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Abstract
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We present a density functional theory (DFT) study of the reactivity towards SO 3 adsorption and dissociation
over the TiO 2 supported Au overlayers. We model different adsorption configurations of SO 3 on the considered
structures. For all adsorption systems, we find that the interaction of SO 3 molecule with the surfaces of Au
atoms is strongly favored. On the TiO 2 supported Au overlayer, SO 3 also dissociated into SO 2 and adsorbed
atomic oxygen. The atomic oxygen binds directly to the Au atoms. The structural properties are explained in
terms of the bond lengths, bond angles and adsorption energies. The electronic structure of the system and
Mulliken population analysis were also studied for the discussion of results. The results indicate that the SO 3
interaction with N-doped TiO 2 -supported Au overlayer is more favorable in energy than the interaction with
undoped one, suggesting the increased sensing capability of N-doped TiO 2 -supported Au towards detection of
SO 3 molecule. The oxygen atoms of the SO 3 molecule bind to the Au and Ti atoms of the TiO 2 supported Au
overlayer in a bridge geometry. The significant overlaps in the PDOSs of the Au and oxygen atoms of the SO 3
molecule, as well as titanium and oxygen atoms indicate the formation of chemical bonds between these atoms.
Our DFT study therefore provides a theoretical basis for why the reactivity of SO 3 molecule with N-doped TiO 2
supported Au overlayer may increase, thus being a helpful procedure in the development of efficient sensor
devices for SO 3 detection.
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