Iron promotion of the TiO2 photosensitization process towards the photocatalytic oxidation of azo dyes under solar-simulated light irradiation
Iron promotion of the TiO2 photosensitization process towards the photocatalytic oxidation of azo dyes under solar-simulated light irradiation
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DOI：
10.1016/j.matchemphys.2011.05.082
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发表时间：
2011-10
影响因子：
4.6
通讯作者：
C. Castro;A. Centeno;S. Giraldo
中科院分区：
文献类型：
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作者：
C. Castro;A. Centeno;S. Giraldo
利用太阳光模拟器研究了负载铁的TiO2（Fe - TiO2）在紫外（UV）、可见光（vis）和紫外-可见同时照射下光催化氧化偶氮染料Orange-II （Or-II）。采用XRD、SEM-EDX、FTIR和DRS对光催化剂进行了表征。在XPS分析中发现，Fe3+是导致可见光吸收增加的原因。此外，DRS分析表明，由于Fe3+加载，带隙减小。光催化实验证明，在紫外-可见同时照射下，Fe修饰增强了tio2光催化活性。尽管如此，在紫外照射下，fe - tio2样品对苯酚的光降解性能低于tio2，这表明紫外光产生的电子-空穴对发生了重组。因此，结果表明Fe3+在Or-II作为光敏剂的tio2光敏过程中促进了电子标题。该过程通过电子转移过程中损失能量使TiO2敏化，从而导致UV-vis照射下的Or-II光氧化反应，同时，被注入的电子促进了TiO2导带中活性氧的形成。
The photocatalytic oxidation of the azo dye Orange-II (Or-II) using Fe loaded TiO2(Fe–TiO2) was studied under ultraviolet (UV), visible (vis) and simultaneous UV–vis irradiations using a solar light simulator. Photocatalysts were characterized by means of XRD, SEM-EDX, FTIR and DRS. Fe3+species, identified in XPS analyses, were responsible of the increased absorption of visible light. Moreover, DRS analyses showed a decrease in the bandgap due to Fe3+loading. Photocatalystic tests proved that Fe modification enhanced the TiO2photocatalytic activity towards Or-II photodegradation under simultaneous UV–vis irradiation. Even so, the performance of the Fe–TiO2samples towards the photodegradation of phenol, under UV irradiation, was lower than TiO2suggesting the recombination of the UV photogenerated electron–hole pair. Therefore, results evidence a Fe3+promotion of the electron caption in the photosensitization process of TiO2by Or-II acting as a sensitizer. Such process leads to the Or-II photooxidation under UV–vis irradiation by losing energy in electron transferring processes to sensitize TiO2, and, the formation of reactive oxygen species promoted by the injected electron to the TiO2conduction band.