A novel strategy for SOx removal by N-doped TiO2/WSe2 nanocomposite as a highly efficient molecule sensor investigated by van der Waals corrected DFT

Abstract

On the basis of density functional theory (DFT) calculations, we demonstrate the potential applicability of TiO2/WSe2 nanocomposite as a highly sensitive molecule sensor for SO2 and SO3 molecules. SOx molecules chemically adsorb on TiO2/WSe2 nanocomposite via strong chemical bonds. With vdW interactions included, the adsorption energies were corrected for long range dispersion energy, indicating adsorption energetic and possible configurations of SOx molecules towards TiO2/WSe2 nanocomposites. The fivefold coordinated titanium atoms in the TiO2 act as the binding sites. On the N-doped TiO2/WSe2 nanocomposite, the adsorption process is found to be more favorable in energy than the adsorption on the intrinsic one, indicating that the N-doped nanocomposites have higher sensing capability than the undoped ones. The charge transfer based on NBO analysis reveals that the SOx molecule behaves as an electron acceptor. The electronic properties of the system were also investigated in view of the projected density of states and molecular orbitals of the TiO2/WSe2 with adsorbed SOx molecules. Over the TiO2/WSe2 nanocomposites, SO3 molecule dissociates into SO2 and detached oxygen atom. The results present a great potential of TiO2/WSe2 nanocomposites for application as a highly efficient molecule sensor for SOx detection.