Synthesis and characterization of nitrogen-doped TiO2 nanophotocatalyst with high visible light activity
Synthesis and characterization of nitrogen-doped TiO2 nanophotocatalyst with high visible light activity
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DOI：
10.1021/jp0685030
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发表时间：
2007-05-17
影响因子：
3.7
通讯作者：
Anpo, Masakazu
中科院分区：
文献类型：
--
作者：
Cong, Ye;Zhang, Jinlong;Anpo, Masakazu
以三乙胺、尿素、硫脲、水合肼等有机物为原料，采用微乳液-水热法成功制备了具有均匀层状结构的氮掺杂TiO 2纳米催化剂。拉曼和X射线光电子能谱分析表明，氮被有效掺杂，大多数氮掺杂剂可能存在于Ti-O-N和O-Ti-N的化学环境中。观察到吸收边向较低能量的偏移和在可见光区的较强吸收。有机污染物罗丹明B在可见光照射下的光降解结果（λ> 420 nm）表明氮掺杂后的TiO 2光催化剂与未掺杂的TiO 2光催化剂和Degussa P-25相比有很大的改善;尤其是以三乙胺为氮源的氮掺杂TiO 2表现出最高的光催化活性，这也显示出对2，4-二氯苯酚的更高的光分解效率。氮掺杂浓度存在一个最佳值，相应的光催化剂表现出最高的光催化活性。这表明氮掺杂对提高TiO 2的光催化活性有重要作用：一方面，氮掺杂可以使TiO 2的禁带宽度变窄，使催化剂的吸附范围扩展到可见光区;另一方面，氮掺杂可以抑制光生电子的复合，从而提高光电流载流子的效率。
Nitrogen-doped TiO2 nanocatalysts with a homogeneous anatase structure were successfully synthesized through a microemulsion-hydrothermal method by using some organic compounds such as triethylamine, urea, thiourea, and hydrazine hydrate. Analysis by Raman and X-ray photoemission spectroscopy indicated that nitrogen was doped effectively and most nitrogen dopants might be present in the chemical environment of Ti-O-N and O-Ti-N. A shift of the absorption edge to a lower energy and a stronger absorption in the visible light region were observed. The results of photodegradation or the organic pollutant rhodamine B in the visible light irradiation (lambda > 420 nm) suggested that the TiO2 photocatalysts after nitrogen doping were greatly improved compared with the undoped TiO2 photocatalysts and Degussa P-25; especially the nitrogen-doped TiO2 using triathylamine as the nitrogen source showed the highest photocatalytic activity, which also showed a higher efficiency for photodecomposition of 2,4-dichlorophenol. The nitrogen doping concentration had an optimal value, and accordingly, the photocatalyst showed the highest photocatalytic activity. This suggested that nitrogen doping has important effects on the improvement of photocatalytic activity: on one hand, nitrogen doping could narrow the band gap of titania to extend the adsorption of catalyst to the visible light region; on the other hand, nitrogen doping could inhibit the recombination of the photoinduced electron and thereafter increase the efficiency of the photocurrent carrier.