of a Cu 3 cluster-decorated CrS 2 monolayer towards harmful gases

Abstract The detection and treatment of harmful gases generated during industrial production processes are of paramount importance. Therefore, this study systematically investigates the adsorption behavior of harmful gases (HF, NO, NO 2 , SO 2 ) on both the pristine CrS 2 monolayer and the Cu 3 cluster-decorated CrS 2 (Cu 3 -CrS 2 ) monolayer using density functional theory (DFT). The results indicate that the adsorption energies of the four gases on the pristine CrS 2 monolayer are all greater than −0.2 eV, indicating weak gas-substrate interactions that are inadequate to elicit detectable changes in electrical resistivity, rendering it unsuitable as an adsorbent or scavenger for these gases. In contrast, the Cu 3 -CrS 2 monolayer exhibits significantly superior gas adsorption performance. Specifically, its adsorption energies for NO, NO 2 , and SO 2 are all below −1 eV. A pronounced interfacial charge transfer (>0.3 |e|) together with distinct hybridization between the gas molecular orbitals and Cu-3d orbitals synergistically strengthens the interaction between the adsorbates and the Cu 3 -CrS 2 monolayer. Furthermore, considering the recovery time after gas adsorption, the Cu 3 -CrS 2 monolayer shows potential as a sensor for HF and SO 2 gases, while it can also function as an effective scavenger material for NO and NO 2 gases. These findings confirm the prominent application potential of the Cu 3 -CrS 2 monolayer in the detection and removal of gases, providing a theoretical foundation for the development of novel gas sensors.