ABSTRACT
Nanometer TiO2 powders was modified by doping with urea as a doping source. The photocatalytic activity of Nitrogen-doped titanium oxide (N-doped TiO2) was evaluated under different nitrogen content by the photodegradation test of methylene blue (MB). The results show that when the dosage of N elements is 2%, the degradation rate of N-doped TiO2 reaches a maximum. From the X-ray Diffraction analysis, it is found that the position of the crystal plane diffraction peak of the doped crystal shifts to a small angle, which indicates that the N enters the crystal lattice and causes distortion, increases the photocatalytic activity center. The modified nano TiO2 is dispersed in the silica sol under the condition of ultrasonic vibration, and the results of Scanning Electron Microscope (SEM) show that the dispersed TiO2 particles are smaller and dispersed evenly in the dispersion. The cement-based specimens loaded nano TiO2 dispersion were respectively prepared by direct mixing method, sprinkle paving method and spraying method. The photocatalytic activity of the specimens was evaluated. It can be concluded that the NO degradation rate of three kinds of specimens increases with the increase of nano TiO2 amount; the specimens prepared by direct mixing method and sprinkle paving method have lower NO degradation rate because TiO2 is wrapped in cement and stone and distributed unevenly; NO degradation rate of the specimens prepared by spraying method can reach 74.7% when the amount of TiO2 is 15 g/m2.
