采用溶胶-凝胶法制备了纯TiO2和N掺杂TiO2纳米颗粒,光吸收特性测量显示,纯TiO2的光吸收主要在紫外部分,N掺杂后,可见光吸收明显增强.能带结构的计算显示:TiO2中不同的晶体缺陷对能带结构都产生影响,从而导致纯TiO2对可见光有一定的吸收;对于N掺杂的TiO2,N取替代位时,杂质能级位于价带顶附近,当浓度足够高时与价带顶重叠,从而导致禁带宽度的减小;当N占据间隙位时,缺陷能级处于禁带深处,容易成为复合中心.因此,N替代掺杂对于提高光催化效率更优越. Pure TiO2 and N-doped TiO2 nanoparticles were prepared by sol-gel method. The measurement of optical absorption showed that the absorption of pure TiO2 was mainly in the ultraviolet region and the visible light absorption was enhanced obviously after N doping. The calculation of band structure : Different crystal defects in TiO2 have an impact on the band structure, resulting in pure TiO2 to some extent visible light absorption; for N-doped TiO2, N substitute sites, the impurity level is located near the top of the valence band, when the concentration When it is high enough, it will overlap with the top of the valence band, resulting in a decrease of the forbidden band width. When N occupies the interstitial sites, the defect level is in the forbidden band and easily becomes the recombination center. Therefore, N substitution for doping improves the photocatalytic efficiency More superior.