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Abstract
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Over the last decades, an interest has arisen in eliminating the increased emissions and serious detrimental effects of atmospheric pollutants such as nitrogen oxides and ammonia molecule. A convenient solution would be a process that could effectively use some metal oxide nanoparticles for adsorbing harmful gas molecules during the surface processes. The molecular adsorption of NOx and NH3 molecules on the photocatalyst titanium dioxide (TiO2) is such a process. Moreover, this process is potentially efficient and suitable for industrial applications. A step toward making this process more operative is to modify TiO2 structures by Nitrogen doping. In present work, density functional theory calculations have been carried out to investigate NO, NO2 and NH3 adsorption on undoped and N-doped TiO2 anatase nanoparticles in order to fully exploit the potential capabilities of these particles in sensing and removing applications. The unit cell of TiO2 anatase has been geometrically optimized to calculate the lattice constants, and the adsorption of gas molecule has been modeled by the help of these optimized nanoparticles. The interaction of adsorbate over the dangling oxygen atom, doped nitrogen atom and fivefold coordinated titanium atom sites of TiO2 nanoparticles including the bond lengths, bond angles, adsorption energies, density of states (DOSs), Mulliken population analysis and molecular orbitals has been extensively investigated in this work. The results show that the adsorption of mentioned gas molecules on the N-doped nanoparticle is more energetically favorable than the adsorption on the pristine one, suggesting the high relative reactivity of N-doped nanoparticle with adsorbed molecule, in comparison with the pristine (undoped) one. So, the N-doped nanoparticles are more active than the undoped ones. Also, based on the obtained results, it can be concluded that the fivefold coordinated titanium atoms are more active than the sixfold coordinated ones and can int
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