Photocatalitic Activity of N-doping TiO₂ Thin Films Deposited by the Sol-Gel Technique

Titanium dioxide (TiO₂) is a very stable semiconductor physically and chemically, it is an abundant material and harmless to nature. Currently, TiO₂ is one of the most used photocatalysts to degrade organic molecules in both water and air during purification processes. In this work, we fabricated Nitrogen-doped TiO₂ powders by the Sol-Gel method, the Titanium tetraisopropoxide and urea were as reagents; subsequently, the materials were supported as thin films on glass using the technique of Doctor Blade. The materials were characterized by using different analytical techniques such as Raman spectroscopy, X-Ray Diffraction (XRD), and diffuse reflectance spectroscopy (DRS). The XRD results indicated that TiO₂ films presented a single crystalline phase, corresponding to the anatase. Besides, Raman spectroscopy verified the nitrogen incorporation in the crystal lattice of TiO₂ after the doping process. Furthermore, DRS results showed an improvement in optical photo-response at the visible region of the electromagnetic spectrum, the band-gap narrowing was verified from 3.25 eV for unmodified TiO₂ thin films until 2.84 eV TiO₂–N(5%) thin films. Finally, the photocatalytic activity of materials was studied during methylene blue (MB) degradation, the photocatalytic degradation results indicated the doping process enhanced photocatalytic activity under visible irradiation.