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Abstract
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We have investigated the adsorption and dissociation of hydrogen sulfide (H 2 S) molecule on the pristine and
nitrogen-doped TiO 2 anatase nanoparticles using first-principles calculations in order to obtain insights into the
adsorption behaviors of H 2 S molecules. We have investigated different adsorption geometries of H 2 S over the
nanoparticles. We have found that the H 2 S adsorption is not energetically more favorable on the pristine
nanoparticle surface, but H 2 S is preferentially adsorbed on the N-doped nanoparticles with a higher favorability
in energy. H 2 S molecule adsorbs on the dangling oxygen, doped nitrogen and fivefold coordinated titanium sites
of the TiO 2 nanoparticle. The hydrogen atom in the H 2 S molecule forms a hydrogen bond with the surface
oxygen or doped nitrogen atom of TiO 2 . We have reported the results of DFT calculations including the bond
lengths/angles, adsorption energies, electronic density of states and molecular orbitals. Charge analysis based on
Mulliken charges reveals a significant charge transfer from the molecule to the TiO 2 anatase particle. The
inclusion of the vdW interactions results in considerable enhancement of H 2 S–TiO 2 interaction, thereby
increasing the adsorption energies of the molecules. The N-doped nanoparticles have stronger adsorption
ability than the undoped ones, indicating the higher sensing capability of N-doped nanoparticles for H 2 S
detection. Our results suggest a great potential of N-doped TiO 2 for application as a highly sensitive H 2 S sensor.
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