Adsorption of CO and NO molecules on Al, P and Si embedded MoS2 nanosheets investigated by DFT calculations

Using density functional theory (DFT), we presented a theoretical investigation of CO and NO gas molecules adsorption on the Al-doped, P-doped and Si-doped MoS2 monolayers. Our main focus is on the interactions between the dopants (Al, P and Si) and gas molecules. The properties of the adsorption system were analyzed in view of the density of states, electron density distribution, charge density differences and electronic band structures. Various orientations of CO and NO molecules were considered on the MoS2 monolayer to search for the most stable configurations. The results suggest that the adsorption of gas molecules on the doped MoS2 monolayers is more favorable in energy than that on the pristine monolayers. This means that the interaction between doped MoS2 and gas molecules is stronger than that between pristine MoS2 and gas molecules. Our calculations show shorter adsorption distance and higher adsorption energy for Al-doped and Si-doped monolayers than the P-doped and pristine ones. Charge density difference calculations show the charge accumulation between the interacting atoms, suggesting the formation of covalent bonds, as evidenced by the projected density of states of the interacting atoms. Our results confirm that Al-doped and Si-doped MoS2 can be used as efficient and promising sensor materials for CO and NO detection in the environment.