Department of Chemistry, Anna University, Chennai 600 025, India.
J Hazard Mater. 2013 May 15;252-253:233-42. doi: 10.1016/j.jhazmat.2013.02.060. Epub 2013 Mar 7.
Photosensitization of TiO2 with other transition metal oxides can extend its light absorption property in the visible region. Such materials could emerge as excellent catalysts for solar photocatalytic degradation. In the present study mesoporous Fe2O3/TiO2 (10, 30, 50, 70 and 90 wt% Fe2O3) photocatalysts were synthesized by sol-gel process and characterized using different techniques. The XRD patterns exhibited the presence of mesoporous structure and isomorphic substitution of Fe(3+) in TiO2 at low Fe(3+) loading and Ti(4+) in Fe2O3 at high Fe(3+) loading. The XPS results revealed the presence of Ti(4+) and Fe(3+) in Fe2O3/TiO2 materials. The DRS UV-vis spectra showed a shift in the band gap excitation of TiO2 to longer wavelength, thus illustrating incorporation of Fe(3+) in TiO2. In addition, free TiO2 and Fe2O3 particles were also present. Their photocatalytic activity was tested for the degradation of 4-chlorophenol in aqueous medium using sunlight. The activity of the catalysts followed the order: meso-30 wt% Fe2O3/TiO2>meso-10 wt% Fe2O3/TiO2>meso-50 wt% Fe2O3/TiO2>meso-70 Fe2O3/TiO2>meso-90 wt% Fe2O3/TiO2>meso-Fe2O3>meso-TiO2. This order concluded that mesoporous Fe2O3/TiO2 could be an active catalyst for pollutant degradation, as TiO2 with framework Fe(3+) and photosensitization with free Fe2O3 were involved in the activity.
TiO2 与其他过渡金属氧化物的敏化作用可以扩展其在可见光区域的光吸收特性。这些材料可能成为太阳能光催化降解的优秀催化剂。在本研究中，通过溶胶-凝胶法合成了介孔 Fe2O3/TiO2（10、30、50、70 和 90wt%Fe2O3）光催化剂，并采用多种技术进行了表征。XRD 图谱表明，在低 Fe3+负载下存在介孔结构和 Ti4+在 TiO2 中的同晶取代，在高 Fe3+负载下存在 Ti4+在 Fe2O3 中的同晶取代。XPS 结果表明，Fe2O3/TiO2 材料中存在 Ti4+和 Fe3+。DRS UV-vis 光谱表明 TiO2 的带隙激发向长波长移动，从而说明了 Fe3+在 TiO2 中的掺入。此外，还存在游离的 TiO2 和 Fe2O3 颗粒。它们的光催化活性在水介质中用阳光测试了对 4-氯苯酚的降解。催化剂的活性顺序为：介孔-30wt%Fe2O3/TiO2＞介孔-10wt%Fe2O3/TiO2＞介孔-50wt%Fe2O3/TiO2＞介孔-70Fe2O3/TiO2＞介孔-90wt%Fe2O3/TiO2＞介孔-Fe2O3＞介孔-TiO2。这一顺序表明，介孔 Fe2O3/TiO2 可能是一种有效的催化剂，用于污染物的降解，因为 TiO2 与骨架 Fe（3+）和游离 Fe2O3 的敏化作用都参与了活性。
