Modified N-doped TiO2 anatase nanoparticle as an ideal O3 gas sensor: Insights from density functional theory calculations

Abstract

Density functional theory calculations were carried out to investigate the adsorption behaviors of O3 molecule on N-doped and Zr/N codoped TiO2 anatase nanoparticles. Although, O3 molecule is weakly adsorbed on the pristine (undoped) nanoparticle, it tends to be strongly chemisorbed over the considered N-doped nanoparticles. In other words, O3 molecule is demonstrated to be more reactive on N-doped particles than on both Zr/N-codoped and Zr-doped ones. The van der Waals (vdW) interactions were included to obtain the most stable geometrical structures of O3TiO2 complexes. The results suggest that the O3 molecule is preferentially adsorbed on the fivefold coordinated titanium sites rather than oxygen and nitrogen sites. The complex systems consisting of the O3 molecule positioned towards the considered nanoparticles were optimized geometrically. The adsorption of O3 molecule on the N-doped particle is energetically more favorable than the adsorption on the undoped particle, indicating the dominant effects of nitrogen doping on the performance of nanoparticles. It can be seen from the spin density distribution plots that the magnetization was mainly located on the O3 molecule. Therefore, N-doped TiO2 anatase particles could potentially be employed as an improved sensor material for removing and sensing the tropospheric ozone in the environment.