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Abstract
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The adsorptions of sulfur trioxide molecule on undoped and N-doped TiO2 anatase nanoparticles were investigated by density functional theory (DFT) calculations. N-doped nanoparticles were constructed by substitution of oxygen atoms of TiO2 by nitrogen atoms. The
results showed that the adsorption energies of SO3on the di®erent nanoparticles following the
order N-doped (N site)>N-doped (ODsite)>Undoped (ODsite). We provide the electronic
structure of the nanoparticles, as well as complex systems containing the sulfur trioxide molecule and discuss the key issues that in°uence the adsorption process. The structural properties
including the bond lengths, bond angles and adsorption energies and the electronic properties
including the projected density of states (PDOSs) and molecular orbitals (MOs) have been
mainly analyzed in detail. The obtained results indicate that the interaction between SO3
molecule and N-doped TiO2 nanoparticle is stronger than that between SO3 and undoped
nanoparticle, which suggests that N-doping helps to strengthen the interaction of SO3 with
TiO2anatase nanoparticles. It is shown that although SO3molecule has no signi¯cant interaction with undoped nanoparticle, it tends to be strongly adsorbed to N-doped anatase nanoparticles with considerable adsorption energies, being as an effective property to be utilized in
gas sensing applications. We also note at this point that the titanium atom and the doped
nitrogen atom sites are more active than the dangling oxygen site, which reveals that the
titanium and doped nitrogen sites provide more stable adsorption geometries.
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