Wu Zhongbiao, Dong Fan, Zhao Weirong, Guo Sen
Department of Environmental Engineering, Zhejiang University, Hangzhou 310027, China.
J Hazard Mater. 2008 Aug 30;157(1):57-63. doi: 10.1016/j.jhazmat.2007.12.079. Epub 2007 Dec 31.
Nitrogen doped TiO(2) nanocrystals with anatase and rutile mixed phases were prepared by incomplete oxidation of titanium nitride at different temperatures. The as-prepared samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), core level X-ray photoelectron spectroscopy (CL XPS), valence band X-ray photoelectron spectroscopy (VB XPS), UV-vis diffuse reflectance spectra (UV-vis DRS), and visible light excited photoluminescence (PL). The photocatalytic activity was evaluated for photocatalytic degradation of toluene in gas phase under visible light irradiation. The visible light absorption and photoactivities of these nitrogen doped TiO(2) nanocrystals can be clearly attributed to the change of the additional electronic (N(-)) states above the valence band of TiO(2) modified by N dopant as revealed by the VB XPS and visible light induced PL. A band gap structure model was established to explain the electron transfer process over nitrogen doped TiO(2) nanocrystals under visible light irradiation, which was consistent with the previous theoretical and experimental results. This model can also be applied to understand visible light induced photocatalysis over other nonmetal doped TiO(2).
通过在不同温度下不完全氧化氮化钛制备了具有锐钛矿和金红石混合相的氮掺杂二氧化钛纳米晶体。采用X射线衍射（XRD）、透射电子显微镜（TEM）、高分辨率透射电子显微镜（HRTEM）、芯能级X射线光电子能谱（CL XPS）、价带X射线光电子能谱（VB XPS）、紫外可见漫反射光谱（UV-vis DRS）和可见光激发光致发光（PL）对所制备的样品进行了表征。在可见光照射下，对气相中甲苯的光催化降解进行了光催化活性评价。VB XPS和可见光诱导PL表明，这些氮掺杂二氧化钛纳米晶体的可见光吸收和光活性可明确归因于N掺杂剂修饰的二氧化钛价带上方额外电子（N(-)）态的变化。建立了能带结构模型来解释可见光照射下氮掺杂二氧化钛纳米晶体上的电子转移过程，这与先前的理论和实验结果一致。该模型也可用于理解其他非金属掺杂二氧化钛上的可见光诱导光催化作用。
