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Iron(III)-doped Q-sized TiO_2 coatings in a fiber-optic cable photochemical reactor

Peill, Nicola J. and Bourne, Lisa and Hoffmann, Michael R. (1997) Iron(III)-doped Q-sized TiO_2 coatings in a fiber-optic cable photochemical reactor. Journal of Photochemistry and Photobiology A: Chemistry, 108 (2-3). pp. 221-228. ISSN 1010-6030. doi:10.1016/S1010-6030(97)00018-X.

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The photochemical quantum efficiencies and oxidation performance of iron(III)-doped quantum-sized TiO_2 (Fe/Q-TiO_2), Degussa P25 (P25), and hybrid Fe/Q-TiO_2/P25 photocatalytic coatings are investigated using an optical fiber bundled array reactor. Fe/Q-TiO_2 coatings made from hydrosols of varying Fe/Q-TiO_2 content, 5–20 wt.%, a 13 wt.% P25 coating, and a hybrid, layered Fe/Q-TiO_2/P25 (5/13 wt.%) coating are tested. The light absorption efficiencies of the Fe/Q-TiO_2 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-TiO_2 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-TiO_2 photocatalyst are found to be significantly lower than those measured for P25, φFe/Q-TiO_2 = 0.002 vs.φ_(P25) = 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-TiO_2 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 φ_(Fe/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 φ_(P25) = 0.012 for the hybrid and P25 coatings, respectively.

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Hoffmann, Michael R.0000-0001-6495-1946
Additional Information:© 1997 Elsevier. Received 18 October 1996; accepted 2 January 1997. Available online 8 April 1998. We are grateful to ARPA and ONR (NAV 5 HFMN N000149J 1901 ) for financial support and to Tim Wu for their help in the lab, and Janet Kesselman, Scot T. Martin, and Wonyong Choi for scientific support. We would also like to thank 3M and Degussa for their donations of the optical fiber samples and the P25 photocatalyst, respectively.
Funding AgencyGrant Number
Advanced Research Projects Agency (ARPA)UNSPECIFIED
Office of Naval Research (ONR)NAV 5 HFMN N000149J1901
Subject Keywords:Iron; TiO2 coatings; Optical fiber reactor; Photooxidation
Issue or Number:2-3
Record Number:CaltechAUTHORS:20150814-081851009
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Official Citation:Nicola J. Peill, Lisa Bourne, Michael R. Hoffmann, Iron(III)-doped Q-sized TiO2 coatings in a fiber-optic cable photochemical reactor, Journal of Photochemistry and Photobiology A: Chemistry, Volume 108, Issues 2–3, 15 August 1997, Pages 221-228, ISSN 1010-6030, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59516
Deposited By: Ruth Sustaita
Deposited On:14 Aug 2015 17:10
Last Modified:10 Nov 2021 22:21

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