材料科学
涂层
光催化
纤维
浸涂
光纤
可见光谱
兴奋剂
吸收(声学)
化学工程
复合材料
光电子学
光学
催化作用
化学
有机化学
工程类
物理
作者
Nicola J. Peill,Lisa Bourne,Michael R. Hoffmann
标识
DOI:10.1016/s1010-6030(97)00018-x
摘要
The photochemical quantum efficiencies and oxidation performance of iron(III)-doped quantum-sized TiO2 (Fe/Q-TiO2), Degussa P25 (P25), and hybrid Fe/Q-TiO2/P25 photocatalytic coatings are investigated using an optical fiber bundled array reactor. Fe/Q-TiO2 coatings made from hydrosols of varying Fe/Q-TiO2 content, 5–20 wt.%, a 13 wt.% P25 coating, and a hybrid, layered Fe/Q-TiO2/P25 (5/13 wt.%) coating are tested. The light absorption efficiencies of the Fe/Q-TiO2 coatings are inferior to the P25 coating, absorbing a maximum of only 80% of the input light compared with greater than 95% for P25 and 90% for the hybrid coating. The Fe/Q-TiO2 coatings are found to increase the linear light transmission in a single optical fiber relative to P25 coated fibers by a factor of two owing to a reduced interfacial surface coverage of the photocatalyst particles on the quartz fiber. The hybrid coating does not significantly enhance linear light transmission. Slurry-phase photoefficiencies for the photooxidation of 4-chlorophenol for the Fe/Q-TiO2 photocatalyst are found to be significantly lower than those measured for P25, φFe/Q-TiO2 = 0.002 vs. φP25 = 0.012. In addition, the length of the coated fiber-bundle used in our reactor is insufficient to capitalize on the increased light transmission for the Fe/Q-TiO2 coating. Thus, we are unable to investigate the effect of increased light transmission on the photoefficiency of the system. Initial reaction rates for the photooxidation of 4-chlorophenol range from 2.0 to 4.5 μM h−1 generally increasing with increasing hydrosol Fe/Q-TiO2 content and an average relative quantum efficiency of φFe/Q-TiO2 = 0.004 ± 0.001 is observed. These values are significantly low compared with initial rates and relative quantum efficiencies of 18.0 μM h−1, and φFe/Q-TiO2/P25 = 0.011 and 20.4 μM h−1 and φP25 = 0.012 for the hybrid and P25 coatings, respectively.
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