Mechanistic Study of Visible-Light-Induced Photodegradation of 4-Chlorophenol by TiO2−xNx with Low Nitrogen Concentration
Mechanistic Study of Visible-Light-Induced Photodegradation of 4-Chlorophenol by TiO2−xNx with Low Nitrogen Concentration
复制标题
DOI：
10.1155/2012/759306
复制
发表时间：
2012
影响因子：
3.2
通讯作者：
G. Shang;Hongbo Fu;Shaogui Yang;Tongguang Xu
中科院分区：
文献类型：
--
作者：
G. Shang;Hongbo Fu;Shaogui Yang;Tongguang Xu
具有低氮掺杂浓度（0.021<𝑥<0.049）的 TiO2−x Nx 粉末是通过在 550°C 的 NH3 流下对商用 TiO2 (P-25) 进行退火来制备的。无论紫外光还是可见光情况下，样品的光活性随着x的增加而降低，并且TiO1.979N0.021在可见光照射下表现出最高的4-氯酚（4-CP）分解活性。 N 掺杂 TiO2 的可见光响应可能源于 N 诱导的中带隙能级，形成于价带 (O 2p) 上方。电子自旋共振 (ESR) 测量和自由基清除剂技术综合证明，活性物质（·OH 和 O2·−）在可见光照射下导致 4-CP 在 TiO2−xNx 上的光分解。详细讨论了可能的光催化机制。
TiO2−x Nx powders with low N-doping concentrations (0.021<𝑥<0.049) were prepared by annealing commercial TiO2 (P-25) under an NH3 flow at 550°C. Regardless of UV or visible case, the photoactivities of the samples decreased as x increased, and TiO1.979N0.021 showed the highest activity for the 4-chlorophenol (4-CP) decomposition under the visible-light irradiation. The visible-light response for N-doped TiO2 could arise from an N-induced midgap level, formed above the valence band (O 2p). Electron spin resonance (ESR) measurements and the radical scavenger technologies gave the combined evidence that the active species (•OH and O2•−) are responsible for the photodecomposition of 4-CP over TiO2−xNx under the visible irradiation. A possible photocatalytic mechanism was discussed in detail.