The Preparation And Photocatalytic Performance Of Nitrogen-Doped Titaniu Dioxide

Nanometer TiO₂, one kind of wide band semiconductor, has beenwidely studied because of its stable performance, non-toxic, as well ashighly effective photocatalysis activeness. However, the large scaleapplication of titanium dioxide as photocatalyst is hampered by the factthat it absorbs only the very small ultraviolet part of solar light due to itswide band-gap of 3.2eV. In this paper, titanium dioxide catalyst withvisible light response was prepared by "hydrolysis-precipitation method"and "peptization-hydrothermal method". The structural and photoelectricproperties of such photocatalysts were characterized by XRD, UV-Vis,TG-DTA/DSC and IR. The photocatalytic degradation of methyl-orangewas used as model reaction to evaluate the visible light activity of TiO₂samples prepared under different conditions or by different method.Moreover, the effect of triethylamine (Et₃N) and HNO₃ to the visible lightactivity of nitrogen-dope TiO₂(prepared by peptization-hydrothermalmethod) and the formation mechanism of nitrogen-dope TiO₂ werestudied. The results showed: (1)The nitrogen-doped TiO₂ (prepared byhydrolysis-precipitation method) calcined at 270℃showed the highestvisible light response; (2)TiO₂ that was prepared by the peptization-hydrothermal method has higher photocatalytic activity than that ofprepared by hydrolysis-precipitation method due to excellent structuralproperties; (3)In this paper, by using Ti(SO₄)₂ and triethylamine (Et₃N) asthe titanium source and the nitrogen source respectively, nitrogen-dopedTiO₂ was prepared by peptization- hydrothermal method. The optimaltechnic parameters for preparing nitrogen-doped TiO₂ were proposed: thenitric acid quantity is 60ml(C=4mol/L), the triethylamine quantity is15ml(M=0.336mol). The results indicated that the ratio of methylorange degeneration after the 30min by using nitrogen-doped TiO₂ asphotochemical catalysis has achieved 79.21ï¼…. After continuesillumination 90min, the methyl orange degraded rate has mostly achieved100ï¼….The state of nitrogen absorbed on TiO₂ in the peptization-hydrothermal process was studied. The Ti-N bond formed on the surfaceof the catalyst could extend the absorption edge to the visible light region(600～750nm).