Molecular design of O 3 and NO 2 sensor devices based on a novel heterostructured N-doped TiO 2/ZnO nanocomposite: a van der Waals corrected DFT study

摘要

We have presented a density functional theory study of the adsorption properties of NO~(2)and O~(3)molecules on heterostructured TiO~(2)/ZnO nanocomposites. The most stable adsorption configurations, adsorption energies and charge transfers were calculated. The electronic properties of the complex TiO~(2)/ZnO heterostructures were described using the density of states and molecular orbital analyses. For NO~(2)adsorption, it was found that the oxygen atoms preferentially move towards the fivefold coordinated titanium atoms, whereas the nitrogen atom binds to the zinc atom. In the case of O~(3)adsorption, the side oxygen atoms bind to the fivefold coordinated titanium sites, and the central oxygen atom does not contribute to the adsorption any longer. Thus, the interaction of NO~(2)and O~(3)molecules with TiO~(2)side of nanocomposite is strongly favored. On the N-doped TiO~(2)/ZnO nanocomposites, the adsorption process is more energetically favorable than that on the pristine ones. The N-doped nanocomposites are far more sensitive to gas detection than the undoped ones. In TiO~(2)/ZnO nanocomposites, the interactions of gas molecule and TiO~(2)are stronger than those between gas molecule and bare TiO~(2)nanoparticles, which reveals that ZnO is conducive to the interaction of NO~(2)and O~(3)molecules with TiO~(2)nanoparticles. Our theoretical results suggest multicomponent TiO~(2)/ZnO nanocomposite as a potential material for gas sensing application. Graphical Abstract