Reactions of Hydroxyl Radicals on Titania, Silica, Alumina, and Gold Surfaces
| Autor: | Myeong Suh, Michael P. Rosynek, Sergei Pak, Paul S. Bagus, Jack H. Lunsford |
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| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry B. 104:2736-2742 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp993653e |
| Popis: | Reaction probabilities of OH• radicals under steady state conditions were determined over TiO2 (anatase and rutile), SiO2 (fused quartz), α-Al2O3, and Au surfaces. The OH• radicals were produced from water in a microwave cavity and were detected by laser-induced fluorescence spectroscopy. At 308 K the reaction probabilities were 2 × 10-4 for TiO2 (anatase and rutile), 2 × 10-3 for SiO2, 5 × 10-3 for α-Al2O3, and > 3 × 10-2 for Au. The relative rate of H2O2(aq) decomposition was found to follow the sequence Au > α-Al2O3 > TiO2 ≃ SiO2, which, except for TiO2, follows the sequence found for the OH• radical reaction probability. For all of the materials except TiO2, a radical mechanism is proposed which describes a common set of reactions for the removal of OH• and the decomposition of H2O2. The first step in this mechanism is the coupling of OH• radicals to form H2O2. The overall rate of reaction for both OH• removal and H2O2 decomposition depends on the concentration of OH on the surface. A theoretical anal... |
| Databáze: | OpenAIRE |
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