N-doped TiO2 photocatalyst samples were prepared by manual grinding the mixture of nanotube titanic acid and ammonium bicarbonate followed by annealing the mixture at different temperatures in Ar atmosphere for 4 h. The samples were characterized by X-ray powder diffraction,X-ray photoelectron spectroscopy (XPS), UV-Vis spectrophotometry, transmission electron microscope, and N2 adsorp-tion-desorption. The XPS results indicated that the N was in the form of interstitial atom, I.e., Ti-O-N bond. The intermediate (NR4)2Ti2O4(OH)2 was formed when the mixture was calcined at different temperatures. Subsequently, the N was released due to the decomposition of (NH4)2Ti2O4(OH)2, resulting in the formation of interstitial-N and oxygen vacancies. N-TiO2 samples showed enhanced visible light absorption and visible light photocatalytic activity because of the existence of interstitial N-dopants and oxygen vacancies. The doped N atoms restrained the phase transition from anatase to rutile at higher temperature. Photocatalytic activity was evaluated by degradation of methyl orange in aqueous solution under xenon lamp irradiation, and the N-TiC>2 sample with n(N)(Ti) = 4 annealed at 500 ℃ exhibited the highest photocatalytic activity. After 130 min irradiation, the photocatalytic degradation rate of methyl orange was up to 100%, almost 30% higher than that of un-doped TiO2.%以纳米管钛酸为前驱体,以NH4HCO3为N源,先机械研磨使二者混合均匀,再在Ar保护下,于不同温度焙烧4h制得N掺杂TiO2 (N-TiO2),并采用X射线粉末衍射、X射线光电子能谱、紫外-可见吸收光谱、透射电镜及N2吸附-脱附对样品进行了表征.结果显示,N以间隙掺杂方式进入TiO2晶格内.在热处理过程中,生成中间体(NH4)2Ti2O4(OH)2,它不仅可在升温过程中缓慢分解并释放出N,使其更均匀地进入TiO2,同时可产生更多的氧空位,显著提高了N-TiO2对光的响应能力.另外,N的掺杂可抑制N-TiO2锐钛矿相向金红石相转化.当焙烧温度为500℃,n(N)(Ti)=4时,所制N-TiO2样品经光照130 min,可使甲基橙完全降解,其活性比未掺杂N的样品提高近30％.
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