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Abstract
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On the basis of density functional theory (DFT) calculations, we demonstrate the potential applicability of
TiO 2 /WSe 2 nanocomposite as a highly sensitive molecule sensor for SO 2 and SO 3 molecules. SO x mole-
cules chemically adsorb on TiO 2 /WSe 2 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 SO x molecules towards TiO 2 /WSe 2 nanocomposites. The fivefold
coordinated titanium atoms in the TiO 2 act as the binding sites. On the N-doped TiO 2 /WSe 2 nanocompos-
ite, 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 SO x 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 TiO 2 /WSe 2 with adsorbed SO x molecules. Over the TiO 2 /WSe 2 nanocompos-
ites, SO 3 molecule dissociates into SO 2 and detached oxygen atom. The results present a great potential of
TiO 2 /WSe 2 nanocomposites for application as a highly efficient molecule sensor for SO x detection.
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