Theoretical study of the adsorption of NOx on TiO2/MoS2 nanocomposites: a comparison between undoped and N-doped nanocomposites

摘要

First-principle calculations within density functional theory were performed to investigate the interactions of NO and NO~(2) molecules with TiO~(2)/MoS~(2) nanocomposites. Given the need to further comprehend the behavior of the NO~(x) molecules positioned between the TiO~(2) nanoparticle and MoS~(2) monolayer, we have geometrically optimized the complex systems consisting of the NO~(x) molecule oriented at appropriate positions between the nanoparticle and MoS~(2) monolayer. The structural properties, such as bond lengths, bond angles, adsorption energies and Mulliken population analysis, and the electronic properties, including the density of states and molecular orbitals, were also analyzed in detail. The results indicate that the interactions between NO~(x) molecules and N-doped TiO~(2) in TiO~(2)-N/MoS~(2) nanocomposites are stronger than those between gas molecules and undoped TiO~(2) in TiO~(2)/MoS~(2) nanocomposites, which reveal that the N-doping helps to strengthen the interaction of toxic gas molecules with hybrid TiO~(2)/MoS~(2) nanocomposites. The N-doped TiO~(2)/MoS~(2) nanocomposites have higher sensing capabilities than the undoped ones, and the interaction of NO~(x) molecules with N-doped nanocomposites is more favorable in energy than the interaction with undoped nanocomposites. Therefore, the obtained results also present a theoretical basis for the potential application of TiO~(2)/MoS~(2) nanocomposite as an extremely sensitive gas sensor for NO and NO~(2) molecules. Graphical Abstract.