Ultrasonic Preparation of Nitrogen-doped TiO₂ Nan crystalline Photo catalysts and Evaluation of Photo catalytic Activity

Pure TiO₂ and N-doped nano-TiO₂ photo catalysts were individually prepared following the sol-gel method under ultrasonic conditions. The photo catalytic decomposition of methyl orange (MO) solution under ultraviolet and visible light irradiation was used as a probe reaction to estimate their photo catalytic activities. The particle size, crystal structure, and optical properties of the prepared TiO₂ were performed by X-ray diffraction, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The results suggest that ultrasound significantly reduced the size of the TiO₂ particles, improved particle dispersion, which in turn improve the photo catalytic activity of TiO₂ under ultraviolet light. Ultrasound also promoted the doping of non-metal nitrogen and markedly enhanced the visible light absorption capacity of the N-doped nano-TiO₂. Compared with pure TiO₂, the degradation rate for MO under visible light of U-N-TiO₂ was increased by 70%.