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

Abstract

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.